Update package-lock.json

Configure GitHub Actions for linting, typechecking, and testing.
Add Husky and lint-staged for pre-commit checks. Implement API
response caching in AsyncStorage for offline support. Move core
tests to packages/core and add vitest configuration.

.editorconfig

@@ -0,0 +1,19 @@
+# EditorConfig for TimeToLeave
+# https://editorconfig.org
+
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 2
+max_line_length = 100
+
+[*.md]
+trim_trailing_whitespace = false
+
+[*.{yml,yaml}]
+indent_size = 2

.env.example

@@ -1,8 +1,21 @@
 # Server port
 PORT=3001
 
+# Public deployment URL used for redirects and generated links
+DEPLOYMENT_URL=https://timetoleave.app
+
 # ÖBB HAFAS API
 HAFAS_URL=https://fahrplan.oebb.at/bin/mgate.exe
+HAFAS_TIMEOUT_MS=10000
+HAFAS_VER=1.36
+HAFAS_LANG=eng
+HAFAS_AID=hf7mcf9bv3nv8g5f
+HAFAS_CLIENT_ID=OEBB
+HAFAS_CLIENT_VER=6020700
+HAFAS_CLIENT_NAME=oebbApp
+
+# Optional ÖBB GTFS enrichment
+OEBB_GTFS_URL=https://static.web.oebb.at/open-data/soll-fahrplan-gtfs/GTFS_Fahrplan_2026.zip
 
 # Nominatim geocoding (OpenStreetMap)
 NOMINATIM_URL=https://nominatim.openstreetmap.org
@@ -12,3 +25,24 @@ OSRM_URL=https://router.project-osrm.org
 
 # Nominatim user-agent / referer (required by their ToS)
 NOMINATIM_USER_AGENT=OebbPlanner/1.0
+
+# Wiener Linien Open Data API
+WIENER_LINIEN_API_URL=https://api.wienerlinien.at/darwin-v2
+
+# CORS Configuration
+CORS_ALLOWED_ORIGINS=http://localhost:3000,http://localhost:3001,https://timetoleave.app
+
+# API rate limiting
+API_RATE_LIMIT_MAX_REQUESTS=120
+API_RATE_LIMIT_WINDOW_MS=60000
+
+# Google Calendar OAuth (required for web Google Calendar sync)
+GOOGLE_CLIENT_ID=
+GOOGLE_CLIENT_SECRET=
+GOOGLE_REDIRECT_URI=http://localhost:3000/api/auth/google/callback
+
+# Version returned by /api/health
+APP_VERSION=0.1.0
+
+# Mobile app backend URL for physical device builds
+EXPO_PUBLIC_API_BASE_URL=http://localhost:3000

.expo/README.md

@@ -0,0 +1,13 @@
+> Why do I have a folder named ".expo" in my project?
+
+The ".expo" folder is created when an Expo project is started using "expo start" command.
+
+> What do the files contain?
+
+- "devices.json": contains information about devices that have recently opened this project. This is used to populate the "Development sessions" list in your development builds.
+- "settings.json": contains the server configuration that is used to serve the application manifest.
+
+> Should I commit the ".expo" folder?
+
+No, you should not share the ".expo" folder. It does not contain any information that is relevant for other developers working on the project, it is specific to your machine.
+Upon project creation, the ".expo" folder is already added to your ".gitignore" file.

.expo/devices.json

@@ -0,0 +1,3 @@
+{
+  "devices": []
+}

.github/workflows/ci.yml

@@ -0,0 +1,37 @@
+name: CI
+
+on:
+  push:
+    branches: [main, master]
+  pull_request:
+    branches: [main, master]
+
+jobs:
+  lint-typecheck-test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: "npm"
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Lint
+        run: npm run lint
+
+      - name: Typecheck
+        run: npm run typecheck
+
+      - name: Test
+        run: npm test
+
+      - name: Build web
+        run: npm run build
+        env:
+          SKIP_ENV_VALIDATION: "true"

.gitignore

@@ -2,6 +2,7 @@
 
 # dependencies
 /node_modules
+**/node_modules
 
 # testing
 /coverage
@@ -27,3 +28,26 @@ npm-debug.log*
 # typescript
 *.tsbuildinfo
 next-env.d.ts
+.aider*
+
+# editor / agent tooling
+.claude/
+.idea/
+.zed/
+AGENTS.md
+CLAUDE.md
+AIDER_RULES.md
+.aider.chat.history.md
+.aider.input.history
+
+# agent loop
+agent_loop/
+
+# agent loop generated output
+logs/
+runs/
+
+# next.js build output (apps)
+apps/web/.next/
+
+apps/mobile/log.txt

.husky/pre-commit

@@ -0,0 +1 @@
+npx lint-staged

.idea/.gitignore

@@ -1,10 +0,0 @@
-# Default ignored files
-/shelf/
-/workspace.xml
-# Editor-based HTTP Client requests
-/httpRequests/
-# Ignored default folder with query files
-/queries/
-# Datasource local storage ignored files
-/dataSources/
-/dataSources.local.xml

.idea/modules.xml

@@ -1,8 +0,0 @@
-<?xml version="1.0" encoding="UTF-8" ?>
-<project version="4">
-  <component name="ProjectModuleManager">
-    <modules>
-      <module fileurl="file://$PROJECT_DIR$/.idea/TimeToLeave.iml" filepath="$PROJECT_DIR$/.idea/TimeToLeave.iml" />
-    </modules>
-  </component>
-</project>

.idea/oebb_planner.iml

@@ -1,8 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<module type="WEB_MODULE" version="4">
-  <component name="NewModuleRootManager">
-    <content url="file://$MODULE_DIR$" />
-    <orderEntry type="inheritedJdk" />
-    <orderEntry type="sourceFolder" forTests="false" />
-  </component>
-</module>

.idea/vcs.xml

@@ -1,6 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="VcsDirectoryMappings">
-    <mapping directory="$PROJECT_DIR$/oebb-planner-app" vcs="Git" />
-  </component>
-</project>

.zed/rules/rewrite.md

@@ -1,114 +0,0 @@
-# Rewrite Agent Rules
-
-These rules apply when implementing the Next.js rewrite on the `rewrite/next` branch.
-
-## Checklist Tracking
-
-`CHECKLIST.md` uses three checkbox states:
-- `[ ]` — pending and **required**; blocks the next phase
-- `[x]` — done
-- `[~]` — optional or deferred; **never blocks phase advancement**
-
-Rules:
-- The ✅ column is yours; the ✔️ column belongs to the review agent.
-- After completing each numbered item, mark its ✅ box by changing `[ ]` to `[x]`.
-- If you complete an optional item (`[~]`), change it to `[x]`. If you skip it, leave it as `[~]`.
-- Before starting any item in a new phase, read `CHECKLIST.md` and confirm that every **required** (`[ ]`/`[x]`) item in all preceding phases has `[x]` in both ✅ and ✔️. Items marked `[~]` in both columns do not need to be completed first.
-- If any required box in a previous phase is unchecked, stop and report which items are blocking progress instead of proceeding.
-
-## Rewrite Context
-
-- `REWRITE_PLAN.md` is the guiding plan for the migration from the current CRA + Express app to a Next.js App Router + TypeScript app.
-- When working on the rewrite, follow the migration phases in `REWRITE_PLAN.md` unless the user explicitly asks for a different order.
-- Treat each numbered migration item as a checkpoint: implement it, update its ✅ box in `CHECKLIST.md`, add or update tests, run the relevant verification, then continue.
-- Prefer building the new Next.js structure in parallel until feature parity is proven. Do not delete `server/`, `oebb-planner-app/`, or `oebb-planner.jsx` before equivalent Next.js behavior is implemented, tested, and the user has clearly asked for cleanup.
-- Preserve existing API contracts and user-visible behavior during migration unless the rewrite plan or user request explicitly changes them.
-- Use `npm` consistently because the existing project uses `package-lock.json`.
-
-## Work Step By Step
-
-- Start by reading the relevant files and identifying the smallest safe next step.
-- State the plan before making non-trivial changes.
-- Implement one coherent change at a time.
-- After each step, review the diff and check whether it still matches the intended behavior.
-- Do not move on to the next step while the current step has unresolved compile errors, failing tests, or obvious regressions.
-- Prefer small, targeted edits over broad rewrites.
-- Preserve existing behavior unless the user explicitly asks to change it.
-- When a task spans multiple rewrite phases, complete one vertical slice at a time where practical: type or library code, route or hook, UI integration, tests, then verification.
-- Keep reusable logic in `src/lib`, side effects in hooks or route handlers, and shared contracts in `src/types`.
-
-## Testing Requirements
-
-- Add or update tests for every new feature, bug fix, and behavior change.
-- Put tests near the code they cover and follow the existing test style.
-- Cover the main success path, important edge cases, and failure behavior.
-- Do not remove or weaken tests just to make the suite pass.
-- If a change cannot reasonably be tested, explain why and add the closest practical verification.
-- For the Next.js rewrite, prefer unit tests for `src/lib`, route tests for `src/app/api`, and component smoke or behavior tests for UI components.
-- Mock external services in automated tests, including ÖBB HAFAS, Nominatim, OSRM, geolocation, time, and calendar downloads. Do not make tests depend on live network availability.
-- Test TypeScript data shapes and boundary parsing where API responses are transformed into app types.
-
-## Verification Before Moving On
-
-- Run the narrowest relevant tests after each meaningful change.
-- Run the broader project checks before finishing.
-- For server changes, run:
-
-```bash
-cd server
-npm test
-```
-
-- For React app changes, run:
-
-```bash
-cd oebb-planner-app
-CI=true npm test -- --watchAll=false
-npm run build
-```
-
-- For the Next.js rewrite, once the root Next.js project exists, run the relevant root checks instead:
-
-```bash
-npm test
-npm run build
-```
-
-- If available, also run type-checking and linting scripts before finishing:
-
-```bash
-npm run typecheck
-npm run lint
-```
-
-- If a change touches both server and app behavior, run both sets of checks.
-- If a command fails, stop, inspect the failure, fix the cause, and rerun the command.
-- Do not claim the work is complete until the relevant checks pass, or until the remaining blocker is clearly reported.
-
-## Quality Bar
-
-- Make sure additions do not introduce compile errors, lint errors, runtime crashes, or broken imports.
-- Check that public APIs, endpoint contracts, props, and data shapes remain compatible with existing callers.
-- Keep error handling explicit and user-facing failures understandable.
-- Avoid hidden global state, timing assumptions, and network-dependent tests unless the project already uses that pattern.
-- Keep dependencies unchanged unless they are necessary for the task and justified.
-- Do not commit generated artifacts, caches, logs, or local environment files.
-- Keep TypeScript strictness intact once introduced. Do not use `any` as a shortcut around unclear domain types.
-- Keep server-only code out of client components. Route handlers and `src/lib` clients that use secrets, privileged headers, or upstream service details must not be imported into browser-only code.
-- Respect Nominatim usage requirements when implementing geocoding: configurable base URL, clear user agent, rate-limit-aware caching, and no direct browser calls to the public service.
-- Keep OSRM and HAFAS clients behind API routes or server-side utilities so failures can be normalized and tested.
-- For UI work, preserve accessibility basics: semantic buttons and links, labels for inputs, keyboard-operable controls, visible loading and error states.
-
-## Completion Checklist
-
-Before finishing a step, confirm:
-
-- The requested behavior is implemented.
-- The ✅ box for the corresponding item in `CHECKLIST.md` is checked.
-- The change matches the relevant phase or numbered item in `REWRITE_PLAN.md`, when applicable.
-- Tests were added or updated where appropriate.
-- Relevant tests and build checks pass.
-- The change is scoped to the request.
-- No unrelated user changes were overwritten.
-- Old implementation files were not removed unless parity is tested and cleanup was requested.
-- Any limitations or skipped checks are reported clearly.

.zed/settings.json

@@ -1,5 +0,0 @@
-// Folder-specific settings
-//
-// For a full list of overridable settings, and general information on folder-specific settings,
-// see the documentation: https://zed.dev/docs/configuring-zed#settings-files
-{}

AGENTS.md

@@ -1,5 +0,0 @@
-<!-- BEGIN:nextjs-agent-rules -->
-# This is NOT the Next.js you know
-
-This version has breaking changes — APIs, conventions, and file structure may all differ from your training data. Read the relevant guide in `node_modules/next/dist/docs/` before writing any code. Heed deprecation notices.
-<!-- END:nextjs-agent-rules -->

BRAND_GUIDELINES.md

@@ -0,0 +1,84 @@
+# TimeToLeave Brand Guidelines
+
+## Logo
+
+The TimeToLeave logo features a **melting clock** flowing into a right-pointing departure arrow, symbolizing "it's time to go" — time literally dripping away as you head out the door.
+
+### Meaning
+- **Melting clock** = Time awareness, urgency, fluidity — like Dali's persistence of memory
+- **Violet→Magenta gradient** = Creativity, energy, modernity
+- **Hot pink arrow** (#FF2D8D) = Departure, leaving, forward motion
+- **Dark background** = Premium, sleek, focused
+
+## Colors
+
+### Primary Gradient
+| Name | Hex | Usage |
+|------|-----|-------|
+| Violet | `#8B5CF6` | Gradient start |
+| Magenta | `#B23CFF` | Gradient mid |
+| Pink | `#D946EF` | Gradient end |
+| Hot Pink | `#FF2D8D` | Accents, arrows, "To" in wordmark |
+
+### Text
+| Name | Hex | Usage |
+|------|-----|-------|
+| Off-White | `#F4F1EA` | Primary text on dark backgrounds |
+
+### Background
+| Name | Hex | Usage |
+|------|-----|-------|
+| Deep Space | `#03030A` | Outer background |
+| Night | `#090816` | Inner background |
+| Twilight | `#17112A` | Highlights, glows |
+
+### Status Colors (Countdown)
+| Status | Color | Meaning |
+|--------|-------|---------|
+| Red | `#FF3B30` | Leave now / Late |
+| Orange | `#FF9500` | Getting close |
+| Yellow | `#FFCC00` | On track |
+| Green | `#34C759` | Plenty of time |
+| Blue | `#5AC8FA` | Confirmed / Done |
+
+## Typography
+
+- **Primary:** Inter, Poppins, Montserrat, Avenir Next, Arial, sans-serif
+- **Weights:** 800 for headlines, 700 for headings, 600 for semibold, 400 for body, 300 for captions
+- **Letter spacing:** -0.02em for headings (tighter, more modern)
+
+## Logo Variants
+
+### Icon Only
+Use `LogoIcon` component for favicons, app icons, loading states.
+
+### Horizontal Logo
+Use `LogoHorizontal` component for headers, navigation, about pages.
+
+### Full Logo (SVG)
+Use `timetoleave_dark_logo.svg` for downloads, print, marketing materials.
+
+## Usage
+
+```tsx
+import { LogoIcon, LogoHorizontal } from "@/app/ui/logos";
+
+// Icon only (48px)
+<LogoIcon size={48} />
+
+// Horizontal header logo
+<LogoHorizontal height={32} />
+
+// Custom sizing
+<LogoIcon size={128} className="drop-shadow-lg" />
+```
+
+## File Locations
+
+| File | Purpose |
+|------|---------|
+| `apps/web/src/app/ui/LogoIcon.tsx` | React icon component |
+| `apps/web/src/app/ui/LogoHorizontal.tsx` | React horizontal logo |
+| `apps/web/src/app/icon.svg` | Web favicon (auto-generated by Next.js) |
+| `apps/web/src/app/opengraph-image.svg` | Social sharing image |
+| `apps/web/src/app/timetoleave_dark_logo.svg` | Master SVG with full wordmark |

CHANGELOG.md

@@ -0,0 +1,92 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+## [Unreleased]
+
+### Mobile Application
+
+- Default to dark theme across the mobile app
+- Filter native calendar events by location to exclude empty ones
+- Async station selection with error handling and alerts
+- Improved notification settings UI
+- Native calendar source selection with CalDAV/DAVx, Apple, Google, Exchange, subscribed, local, CardDAV, ActiveSync, and other source labels
+- Event detail sections split into reusable header, journey, bike, and nearby-stop components
+
+### Calendar Integration
+
+- **Google Calendar sync** via full OAuth 2.0 flow (token exchange, refresh, and status checks)
+- UI for connecting, syncing, and disconnecting Google accounts in the Calendar panel
+- Batch edit panel for managing event destinations on the web calendar
+- Edit support in AddEventModal for modifying existing events
+
+### Public Transport
+
+- HAFAS LocMatch method in API client for finding nearest station to current location
+- Improved station selection with async search and error handling
+- WienerLinien departures hook improvements
+- HAFAS response enrichment through the ÖBB GTFS fallback when available
+- Arrive-by journey search with fallback search window
+
+### API Client
+
+- Added `findStationByExtId` for resolving a saved station ID
+- Added `findNearestStationByCoords` for geolocation-based station lookup
+- Added base URL failover for backend availability issues
+- Enhanced HAFAS request handling
+
+### Documentation
+
+- Updated README, development, architecture, API, user, privacy, and testing documentation to match the current route tree and app behavior
+
+---
+
+## [1.0.0] — 2025-01-27
+
+### 🎉 Initial MVP Release
+
+First stable release of TimeToLeave: a smart departure planner that integrates
+your calendar with real-time public transport data to tell you exactly when to leave.
+
+### Web Application
+
+- Next.js 16 web dashboard with Tailwind CSS 4
+- Calendar sync via `.ics` file import or URL
+- Station search and journey planning for upcoming events
+- Real-time departures with dynamic leave-status countdown
+- Browser-based leave reminders with push notifications
+- Dark/light theme toggle
+- Debounced search and optimized calendar loading
+- Docker support with multi-stage build and standalone output
+
+### Mobile Application
+
+- React Native 0.81 / Expo 54 mobile client
+- Five-screen navigation: Event List, Add Event, Event Detail, Origin Setup, Settings
+- Native calendar import via `expo-calendar`
+- Geolocation-based origin detection via `expo-location`
+- Local push notifications via `expo-notifications`
+- Persistent settings and state via AsyncStorage
+
+### Public Transport Integration
+
+- HAFAS protocol support for Austrian railway (ÖBB) real-time departures
+- WienerLinien integration for Vienna U-Bahn, tram, and bus departures
+- Accurate timezone-aware HAFAS time parsing with DST transition handling for `Europe/Vienna`
+- Support for repeated stop IDs and multiple connections
+
+### Routing
+
+- Bike route calculation and final walking route calculation via OSRM
+- Geocoding API integration for station lookups
+- Fallback and caching logic for API failures
+
+### Shared Infrastructure
+
+- Monorepo structure with npm workspaces
+- `@timetoleave/core` — shared types, countdown utilities, and leave-status logic
+- `@timetoleave/api-client` — typed client for HAFAS, calendar, geocoding, and bike routing
+- Correlation IDs for request tracing and monitoring
+- Comprehensive test coverage across web (Vitest) and mobile (Jest)
+- Strict TypeScript type-checking across all workspaces
+- ESLint linting across the codebase

CHECKLIST.md

@@ -1,62 +1,47 @@
 # TimeToLeave — Implementation Checklist
 
-> **Source:** [REWRITE_PLAN.md](./REWRITE_PLAN.md)
-> **Total:** 4 phases, 14 steps, ~5 hours estimated effort
+## Phase 1 — Workspace + Shared Packages (Steps 1-9)
+
+| # | Step | ✅ | ✔️ |
+|---|---|----|-|
+| 1 | Create safety baseline (typecheck, lint, test, build) | [x] | [x] |
+| 2 | Add workspace support to root `package.json` | [x] | [x] |
+| 3 | Move web app into `apps/web/` | [x] | [x] |
+| 4 | Create `packages/core/` with shared types + utilities | [x] | [x] |
+| 5 | Update web imports to use `@timetoleave/core` | [x] | [x] |
+| 6 | Create `packages/api-client/` with typed API wrapper | [x] | [x] |
+| 7 | Refactor web hooks to use `api-client` | [x] | [x] |
+| 8 | Run web verification again (typecheck, lint, test, build) | [x] | [x] |
+| 9 | Phase 1 summary verification (all packages compile) | [x] | [x] |
+
+## Phase 2 — Expo Mobile MVP (Steps 10-18)
+
+| # | Step | ✅ | ✔️ |
+|---|---|----|-|
+| 10 | Scaffold Expo mobile app with TypeScript | [x] | [x] |
+| 11 | Configure mobile API base URL (`.env` + singleton) | [x] | [x] |
+| 12 | Add mobile app shell (navigation + 5 screens) | [x] | [x] |
+| 13 | Add mobile event store (AsyncStorage) | [x] | [x] |
+| 14 | Build Event List screen | [x] | [x] |
+| 15 | Build Add Event screen with validation | [x] | [x] |
+| 16 | Build Origin Setup in Settings | [x] | [x] |
+| 17 | Build Event Detail screen (trains + bike + errors) | [x] | [x] |
+| 18 | Phase 2 summary verification | [x] | [x] |
+
+## Phase 3 — Notifications, Calendar, Deployment (Steps 19-24)
+
+| # | Step | ✅ | ✔️ |
+|---|---|----|-|
+| 19 | Add local notifications (expo-notifications) | [x] | [x] |
+| 20 | Add native calendar import with calendar selection | [x] | [x] |
+| 21 | Add mobile tests (core + API + store + screens) | [x] | [x] |
+| 22 | Prepare deployment (web backend + EAS mobile) | [x] | [x] |
+| 23 | Release MVP (verify acceptance criteria) | [x] | [x] |
+| 24 | Plan post-MVP improvements | [x] | [x] |
 
 ---
 
-## Phase 1 — Unblock Runtime (~45 min)
-
-Fix bugs that crash the app or lose user data.
-
-| Step | ✅ Implemented | ✔️ Reviewed | Notes |
-|------|:--------------:|:-----------:|-------|
-| **Step 1: Fix SSR Crash in `useBikeRoute`** (~10 min) | [x] | [x] | Relative URL fetch replaces `window.location.href` — SSR-safe. `isMounted` guard intact. |
-| **Step 2: Wire Calendar Events into `EventsStore`** (~15 min) | [x] | [x] | `CalendarPanel.tsx` merges via `useEffect` when calendar events arrive. `mergeEvents()` converts `CalendarEvent` (string `eventTime`) → `Event` (Date `eventTime`). Bonus: localStorage persistence with rehydration. |
-| **Step 3: Add Input Validation to `/api/hafas`** (~20 min) | [x] | [x] | Validates `svcReqL` array shape, method allowlist (TripSearch/LocMatch), caps `numF` at 10. Extra type guard on `svcReq.meth` (`typeof svcReq.meth !== 'string'`) exceeds spec. |
-
----
-
-## Phase 2 — Deduplicate Code (~2 hours)
-
-Eliminate duplicated logic so each integration has one source of truth.
-
-| Step | ✅ Implemented | ✔️ Reviewed | Notes |
-|------|:------:|:------:|-------|
-| **Step 4: Consolidate HAFAS Journey Parsing** (~40 min) | [x] | [x] | parseHafasJourneys moved to hafas-client.ts, exported, imported by useJourneys.ts. Option A followed. |
-| **Step 5: Wire API Routes to Use Library Clients** (~30 min) | [x] | [x] | Both routes use module-level singleton clients. Param validation, error handling, and try/catch intact. |
-| **Step 6: Remove Dead Code** (~5 min) | [x] | [x] | live-status-utils.ts deleted, export removed from index.ts. No remaining references. |
-| **Step 7: Create Missing Test Setup File** (~10 min) | [x] | [x] | src/test/setup.ts created with jest-dom vitest import. Referenced correctly in vitest.config.ts. |
-
----
-
-## Phase 3 — Performance & UX (~1.5 hours)
-
-| Step | ✅ Implemented | ✔️ Reviewed | Notes |
-|------|:------:|:------:|-------|
-| **Step 8: Add Debounce to Lookup Hooks** (~25 min) | [x] | [x] | 400ms setTimeout + AbortController in `useGeocode.ts` and `useDestinationStation.ts`. AbortError silently ignored. |
-| **Step 9: Pre-Group Calendar Events by Date** (~20 min) | [x] | [x] | `useMemo` builds `Map<string, Event[]>` keyed by `YYYY-MM-DD`. Per-cell `filter()` replaced with O(1) map lookup. |
-| **Step 10: Add Dark Mode Toggle** (~20 min) | [x] | [x] | `useTheme.ts` created (localStorage + prefers-color-scheme). Sun/moon toggle button added to `Header.tsx`. |
-| **Step 11: Fix Bike Route Steps** (~5 min) | [x] | [x] | `steps: "true"` already present in `BikeRoutingClient.getBikeRoute()` query params. |
-
----
-
-## Phase 4 — Monitoring & Testing (~1 hour)
-
-| Step | ✅ Implemented | ✔️ Reviewed | Notes |
-|------|:------:|:------:|-------|
-| **Step 12: Add Correlation IDs to API Errors** (~15 min) | [x] | [x] | `randomUUID().slice(0, 8)` in catch blocks of `bike-route`, `geocode`, `hafas`, `calendar`, `calendar/parse`. Logged server-side, returned in JSON. Existing API tests updated to assert `correlationId`. |
-| **Step 13: Add Hook Tests** (~30 min) | [x] | [x] | `useJourneys.test.ts` (4 tests: no-op when missing IDs, success, HTTP error, fetch throw). `useBikeRoute.test.ts` (4 tests: no-op when missing coords, success, HTTP error, fetch throw). |
-| **Step 14: Add Component Tests** (~15 min) | [x] | [x] | `EventCard.test.tsx` (renders title + destination, hooks mocked). `CalendarView.test.tsx` (3 tests: month header, event on correct day, overflow indicator). |
-
----
-
-## Summary
-
-| Phase | Steps | Est. Time |
-|-------|-------|-----------|
-| 1 — Unblock Runtime | 1–3 | ~45 min |
-| 2 — Deduplicate Code | 4–7 | ~2 hours |
-| 3 — Performance & UX | 8–11 | ~1.5 hours |
-| 4 — Monitoring & Testing | 12–14 | ~1 hour |
-| **Total** | **14** | **~5 hours** |
+**Legend:**
+- ✅ = Done (code written)
+- ✔️ = Verified (tests/builds pass)
+- `[~]` = Optional or deferred (never blocks phase advancement)

CLAUDE.md

@@ -1 +0,0 @@
-@AGENTS.md

FEATURES_CHECKLIST.md

@@ -0,0 +1,57 @@
+# TimeToLeave - Features Implementation Checklist
+
+This checklist tracks the route-planning and settings features currently implemented across the web and shared packages.
+
+## Settings Infrastructure
+
+| # | Step | Done | Verified |
+| --- | --- | --- | --- |
+| 1 | Extend `ReminderSettings` with arrival buffer, walking visibility, and bike visibility | [x] | [x] |
+| 2 | Persist reminder settings in web `localStorage` and mobile `AsyncStorage` | [x] | [x] |
+| 3 | Add settings UI for reminder buffer, arrival buffer, notifications, walking, and bike options | [x] | [x] |
+
+## Routing Infrastructure
+
+| # | Step | Done | Verified |
+| --- | --- | --- | --- |
+| 4 | Add OSRM walking client and `/api/walk-route` endpoint | [x] | [x] |
+| 5 | Add OSRM bike client and `/api/bike-route` endpoint | [x] | [x] |
+| 6 | Add `getWalkRoute()` and `getBikeRoute()` to `@timetoleave/api-client` | [x] | [x] |
+| 7 | Add web/mobile hooks for walking and bike routes | [x] | [x] |
+
+## Departure Calculation
+
+| # | Step | Done | Verified |
+| --- | --- | --- | --- |
+| 8 | Calculate leave-by time from selected transport mode | [x] | [x] |
+| 9 | Account for final walking time before choosing train journeys | [x] | [x] |
+| 10 | Support HAFAS arrive-by journey search with fallback window | [x] | [x] |
+| 11 | Update countdown logic to use computed departure time | [x] | [x] |
+
+## Calendar and Event Management
+
+| # | Step | Done | Verified |
+| --- | --- | --- | --- |
+| 12 | Import web calendars from URL and local ICS files | [x] | [x] |
+| 13 | Add Google Calendar OAuth sync on web | [x] | [x] |
+| 14 | Add batch destination review/editing for imported web events | [x] | [x] |
+| 15 | Add mobile native calendar sync with calendar selection | [x] | [x] |
+| 16 | Add event editing on web and mobile | [x] | [x] |
+
+## Transit Integrations
+
+| # | Step | Done | Verified |
+| --- | --- | --- | --- |
+| 17 | Add HAFAS station search and nearest-station lookup | [x] | [x] |
+| 18 | Add HAFAS journey parsing with real-time delay/cancellation support | [x] | [x] |
+| 19 | Add optional ÖBB GTFS train metadata enrichment | [x] | [x] |
+| 20 | Add Wiener Linien nearby stops and monitor departures | [x] | [x] |
+
+## Verification
+
+| # | Step | Done | Verified |
+| --- | --- | --- | --- |
+| 21 | Web unit and route tests | [x] | [x] |
+| 22 | Mobile store, calendar, notification, and screen tests | [x] | [x] |
+| 23 | Root lint/typecheck/test scripts documented | [x] | [x] |
+| 24 | Manual integration checklist updated | [x] | [x] |

MANUAL_TESTING_CHECKLIST.md

@@ -0,0 +1,145 @@
+# TimeToLeave - Manual Testing Checklist
+
+Use this checklist for browser, mobile, and integration testing before release.
+
+## Prerequisites
+
+- [ ] `npm install` has been run.
+- [ ] Required environment variables are configured.
+- [ ] Web app is running locally or deployed.
+- [ ] Mobile app has a reachable `EXPO_PUBLIC_API_BASE_URL` when tested on a device.
+- [ ] Network access is available for HAFAS, Nominatim, OSRM, Wiener Linien, and calendar providers.
+
+## Web Dashboard
+
+- [ ] Open `/`.
+- [ ] Verify the departure desk loads without console errors.
+- [ ] Add or import at least two future events.
+- [ ] Verify the dashboard shows the next upcoming event.
+- [ ] Verify edit and remove actions work from the event card.
+- [ ] Verify event data persists after browser refresh.
+
+## Web Calendar Import
+
+- [ ] Open `/calendar`.
+- [ ] Import a valid allowed ICS URL.
+- [ ] Upload a local `.ics` file.
+- [ ] Verify imported events with locations merge into the local event store.
+- [ ] Verify duplicate imports do not create unusable duplicate records.
+- [ ] Use batch destination editing and confirm edited destinations are retained.
+
+## Google Calendar Web Sync
+
+- [ ] Confirm `GOOGLE_CLIENT_ID`, `GOOGLE_CLIENT_SECRET`, `GOOGLE_REDIRECT_URI`, and `DEPLOYMENT_URL` are configured.
+- [ ] Open the Google tab on `/calendar`.
+- [ ] Connect Google Calendar through OAuth.
+- [ ] Verify sync returns upcoming events with locations.
+- [ ] Disconnect Google Calendar.
+- [ ] Verify status returns to disconnected.
+
+## Settings and Reminders
+
+- [ ] Enable browser notifications when prompted.
+- [ ] Change reminder buffer and arrival buffer.
+- [ ] Toggle walking option off and on.
+- [ ] Toggle bike option off and on.
+- [ ] Refresh the page and verify settings persist.
+- [ ] Verify disabling bike hides or disables bike mode.
+- [ ] Verify disabling walking removes the final-walk adjustment from train mode.
+
+## Train Mode
+
+- [ ] Use an event with a real destination and origin station.
+- [ ] Verify destination geocoding completes.
+- [ ] Verify destination station lookup completes.
+- [ ] Verify `/api/hafas` is called with `TripSearch`.
+- [ ] Verify journey rows show departure, arrival, platform, train labels, delay, changes, and cancellations when present.
+- [ ] Verify leave-by time is based on a journey that arrives before the event minus arrival buffer and final walk.
+- [ ] Increase arrival buffer and verify leave-by can move earlier.
+
+## Bike and Walking Routes
+
+- [ ] Switch to bike mode.
+- [ ] Verify `/api/bike-route` is called with four coordinate parameters.
+- [ ] Verify bike duration, distance, and steps are displayed.
+- [ ] Switch back to train mode with walking enabled.
+- [ ] Verify `/api/walk-route` is called for station-to-destination walking.
+- [ ] Verify walking duration and distance appear in the train section.
+- [ ] Test route error handling with invalid or very distant coordinates.
+
+## Wiener Linien
+
+- [ ] Use a destination near Vienna public transport.
+- [ ] Verify `/api/wienerlinien/stops` returns nearby stops.
+- [ ] Verify `/api/wienerlinien/monitor` returns live departures for selected stops.
+- [ ] Verify loading, empty, and error states are readable.
+
+## API Guards
+
+- [ ] Verify remote calendar URLs from unsupported hosts are rejected.
+- [ ] Verify private or localhost calendar URLs are rejected.
+- [ ] Verify overly large HAFAS POST bodies are rejected.
+- [ ] Verify invalid coordinates return client errors.
+- [ ] Verify CORS allows only configured origins.
+- [ ] Verify rate limiting returns `429` after the configured threshold.
+
+## Mobile Event Flow
+
+- [ ] Start the Expo app.
+- [ ] Add a manual event.
+- [ ] Edit the event.
+- [ ] Delete the event.
+- [ ] Restart the app and verify stored events persist.
+- [ ] Open event detail and verify train, bike, walking, and nearby-stop sections load when data is available.
+
+## Mobile Calendar Import
+
+- [ ] Import an ICS URL.
+- [ ] Grant calendar permission.
+- [ ] Verify native calendars are listed.
+- [ ] Select and deselect individual calendars.
+- [ ] Use select all and deselect all.
+- [ ] Sync native calendars for the next 30 days.
+- [ ] Verify events without locations are excluded.
+- [ ] Verify CalDAV/DAVx, Apple, Google, Exchange, subscribed, local, and other source labels render correctly when available on the device.
+
+## Mobile Settings and Notifications
+
+- [ ] Search for an origin station.
+- [ ] Use current location to find nearest origin station.
+- [ ] Change reminder buffer and arrival buffer.
+- [ ] Toggle walking and bike options.
+- [ ] Toggle notifications.
+- [ ] Verify notification settings persist after app restart.
+- [ ] Verify scheduled notifications are recreated when settings change.
+- [ ] Toggle dark/light theme and verify it persists.
+
+## Offline and Failure States
+
+- [ ] Disable network and open web event detail data.
+- [ ] Verify geocoding, HAFAS, route, and Wiener Linien errors are visible and non-blocking.
+- [ ] Re-enable network and verify retry/refresh paths work.
+- [ ] Test mobile with the backend URL unavailable and verify errors are understandable.
+
+## Accessibility and Layout
+
+- [ ] Navigate web controls with keyboard only.
+- [ ] Verify modal focus and close behavior.
+- [ ] Verify buttons and interactive controls have accessible labels or readable text.
+- [ ] Test narrow mobile browser width, tablet width, and desktop width.
+- [ ] Verify mobile screens do not clip primary controls.
+
+## Sign-Off
+
+- [ ] Web smoke test passed.
+- [ ] Mobile smoke test passed.
+- [ ] Calendar import tested.
+- [ ] Live transit integration tested.
+- [ ] Notifications tested.
+- [ ] No critical bugs remain.
+
+Tested by:
+
+Date:
+
+Build/version:

POST_MVP_PLAN.md

@@ -0,0 +1,87 @@
+# TimeToLeave - Post-MVP Improvements Plan
+
+> **Last updated:** 2026-05-19
+> This plan reflects the current state of the codebase after the initial MVP and mobile rewrite.
+
+## Already Implemented (No Longer TODO)
+
+The following items from earlier versions of this plan have been completed and are in production:
+
+- **Native Calendar Import** — `expo-calendar` integration with device calendar sync, permission requests, and multiple calendar source selection.
+- **Push / Local Notifications** — `expo-notifications` with local notification scheduling. Server-side push (FCM/APNs) for live journey updates remains deferred.
+- **Dark / Light Theming** — System theme following and manual dark/light toggle on both web and mobile.
+- **Auto-Refresh** — `useFocusEffect`-based refresh on mobile when returning to foreground.
+
+---
+
+## High Priority
+
+### 1. Offline-First Architecture
+- Cache journey and route data in `AsyncStorage` / `localStorage` for offline viewing.
+- Background sync when connection is restored.
+- Add explicit "offline mode" UI indicators.
+- Conflict resolution for concurrent event edits.
+
+### 2. Real Map Integration
+- Integrate `expo-maps` / `@vis.gl/react-google-maps` for visual route display.
+- Show origin, destination, and train stations on a map.
+- Display bike route with turn-by-turn directions.
+- Alternative route suggestions (e.g., faster vs. fewer changes).
+
+### 3. Multiple Origins Support
+- Allow different origins per event (Home, Work, Custom presets).
+- Quick origin switching in event detail and settings.
+- Store origin presets in persistent settings.
+
+---
+
+## Medium Priority
+
+### 4. Server-Side Push Notifications
+- Implement FCM for Android and APNs for iOS for real-time journey disruption alerts.
+- Real-time delay/cancellation push notifications.
+- Fallback to local notifications when the server is unreachable.
+
+### 5. Accessibility
+- TalkBack / VoiceOver screen reader support on mobile.
+- Dynamic type scaling.
+- High contrast mode.
+- WCAG 2.1 AA compliance audit on web.
+
+### 6. Analytics & Crash Reporting
+- Integrate Sentry for error tracking on web and mobile.
+- Opt-in usage analytics.
+- Performance monitoring (Web Vitals, React Native startup time).
+- In-app user feedback collection.
+
+---
+
+## Lower Priority
+
+### 7. Advanced Features
+- Shared events with friends / family (collaborative departure planning).
+- Recurring event templates.
+- Journey history and statistics dashboard.
+- Export / import event data (ICS, JSON).
+
+---
+
+## Technical Debt & Quality
+
+### 8. Code Quality
+- Extract shared hooks to `packages/hooks` (deduplicate web and mobile hook implementations).
+- Increase unit test coverage across all packages.
+- Add Playwright E2E tests for web critical flows.
+- Add Detox E2E tests for mobile critical flows.
+- Bundle size analysis and reduction.
+
+### 9. Developer Experience
+- Consolidate ESLint to Flat Config everywhere.
+- Add pre-commit hooks (`husky` + `lint-staged`).
+- Add GitHub Actions CI pipeline.
+- Architecture Decision Records (ADRs) in `docs/adr/`.
+
+### 10. Documentation
+- Keep `POST_MVP_PLAN.md` and `CHECKLIST.md` in sync with reality.
+- Contributing guidelines (`CONTRIBUTING.md`).
+- API versioning policy once the backend grows.

PRIVACY_POLICY.md

@@ -0,0 +1,45 @@
+# Privacy Policy
+
+TimeToLeave is designed to keep user data local where possible. The app does not include third-party analytics or advertising trackers.
+
+## Data Stored Locally
+
+- Web events and reminder settings are stored in browser `localStorage`.
+- Mobile events, origin station, notification settings, theme, and selected native calendars are stored in `AsyncStorage`.
+- Mobile notifications are scheduled locally through Expo notifications.
+
+## Data Sent to External Services
+
+Some features require network calls to calculate routes or import calendars:
+
+| Data | Sent to | Purpose |
+| --- | --- | --- |
+| Destination text or address | Nominatim | Convert a place into coordinates. |
+| Coordinates | OSRM | Calculate bike and walking routes. |
+| Station IDs, dates, and times | ÖBB HAFAS | Search stations and live public-transport journeys. |
+| Coordinates or stop IDs | Wiener Linien | Find nearby stops and live departures. |
+| Calendar URL | TimeToLeave backend, then the calendar host | Fetch and parse remote ICS feeds. |
+| Google Calendar authorization code and tokens | Google and the TimeToLeave backend | Connect and sync Google Calendar on web. |
+| Device calendar event fields | Local mobile app process | Import native calendar events with locations. |
+
+Remote ICS imports are restricted by server-side URL validation. Private and reserved hosts are blocked.
+
+## Google Calendar
+
+Google Calendar sync is optional. When connected on the web app, OAuth tokens are stored in HTTP-only cookies and used only to fetch calendar events. Disconnecting Google Calendar deletes the token cookie.
+
+## Location
+
+Location access is optional and used to find nearby stations or calculate routes. Coordinates may be sent to route, geocoding, or transit APIs only when the corresponding feature is used.
+
+## Calendar Data
+
+Only events with locations are useful to TimeToLeave. Imported events are normalized to title, destination, event time, source, and ID. The app stores those normalized events locally.
+
+## Data Retention
+
+Local data remains until the user clears app/browser storage, deletes events, disconnects Google Calendar, or uninstalls the app. Server-side proxy routes are intended for request handling and do not provide application-level persistent event storage.
+
+## Changes
+
+This policy may be updated as the app changes. Updates are made in this repository.

README.md

@@ -0,0 +1,128 @@
+# TimeToLeave
+
+TimeToLeave is a departure planner for calendar-driven travel. It imports events with locations, resolves the closest public-transport station, checks live ÖBB HAFAS and Wiener Linien data, and shows when to leave by train or bike.
+
+![TimeToLeave Logo](apps/web/public/timetoleave_logo.png)
+
+![Platform](https://img.shields.io/badge/platform-Web_%26_Mobile-blue) ![Next.js](https://img.shields.io/badge/Next.js-16.2-green) ![React Native](https://img.shields.io/badge/React%20Native-0.81-blue) ![Expo](https://img.shields.io/badge/Expo-54-black) ![TypeScript](https://img.shields.io/badge/TypeScript-5-blue)
+
+## What It Does
+
+1. Imports events from ICS URLs, ICS files, Google Calendar on web, or native device calendars on mobile.
+2. Stores events locally in browser `localStorage` or mobile `AsyncStorage`.
+3. Uses browser or device geolocation, a saved station, or the default Mödling origin.
+4. Geocodes event destinations and resolves nearby stations through HAFAS `LocMatch`.
+5. Searches ÖBB HAFAS journeys, enriches train data with the ÖBB GTFS fallback when available, and shows real-time delays and cancellations.
+6. Calculates bike and final walking routes through OSRM.
+7. Shows a live leave-by countdown and optional browser/mobile notifications.
+
+## Repository Layout
+
+| Path | Purpose |
+| --- | --- |
+| `apps/web/` | Next.js 16 App Router web UI plus backend proxy routes for HAFAS, geocoding, routing, calendar parsing, Google Calendar, and Wiener Linien. |
+| `apps/mobile/` | Expo 54 / React Native 0.81 mobile app with native calendar, location, notification, and local storage integrations. |
+| `packages/core/` | Shared types, defaults, HAFAS time parsing, journey parsing/scoring, countdown, formatting, and status utilities. |
+| `packages/api-client/` | Shared client for calling the web app's `/api/*` backend routes from web hooks and the mobile app. |
+| `docs/` | Architecture, development, API, user, and codebase reference documentation. |
+
+## Prerequisites
+
+- Node.js 20 or newer
+- npm 9 or newer
+- For mobile native builds: Expo/EAS prerequisites plus Android Studio or Xcode as needed
+
+## Setup
+
+```bash
+npm install
+cp .env.example .env
+```
+
+The web app reads environment variables from the workspace process. For deployment, configure the same values in the hosting environment.
+
+Important variables:
+
+| Variable | Purpose |
+| --- | --- |
+| `HAFAS_URL` | ÖBB HAFAS endpoint. Defaults to `https://fahrplan.oebb.at/bin/mgate.exe`. |
+| `NOMINATIM_URL` and `NOMINATIM_USER_AGENT` | Geocoding endpoint and required user agent. |
+| `OSRM_URL` | Routing endpoint used for bike and foot profiles. |
+| `WIENER_LINIEN_API_URL` | Wiener Linien live data base URL. |
+| `OEBB_GTFS_URL` | Optional ÖBB GTFS ZIP used to enrich HAFAS train metadata. |
+| `CORS_ALLOWED_ORIGINS` | Comma-separated origins allowed to call `/api/*`. |
+| `DEPLOYMENT_URL` | Public base URL used by Google OAuth redirects. |
+| `GOOGLE_CLIENT_ID`, `GOOGLE_CLIENT_SECRET`, `GOOGLE_REDIRECT_URI` | Required for Google Calendar sync on web. |
+| `EXPO_PUBLIC_API_BASE_URL` | Mobile backend URL. Set this for device builds so the app can reach the deployed web backend. |
+
+## Development
+
+| Command | Description |
+| --- | --- |
+| `npm run dev` | Start the Next.js web app on `http://localhost:3000`. |
+| `npm run dev:mobile` | Start the Expo development server. |
+| `npm run build` | Build the web app. |
+| `npm run start` | Start the built web app. |
+| `npm run test` | Run web Vitest and mobile Jest suites. |
+| `npm run lint` | Run ESLint across web, mobile, core, and api-client workspaces. |
+| `npm run typecheck` | Run TypeScript checks across all workspaces. |
+
+## Web App
+
+Current user-facing routes:
+
+| Route | Description |
+| --- | --- |
+| `/` | Departure desk. Shows the next upcoming event, leave-by status, transport mode selector, train journeys, bike route, final walk, and nearby Wiener Linien departures. |
+| `/calendar` | Calendar import and management view with URL, file, and Google Calendar tabs plus batch destination editing. |
+
+The add/edit event UI is a modal component, not a standalone page route.
+
+## Backend Proxy Routes
+
+All backend routes live under `apps/web/src/app/api/` and are protected by strict CORS plus per-IP rate limiting in `apps/web/src/proxy.ts`.
+
+| Endpoint | Methods | Purpose |
+| --- | --- | --- |
+| `/api/health` | `GET` | Returns `{ ok, ts, version }`. |
+| `/api/hafas` | `GET`, `POST` | Convenience journey search or validated HAFAS relay for `TripSearch` and `LocMatch`. |
+| `/api/geocode` | `GET` | Forward geocoding through Nominatim. |
+| `/api/bike-route` | `GET` | OSRM bicycle route between two coordinates. |
+| `/api/walk-route` | `GET` | OSRM foot route between two coordinates. |
+| `/api/calendar` | `GET` | Fetch and parse an allowed remote ICS URL. |
+| `/api/calendar/parse` | `POST` | Parse uploaded/raw ICS text. |
+| `/api/calendar/google` | `GET` | Fetch Google Calendar events using OAuth cookies. |
+| `/api/auth/google` | `GET` | Start Google OAuth. |
+| `/api/auth/google/callback` | `GET` | Complete Google OAuth and store token cookie. |
+| `/api/auth/google/status` | `GET` | Report Google configuration and connection state. |
+| `/api/auth/google/disconnect` | `POST` | Delete the Google token cookie. |
+| `/api/wienerlinien/stops` | `GET` | Find nearby Wiener Linien stops. |
+| `/api/wienerlinien/monitor` | `GET` | Fetch and flatten live stop departures. |
+
+## Mobile App
+
+The mobile app includes event list, add/edit event, event detail, calendar import, and settings screens. It supports:
+
+- Native calendar sync for the next 30 days.
+- Calendar-source selection, including CalDAV/DAVx, Apple, Google, Exchange, subscribed, and local calendars when exposed by the device.
+- Saved origin station with current-location lookup.
+- Train, bike, walking, and Wiener Linien live sections on event detail.
+- Local notifications scheduled from stored event/settings data.
+- Dark/light theme toggle.
+
+## Documentation
+
+Start with [docs/README.md](docs/README.md), then use:
+
+- [Architecture](docs/ARCHITECTURE.md)
+- [Development Guide](docs/DEVELOPMENT.md)
+- [Core & API Client Reference](docs/API_REFERENCE.md)
+- [User Guide](docs/USER_GUIDE.md)
+- [Codebase Function Guide](docs/CODEBASE_FUNCTION_GUIDE.md)
+
+## Important Implementation Notes
+
+- HAFAS date/time values are Vienna-local strings. Use `parseHafasTime()` and `hafasDateTime()` from `@timetoleave/core`; avoid ad hoc `Date` parsing for HAFAS payloads.
+- Remote calendar URLs are restricted to known calendar providers and private/reserved hosts are blocked.
+- Mobile devices must use a reachable `EXPO_PUBLIC_API_BASE_URL`; same-origin empty base URLs only work in the web app.
+- This repo uses Next.js 16. Before changing Next.js routing, middleware/proxy, or framework conventions, read the relevant guide in `node_modules/next/dist/docs/`.

REVIEW_RULES.md

@@ -1,32 +1,32 @@
 # Review Agent Rules
 
-These rules apply when reviewing completed implementation steps on the `rewrite/next` branch.
+These rules apply when reviewing completed implementation steps on the `main` branch.
 
 ## Checklist Tracking
 
-`CHECKLIST.md` uses three checkbox states:
+`FEATURES_CHECKLIST.md` uses three checkbox states:
 - `[ ]` — pending and **required**; blocks the next phase
 - `[x]` — done
 - `[~]` — optional or deferred; **never blocks phase advancement**
 
 Rules:
-- The ✅ column belongs to the rewrite agent; the ✔️ column is yours.
+- The ✅ column belongs to the implementation agent; the ✔️ column is yours.
 - Only review items whose ✅ box is already `[x]`. Do not attempt to review unimplemented items.
 - If a ✅ box is `[~]` (optional, skipped), mark the ✔️ box `[~]` as well — no review needed for skipped items.
 - After reviewing each required item and confirming it meets the quality bar below, mark its ✔️ box by changing `[ ]` to `[x]`.
-- Before reviewing any item in a new phase, read `CHECKLIST.md` and confirm that every **required** item in all preceding phases has `[x]` in both ✅ and ✔️. Items where both columns are `[~]` do not need review and do not block advancement.
+- Before reviewing any item in a new phase, read `FEATURES_CHECKLIST.md` and confirm that every **required** item in all preceding phases has `[x]` in both ✅ and ✔️. Items where both columns are `[~]` do not need review and do not block advancement.
 - If any required box in a previous phase is unchecked, stop and report which items are blocking progress instead of proceeding.
 
 ## Review Scope
 
-- Review one phase at a time. Within a phase, review items in the order they appear in `CHECKLIST.md`.
-- For each item, cross-reference the implementation against `REWRITE_PLAN.md` and the quality criteria below.
+- Review one phase at a time. Within a phase, review items in the order they appear in `FEATURES_CHECKLIST.md`.
+- For each item, cross-reference the implementation against `FEATURES_PLAN.md` and the quality criteria below.
 - Report concrete issues with file paths and line numbers. Do not flag style nitpicks that are not covered by a project guideline.
 
 ## What to Check
 
 **Correctness**
-- The behavior matches the intent described in `REWRITE_PLAN.md` and the checklist item.
+- The behavior matches the intent described in `FEATURES_PLAN.md` and the checklist item.
 - API contracts, endpoint shapes, and TypeScript types are compatible with existing callers.
 - No regressions are introduced in previously working behavior.
 
@@ -43,10 +43,11 @@ Rules:
 - Error handling is explicit and user-facing failures are understandable.
 - No generated artifacts, caches, logs, or local environment files are committed.
 - Dependencies are unchanged unless necessary and justified.
+- Package boundaries are respected — shared types in `packages/core`, API wrappers in `packages/api-client`, app code in `apps/web`.
 
 **Scope**
 - The change is scoped to the checklist item — no unrelated modifications.
-- Old implementation files (`server/`, `oebb-planner-app/`, `oebb-planner.jsx`) were not removed unless parity is tested and cleanup was explicitly requested.
+- Existing implementation files were not removed unless parity is tested and cleanup was explicitly requested.
 
 **Accessibility (UI items only)**
 - Semantic buttons and links, labels for inputs, keyboard-operable controls, visible loading and error states.
@@ -56,21 +57,23 @@ Rules:
 - Run the relevant test and build checks to confirm the implementation passes before marking ✔️:
 
 ```bash
+npm run typecheck -w packages/core
+npm run typecheck -w packages/api-client
+npm run typecheck -w apps/web
+npm run lint -w apps/web
+npm run build -w apps/web
 npm test
-npm run build
-npm run typecheck
-npm run lint
 ```
 
-- If a check fails, do not mark the ✔️ box. Report the failure with the exact output and leave the item for the rewrite agent to fix.
+- If a check fails, do not mark the ✔️ box. Report the failure with the exact output and leave the item for the implementation agent to fix.
 
 ## Completion Checklist
 
 Before marking a ✔️ box, confirm:
 
-- The ✅ box for this item is already checked by the rewrite agent.
+- The ✅ box for this item is already checked by the implementation agent.
 - All preceding phase items have both ✅ and ✔️ checked.
-- The implementation matches the intent in `REWRITE_PLAN.md`.
+- The implementation matches the intent in `FEATURES_PLAN.md`.
 - Tests exist, are meaningful, and pass.
 - Build and type checks pass.
 - No quality issues from the criteria above remain unresolved.

android/.gitignore

@@ -0,0 +1,16 @@
+# OSX
+#
+.DS_Store
+
+# Android/IntelliJ
+#
+build/
+.idea
+.gradle
+local.properties
+*.iml
+*.hprof
+.cxx/
+
+# Bundle artifacts
+*.jsbundle

android/app/build.gradle

@@ -0,0 +1,182 @@
+apply plugin: "com.android.application"
+apply plugin: "org.jetbrains.kotlin.android"
+apply plugin: "com.facebook.react"
+
+def projectRoot = rootDir.getAbsoluteFile().getParentFile().getAbsolutePath()
+
+/**
+ * This is the configuration block to customize your React Native Android app.
+ * By default you don't need to apply any configuration, just uncomment the lines you need.
+ */
+react {
+    entryFile = file(["node", "-e", "require('expo/scripts/resolveAppEntry')", projectRoot, "android", "absolute"].execute(null, rootDir).text.trim())
+    reactNativeDir = new File(["node", "--print", "require.resolve('react-native/package.json')"].execute(null, rootDir).text.trim()).getParentFile().getAbsoluteFile()
+    hermesCommand = new File(["node", "--print", "require.resolve('react-native/package.json')"].execute(null, rootDir).text.trim()).getParentFile().getAbsolutePath() + "/sdks/hermesc/%OS-BIN%/hermesc"
+    codegenDir = new File(["node", "--print", "require.resolve('@react-native/codegen/package.json', { paths: [require.resolve('react-native/package.json')] })"].execute(null, rootDir).text.trim()).getParentFile().getAbsoluteFile()
+
+    enableBundleCompression = (findProperty('android.enableBundleCompression') ?: false).toBoolean()
+    // Use Expo CLI to bundle the app, this ensures the Metro config
+    // works correctly with Expo projects.
+    cliFile = new File(["node", "--print", "require.resolve('@expo/cli', { paths: [require.resolve('expo/package.json')] })"].execute(null, rootDir).text.trim())
+    bundleCommand = "export:embed"
+
+    /* Folders */
+     //   The root of your project, i.e. where "package.json" lives. Default is '../..'
+    // root = file("../../")
+    //   The folder where the react-native NPM package is. Default is ../../node_modules/react-native
+    // reactNativeDir = file("../../node_modules/react-native")
+    //   The folder where the react-native Codegen package is. Default is ../../node_modules/@react-native/codegen
+    // codegenDir = file("../../node_modules/@react-native/codegen")
+
+    /* Variants */
+    //   The list of variants to that are debuggable. For those we're going to
+    //   skip the bundling of the JS bundle and the assets. By default is just 'debug'.
+    //   If you add flavors like lite, prod, etc. you'll have to list your debuggableVariants.
+    // debuggableVariants = ["liteDebug", "prodDebug"]
+
+    /* Bundling */
+    //   A list containing the node command and its flags. Default is just 'node'.
+    // nodeExecutableAndArgs = ["node"]
+
+    //
+    //   The path to the CLI configuration file. Default is empty.
+    // bundleConfig = file(../rn-cli.config.js)
+    //
+    //   The name of the generated asset file containing your JS bundle
+    // bundleAssetName = "MyApplication.android.bundle"
+    //
+    //   The entry file for bundle generation. Default is 'index.android.js' or 'index.js'
+    // entryFile = file("../js/MyApplication.android.js")
+    //
+    //   A list of extra flags to pass to the 'bundle' commands.
+    //   See https://github.com/react-native-community/cli/blob/main/docs/commands.md#bundle
+    // extraPackagerArgs = []
+
+    /* Hermes Commands */
+    //   The hermes compiler command to run. By default it is 'hermesc'
+    // hermesCommand = "$rootDir/my-custom-hermesc/bin/hermesc"
+    //
+    //   The list of flags to pass to the Hermes compiler. By default is "-O", "-output-source-map"
+    // hermesFlags = ["-O", "-output-source-map"]
+
+    /* Autolinking */
+    autolinkLibrariesWithApp()
+}
+
+/**
+ * Set this to true in release builds to optimize the app using [R8](https://developer.android.com/topic/performance/app-optimization/enable-app-optimization).
+ */
+def enableMinifyInReleaseBuilds = (findProperty('android.enableMinifyInReleaseBuilds') ?: false).toBoolean()
+
+/**
+ * The preferred build flavor of JavaScriptCore (JSC)
+ *
+ * For example, to use the international variant, you can use:
+ * `def jscFlavor = 'org.webkit:android-jsc-intl:+'`
+ *
+ * The international variant includes ICU i18n library and necessary data
+ * allowing to use e.g. `Date.toLocaleString` and `String.localeCompare` that
+ * give correct results when using with locales other than en-US. Note that
+ * this variant is about 6MiB larger per architecture than default.
+ */
+def jscFlavor = 'io.github.react-native-community:jsc-android:2026004.+'
+
+android {
+    ndkVersion rootProject.ext.ndkVersion
+
+    buildToolsVersion rootProject.ext.buildToolsVersion
+    compileSdk rootProject.ext.compileSdkVersion
+
+    namespace 'com.floegger.timetoleave'
+    defaultConfig {
+        applicationId 'com.floegger.timetoleave'
+        minSdkVersion rootProject.ext.minSdkVersion
+        targetSdkVersion rootProject.ext.targetSdkVersion
+        versionCode 1
+        versionName "1.0.0"
+
+        buildConfigField "String", "REACT_NATIVE_RELEASE_LEVEL", "\"${findProperty('reactNativeReleaseLevel') ?: 'stable'}\""
+    }
+    signingConfigs {
+        debug {
+            storeFile file('debug.keystore')
+            storePassword 'android'
+            keyAlias 'androiddebugkey'
+            keyPassword 'android'
+        }
+    }
+    buildTypes {
+        debug {
+            signingConfig signingConfigs.debug
+        }
+        release {
+            // Caution! In production, you need to generate your own keystore file.
+            // see https://reactnative.dev/docs/signed-apk-android.
+            signingConfig signingConfigs.debug
+            def enableShrinkResources = findProperty('android.enableShrinkResourcesInReleaseBuilds') ?: 'false'
+            shrinkResources enableShrinkResources.toBoolean()
+            minifyEnabled enableMinifyInReleaseBuilds
+            proguardFiles getDefaultProguardFile("proguard-android.txt"), "proguard-rules.pro"
+            def enablePngCrunchInRelease = findProperty('android.enablePngCrunchInReleaseBuilds') ?: 'true'
+            crunchPngs enablePngCrunchInRelease.toBoolean()
+        }
+    }
+    packagingOptions {
+        jniLibs {
+            def enableLegacyPackaging = findProperty('expo.useLegacyPackaging') ?: 'false'
+            useLegacyPackaging enableLegacyPackaging.toBoolean()
+        }
+    }
+    androidResources {
+        ignoreAssetsPattern '!.svn:!.git:!.ds_store:!*.scc:!CVS:!thumbs.db:!picasa.ini:!*~'
+    }
+}
+
+// Apply static values from `gradle.properties` to the `android.packagingOptions`
+// Accepts values in comma delimited lists, example:
+// android.packagingOptions.pickFirsts=/LICENSE,**/picasa.ini
+["pickFirsts", "excludes", "merges", "doNotStrip"].each { prop ->
+    // Split option: 'foo,bar' -> ['foo', 'bar']
+    def options = (findProperty("android.packagingOptions.$prop") ?: "").split(",");
+    // Trim all elements in place.
+    for (i in 0..<options.size()) options[i] = options[i].trim();
+    // `[] - ""` is essentially `[""].filter(Boolean)` removing all empty strings.
+    options -= ""
+
+    if (options.length > 0) {
+        println "android.packagingOptions.$prop += $options ($options.length)"
+        // Ex: android.packagingOptions.pickFirsts += '**/SCCS/**'
+        options.each {
+            android.packagingOptions[prop] += it
+        }
+    }
+}
+
+dependencies {
+    // The version of react-native is set by the React Native Gradle Plugin
+    implementation("com.facebook.react:react-android")
+
+    def isGifEnabled = (findProperty('expo.gif.enabled') ?: "") == "true";
+    def isWebpEnabled = (findProperty('expo.webp.enabled') ?: "") == "true";
+    def isWebpAnimatedEnabled = (findProperty('expo.webp.animated') ?: "") == "true";
+
+    if (isGifEnabled) {
+        // For animated gif support
+        implementation("com.facebook.fresco:animated-gif:${expoLibs.versions.fresco.get()}")
+    }
+
+    if (isWebpEnabled) {
+        // For webp support
+        implementation("com.facebook.fresco:webpsupport:${expoLibs.versions.fresco.get()}")
+        if (isWebpAnimatedEnabled) {
+            // Animated webp support
+            implementation("com.facebook.fresco:animated-webp:${expoLibs.versions.fresco.get()}")
+        }
+    }
+
+    if (hermesEnabled.toBoolean()) {
+        implementation("com.facebook.react:hermes-android")
+    } else {
+        implementation jscFlavor
+    }
+}

android/app/proguard-rules.pro

@@ -0,0 +1,14 @@
+# Add project specific ProGuard rules here.
+# By default, the flags in this file are appended to flags specified
+# in /usr/local/Cellar/android-sdk/24.3.3/tools/proguard/proguard-android.txt
+# You can edit the include path and order by changing the proguardFiles
+# directive in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# react-native-reanimated
+-keep class com.swmansion.reanimated.** { *; }
+-keep class com.facebook.react.turbomodule.** { *; }
+
+# Add any project specific keep options here:

android/app/src/debug/AndroidManifest.xml

@@ -0,0 +1,7 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
+
+    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
+
+    <application android:usesCleartextTraffic="true" tools:targetApi="28" tools:ignore="GoogleAppIndexingWarning" tools:replace="android:usesCleartextTraffic" />
+</manifest>

android/app/src/debugOptimized/AndroidManifest.xml

@@ -0,0 +1,7 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
+
+    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
+
+    <application android:usesCleartextTraffic="true" tools:targetApi="28" tools:ignore="GoogleAppIndexingWarning" tools:replace="android:usesCleartextTraffic" />
+</manifest>

android/app/src/main/AndroidManifest.xml

@@ -0,0 +1,31 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+  <uses-permission android:name="android.permission.INTERNET"/>
+  <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
+  <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
+  <uses-permission android:name="android.permission.VIBRATE"/>
+  <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
+  <queries>
+    <intent>
+      <action android:name="android.intent.action.VIEW"/>
+      <category android:name="android.intent.category.BROWSABLE"/>
+      <data android:scheme="https"/>
+    </intent>
+  </queries>
+  <application android:name=".MainApplication" android:label="@string/app_name" android:icon="@mipmap/ic_launcher" android:roundIcon="@mipmap/ic_launcher_round" android:allowBackup="true" android:theme="@style/AppTheme" android:supportsRtl="true" android:enableOnBackInvokedCallback="false">
+    <meta-data android:name="expo.modules.updates.ENABLED" android:value="false"/>
+    <meta-data android:name="expo.modules.updates.EXPO_UPDATES_CHECK_ON_LAUNCH" android:value="ALWAYS"/>
+    <meta-data android:name="expo.modules.updates.EXPO_UPDATES_LAUNCH_WAIT_MS" android:value="0"/>
+    <activity android:name=".MainActivity" android:configChanges="keyboard|keyboardHidden|orientation|screenSize|screenLayout|uiMode" android:launchMode="singleTask" android:windowSoftInputMode="adjustResize" android:theme="@style/Theme.App.SplashScreen" android:exported="true">
+      <intent-filter>
+        <action android:name="android.intent.action.MAIN"/>
+        <category android:name="android.intent.category.LAUNCHER"/>
+      </intent-filter>
+      <intent-filter>
+        <action android:name="android.intent.action.VIEW"/>
+        <category android:name="android.intent.category.DEFAULT"/>
+        <category android:name="android.intent.category.BROWSABLE"/>
+        <data android:scheme="exp+time-to-leave"/>
+      </intent-filter>
+    </activity>
+  </application>
+</manifest>

android/app/src/main/java/com/floegger/timetoleave/MainActivity.kt

@@ -0,0 +1,61 @@
+package com.floegger.timetoleave
+
+import android.os.Build
+import android.os.Bundle
+
+import com.facebook.react.ReactActivity
+import com.facebook.react.ReactActivityDelegate
+import com.facebook.react.defaults.DefaultNewArchitectureEntryPoint.fabricEnabled
+import com.facebook.react.defaults.DefaultReactActivityDelegate
+
+import expo.modules.ReactActivityDelegateWrapper
+
+class MainActivity : ReactActivity() {
+  override fun onCreate(savedInstanceState: Bundle?) {
+    // Set the theme to AppTheme BEFORE onCreate to support
+    // coloring the background, status bar, and navigation bar.
+    // This is required for expo-splash-screen.
+    setTheme(R.style.AppTheme);
+    super.onCreate(null)
+  }
+
+  /**
+   * Returns the name of the main component registered from JavaScript. This is used to schedule
+   * rendering of the component.
+   */
+  override fun getMainComponentName(): String = "main"
+
+  /**
+   * Returns the instance of the [ReactActivityDelegate]. We use [DefaultReactActivityDelegate]
+   * which allows you to enable New Architecture with a single boolean flags [fabricEnabled]
+   */
+  override fun createReactActivityDelegate(): ReactActivityDelegate {
+    return ReactActivityDelegateWrapper(
+          this,
+          BuildConfig.IS_NEW_ARCHITECTURE_ENABLED,
+          object : DefaultReactActivityDelegate(
+              this,
+              mainComponentName,
+              fabricEnabled
+          ){})
+  }
+
+  /**
+    * Align the back button behavior with Android S
+    * where moving root activities to background instead of finishing activities.
+    * @see <a href="https://developer.android.com/reference/android/app/Activity#onBackPressed()">onBackPressed</a>
+    */
+  override fun invokeDefaultOnBackPressed() {
+      if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.R) {
+          if (!moveTaskToBack(false)) {
+              // For non-root activities, use the default implementation to finish them.
+              super.invokeDefaultOnBackPressed()
+          }
+          return
+      }
+
+      // Use the default back button implementation on Android S
+      // because it's doing more than [Activity.moveTaskToBack] in fact.
+      super.invokeDefaultOnBackPressed()
+  }
+}

android/app/src/main/java/com/floegger/timetoleave/MainApplication.kt

@@ -0,0 +1,56 @@
+package com.floegger.timetoleave
+
+import android.app.Application
+import android.content.res.Configuration
+
+import com.facebook.react.PackageList
+import com.facebook.react.ReactApplication
+import com.facebook.react.ReactNativeApplicationEntryPoint.loadReactNative
+import com.facebook.react.ReactNativeHost
+import com.facebook.react.ReactPackage
+import com.facebook.react.ReactHost
+import com.facebook.react.common.ReleaseLevel
+import com.facebook.react.defaults.DefaultNewArchitectureEntryPoint
+import com.facebook.react.defaults.DefaultReactNativeHost
+
+import expo.modules.ApplicationLifecycleDispatcher
+import expo.modules.ReactNativeHostWrapper
+
+class MainApplication : Application(), ReactApplication {
+
+  override val reactNativeHost: ReactNativeHost = ReactNativeHostWrapper(
+      this,
+      object : DefaultReactNativeHost(this) {
+        override fun getPackages(): List<ReactPackage> =
+            PackageList(this).packages.apply {
+              // Packages that cannot be autolinked yet can be added manually here, for example:
+              // add(MyReactNativePackage())
+            }
+
+          override fun getJSMainModuleName(): String = ".expo/.virtual-metro-entry"
+
+          override fun getUseDeveloperSupport(): Boolean = BuildConfig.DEBUG
+
+          override val isNewArchEnabled: Boolean = BuildConfig.IS_NEW_ARCHITECTURE_ENABLED
+      }
+  )
+
+  override val reactHost: ReactHost
+    get() = ReactNativeHostWrapper.createReactHost(applicationContext, reactNativeHost)
+
+  override fun onCreate() {
+    super.onCreate()
+    DefaultNewArchitectureEntryPoint.releaseLevel = try {
+      ReleaseLevel.valueOf(BuildConfig.REACT_NATIVE_RELEASE_LEVEL.uppercase())
+    } catch (e: IllegalArgumentException) {
+      ReleaseLevel.STABLE
+    }
+    loadReactNative(this)
+    ApplicationLifecycleDispatcher.onApplicationCreate(this)
+  }
+
+  override fun onConfigurationChanged(newConfig: Configuration) {
+    super.onConfigurationChanged(newConfig)
+    ApplicationLifecycleDispatcher.onConfigurationChanged(this, newConfig)
+  }
+}

android/app/src/main/res/drawable/ic_launcher_background.xml

@@ -0,0 +1,6 @@
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+  <item android:drawable="@color/splashscreen_background"/>
+  <item>
+    <bitmap android:gravity="center" android:src="@drawable/splashscreen_logo"/>
+  </item>
+</layer-list>

android/app/src/main/res/drawable/rn_edit_text_material.xml

@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2014 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<inset xmlns:android="http://schemas.android.com/apk/res/android"
+       android:insetLeft="@dimen/abc_edit_text_inset_horizontal_material"
+       android:insetRight="@dimen/abc_edit_text_inset_horizontal_material"
+       android:insetTop="@dimen/abc_edit_text_inset_top_material"
+       android:insetBottom="@dimen/abc_edit_text_inset_bottom_material"
+       >
+
+    <selector>
+        <!--
+          This file is a copy of abc_edit_text_material (https://bit.ly/3k8fX7I).
+          The item below with state_pressed="false" and state_focused="false" causes a NullPointerException.
+          NullPointerException:tempt to invoke virtual method 'android.graphics.drawable.Drawable android.graphics.drawable.Drawable$ConstantState.newDrawable(android.content.res.Resources)'
+
+          <item android:state_pressed="false" android:state_focused="false" android:drawable="@drawable/abc_textfield_default_mtrl_alpha"/>
+
+          For more info, see https://bit.ly/3CdLStv (react-native/pull/29452) and https://bit.ly/3nxOMoR.
+        -->
+        <item android:state_enabled="false" android:drawable="@drawable/abc_textfield_default_mtrl_alpha"/>
+        <item android:drawable="@drawable/abc_textfield_activated_mtrl_alpha"/>
+    </selector>
+
+</inset>

android/app/src/main/res/values-night/colors.xml

@@ -0,0 +1 @@
+<resources/>

android/app/src/main/res/values/colors.xml

@@ -0,0 +1,5 @@
+<resources>
+  <color name="splashscreen_background">#FFFFFF</color>
+  <color name="colorPrimary">#023c69</color>
+  <color name="colorPrimaryDark">#ffffff</color>
+</resources>

android/app/src/main/res/values/strings.xml

@@ -0,0 +1,3 @@
+<resources>
+  <string name="app_name">time-to-leave</string>
+</resources>

android/app/src/main/res/values/styles.xml

@@ -0,0 +1,11 @@
+<resources xmlns:tools="http://schemas.android.com/tools">
+  <style name="AppTheme" parent="Theme.AppCompat.DayNight.NoActionBar">
+    <item name="android:enforceNavigationBarContrast" tools:targetApi="29">true</item>
+    <item name="android:editTextBackground">@drawable/rn_edit_text_material</item>
+    <item name="colorPrimary">@color/colorPrimary</item>
+    <item name="android:statusBarColor">#ffffff</item>
+  </style>
+  <style name="Theme.App.SplashScreen" parent="AppTheme">
+    <item name="android:windowBackground">@drawable/ic_launcher_background</item>
+  </style>
+</resources>

android/build.gradle

@@ -0,0 +1,24 @@
+// Top-level build file where you can add configuration options common to all sub-projects/modules.
+
+buildscript {
+  repositories {
+    google()
+    mavenCentral()
+  }
+  dependencies {
+    classpath('com.android.tools.build:gradle')
+    classpath('com.facebook.react:react-native-gradle-plugin')
+    classpath('org.jetbrains.kotlin:kotlin-gradle-plugin')
+  }
+}
+
+allprojects {
+  repositories {
+    google()
+    mavenCentral()
+    maven { url 'https://www.jitpack.io' }
+  }
+}
+
+apply plugin: "expo-root-project"
+apply plugin: "com.facebook.react.rootproject"

android/gradle.properties

@@ -0,0 +1,65 @@
+# Project-wide Gradle settings.
+
+# IDE (e.g. Android Studio) users:
+# Gradle settings configured through the IDE *will override*
+# any settings specified in this file.
+
+# For more details on how to configure your build environment visit
+# http://www.gradle.org/docs/current/userguide/build_environment.html
+
+# Specifies the JVM arguments used for the daemon process.
+# The setting is particularly useful for tweaking memory settings.
+# Default value: -Xmx512m -XX:MaxMetaspaceSize=256m
+org.gradle.jvmargs=-Xmx2048m -XX:MaxMetaspaceSize=512m
+
+# When configured, Gradle will run in incubating parallel mode.
+# This option should only be used with decoupled projects. More details, visit
+# http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
+org.gradle.parallel=true
+
+# AndroidX package structure to make it clearer which packages are bundled with the
+# Android operating system, and which are packaged with your app's APK
+# https://developer.android.com/topic/libraries/support-library/androidx-rn
+android.useAndroidX=true
+
+# Enable AAPT2 PNG crunching
+android.enablePngCrunchInReleaseBuilds=true
+
+# Use this property to specify which architecture you want to build.
+# You can also override it from the CLI using
+# ./gradlew <task> -PreactNativeArchitectures=x86_64
+reactNativeArchitectures=armeabi-v7a,arm64-v8a,x86,x86_64
+
+# Use this property to enable support to the new architecture.
+# This will allow you to use TurboModules and the Fabric render in
+# your application. You should enable this flag either if you want
+# to write custom TurboModules/Fabric components OR use libraries that
+# are providing them.
+newArchEnabled=true
+
+# Use this property to enable or disable the Hermes JS engine.
+# If set to false, you will be using JSC instead.
+hermesEnabled=true
+
+# Use this property to enable edge-to-edge display support.
+# This allows your app to draw behind system bars for an immersive UI.
+# Note: Only works with ReactActivity and should not be used with custom Activity.
+edgeToEdgeEnabled=true
+
+# Enable GIF support in React Native images (~200 B increase)
+expo.gif.enabled=true
+# Enable webp support in React Native images (~85 KB increase)
+expo.webp.enabled=true
+# Enable animated webp support (~3.4 MB increase)
+# Disabled by default because iOS doesn't support animated webp
+expo.webp.animated=false
+
+# Enable network inspector
+EX_DEV_CLIENT_NETWORK_INSPECTOR=true
+
+# Use legacy packaging to compress native libraries in the resulting APK.
+expo.useLegacyPackaging=false
+
+# Specifies whether the app is configured to use edge-to-edge via the app config or plugin
+# WARNING: This property has been deprecated and will be removed in Expo SDK 55. Use `edgeToEdgeEnabled` or `react.edgeToEdgeEnabled` to determine whether the project is using edge-to-edge.
+expo.edgeToEdgeEnabled=true

android/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.14.3-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

android/gradlew

@@ -0,0 +1,251 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s\n' "$PWD" ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH="\\\"\\\""
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

android/gradlew.bat

@@ -0,0 +1,94 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

android/settings.gradle

@@ -0,0 +1,39 @@
+pluginManagement {
+  def reactNativeGradlePlugin = new File(
+    providers.exec {
+      workingDir(rootDir)
+      commandLine("node", "--print", "require.resolve('@react-native/gradle-plugin/package.json', { paths: [require.resolve('react-native/package.json')] })")
+    }.standardOutput.asText.get().trim()
+  ).getParentFile().absolutePath
+  includeBuild(reactNativeGradlePlugin)
+  
+  def expoPluginsPath = new File(
+    providers.exec {
+      workingDir(rootDir)
+      commandLine("node", "--print", "require.resolve('expo-modules-autolinking/package.json', { paths: [require.resolve('expo/package.json')] })")
+    }.standardOutput.asText.get().trim(),
+    "../android/expo-gradle-plugin"
+  ).absolutePath
+  includeBuild(expoPluginsPath)
+}
+
+plugins {
+  id("com.facebook.react.settings")
+  id("expo-autolinking-settings")
+}
+
+extensions.configure(com.facebook.react.ReactSettingsExtension) { ex ->
+  if (System.getenv('EXPO_USE_COMMUNITY_AUTOLINKING') == '1') {
+    ex.autolinkLibrariesFromCommand()
+  } else {
+    ex.autolinkLibrariesFromCommand(expoAutolinking.rnConfigCommand)
+  }
+}
+expoAutolinking.useExpoModules()
+
+rootProject.name = 'time-to-leave'
+
+expoAutolinking.useExpoVersionCatalog()
+
+include ':app'
+includeBuild(expoAutolinking.reactNativeGradlePlugin)

app.json

@@ -0,0 +1,18 @@
+{
+  "expo": {
+    "extra": {
+      "eas": {
+        "projectId": "78e8f448-5ce1-4d2e-b589-481c67cb7aef"
+      }
+    },
+    "ios": {
+      "bundleIdentifier": "com.floegger.timetoleave",
+      "infoPlist": {
+        "ITSAppUsesNonExemptEncryption": false
+      }
+    },
+    "android": {
+      "package": "com.floegger.timetoleave"
+    }
+  }
+}

apps/mobile/.gitignore

@@ -0,0 +1,47 @@
+# Learn more https://docs.github.com/en/get-started/getting-started-with-git/ignoring-files
+
+# dependencies
+node_modules/
+
+# Expo
+.expo/
+dist/
+web-build/
+expo-env.d.ts
+
+# Native
+.kotlin/
+*.orig.*
+*.jks
+*.p8
+*.p12
+*.key
+*.mobileprovision
+
+# Metro
+.metro-health-check*
+
+# debug
+npm-debug.*
+yarn-debug.*
+yarn-error.*
+
+# macOS
+.DS_Store
+*.pem
+
+# local env files
+.env
+.env*.local
+
+# typescript
+*.tsbuildinfo
+
+# generated native folders
+/ios
+/android
+
+.claude/
+.idea/
+.zed/
+agent_loop

apps/mobile/App.tsx

@@ -0,0 +1,31 @@
+import { useEffect, useRef } from 'react';
+import * as Notifications from './src/services/expoNotifications';
+import AppNavigator from './src/navigation/AppNavigator';
+
+export default function App() {
+  const initRef = useRef(false);
+
+  useEffect(() => {
+    // Run initialization only once
+    if (initRef.current) return;
+    initRef.current = true;
+
+    (async () => {
+      // Request notification permissions
+      await Notifications.requestPermissionsAsync();
+
+      // Set up notification handler (called exactly once)
+      Notifications.setNotificationHandler({
+        handleNotification: async () => ({
+          shouldShowAlert: true,
+          shouldPlaySound: true,
+          shouldSetBadge: false,
+          shouldShowBanner: true,
+          shouldShowList: true,
+        }),
+      });
+    })();
+  }, []);
+
+  return <AppNavigator />;
+}

apps/mobile/app.json

@@ -0,0 +1,53 @@
+{
+  "expo": {
+    "name": "Time To Leave",
+    "slug": "timetoleave",
+    "version": "1.0.0",
+    "orientation": "portrait",
+    "icon": "./assets/icon.png",
+    "userInterfaceStyle": "dark",
+    "newArchEnabled": true,
+    "splash": {
+      "image": "./assets/splash-icon.png",
+      "resizeMode": "contain",
+      "backgroundColor": "#090816"
+    },
+    "ios": {
+      "supportsTablet": true,
+      "bundleIdentifier": "com.timetoleave.app",
+      "infoPlist": {
+        "NSLocationWhenInUseUsageDescription": "This app uses your location to find nearby stations and calculate travel times.",
+        "NSUserNotificationUsageDescription": "This app uses notifications to remind you about events."
+      }
+    },
+    "android": {
+      "adaptiveIcon": {
+        "foregroundImage": "./assets/adaptive-icon.png",
+        "backgroundColor": "#090816"
+      },
+      "edgeToEdgeEnabled": true,
+      "predictiveBackGestureEnabled": false,
+      "package": "com.timetoleave.app",
+      "permissions": [
+        "android.permission.ACCESS_FINE_LOCATION",
+        "android.permission.POST_NOTIFICATIONS",
+        "android.permission.INTERNET",
+        "android.permission.ACCESS_COARSE_LOCATION"
+      ]
+    },
+    "web": {
+      "favicon": "./assets/favicon.png"
+    },
+    "plugins": [
+      "expo-location",
+      "expo-notifications"
+    ],
+    "privacyPolicyUrl": "https://timetoleave.app/privacy-policy",
+    "extra": {
+      "eas": {
+        "projectId": "2467d09e-f838-404b-b5a9-14d48ac76bec"
+      }
+    },
+    "owner": "floegger"
+  }
+}

apps/mobile/assets/logo.svg

@@ -0,0 +1,58 @@
+<svg width="1024" height="1024" viewBox="0 0 1024 1024" fill="none" xmlns="http://www.w3.org/2000/svg" role="img" aria-labelledby="title desc">
+  <title id="title">TimeToLeave app icon</title>
+  <desc id="desc">An icon-only TimeToLeave mark: a violet and magenta melting clock on a dark rounded-square background, flowing into a right arrow.</desc>
+  <defs>
+    <radialGradient id="iconBg" cx="50%" cy="36%" r="76%">
+      <stop offset="0%" stop-color="#17112A"/>
+      <stop offset="55%" stop-color="#090816"/>
+      <stop offset="100%" stop-color="#03030A"/>
+    </radialGradient>
+    <linearGradient id="iconMelt" x1="205" y1="170" x2="840" y2="745" gradientUnits="userSpaceOnUse">
+      <stop offset="0%" stop-color="#8B5CF6"/>
+      <stop offset="40%" stop-color="#B23CFF"/>
+      <stop offset="72%" stop-color="#D946EF"/>
+      <stop offset="100%" stop-color="#FF2D8D"/>
+    </linearGradient>
+    <filter id="iconGlow" x="-25%" y="-25%" width="150%" height="150%">
+      <feGaussianBlur stdDeviation="9" result="blur"/>
+      <feColorMatrix in="blur" type="matrix" values="0.72 0 0 0 0.26 0 0.18 0 0 0.92 0 0 0.34 0 1 0 0 0 0.35 0" result="glow"/>
+      <feMerge>
+        <feMergeNode in="glow"/>
+        <feMergeNode in="SourceGraphic"/>
+      </feMerge>
+    </filter>
+    <style>
+      .iconStroke { stroke: url(#iconMelt); stroke-width: 56; stroke-linecap: round; stroke-linejoin: round; }
+      .iconTick { stroke: #F4F1EA; stroke-width: 16; stroke-linecap: round; opacity: 0.96; }
+      .iconHand { stroke: #F4F1EA; stroke-width: 22; stroke-linecap: round; }
+    </style>
+  </defs>
+
+  <rect width="1024" height="1024" rx="218" fill="url(#iconBg)"/>
+
+  <g filter="url(#iconGlow)">
+    <!-- Simplified app-icon melting clock -->
+    <path class="iconStroke" d="M266 544 C254 478 271 406 316 350 C372 280 456 246 543 256 C644 268 724 349 738 451 C744 495 737 535 731 559 C726 585 738 604 762 612 C790 621 793 582 815 578 C842 574 850 611 836 642 C826 664 811 674 790 671"/>
+    <path class="iconStroke" d="M266 544 C251 589 263 628 303 632 C339 635 324 578 361 578 C397 578 385 653 430 653 C473 653 463 590 508 590 C551 590 548 671 602 698 C671 734 757 712 821 668"/>
+    <path class="iconStroke" d="M430 653 C428 707 429 753 449 753 C470 753 469 708 474 662"/>
+    <path class="iconStroke" d="M821 668 C855 643 890 626 928 615"/>
+    <path d="M897 564 L1010 609 L916 687 L928 636 Z" fill="#FF2D8D"/>
+  </g>
+
+  <!-- Minimal face details for small-size legibility -->
+  <g>
+    <line class="iconTick" x1="512" y1="326" x2="512" y2="354"/>
+    <line class="iconTick" x1="640" y1="381" x2="663" y2="358"/>
+    <line class="iconTick" x1="704" y1="514" x2="737" y2="514"/>
+    <line class="iconTick" x1="512" y1="649" x2="512" y2="680"/>
+    <line class="iconTick" x1="388" y1="640" x2="411" y2="617"/>
+    <line class="iconTick" x1="318" y1="514" x2="351" y2="514"/>
+    <line class="iconTick" x1="388" y1="388" x2="411" y2="411"/>
+  </g>
+
+  <g>
+    <line class="iconHand" x1="512" y1="514" x2="512" y2="394"/>
+    <line class="iconHand" x1="512" y1="514" x2="631" y2="590"/>
+    <circle cx="512" cy="514" r="29" fill="#F4F1EA"/>
+  </g>
+</svg>

apps/mobile/eas.json

@@ -0,0 +1,34 @@
+{
+  "cli": {
+    "version": ">= 10.0.0"
+  },
+  "build": {
+    "development": {
+      "developmentClient": true,
+      "distribution": "internal",
+      "android": {
+        "buildType": "apk"
+      }
+    },
+    "preview": {
+      "distribution": "internal",
+      "android": {
+        "buildType": "apk"
+      }
+    },
+    "production": {
+      "android": {
+        "buildType": "app-bundle",
+        "distribution": "store"
+      }
+    }
+  },
+  "submit": {
+    "production": {
+      "android": {
+        "serviceAccountKeyPath": "./google-service-account.json",
+        "track": "production"
+      }
+    }
+  }
+}

apps/mobile/eslint.config.js

@@ -0,0 +1,89 @@
+import js from "@eslint/js";
+import ts from "typescript-eslint";
+import reactPlugin from "eslint-plugin-react";
+import { fileURLToPath } from "url";
+import path from "path";
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+
+// We have no .eslintrc, so we must define everything here.
+
+export default ts.config(
+  {
+    ignores: ["dist/**"],
+  },
+  {
+    extends: [js.configs.recommended, ts.configs.recommended],
+    files: ["**/*.ts", "**/*.tsx", "**/*.js", "**/*.jsx"],
+    languageOptions: {
+      ecmaVersion: 2022,
+      sourceType: "module",
+      globals: {
+        // React Native globals
+        __DEV__: "readonly",
+        alert: "readonly",
+        console: "readonly",
+        document: "readonly",
+        navigator: "readonly",
+        window: "readonly",
+        require: "readonly",
+        module: "readonly",
+        exports: "readonly",
+        process: "readonly",
+        jest: "readonly",
+        describe: "readonly",
+        it: "readonly",
+        test: "readonly",
+        expect: "readonly",
+        beforeEach: "readonly",
+        afterEach: "readonly",
+        beforeAll: "readonly",
+        afterAll: "readonly",
+      },
+      parserOptions: {
+        ecmaFeatures: {
+          jsx: true,
+        },
+        tsconfigRootDir: path.resolve(__dirname),
+      },
+    },
+    plugins: {
+      react: reactPlugin,
+    },
+    rules: {
+      ...js.configs.recommended.rules,
+      ...ts.configs.recommended.rules,
+      // TypeScript handles type-related issues
+      "no-undef": "off",
+      "@typescript-eslint/no-explicit-any": "off",
+      // Allow _-prefixed parameters and variables to signal intentionally unused
+      "no-unused-vars": [
+        "warn",
+        {
+          varsIgnorePattern: "^_",
+          argsIgnorePattern: "^_",
+          caughtErrorsIgnorePattern: "^_",
+        },
+      ],
+      "@typescript-eslint/no-unused-vars": [
+        "warn",
+        {
+          varsIgnorePattern: "^_",
+          argsIgnorePattern: "^_",
+          caughtErrorsIgnorePattern: "^_",
+        },
+      ],
+      // React Native uses require() heavily
+      "no-var-requires": "off",
+      // We use React Native's StyleSheet
+      "react/no-unknown-property": [
+        "error",
+        {
+          ignore: ["flex", "justifyContent", "alignItems", "width", "height", "margin", "padding"],
+        },
+      ],
+      // Allow console.log for debugging
+      "no-console": "off",
+    },
+  },
+);

apps/mobile/index.ts

@@ -0,0 +1,9 @@
+import './src/polyfills/sharedArrayBuffer';
+import { registerRootComponent } from 'expo';
+
+import App from './App';
+
+// registerRootComponent calls AppRegistry.registerComponent('main', () => App);
+// It also ensures that whether you load the app in Expo Go or in a native build,
+// the environment is set up appropriately
+registerRootComponent(App);

apps/mobile/jest.config.cjs

@@ -0,0 +1,11 @@
+module.exports = {
+  preset: 'jest-expo',
+  testMatch: ['**/__tests__/**/*.test.[jt]s?(x)'],
+  moduleNameMapper: {
+    '^@react-native-async-storage/async-storage$':
+      '@react-native-async-storage/async-storage/jest/async-storage-mock',
+  },
+  transformIgnorePatterns: [
+    'node_modules/(?!((jest-)?react-native|@react-native(-community)?)|expo(nent)?|@expo(nent)?/.*|@expo-google-fonts/.*|react-navigation|@react-navigation/.*|@unimodules/.*|unimodules|sentry-expo|native-base|@sentry/.*|@fortawesome/.*)',
+  ],
+};

apps/mobile/metro.config.js

@@ -0,0 +1,27 @@
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { getDefaultConfig } from 'expo/metro-config.js';
+
+const projectRoot = path.dirname(fileURLToPath(import.meta.url));
+const workspaceRoot = path.resolve(projectRoot, '../..');
+
+const config = getDefaultConfig(projectRoot);
+
+config.resolver.disableHierarchicalLookup = true;
+config.resolver.nodeModulesPaths = [
+  path.resolve(projectRoot, 'node_modules'),
+  path.resolve(workspaceRoot, 'node_modules'),
+];
+config.resolver.extraNodeModules = {
+  react: path.resolve(projectRoot, 'node_modules/react'),
+  'react-test-renderer': path.resolve(projectRoot, 'node_modules/react-test-renderer'),
+  'react-native-safe-area-context': path.resolve(projectRoot, 'node_modules/react-native-safe-area-context'),
+  'react-native-screens': path.resolve(projectRoot, 'node_modules/react-native-screens'),
+  '@react-native-async-storage/async-storage': path.resolve(
+    projectRoot,
+    'node_modules/@react-native-async-storage/async-storage',
+  ),
+  'expo-application': path.resolve(projectRoot, 'node_modules/expo-notifications/node_modules/expo-application'),
+};
+
+export default config;

apps/mobile/package.json

@@ -0,0 +1,50 @@
+{
+  "name": "@timetoleave/mobile",
+  "version": "1.0.0",
+  "type": "module",
+  "main": "index.ts",
+  "scripts": {
+    "start": "expo start",
+    "android": "expo run:android",
+    "ios": "expo run:ios",
+    "web": "expo start --web",
+    "typecheck": "tsc --noEmit -p tsconfig.typecheck.json",
+    "lint": "eslint src/",
+    "test": "jest"
+  },
+  "dependencies": {
+    "@fortawesome/free-solid-svg-icons": "^7.2.0",
+    "@fortawesome/react-native-fontawesome": "^1.0.0",
+    "@react-native-async-storage/async-storage": "2.2.0",
+    "@react-navigation/native": "^7.2.4",
+    "@react-navigation/native-stack": "^7.14.14",
+    "@timetoleave/api-client": "*",
+    "@timetoleave/core": "*",
+    "expo": "~54.0.34",
+    "expo-calendar": "~15.0.8",
+    "expo-dev-client": "~6.0.21",
+    "expo-location": "~19.0.8",
+    "expo-notifications": "~0.32.17",
+    "expo-status-bar": "~3.0.9",
+    "react": "19.1.0",
+    "react-native": "0.81.5",
+    "react-native-maps": "^1.20.0",
+    "react-native-safe-area-context": "~5.6.0",
+    "react-native-screens": "~4.16.0",
+    "react-native-svg": "^15.15.5"
+  },
+  "devDependencies": {
+    "@eslint/js": "^9.39.4",
+    "@testing-library/react-native": "^13.3.3",
+    "@types/jest": "29.5.14",
+    "@types/react": "~19.1.10",
+    "eslint-plugin-react": "^7.37.5",
+    "jest": "^29.7.0",
+    "jest-expo": "~54.0.0",
+    "react-test-renderer": "19.1.0",
+    "ts-jest": "^29.4.9",
+    "typescript": "~5.9.2",
+    "typescript-eslint": "^8.59.3"
+  },
+  "private": true
+}

apps/mobile/src/__tests__/apiCache.test.ts

@@ -0,0 +1,87 @@
+import {
+  setCachedJourneys,
+  getCachedJourneys,
+  setCachedBikeRoute,
+  getCachedBikeRoute,
+  setCachedWalkRoute,
+  getCachedWalkRoute,
+  clearApiCache,
+} from '../store/apiCache';
+import type { Journey, BikeRoute, WalkRoute } from '@timetoleave/core';
+
+const mockJourneys: Journey[] = [
+  {
+    id: 'journey-1',
+    sD: new Date('2099-01-01T08:00:00Z'),
+    rD: new Date('2099-01-01T08:00:00Z'),
+    sA: new Date('2099-01-01T09:00:00Z'),
+    rA: new Date('2099-01-01T09:00:00Z'),
+    delay: 0,
+    platform: '1',
+    changes: 0,
+    trains: ['S1'],
+    cancelled: false,
+  },
+];
+
+const mockBikeRoute: BikeRoute = {
+  distance: 5000,
+  duration: 1200,
+  steps: [{ name: 'Step 1', distance: 5000, duration: 1200, instruction: 'Ride' }],
+};
+
+const mockWalkRoute: WalkRoute = {
+  distance: 700,
+  duration: 600,
+  steps: [{ name: 'Step 1', distance: 700, duration: 600, instruction: 'Walk' }],
+};
+
+describe('apiCache', () => {
+  beforeEach(async () => {
+    await clearApiCache();
+  });
+
+  it('stores and retrieves journeys', async () => {
+    await setCachedJourneys('event-1', mockJourneys);
+    const retrieved = await getCachedJourneys('event-1');
+    expect(retrieved).toHaveLength(1);
+    expect(retrieved![0].id).toBe('journey-1');
+    expect(retrieved![0].rD).toEqual(new Date('2099-01-01T08:00:00Z'));
+  });
+
+  it('stores and retrieves bike routes', async () => {
+    await setCachedBikeRoute('event-1', mockBikeRoute);
+    const retrieved = await getCachedBikeRoute('event-1');
+    expect(retrieved).toEqual(mockBikeRoute);
+  });
+
+  it('stores and retrieves walk routes', async () => {
+    await setCachedWalkRoute('event-1', mockWalkRoute);
+    const retrieved = await getCachedWalkRoute('event-1');
+    expect(retrieved).toEqual(mockWalkRoute);
+  });
+
+  it('returns null for missing cache entries', async () => {
+    expect(await getCachedJourneys('missing')).toBeNull();
+    expect(await getCachedBikeRoute('missing')).toBeNull();
+    expect(await getCachedWalkRoute('missing')).toBeNull();
+  });
+
+  it('expires entries older than 30 minutes', async () => {
+    // Use jest fake timers to simulate 31 minutes passing
+    jest.useFakeTimers();
+    await setCachedBikeRoute('event-1', mockBikeRoute);
+    jest.advanceTimersByTime(31 * 60 * 1000);
+    const retrieved = await getCachedBikeRoute('event-1');
+    expect(retrieved).toBeNull();
+    jest.useRealTimers();
+  });
+
+  it('clears all cache entries', async () => {
+    await setCachedJourneys('event-1', mockJourneys);
+    await setCachedBikeRoute('event-2', mockBikeRoute);
+    await clearApiCache();
+    expect(await getCachedJourneys('event-1')).toBeNull();
+    expect(await getCachedBikeRoute('event-2')).toBeNull();
+  });
+});

apps/mobile/src/__tests__/calendar.test.ts

@@ -0,0 +1,158 @@
+import * as Calendar from 'expo-calendar';
+import { ensureCalendarPermission, fetchNativeEvents } from '../services/calendar';
+
+// Mock expo-calendar
+jest.mock('expo-calendar', () => ({
+  requestCalendarPermissionsAsync: jest.fn(),
+  isAvailableAsync: jest.fn(),
+  getCalendarsAsync: jest.fn(),
+  getEventsAsync: jest.fn(),
+  EntityTypes: {
+    EVENTS: 'EVENTS',
+  },
+}));
+
+const mockCalendar = Calendar as jest.Mocked<typeof Calendar>;
+
+describe('calendar service', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  describe('ensureCalendarPermission', () => {
+    it('returns true when permission granted and calendar available', async () => {
+      mockCalendar.requestCalendarPermissionsAsync.mockResolvedValue({ status: 'granted' as Calendar.PermissionStatus, granted: true, expires: 'never' as const, canAskAgain: true });
+      mockCalendar.isAvailableAsync.mockResolvedValue(true);
+
+      const result = await ensureCalendarPermission();
+      expect(result).toBe(true);
+    });
+
+    it('returns false when permission denied', async () => {
+      mockCalendar.requestCalendarPermissionsAsync.mockResolvedValue({ status: 'denied' as Calendar.PermissionStatus, granted: false, expires: 'never' as const, canAskAgain: true });
+
+      const result = await ensureCalendarPermission();
+      expect(result).toBe(false);
+      expect(mockCalendar.isAvailableAsync).not.toHaveBeenCalled();
+    });
+
+    it('returns false when calendar not available', async () => {
+      mockCalendar.requestCalendarPermissionsAsync.mockResolvedValue({ status: 'granted' as Calendar.PermissionStatus, granted: true, expires: 'never' as const, canAskAgain: true });
+      mockCalendar.isAvailableAsync.mockResolvedValue(false);
+
+      const result = await ensureCalendarPermission();
+      expect(result).toBe(false);
+    });
+  });
+
+  describe('fetchNativeEvents', () => {
+    it('returns empty array when no permission', async () => {
+      mockCalendar.requestCalendarPermissionsAsync.mockResolvedValue({ status: 'denied' as Calendar.PermissionStatus, granted: false, expires: 'never' as const, canAskAgain: true });
+
+      const result = await fetchNativeEvents(new Date(), new Date());
+      expect(result).toEqual([]);
+    });
+
+    it('returns empty array when no calendars', async () => {
+      mockCalendar.requestCalendarPermissionsAsync.mockResolvedValue({ status: 'granted' as Calendar.PermissionStatus, granted: true, expires: 'never' as const, canAskAgain: true });
+      mockCalendar.isAvailableAsync.mockResolvedValue(true);
+      mockCalendar.getCalendarsAsync.mockResolvedValue([]);
+
+      const result = await fetchNativeEvents(new Date(), new Date());
+      expect(result).toEqual([]);
+    });
+
+    it('returns mapped events from native calendar', async () => {
+      const startDate = new Date('2025-01-01');
+      const endDate = new Date('2025-01-31');
+
+      mockCalendar.requestCalendarPermissionsAsync.mockResolvedValue({ status: 'granted' as Calendar.PermissionStatus, granted: true, expires: 'never' as const, canAskAgain: true });
+      mockCalendar.isAvailableAsync.mockResolvedValue(true);
+      mockCalendar.getCalendarsAsync.mockResolvedValue([
+        { id: 'cal1', title: 'Work' },
+        { id: 'cal2', title: 'Personal' },
+      ] as Calendar.Calendar[]);
+      mockCalendar.getEventsAsync.mockResolvedValue([
+        {
+          id: 'evt1',
+          calendarId: 'cal1',
+          title: 'Team Meeting',
+          location: 'Berlin',
+          startDate: new Date('2025-01-15T10:00:00'),
+        },
+        {
+          id: 'evt2',
+          calendarId: 'cal2',
+          title: 'Dentist',
+          location: null,
+          startDate: new Date('2025-01-20T14:00:00'),
+        },
+      ] as Calendar.Event[]);
+
+      const result = await fetchNativeEvents(startDate, endDate);
+
+      // Only the event with a location is returned; events without a location are filtered out
+      expect(result).toHaveLength(1);
+      expect(result[0]).toEqual({
+        id: 'evt1',
+        title: 'Team Meeting',
+        destination: 'Berlin',
+        eventTime: new Date('2025-01-15T10:00:00'),
+        source: 'native:cal1',
+      });
+
+      expect(mockCalendar.getEventsAsync).toHaveBeenCalledWith(
+        ['cal1', 'cal2'],
+        startDate,
+        endDate,
+      );
+    });
+
+    it('filters out events with no location', async () => {
+      mockCalendar.requestCalendarPermissionsAsync.mockResolvedValue({ status: 'granted' as Calendar.PermissionStatus, granted: true, expires: 'never' as const, canAskAgain: true });
+      mockCalendar.isAvailableAsync.mockResolvedValue(true);
+      mockCalendar.getCalendarsAsync.mockResolvedValue([{ id: 'cal1', title: 'Default' }] as Calendar.Calendar[]);
+      mockCalendar.getEventsAsync.mockResolvedValue([
+        {
+          id: 'evt1',
+          calendarId: 'cal1',
+          title: 'No Location Event',
+          location: null,
+          startDate: new Date('2025-01-15T10:00:00'),
+        },
+        {
+          id: 'evt2',
+          calendarId: 'cal1',
+          title: 'Empty Location Event',
+          location: '   ',
+          startDate: new Date('2025-01-16T10:00:00'),
+        },
+      ] as Calendar.Event[]);
+
+      const result = await fetchNativeEvents(new Date(), new Date());
+
+      expect(result).toHaveLength(0);
+    });
+
+    it('handles events with missing title', async () => {
+      mockCalendar.requestCalendarPermissionsAsync.mockResolvedValue({ status: 'granted' as Calendar.PermissionStatus, granted: true, expires: 'never' as const, canAskAgain: true });
+      mockCalendar.isAvailableAsync.mockResolvedValue(true);
+      mockCalendar.getCalendarsAsync.mockResolvedValue([{ id: 'cal1', title: 'Default' }] as Calendar.Calendar[]);
+      mockCalendar.getEventsAsync.mockResolvedValue([
+        {
+          id: 'evt1',
+          calendarId: 'cal1',
+          title: null as unknown as string,
+          location: 'Wien Hbf',
+          startDate: null as unknown as string | Date,
+        },
+      ] as Calendar.Event[]);
+
+      const result = await fetchNativeEvents(new Date(), new Date());
+
+      expect(result).toHaveLength(1);
+      expect(result[0].title).toBe('Untitled Event');
+      expect(result[0].destination).toBe('Wien Hbf');
+    });
+  });
+});

apps/mobile/src/__tests__/core-utils.test.ts

@@ -0,0 +1,143 @@
+// Tests for core utilities
+import { calculateCountdown, rankJourneys } from '@timetoleave/core';
+import type { Journey } from '@timetoleave/core';
+
+function journey(overrides: Partial<Journey>): Journey {
+  return {
+    id: 'journey',
+    sD: new Date('2025-01-01T10:00:00Z'),
+    rD: new Date('2025-01-01T10:00:00Z'),
+    sA: new Date('2025-01-01T11:00:00Z'),
+    rA: new Date('2025-01-01T11:00:00Z'),
+    delay: 0,
+    platform: '1',
+    changes: 0,
+    trains: ['REX1 -> Wr. Neustadt Hbf'],
+    cancelled: false,
+    ...overrides,
+  };
+}
+
+describe('core utilities', () => {
+  describe('calculateCountdown', () => {
+    beforeEach(() => {
+      // Mock Date for consistent tests
+      jest.useFakeTimers();
+      jest.setSystemTime(new Date('2025-01-01T12:00:00Z'));
+    });
+
+    afterEach(() => {
+      jest.useRealTimers();
+    });
+
+    it('should return urgent status for past events', () => {
+      const targetDate = new Date('2025-01-01T11:00:00Z');
+      const result = calculateCountdown(targetDate);
+
+      expect(result.label).toBe('Now');
+      expect(result.color).toBe('red');
+      expect(result.urgent).toBe(true);
+    });
+
+    it('should return urgent status for events within 10 minutes', () => {
+      const targetDate = new Date('2025-01-01T12:05:00Z');
+      const result = calculateCountdown(targetDate);
+
+      expect(result.label).toBe('5min');
+      expect(result.color).toBe('orange');
+      expect(result.urgent).toBe(true);
+    });
+
+    it('should return yellow for events within 30 minutes', () => {
+      const targetDate = new Date('2025-01-01T12:20:00Z');
+      const result = calculateCountdown(targetDate);
+
+      expect(result.label).toBe('20min');
+      expect(result.color).toBe('yellow');
+      expect(result.urgent).toBe(false);
+    });
+
+    it('should return green for events within 60 minutes', () => {
+      const targetDate = new Date('2025-01-01T12:45:00Z');
+      const result = calculateCountdown(targetDate);
+
+      expect(result.label).toBe('45min');
+      expect(result.color).toBe('green');
+      expect(result.urgent).toBe(false);
+    });
+
+    it('should return hours and minutes for events more than 1 hour away', () => {
+      const targetDate = new Date('2025-01-01T15:30:00Z');
+      const result = calculateCountdown(targetDate);
+
+      expect(result.label).toBe('3h 30min');
+      expect(result.color).toBe('blue');
+      expect(result.urgent).toBe(false);
+    });
+
+    it('should handle exact boundaries correctly', () => {
+      // Exactly 10 minutes
+      let targetDate = new Date('2025-01-01T12:10:00Z');
+      let result = calculateCountdown(targetDate);
+      expect(result.urgent).toBe(true);
+
+      // Exactly 30 minutes
+      targetDate = new Date('2025-01-01T12:30:00Z');
+      result = calculateCountdown(targetDate);
+      expect(result.urgent).toBe(false);
+      expect(result.color).toBe('yellow');
+
+      // Exactly 60 minutes
+      targetDate = new Date('2025-01-01T13:00:00Z');
+      result = calculateCountdown(targetDate);
+      expect(result.label).toBe('60min');
+      expect(result.color).toBe('green');
+    });
+  });
+
+  describe('rankJourneys', () => {
+    it('ranks the connection closest to the target arrival highest', () => {
+      const target = new Date('2025-01-01T11:00:00Z');
+      // All journeys have the same changes and similar duration so only
+      // arrival fit influences the ranking.
+      const early = journey({
+        id: 'early',
+        sD: new Date('2025-01-01T10:00:00Z'),
+        rD: new Date('2025-01-01T10:00:00Z'),
+        sA: new Date('2025-01-01T10:40:00Z'),
+        rA: new Date('2025-01-01T10:40:00Z'),
+        changes: 0,
+      });
+      const close = journey({
+        id: 'close',
+        sD: new Date('2025-01-01T10:00:00Z'),
+        rD: new Date('2025-01-01T10:00:00Z'),
+        sA: new Date('2025-01-01T10:58:00Z'),
+        rA: new Date('2025-01-01T10:58:00Z'),
+        changes: 0,
+      });
+      const late = journey({
+        id: 'late',
+        sD: new Date('2025-01-01T10:00:00Z'),
+        rD: new Date('2025-01-01T10:00:00Z'),
+        sA: new Date('2025-01-01T11:05:00Z'),
+        rA: new Date('2025-01-01T11:05:00Z'),
+        changes: 0,
+      });
+
+      const ranked = rankJourneys([early, late, close], target);
+
+      expect(ranked[0].journey.id).toBe('close');
+    });
+
+    it('uses directness and duration as tie breakers after arrival fit', () => {
+      const target = new Date('2025-01-01T11:00:00Z');
+      const oneChange = journey({ id: 'change', changes: 1 });
+      const direct = journey({ id: 'direct', changes: 0 });
+
+      const ranked = rankJourneys([oneChange, direct], target);
+
+      expect(ranked[0].journey.id).toBe('direct');
+    });
+  });
+});

apps/mobile/src/__tests__/eventStore.test.ts

@@ -0,0 +1,242 @@
+// Tests for event store persistence and behavior
+import AsyncStorage from '@react-native-async-storage/async-storage';
+import {
+  loadEvents,
+  saveEvents,
+  addEvent,
+  removeEvent,
+  loadOriginStation,
+  saveOriginStation,
+  loadNotificationSettings,
+  saveNotificationSettings,
+  rescheduleAllNotifications
+} from '../store/eventStore';
+import { calculateLeaveByTime } from '../services/notifications';
+import * as Notifications from '../services/expoNotifications';
+
+// Mock AsyncStorage
+jest.mock('@react-native-async-storage/async-storage', () => ({
+  getItem: jest.fn(),
+  setItem: jest.fn(),
+  removeItem: jest.fn(),
+}));
+
+// Mock notification adapter
+jest.mock('../services/expoNotifications', () => ({
+  getAllScheduledNotificationsAsync: jest.fn(),
+  cancelScheduledNotificationAsync: jest.fn(),
+  cancelAllScheduledNotificationsAsync: jest.fn(),
+  scheduleNotificationAsync: jest.fn(),
+  SchedulableTriggerInputTypes: {
+    DATE: 'date',
+  },
+  setNotificationHandler: jest.fn(),
+}));
+
+// Mock calculateLeaveByTime
+jest.mock('../services/notifications', () => ({
+  ...jest.requireActual('../services/notifications'),
+  calculateLeaveByTime: jest.fn(),
+}));
+
+describe('eventStore', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  describe('events', () => {
+    it('should load empty events when none exist', async () => {
+      (AsyncStorage.getItem as jest.Mock).mockResolvedValue(null);
+
+      const events = await loadEvents();
+      expect(events).toEqual([]);
+    });
+
+    it('should load events from AsyncStorage', async () => {
+      const mockEvents = [
+        {
+          id: 'test-1',
+          title: 'Test Event',
+          destination: 'Test Destination',
+          eventTime: new Date('2025-01-01T10:00:00Z'),
+          source: 'manual',
+        }
+      ];
+
+      (AsyncStorage.getItem as jest.Mock).mockResolvedValue(JSON.stringify(mockEvents));
+
+      const events = await loadEvents();
+      expect(events).toEqual(mockEvents);
+      expect(events[0].eventTime).toBeInstanceOf(Date);
+    });
+
+    it('should save events to AsyncStorage', async () => {
+      const events = [
+        {
+          id: 'test-1',
+          title: 'Test Event',
+          destination: 'Test Destination',
+          eventTime: new Date('2025-01-01T10:00:00Z'),
+          source: 'manual',
+        }
+      ];
+
+      await saveEvents(events);
+
+      expect(AsyncStorage.setItem).toHaveBeenCalledWith(
+        '@timetoleave_events',
+        JSON.stringify(events)
+      );
+    });
+
+    it('should add event and schedule notification', async () => {
+      const event = {
+        id: 'test-1',
+        title: 'Test Event',
+        destination: 'Test Destination',
+        eventTime: new Date('2025-01-01T10:00:00Z'),
+        source: 'manual',
+      };
+
+      (AsyncStorage.getItem as jest.Mock).mockResolvedValue('[]');
+      (calculateLeaveByTime as jest.Mock).mockResolvedValue(new Date('2025-01-01T09:30:00Z'));
+
+      await addEvent(event);
+
+      expect(AsyncStorage.setItem).toHaveBeenCalledWith(
+        '@timetoleave_events',
+        JSON.stringify([event])
+      );
+    });
+
+    it('should remove event and cancel notifications', async () => {
+      const event = {
+        id: 'test-1',
+        title: 'Test Event',
+        destination: 'Test Destination',
+        eventTime: new Date('2025-01-01T10:00:00Z'),
+        source: 'manual',
+      };
+
+      (AsyncStorage.getItem as jest.Mock).mockResolvedValue(JSON.stringify([event]));
+      (Notifications.getAllScheduledNotificationsAsync as jest.Mock).mockResolvedValue([
+        {
+          identifier: 'notif-1',
+          content: { data: { eventId: 'test-1' } }
+        }
+      ]);
+
+      await removeEvent('test-1');
+
+      expect(AsyncStorage.setItem).toHaveBeenCalledWith(
+        '@timetoleave_events',
+        '[]'
+      );
+      expect(Notifications.cancelScheduledNotificationAsync).toHaveBeenCalled();
+    });
+  });
+
+  describe('origin station', () => {
+    it('should load the default origin when no saved origin exists', async () => {
+      (AsyncStorage.getItem as jest.Mock).mockResolvedValue(null);
+
+      const station = await loadOriginStation();
+      expect(station).toEqual({
+        name: 'Goethegasse 36, 2340 Moedling',
+        extId: '1231701',
+        lat: 48.0806926,
+        lng: 16.2908052,
+      });
+    });
+
+    it('should load origin station from AsyncStorage', async () => {
+      const mockStation = {
+        extId: 'station-1',
+        name: 'Test Station',
+        lat: 48.2,
+        lng: 16.3,
+      };
+
+      (AsyncStorage.getItem as jest.Mock).mockResolvedValue(JSON.stringify(mockStation));
+
+      const station = await loadOriginStation();
+      expect(station).toEqual(mockStation);
+    });
+
+    it('should save origin station to AsyncStorage', async () => {
+      const station = {
+        extId: 'station-1',
+        name: 'Test Station',
+        lat: 48.2,
+        lng: 16.3,
+      };
+
+      await saveOriginStation(station);
+
+      expect(AsyncStorage.setItem).toHaveBeenCalledWith(
+        '@timetoleave_origin',
+        JSON.stringify(station)
+      );
+    });
+  });
+
+  describe('notification settings', () => {
+    it('should load default settings when none exist', async () => {
+      (AsyncStorage.getItem as jest.Mock).mockResolvedValue(null);
+
+      const settings = await loadNotificationSettings();
+      expect(settings).toEqual({
+        bufferMinutes: 30,
+        enabled: true,
+        arrivalBufferMinutes: 5,
+        showWalkingOption: true,
+        showBikeOption: true,
+      });
+    });
+
+    it('should load notification settings from AsyncStorage', async () => {
+      const mockSettings = {
+        bufferMinutes: 45,
+        enabled: false,
+      };
+
+      (AsyncStorage.getItem as jest.Mock).mockResolvedValue(JSON.stringify(mockSettings));
+
+      const settings = await loadNotificationSettings();
+      expect(settings).toEqual(mockSettings);
+    });
+
+    it('should save notification settings to AsyncStorage', async () => {
+      const settings = {
+        bufferMinutes: 45,
+        enabled: false,
+        arrivalBufferMinutes: 5,
+        showWalkingOption: true,
+        showBikeOption: true,
+      };
+
+      await saveNotificationSettings(settings);
+
+      expect(AsyncStorage.setItem).toHaveBeenCalledWith(
+        '@timetoleave_notifications',
+        JSON.stringify(settings)
+      );
+    });
+  });
+
+  describe('rescheduleAllNotifications', () => {
+    it('should cancel all existing notifications and schedule new ones', async () => {
+      (AsyncStorage.getItem as jest.Mock)
+        .mockResolvedValueOnce(JSON.stringify([])) // events
+        .mockResolvedValueOnce(JSON.stringify({ bufferMinutes: 30, enabled: true })); // settings
+
+      (Notifications.getAllScheduledNotificationsAsync as jest.Mock).mockResolvedValue([]);
+      (calculateLeaveByTime as jest.Mock).mockResolvedValue(new Date('2025-01-01T09:30:00Z'));
+
+      await rescheduleAllNotifications();
+
+      expect(Notifications.cancelAllScheduledNotificationsAsync).toHaveBeenCalled();
+      // We can't easily verify scheduling due to complex mocks, but we can check it was called
+    });
+  });
+});

apps/mobile/src/__tests__/notifications.test.ts

@@ -0,0 +1,181 @@
+// Tests for notification service
+// Mock notification adapter before importing
+jest.mock('../services/expoNotifications', () => ({
+  setNotificationHandler: jest.fn(),
+  requestPermissionsAsync: jest.fn().mockResolvedValue({ status: 'granted' }),
+  scheduleNotificationAsync: jest.fn().mockResolvedValue({ identifier: 'mock-id' }),
+  cancelScheduledNotificationAsync: jest.fn().mockResolvedValue(undefined),
+  getAllScheduledNotificationsAsync: jest.fn().mockResolvedValue([]),
+  cancelAllScheduledNotificationsAsync: jest.fn().mockResolvedValue(undefined),
+  SchedulableTriggerInputTypes: {
+    DATE: 'date',
+    CALENDAR: 'calendar',
+    DAILY: 'daily',
+    WEEKLY: 'weekly',
+    MONTHLY: 'monthly',
+    YEARLY: 'yearly',
+    TIME_INTERVAL: 'timeInterval',
+  },
+}));
+
+import { calculateLeaveByTime } from '../services/notifications';
+import type { Event, Journey } from '@timetoleave/core';
+
+describe('notifications service', () => {
+  describe('calculateLeaveByTime', () => {
+    it('should calculate leave-by time from event time minus arrival buffer minus reminder buffer', () => {
+      const event: Event = {
+        id: 'test-1',
+        title: 'Test Event',
+        destination: 'Test Destination',
+        eventTime: new Date('2025-01-01T10:00:00Z'),
+        source: 'manual',
+      };
+
+      const leaveByTime = calculateLeaveByTime(event, [], 30, 5);
+
+      // Leave-by time should be 30 minutes before event time
+      // (arrival buffer) minus 5 minutes reminder buffer
+      // = event time - 35 minutes total
+      const expectedTime = new Date('2025-01-01T09:25:00Z');
+      expect(leaveByTime.getTime()).toBe(expectedTime.getTime());
+    });
+
+    it('should use earliest journey departure time if available', () => {
+      const event: Event = {
+        id: 'test-1',
+        title: 'Test Event',
+        destination: 'Test Destination',
+        eventTime: new Date('2025-01-01T10:00:00Z'),
+        source: 'manual',
+      };
+
+      const journeys: Journey[] = [
+        {
+          id: 'journey-1',
+          sD: new Date('2025-01-01T08:00:00Z'),
+          rD: new Date('2025-01-01T08:00:00Z'),
+          sA: new Date('2025-01-01T09:00:00Z'),
+          rA: new Date('2025-01-01T09:00:00Z'),
+          delay: 0,
+          platform: '1',
+          changes: 0,
+          trains: ['S1'],
+          cancelled: false,
+        },
+        {
+          id: 'journey-2',
+          sD: new Date('2025-01-01T07:00:00Z'),
+          rD: new Date('2025-01-01T07:00:00Z'),
+          sA: new Date('2025-01-01T08:00:00Z'),
+          rA: new Date('2025-01-01T08:00:00Z'),
+          delay: 0,
+          platform: '2',
+          changes: 1,
+          trains: ['U3', 'S2'],
+          cancelled: false,
+        },
+      ];
+
+      const leaveByTime = calculateLeaveByTime(event, journeys, 30, 5);
+
+      // Should use earliest non-cancelled journey (journey-2 at 07:00)
+      // Leave-by time = journey departure (07:00) - reminder buffer (5 min)
+      const expectedTime = new Date('2025-01-01T06:55:00Z');
+      expect(leaveByTime.getTime()).toBe(expectedTime.getTime());
+    });
+
+    it('should skip cancelled journeys', () => {
+      const event: Event = {
+        id: 'test-1',
+        title: 'Test Event',
+        destination: 'Test Destination',
+        eventTime: new Date('2025-01-01T10:00:00Z'),
+        source: 'manual',
+      };
+
+      const journeys: Journey[] = [
+        {
+          id: 'journey-1',
+          sD: new Date('2025-01-01T08:00:00Z'),
+          rD: new Date('2025-01-01T08:00:00Z'),
+          sA: new Date('2025-01-01T09:00:00Z'),
+          rA: new Date('2025-01-01T09:00:00Z'),
+          delay: 0,
+          platform: '1',
+          changes: 0,
+          trains: ['S1'],
+          cancelled: true,
+        },
+        {
+          id: 'journey-2',
+          sD: new Date('2025-01-01T07:00:00Z'),
+          rD: new Date('2025-01-01T07:00:00Z'),
+          sA: new Date('2025-01-01T08:00:00Z'),
+          rA: new Date('2025-01-01T08:00:00Z'),
+          delay: 0,
+          platform: '2',
+          changes: 1,
+          trains: ['U3', 'S2'],
+          cancelled: false,
+        },
+      ];
+
+      const leaveByTime = calculateLeaveByTime(event, journeys, 30, 5);
+
+      // Should use journey-2 since journey-1 is cancelled
+      // Leave-by time = journey departure (07:00) - reminder buffer (5 min)
+      const expectedTime = new Date('2025-01-01T06:55:00Z');
+      expect(leaveByTime.getTime()).toBe(expectedTime.getTime());
+    });
+
+    it('should fall back to event time minus buffer when all journeys cancelled', () => {
+      const event: Event = {
+        id: 'test-1',
+        title: 'Test Event',
+        destination: 'Test Destination',
+        eventTime: new Date('2025-01-01T10:00:00Z'),
+        source: 'manual',
+      };
+
+      const journeys: Journey[] = [
+        {
+          id: 'journey-1',
+          sD: new Date('2025-01-01T08:00:00Z'),
+          rD: new Date('2025-01-01T08:00:00Z'),
+          sA: new Date('2025-01-01T09:00:00Z'),
+          rA: new Date('2025-01-01T09:00:00Z'),
+          delay: 0,
+          platform: '1',
+          changes: 0,
+          trains: ['S1'],
+          cancelled: true,
+        },
+      ];
+
+      const leaveByTime = calculateLeaveByTime(event, journeys, 30, 5);
+
+      // All journeys cancelled, fall back to event time minus arrival buffer minus reminder buffer
+      // = 10:00 - 30 min - 5 min = 09:25
+      const expectedTime = new Date('2025-01-01T09:25:00Z');
+      expect(leaveByTime.getTime()).toBe(expectedTime.getTime());
+    });
+
+    it('should handle zero buffer correctly', () => {
+      const event: Event = {
+        id: 'test-1',
+        title: 'Test Event',
+        destination: 'Test Destination',
+        eventTime: new Date('2025-01-01T10:00:00Z'),
+        source: 'manual',
+      };
+
+      const leaveByTime = calculateLeaveByTime(event, [], 30, 0);
+
+      // With zero reminder buffer, leave-by time = event time - arrival buffer
+      // = 10:00 AM - 30 minutes = 09:30 AM
+      const expectedTime = new Date('2025-01-01T09:30:00Z');
+      expect(leaveByTime.getTime()).toBe(expectedTime.getTime());
+    });
+  });
+});

apps/mobile/src/__tests__/screens.test.tsx

@@ -0,0 +1,293 @@
+// Tests for UI screens
+import { fireEvent, render, waitFor } from '@testing-library/react-native';
+import type { NativeStackNavigationProp } from '@react-navigation/native-stack';
+import type { RouteProp } from '@react-navigation/native';
+import { EventListScreen } from '../screens/EventListScreen';
+import { AddEventScreen } from '../screens/AddEventScreen';
+import { loadEvents, loadNotificationSettings, loadOriginStation } from '../store/eventStore';
+import { calculateCountdown } from '@timetoleave/core';
+
+// Mock the store and utilities
+jest.mock('../store/eventStore', () => ({
+  loadEvents: jest.fn(),
+  loadOriginStation: jest.fn(),
+  loadNotificationSettings: jest.fn(),
+  removeEvent: jest.fn(),
+}));
+
+jest.mock('@timetoleave/core', () => ({
+  ...jest.requireActual('@timetoleave/core'),
+  calculateCountdown: jest.fn(),
+}));
+
+jest.mock('../hooks/useColors', () => ({
+  useColors: () => ({
+    background: '#000',
+    card: '#111',
+    text: '#fff',
+    subtext: '#aaa',
+    accent: '#8B5CF6',
+    border: '#333',
+    delete: '#ff3b30',
+    error: '#ff3b30',
+    overlay: '#111',
+  }),
+}));
+
+jest.mock('../hooks/useDestinationStation', () => ({
+  useDestinationStation: () => ({
+    station: { name: 'Ziel Bahnhof', extId: '8103000', lat: 48.2, lng: 16.3 },
+    loading: false,
+    error: null,
+  }),
+}));
+
+jest.mock('../hooks/useGeocode', () => ({
+  useGeocode: () => ({
+    coords: { lat: 48.21, lng: 16.31, display_name: 'Test Destination' },
+    loading: false,
+    error: null,
+  }),
+}));
+
+jest.mock('../hooks/useWalkRoute', () => ({
+  useWalkRoute: () => ({
+    walkRoute: null,
+    loading: false,
+    error: null,
+  }),
+}));
+
+jest.mock('../hooks/useOriginStationWalk', () => ({
+  useOriginStationWalk: () => ({
+    station: { name: 'Mödling Bahnhof', extId: '1231701', lat: 48.085, lng: 16.296 },
+    walkRoute: { distance: 700, duration: 600, steps: [] },
+    loading: false,
+    error: null,
+  }),
+}));
+
+jest.mock('../services/api', () => ({
+  api: {
+    findStationByExtId: jest.fn().mockResolvedValue({
+      name: 'Mödling Bahnhof',
+      extId: '1231701',
+      lat: 48.085,
+      lng: 16.296,
+    }),
+    searchJourneys: jest.fn().mockResolvedValue([
+      {
+        id: 'journey-1',
+        sD: new Date('2099-01-01T08:00:00Z'),
+        rD: new Date('2099-01-01T08:00:00Z'),
+        sA: new Date('2099-01-01T09:00:00Z'),
+        rA: new Date('2099-01-01T09:00:00Z'),
+        delay: 0,
+        platform: '1',
+        changes: 0,
+        trains: ['S1 -> Wien'],
+        cancelled: false,
+      },
+    ]),
+  },
+}));
+
+// Mock useFocusEffect so EventListScreen can render without NavigationContainer
+jest.mock('@react-navigation/native', () => ({
+  ...jest.requireActual('@react-navigation/native'),
+  useFocusEffect: (callback: () => void) => {
+    const React = jest.requireActual('react');
+    React.useEffect(() => {
+      callback();
+    }, [callback]);
+  },
+}));
+
+// --- Mock navigation factories ---
+
+type RootStack = {
+  EventList: undefined;
+  EventDetail: { eventId: string };
+  AddEvent: undefined;
+  Settings: undefined;
+  CalendarImport: undefined;
+};
+
+function createMockNavigationProp<
+  S extends Record<string, undefined | Record<string, unknown>>,
+  T extends keyof S
+>(overrides?: Partial<NativeStackNavigationProp<S, T>>): NativeStackNavigationProp<S, T> {
+  const mocks: Partial<NativeStackNavigationProp<S, T>> = {
+    navigate: jest.fn(),
+    dispatch: jest.fn(() => {}),
+    goBack: jest.fn(),
+    isFocused: jest.fn(() => true),
+    setParams: jest.fn(),
+    setOptions: jest.fn(),
+    reset: jest.fn(),
+    pop: jest.fn(),
+    preload: jest.fn(),
+    push: jest.fn(),
+    replace: jest.fn(),
+    canGoBack: jest.fn(() => false),
+    ...overrides,
+  };
+  return mocks as NativeStackNavigationProp<S, T>;
+}
+
+const mockRouteEventList = { name: 'EventList' as const, params: undefined } as unknown as RouteProp<RootStack, 'EventList'>;
+const mockRouteAddEvent = { name: 'AddEvent' as const, params: undefined } as unknown as RouteProp<RootStack, 'AddEvent'>;
+
+// --- End mock factories ---
+
+describe('EventListScreen', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+    (loadOriginStation as jest.Mock).mockResolvedValue({
+      name: 'Mödling Bahnhof',
+      extId: '1231701',
+      lat: 48.08,
+      lng: 16.29,
+    });
+    (loadNotificationSettings as jest.Mock).mockResolvedValue({
+      bufferMinutes: 30,
+      enabled: true,
+      arrivalBufferMinutes: 5,
+      showWalkingOption: true,
+      showBikeOption: true,
+    });
+  });
+
+  it('should render empty state when no events', async () => {
+    (loadEvents as jest.Mock).mockResolvedValue([]);
+
+    const { getByText } = render(
+      <EventListScreen navigation={createMockNavigationProp<RootStack, 'EventList'>()} route={mockRouteEventList} />
+    );
+
+    await waitFor(() => {
+      expect(getByText('No upcoming events')).toBeTruthy();
+    });
+  });
+
+  it('should render events when they exist', async () => {
+    const mockEvents = [
+      {
+        id: 'test-1',
+        title: 'Test Event',
+        destination: 'Test Destination',
+        eventTime: new Date('2099-01-01T10:00:00Z'),
+        source: 'manual',
+      }
+    ];
+
+    (loadEvents as jest.Mock).mockResolvedValue(mockEvents);
+    (calculateCountdown as jest.Mock).mockReturnValue({
+      label: '30min',
+      color: 'green',
+      urgent: false
+    });
+
+    const { getByText } = render(
+      <EventListScreen navigation={createMockNavigationProp<RootStack, 'EventList'>()} route={mockRouteEventList} />
+    );
+
+    await waitFor(() => {
+      expect(getByText('Test Event')).toBeTruthy();
+      expect(getByText('Test Destination')).toBeTruthy();
+    });
+  });
+
+  it('should handle refresh correctly', async () => {
+    const mockEvents = [
+      {
+        id: 'test-1',
+        title: 'Test Event',
+        destination: 'Test Destination',
+        eventTime: new Date('2099-01-01T10:00:00Z'),
+        source: 'manual',
+      }
+    ];
+
+    (loadEvents as jest.Mock).mockResolvedValue(mockEvents);
+    (calculateCountdown as jest.Mock).mockReturnValue({
+      label: '30min',
+      color: 'green',
+      urgent: false
+    });
+
+    const { getByText } = render(
+      <EventListScreen navigation={createMockNavigationProp<RootStack, 'EventList'>()} route={mockRouteEventList} />
+    );
+
+    await waitFor(() => {
+      expect(getByText('Test Event')).toBeTruthy();
+    });
+  });
+});
+
+describe('AddEventScreen', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it('should render form correctly', () => {
+    const { getByPlaceholderText, getByText } = render(
+      <AddEventScreen navigation={createMockNavigationProp<RootStack, 'AddEvent'>()} route={mockRouteAddEvent} />
+    );
+
+    expect(getByPlaceholderText('e.g. Team Meeting')).toBeTruthy();
+    expect(getByPlaceholderText('e.g. Technikum Wien')).toBeTruthy();
+    expect(getByPlaceholderText('YYYY-MM-DD')).toBeTruthy();
+    expect(getByPlaceholderText('HH:MM')).toBeTruthy();
+    expect(getByText('Save')).toBeTruthy();
+    expect(getByText('Cancel')).toBeTruthy();
+  });
+
+  it('should show validation errors', () => {
+    const { getByText } = render(
+      <AddEventScreen navigation={createMockNavigationProp<RootStack, 'AddEvent'>()} route={mockRouteAddEvent} />
+    );
+
+    // Try to save without filling form
+    const saveButton = getByText('Save');
+    fireEvent.press(saveButton);
+
+    // Should show error text
+    expect(getByText('Title required')).toBeTruthy();
+  });
+
+  it('should validate date format', () => {
+    const { getByPlaceholderText, getByText } = render(
+      <AddEventScreen navigation={createMockNavigationProp<RootStack, 'AddEvent'>()} route={mockRouteAddEvent} />
+    );
+
+    // Fill in all required fields except date format is invalid
+    fireEvent.changeText(getByPlaceholderText('e.g. Team Meeting'), 'Meeting');
+    fireEvent.changeText(getByPlaceholderText('e.g. Technikum Wien'), 'Wien');
+    fireEvent.changeText(getByPlaceholderText('YYYY-MM-DD'), 'invalid-date');
+    fireEvent.changeText(getByPlaceholderText('HH:MM'), '12:00');
+
+    const saveButton = getByText('Save');
+    fireEvent.press(saveButton);
+
+    expect(getByText('Invalid date')).toBeTruthy();
+  });
+
+  it('should validate future date', () => {
+    const { getByPlaceholderText, getByText } = render(
+      <AddEventScreen navigation={createMockNavigationProp<RootStack, 'AddEvent'>()} route={mockRouteAddEvent} />
+    );
+
+    // Fill in all required fields with a past date
+    fireEvent.changeText(getByPlaceholderText('e.g. Team Meeting'), 'Meeting');
+    fireEvent.changeText(getByPlaceholderText('e.g. Technikum Wien'), 'Wien');
+    fireEvent.changeText(getByPlaceholderText('YYYY-MM-DD'), '2020-01-01');
+    fireEvent.changeText(getByPlaceholderText('HH:MM'), '12:00');
+
+    const saveButton = getByText('Save');
+    fireEvent.press(saveButton);
+
+    expect(getByText('Date must be in the future')).toBeTruthy();
+  });
+});

apps/mobile/src/assets.d.ts

@@ -0,0 +1,4 @@
+declare module '*.png' {
+  const value: number;
+  export default value;
+}

apps/mobile/src/components/BikeSection.tsx

@@ -0,0 +1,72 @@
+import { ActivityIndicator, StyleSheet, Text, View } from 'react-native';
+import { FontAwesomeIcon } from '@fortawesome/react-native-fontawesome';
+import { faClock, faRuler } from '@fortawesome/free-solid-svg-icons';
+import { formatDuration, formatDistance } from '@timetoleave/core';
+import type { BikeRoute, Station } from '@timetoleave/core';
+import type { AppColors } from '../hooks/useColors';
+import { RouteMap } from './RouteMap';
+
+/** Props for the bike route information section shown on event detail. */
+interface Props {
+  bikeRoute: BikeRoute | null;
+  loading: boolean;
+  origin: Station | null;
+  colors: AppColors;
+}
+
+/**
+ * Displays cycling route duration, distance, and an interactive map for the
+ * event's origin → destination leg. Shows contextual empty states when no
+ * origin is set or no route is available.
+ */
+export function BikeSection({ bikeRoute, loading, origin, colors }: Props) {
+  return (
+    <View style={[styles.container, { backgroundColor: colors.background }]}>
+      <Text style={[styles.sectionTitle, { color: colors.text }]}>Bike route</Text>
+
+      {loading ? (
+        <View style={styles.centered}>
+          <ActivityIndicator size="small" color={colors.accent} />
+          <Text style={[styles.hint, { color: colors.subtext }]}>Loading bike route…</Text>
+        </View>
+      ) : bikeRoute ? (
+        <View style={[styles.card, { backgroundColor: colors.card, borderColor: colors.border }]}>
+          <View style={styles.row}>
+            <View style={styles.labelRow}>
+              <FontAwesomeIcon icon={faClock} size={13} color={colors.text} />
+              <Text style={[styles.label, { color: colors.text }]}>Dauer</Text>
+            </View>
+            <Text style={[styles.value, { color: colors.accent }]}>{formatDuration(bikeRoute.duration)}</Text>
+          </View>
+          <View style={styles.row}>
+            <View style={styles.labelRow}>
+              <FontAwesomeIcon icon={faRuler} size={13} color={colors.text} />
+              <Text style={[styles.label, { color: colors.text }]}>Distanz</Text>
+            </View>
+            <Text style={[styles.value, { color: colors.accent }]}>{formatDistance(bikeRoute.distance)}</Text>
+          </View>
+          {bikeRoute.geometry && (
+            <RouteMap geometry={bikeRoute.geometry} colors={colors} mode="bike" />
+          )}
+        </View>
+      ) : (
+        <Text style={[styles.empty, { color: colors.subtext }]}>
+          {origin ? 'No bike route available' : 'Set origin station'}
+        </Text>
+      )}
+    </View>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: { padding: 20 },
+  sectionTitle: { fontSize: 18, fontWeight: '600', marginBottom: 12 },
+  centered: { alignItems: 'center', gap: 8 },
+  hint: { fontSize: 15, marginTop: 12 },
+  empty: { fontSize: 14 },
+  card: { borderRadius: 10, padding: 14, borderWidth: 1 },
+  row: { flexDirection: 'row', justifyContent: 'space-between', alignItems: 'center', paddingVertical: 6 },
+  labelRow: { flexDirection: 'row', alignItems: 'center', gap: 6 },
+  label: { fontSize: 15, fontWeight: '500' },
+  value: { fontSize: 15, fontWeight: '600' },
+});

apps/mobile/src/components/EventHeader.tsx

@@ -0,0 +1,76 @@
+import { StyleSheet, Text, View } from 'react-native';
+import type { Event } from '@timetoleave/core';
+import type { AppColors } from '../hooks/useColors';
+
+/** Props for the event detail header showing title, destination, times, and buffers. */
+interface Props {
+  event: Event;
+  leaveByTime: Date | null;
+  arrivalBufferMinutes: number;
+  colors: AppColors;
+}
+
+/**
+ * Renders the event title, destination, leave-by time, data source, and a
+ * three-column grid with leave-by time, arrive-by time, and buffer.
+ */
+export function EventHeader({ event, leaveByTime, arrivalBufferMinutes, colors }: Props) {
+  const arriveByTime = new Date(event.eventTime.getTime() - arrivalBufferMinutes * 60_000);
+
+  return (
+    <View style={[styles.container, { backgroundColor: colors.card }]}>
+      <Text style={[styles.title, { color: colors.text }]}>{event.title}</Text>
+      <Text style={[styles.destination, { color: colors.subtext }]}>{event.destination}</Text>
+      <Text style={[styles.leaveTime, { color: leaveByTime ? colors.accent : colors.subtext }]}>
+        {leaveByTime
+          ? `Losgehen um ${leaveByTime.toLocaleTimeString('de-AT', { hour: '2-digit', minute: '2-digit' })}`
+          : 'Losgehzeit wird berechnet'}
+      </Text>
+      <Text style={[styles.source, { color: colors.subtext }]}>Quelle: {event.source}</Text>
+
+      <View style={[styles.infoGrid, { borderTopColor: colors.border }]}>
+        <View style={styles.infoBox}>
+          <Text style={[styles.infoLabel, { color: colors.subtext }]}>Losgehen um</Text>
+          <Text style={[styles.infoValue, { color: colors.text }]}>
+            {leaveByTime
+              ? leaveByTime.toLocaleTimeString('de-AT', { hour: '2-digit', minute: '2-digit' })
+              : '—'}
+          </Text>
+        </View>
+        <View style={styles.infoBox}>
+          <Text style={[styles.infoLabel, { color: colors.subtext }]}>Ankommen um</Text>
+          <Text style={[styles.infoValue, { color: colors.text }]}>
+            {arriveByTime.toLocaleTimeString('de-AT', { hour: '2-digit', minute: '2-digit' })}
+          </Text>
+        </View>
+        <View style={styles.infoBox}>
+          <Text style={[styles.infoLabel, { color: colors.subtext }]}>Puffer</Text>
+          <Text style={[styles.infoValue, { color: colors.text }]}>{arrivalBufferMinutes} min</Text>
+        </View>
+      </View>
+    </View>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: { padding: 20, marginBottom: 12 },
+  title: { fontSize: 22, fontWeight: '700' },
+  destination: { fontSize: 16, marginTop: 4 },
+  leaveTime: { fontSize: 18, fontWeight: '700', marginTop: 10 },
+  source: { fontSize: 12, marginTop: 4 },
+  infoGrid: {
+    flexDirection: 'row',
+    justifyContent: 'space-between',
+    marginTop: 16,
+    paddingTop: 16,
+    borderTopWidth: 1,
+  },
+  infoBox: { alignItems: 'center' },
+  infoLabel: {
+    fontSize: 11,
+    fontWeight: '600',
+    textTransform: 'uppercase',
+    letterSpacing: 1,
+  },
+  infoValue: { fontSize: 16, fontWeight: '700', marginTop: 4 },
+});

apps/mobile/src/components/JourneyList.tsx

@@ -0,0 +1,170 @@
+import { useMemo, useState } from 'react';
+import { ActivityIndicator, StyleSheet, Text, TouchableOpacity, View } from 'react-native';
+import { formatDuration, formatDistance, rankJourneys } from '@timetoleave/core';
+import type { Journey, Station, WalkRoute } from '@timetoleave/core';
+import type { AppColors } from '../hooks/useColors';
+import { RouteMap } from './RouteMap';
+
+/** Props for the train journey list and optional final walk leg. */
+interface Props {
+  journeys: Journey[];
+  destStationLoading: boolean;
+  walkRoute: WalkRoute | null;
+  loadingWalk: boolean;
+  showWalkingOption: boolean;
+  eventTime: Date;
+  arrivalBufferMinutes: number;
+  origin: Station | null;
+  colors: AppColors;
+}
+
+/**
+ * Renders each journey card with train lines, departure/arrival times, platform,
+ * transfer count, and delay/cancellation badges. Cards that arrive too late are
+ * visually dimmed and bordered in red. Optionally shows the final walking leg
+ * from the destination station to the event location.
+ */
+export function JourneyList({
+  journeys,
+  destStationLoading,
+  walkRoute,
+  loadingWalk,
+  showWalkingOption,
+  eventTime,
+  arrivalBufferMinutes,
+  origin,
+  colors,
+}: Props) {
+  const [expanded, setExpanded] = useState(false);
+  const walkDurationMs = showWalkingOption ? (walkRoute?.duration ?? 0) * 1000 : 0;
+  const targetArrivalTime = new Date(eventTime.getTime() - arrivalBufferMinutes * 60_000);
+  const rankedJourneys = useMemo(
+    () => rankJourneys(journeys, targetArrivalTime, walkDurationMs),
+    [journeys, targetArrivalTime, walkDurationMs],
+  );
+  const visibleJourneys = expanded ? rankedJourneys : rankedJourneys.slice(0, 1);
+
+  return (
+    <View style={[styles.container, { backgroundColor: colors.background }]}>
+      <Text style={[styles.sectionTitle, { color: colors.text }]}>Train connections</Text>
+
+      {destStationLoading && (
+        <View style={styles.centered}>
+          <ActivityIndicator size="small" color={colors.accent} />
+          <Text style={[styles.hint, { color: colors.subtext }]}>Resolving destination station…</Text>
+        </View>
+      )}
+
+      {journeys.length === 0 && !destStationLoading ? (
+        <Text style={[styles.empty, { color: colors.subtext }]}>
+          {origin ? 'No connections found' : 'Set origin station'}
+        </Text>
+      ) : (
+        <TouchableOpacity
+          activeOpacity={rankedJourneys.length > 1 ? 0.75 : 1}
+          onPress={() => rankedJourneys.length > 1 && setExpanded((current) => !current)}
+          accessibilityRole={rankedJourneys.length > 1 ? 'button' : undefined}
+          accessibilityLabel={expanded ? 'Show fewer train connections' : 'Show all train connections'}
+        >
+          {visibleJourneys.map(({ journey: j }, index) => {
+          const finalArrival = new Date(j.rA.getTime() + walkDurationMs);
+          const arrivesTooLate = finalArrival.getTime() > targetArrivalTime.getTime();
+          const durationMinutes = Math.max(0, Math.round((j.rA.getTime() - j.rD.getTime()) / 60_000));
+
+          return (
+          <View
+            key={j.id}
+            style={[
+              styles.card,
+              { backgroundColor: colors.card, borderColor: arrivesTooLate ? colors.error : colors.border },
+              arrivesTooLate && styles.lateCard,
+            ]}
+          >
+            <View style={styles.row}>
+              <Text style={[styles.line, { color: colors.text }]} numberOfLines={2}>
+                {j.trains.length > 0 ? j.trains.join(', ') : '—'}
+              </Text>
+              {index === 0 && (
+                <Text style={[styles.bestBadge, { backgroundColor: colors.accent }]}>Top</Text>
+              )}
+              {j.delay > 0 && (
+                <Text style={[styles.delayBadge, { backgroundColor: colors.error }]}>+{j.delay} min</Text>
+              )}
+              {j.cancelled && (
+                <Text style={[styles.cancelBadge, { backgroundColor: colors.text }]}>Cancelled</Text>
+              )}
+            </View>
+            <Text style={[styles.detail, { color: colors.text }]}>
+              Departure: {new Date(j.sD).toLocaleTimeString('en-US', { hour: '2-digit', minute: '2-digit' })}
+              {' '}(Platform {j.platform || '—'})
+            </Text>
+            <Text style={[styles.detail, { color: colors.subtext }]}>
+              Arrival: {new Date(j.sA).toLocaleTimeString('en-US', { hour: '2-digit', minute: '2-digit' })}
+              {' '}({j.changes === 0 ? 'Direct' : `${j.changes} tr.`})
+            </Text>
+            <Text style={[styles.detail, { color: colors.subtext }]}>
+              Duration: {durationMinutes} min
+            </Text>
+            {walkDurationMs > 0 && (
+              <Text style={[styles.detail, { color: arrivesTooLate ? colors.error : colors.subtext }]}>
+                Arrive: {finalArrival.toLocaleTimeString('en-US', { hour: '2-digit', minute: '2-digit' })}
+                {arrivesTooLate ? ' (too late)' : ''}
+              </Text>
+            )}
+          </View>
+          );
+          })}
+          {rankedJourneys.length > 1 && (
+            <Text style={[styles.expandHint, { color: colors.accent }]}>
+              {expanded ? 'Show fewer connections' : `Show ${rankedJourneys.length - 1} more connections`}
+            </Text>
+          )}
+        </TouchableOpacity>
+      )}
+
+      {showWalkingOption && walkRoute && (
+        <View style={[styles.card, { backgroundColor: colors.card, borderColor: colors.border, marginTop: 10 }]}>
+          <Text style={[styles.walkTitle, { color: colors.text }]}>Final walk</Text>
+          <View style={styles.row}>
+            <Text style={[styles.walkLabel, { color: colors.text }]}>Duration</Text>
+            <Text style={[styles.walkValue, { color: colors.accent }]}>{formatDuration(walkRoute.duration)}</Text>
+          </View>
+          <View style={styles.row}>
+            <Text style={[styles.walkLabel, { color: colors.text }]}>Distance</Text>
+            <Text style={[styles.walkValue, { color: colors.accent }]}>{formatDistance(walkRoute.distance)}</Text>
+          </View>
+          {walkRoute.geometry && (
+            <RouteMap geometry={walkRoute.geometry} colors={colors} mode="walk" />
+          )}
+        </View>
+      )}
+
+      {showWalkingOption && loadingWalk && (
+        <View style={styles.centered}>
+          <ActivityIndicator size="small" color={colors.accent} />
+          <Text style={[styles.hint, { color: colors.subtext }]}>Loading walk route…</Text>
+        </View>
+      )}
+    </View>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: { padding: 20 },
+  sectionTitle: { fontSize: 18, fontWeight: '600', marginBottom: 12 },
+  centered: { alignItems: 'center', gap: 8 },
+  hint: { fontSize: 15, marginTop: 12 },
+  empty: { fontSize: 14 },
+  card: { borderRadius: 10, padding: 14, marginBottom: 10, borderWidth: 1 },
+  lateCard: { opacity: 0.55 },
+  row: { flexDirection: 'row', alignItems: 'center', justifyContent: 'space-between', gap: 8 },
+  line: { flex: 1, fontSize: 16, fontWeight: '600' },
+  bestBadge: { color: '#fff', fontSize: 12, paddingHorizontal: 8, paddingVertical: 2, borderRadius: 6, overflow: 'hidden' },
+  delayBadge: { color: '#fff', fontSize: 12, paddingHorizontal: 8, paddingVertical: 2, borderRadius: 6 },
+  cancelBadge: { color: '#fff', fontSize: 12, paddingHorizontal: 8, paddingVertical: 2, borderRadius: 6 },
+  detail: { fontSize: 13, marginTop: 6 },
+  expandHint: { fontSize: 13, fontWeight: '600', marginTop: 2, marginBottom: 12, textAlign: 'center' },
+  walkTitle: { fontSize: 15, fontWeight: '600', marginBottom: 8 },
+  walkLabel: { fontSize: 14, fontWeight: '500' },
+  walkValue: { fontSize: 14, fontWeight: '600' },
+});

apps/mobile/src/components/NearbyStops.tsx

@@ -0,0 +1,83 @@
+import { ActivityIndicator, StyleSheet, Text, View } from 'react-native';
+import { FontAwesomeIcon } from '@fortawesome/react-native-fontawesome';
+import { faBusSimple } from '@fortawesome/free-solid-svg-icons';
+import type { WienerLinienStop } from '@timetoleave/core';
+import type { DepartureRow } from '../hooks/useWienerLinien';
+import type { AppColors } from '../hooks/useColors';
+
+/** Props for the nearby public transport stops section. */
+interface Props {
+  stops: WienerLinienStop[];
+  departures: DepartureRow[];
+  loading: boolean;
+  error: string | null;
+  colors: AppColors;
+}
+
+/**
+ * Shows public transport stops near the event destination and their upcoming
+ * departures. Caps the departure list at 8 items to avoid overwhelming the UI.
+ * Falls back to showing plain stop names when no departure data is available.
+ */
+export function NearbyStops({ stops, departures, loading, error, colors }: Props) {
+  if (!loading && stops.length === 0 && !error) return null;
+
+  return (
+    <View style={[styles.container, { backgroundColor: colors.background }]}>
+      <View style={styles.sectionTitleRow}>
+        <FontAwesomeIcon icon={faBusSimple} size={16} color={colors.text} />
+        <Text style={[styles.sectionTitle, { color: colors.text }]}>Public transit near destination</Text>
+      </View>
+
+      {loading ? (
+        <View style={styles.centered}>
+          <ActivityIndicator size="small" color={colors.accent} />
+          <Text style={[styles.hint, { color: colors.subtext }]}>Loading stops…</Text>
+        </View>
+      ) : departures.length > 0 ? (
+        departures.slice(0, 8).map((dep, i) => (
+          <View
+            key={`${dep.stopId}-${dep.lineName}-${i}`}
+            style={[styles.depCard, { backgroundColor: colors.card, borderColor: colors.border }]}
+          >
+            <View style={styles.depRow}>
+              <View style={[styles.lineBadge, { backgroundColor: colors.accent }]}>
+                <Text style={styles.lineBadgeText}>{dep.lineName}</Text>
+              </View>
+              <Text style={[styles.direction, { color: colors.text }]} numberOfLines={1}>
+                {dep.direction}
+              </Text>
+              <Text style={[styles.minutes, { color: dep.minutes <= 2 ? colors.error : colors.accent }]}>
+                {dep.minutes === 0 ? 'now' : `${dep.minutes} min`}
+              </Text>
+            </View>
+          </View>
+        ))
+      ) : (
+        stops.slice(0, 5).map((stop) => (
+          <View key={stop.id} style={[styles.stopCard, { backgroundColor: colors.card, borderColor: colors.border }]}>
+            <Text style={[styles.stopName, { color: colors.text }]}>{stop.name}</Text>
+          </View>
+        ))
+      )}
+
+      {error && <Text style={[styles.hint, { color: colors.subtext }]}>{error}</Text>}
+    </View>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: { padding: 20 },
+  sectionTitleRow: { flexDirection: 'row', alignItems: 'center', gap: 8, marginBottom: 12 },
+  sectionTitle: { fontSize: 18, fontWeight: '600' },
+  centered: { alignItems: 'center', gap: 8 },
+  hint: { fontSize: 14 },
+  depCard: { borderRadius: 10, padding: 10, marginBottom: 6, borderWidth: 1 },
+  depRow: { flexDirection: 'row', alignItems: 'center', gap: 8 },
+  lineBadge: { paddingHorizontal: 8, paddingVertical: 3, borderRadius: 6, minWidth: 36, alignItems: 'center' },
+  lineBadgeText: { color: '#fff', fontSize: 12, fontWeight: '700' },
+  direction: { flex: 1, fontSize: 13 },
+  minutes: { fontSize: 13, fontWeight: '700', minWidth: 40, textAlign: 'right' },
+  stopCard: { borderRadius: 10, padding: 12, marginBottom: 8, borderWidth: 1 },
+  stopName: { fontSize: 14, fontWeight: '500' },
+});

apps/mobile/src/components/RouteMap.tsx

@@ -0,0 +1,85 @@
+import { useMemo } from 'react';
+import { StyleSheet, View } from 'react-native';
+import MapView, { Marker, Polyline } from 'react-native-maps';
+import { decodePolyline } from '../utils/polyline';
+import type { AppColors } from '../hooks/useColors';
+
+interface Props {
+  geometry: string;
+  colors: AppColors;
+  mode: 'bike' | 'walk';
+}
+
+function getRegionFromCoordinates(
+  coords: Array<{ latitude: number; longitude: number }>,
+) {
+  let minLat = Infinity;
+  let maxLat = -Infinity;
+  let minLng = Infinity;
+  let maxLng = -Infinity;
+
+  for (const c of coords) {
+    minLat = Math.min(minLat, c.latitude);
+    maxLat = Math.max(maxLat, c.latitude);
+    minLng = Math.min(minLng, c.longitude);
+    maxLng = Math.max(maxLng, c.longitude);
+  }
+
+  const latDelta = (maxLat - minLat) * 1.3; // 30 % padding
+  const lngDelta = (maxLng - minLng) * 1.3;
+
+  return {
+    latitude: (minLat + maxLat) / 2,
+    longitude: (minLng + maxLng) / 2,
+    latitudeDelta: Math.max(latDelta, 0.005),
+    longitudeDelta: Math.max(lngDelta, 0.005),
+  };
+}
+
+/**
+ * Renders an interactive map with the decoded route polyline and start/end
+ * markers. Automatically centres and zooms to fit the entire route.
+ */
+export function RouteMap({ geometry, colors, mode }: Props) {
+  const coords = useMemo(() => decodePolyline(geometry), [geometry]);
+
+  const region = useMemo(() => {
+    if (coords.length < 2) return null;
+    return getRegionFromCoordinates(coords);
+  }, [coords]);
+
+  if (!region || coords.length < 2) {
+    return null;
+  }
+
+  const strokeColor = mode === 'bike' ? colors.accent : colors.success;
+  const startCoord = coords[0];
+  const endCoord = coords[coords.length - 1];
+
+  return (
+    <View style={[styles.container, { borderColor: colors.border }]}>
+      <MapView style={styles.map} initialRegion={region} scrollEnabled={false} zoomEnabled={false} rotateEnabled={false} pitchEnabled={false}>
+        <Polyline
+          coordinates={coords}
+          strokeColor={strokeColor}
+          strokeWidth={4}
+        />
+        <Marker coordinate={startCoord} pinColor={colors.accent} />
+        <Marker coordinate={endCoord} pinColor={colors.success} />
+      </MapView>
+    </View>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: {
+    marginTop: 10,
+    height: 220,
+    borderRadius: 8,
+    overflow: 'hidden',
+    borderWidth: 1,
+  },
+  map: {
+    ...StyleSheet.absoluteFillObject,
+  },
+});

apps/mobile/src/hooks/useColors.ts

@@ -0,0 +1,45 @@
+import { useTheme } from './useTheme';
+
+const DARK = {
+  background: '#090816',
+  card: '#17112A',
+  text: '#F4F1EA',
+  subtext: 'rgba(244,241,234,0.5)',
+  accent: '#8B5CF6',
+  border: '#38383a',
+  error: '#ff453a',
+  success: '#30d158',
+  warning: '#ff9f0a',
+  purple: '#B23CFF',
+  delete: '#FF3B30',
+  overlay: 'rgba(28,28,30,0.95)',
+  highlight: '#1a3a5c',
+} as const;
+
+const LIGHT = {
+  background: '#f2f2f7',
+  card: '#ffffff',
+  text: '#1c1c1e',
+  subtext: '#8e8e93',
+  accent: '#B23CFF',
+  border: '#e5e5ea',
+  error: '#FF3B30',
+  success: '#34C759',
+  warning: '#FF9500',
+  purple: '#8B5CF6',
+  delete: '#FF3B30',
+  overlay: 'rgba(255,255,255,0.95)',
+  highlight: '#e8f4fd',
+} as const;
+
+/** Color token type — every theme variant shares the same keys. */
+export type AppColors = Record<keyof typeof DARK, string>;
+
+/**
+ * Returns the full color palette (dark or light) based on the current theme.
+ * Derives from {@link useTheme} so it stays in sync with user preferences.
+ */
+export function useColors(): AppColors {
+  const { dark } = useTheme();
+  return dark ? DARK : LIGHT;
+}

apps/mobile/src/hooks/useDepartureTime.ts

@@ -0,0 +1,87 @@
+import { useMemo } from 'react';
+import type { Journey } from '@timetoleave/core';
+
+interface DepartureTimeResult {
+  departureTime: Date | null;
+  arrivalTime: Date | null;
+  mode: 'train' | 'bike' | null;
+}
+
+/**
+ * Calculate departure time based on selected transport mode.
+ *
+ * For train mode, picks the latest-departing journey that still arrives on time
+ * (factoring in the final walking leg). For bike mode, simply subtracts the
+ * cycling duration from the target arrival time.
+ *
+ * Mirrors the web app's useDepartureTime hook.
+ *
+ * @param eventTime - The scheduled event start time.
+ * @param journeys - Available train journeys (may be null if not loaded yet).
+ * @param bikeDurationSeconds - Cycling duration in seconds, or null if unavailable.
+ * @param activeMode - The currently selected transport mode.
+ * @param arrivalBufferMinutes - Minutes to arrive before the event starts.
+ * @param trainWalkDurationSeconds - Walking time from destination station to event (seconds).
+ * @param originWalkDurationSeconds - Walking time from start point to origin station (seconds).
+ */
+export function useDepartureTime(
+  eventTime: Date,
+  journeys: Journey[] | null,
+  bikeDurationSeconds: number | null,
+  activeMode: 'train' | 'bike' | null,
+  arrivalBufferMinutes: number,
+  trainWalkDurationSeconds = 0,
+  originWalkDurationSeconds = 0,
+): DepartureTimeResult {
+  return useMemo(() => {
+    // Calculate target arrival time (event time minus buffer)
+    const targetArrivalTime = new Date(eventTime);
+    targetArrivalTime.setMinutes(targetArrivalTime.getMinutes() - arrivalBufferMinutes);
+
+    // Filter out cancelled journeys
+    const validJourneys = journeys?.filter((journey) => !journey.cancelled) || [];
+
+    let departureTime: Date | null = null;
+    let arrivalTime: Date | null = null;
+    let mode: 'train' | 'bike' | null = null;
+
+    if (activeMode === 'train' && validJourneys.length > 0) {
+      // Find journeys that arrive by target time
+      const walkDurationMs = trainWalkDurationSeconds * 1000;
+      const onTimeJourneys = validJourneys.filter(
+        (journey) => journey.rA.getTime() + walkDurationMs <= targetArrivalTime.getTime(),
+      );
+
+      if (onTimeJourneys.length > 0) {
+        // Pick the journey with the latest departure that still arrives on time
+        const bestJourney = onTimeJourneys.reduce((latest, current) =>
+          current.rD.getTime() > latest.rD.getTime() ? current : latest,
+        );
+
+        departureTime = new Date(bestJourney.rD.getTime() - originWalkDurationSeconds * 1000);
+        arrivalTime = new Date(bestJourney.rA.getTime() + walkDurationMs);
+        mode = 'train';
+      }
+    }
+
+    if (activeMode === 'bike' && bikeDurationSeconds !== null && bikeDurationSeconds > 0) {
+      const bikeDurationMs = bikeDurationSeconds * 1000;
+      const totalBufferMs = arrivalBufferMinutes * 60 * 1000;
+      const targetArrivalMs = eventTime.getTime() - totalBufferMs;
+
+      departureTime = new Date(targetArrivalMs - bikeDurationMs);
+      arrivalTime = new Date(targetArrivalMs);
+      mode = 'bike';
+    }
+
+    return { departureTime, arrivalTime, mode };
+  }, [
+    eventTime,
+    journeys,
+    bikeDurationSeconds,
+    activeMode,
+    arrivalBufferMinutes,
+    trainWalkDurationSeconds,
+    originWalkDurationSeconds,
+  ]);
+}

apps/mobile/src/hooks/useDestinationStation.ts

@@ -0,0 +1,113 @@
+import { useState, useEffect } from 'react';
+import type { Station } from '@timetoleave/core';
+import { api } from '../services/api';
+
+/**
+ * Geocodes a destination string to the nearest HAFAS station.
+ *
+ * Two-step process: first geocodes the address to lat/lng via Nominatim,
+ * then sends those coordinates to HAFAS LocMatch to find the closest station.
+ * Debounces lookups by 400 ms to avoid excessive API calls while typing.
+ */
+/** Intermediate shape returned by HAFAS LocMatch before we pick the best station. */
+interface HafasLocation {
+  type: string;
+  name: string;
+  extId: string;
+  lat?: number;
+  lon?: number;
+  crd?: {
+    x?: number;
+    y?: number;
+  };
+}
+
+/** HAFAS can return coordinates in either raw degrees or micro-degrees (×1e6). */
+function normalizeHafasCoordinate(value: number | undefined): number | undefined {
+  if (value == null) return undefined;
+  return Math.abs(value) > 1000 ? value / 1e6 : value;
+}
+
+export function useDestinationStation(destination: string | undefined) {
+  const [station, setStation] = useState<Station | null>(null);
+  const [loading, setLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => {
+    if (!destination?.trim()) {
+      setStation(null);
+      return;
+    }
+
+    let isMounted = true;
+
+    // Debounce the lookup
+    const timeoutId = setTimeout(async () => {
+      setLoading(true);
+      setError(null);
+
+      try {
+        // First geocode the destination to get coordinates
+        const geocodeResults = await api.geocode(destination, 'at');
+        const coords = geocodeResults[0];
+
+        if (!coords) {
+          if (isMounted) {
+            setStation(null);
+            setLoading(false);
+          }
+          return;
+        }
+
+        // Then use HAFAS LocMatch to find the nearest station
+        const body = {
+          svcReqL: [
+            {
+              meth: 'LocMatch',
+              req: {
+                input: {
+                  loc: {
+                    crd: {
+                      x: Math.round(coords.lng * 1e6),
+                      y: Math.round(coords.lat * 1e6),
+                    },
+                    type: 'S',
+                  },
+                  maxLoc: 1,
+                  field: 'S',
+                },
+              },
+            },
+          ],
+        };
+
+        const data = await api.hafasRequest<{ svcResL?: Array<{ res?: { match?: { locL?: HafasLocation[] } } }> }>(body);
+        const locL: HafasLocation[] = data?.svcResL?.[0]?.res?.match?.locL ?? [];
+        const stations = locL
+          .filter((l) => l.type === 'S')
+          .map((l) => ({
+            name: l.name,
+            extId: l.extId,
+            lat: normalizeHafasCoordinate(l.lat ?? l.crd?.y),
+            lng: normalizeHafasCoordinate(l.lon ?? l.crd?.x),
+          }));
+
+        if (!isMounted) return;
+        setStation(stations[0] ?? null);
+        setLoading(false);
+      } catch (err) {
+        if (isMounted) {
+          setError(err instanceof Error ? err.message : 'Station lookup failed');
+          setLoading(false);
+        }
+      }
+    }, 400);
+
+    return () => {
+      isMounted = false;
+      clearTimeout(timeoutId);
+    };
+  }, [destination]);
+
+  return { station, loading, error };
+}

apps/mobile/src/hooks/useGeocode.ts

@@ -0,0 +1,49 @@
+import { useState, useEffect } from 'react';
+import type { GeocodeResult } from '@timetoleave/core';
+import { api } from '../services/api';
+
+/**
+ * Geocode a destination name to coordinates.
+ * Debounces API calls by 400 ms. Automatically resets to null when the
+ * destination is cleared or becomes empty.
+ * Mirrors the web app's useGeocode hook.
+ */
+export function useGeocode(destination: string | undefined) {
+  const [coords, setCoords] = useState<GeocodeResult | null>(null);
+  const [loading, setLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => {
+    if (!destination?.trim()) {
+      setCoords(null);
+      return;
+    }
+
+    let isMounted = true;
+
+    const timeoutId = setTimeout(async () => {
+      setLoading(true);
+      setError(null);
+
+      try {
+        const results = await api.geocode(destination, 'at');
+        if (isMounted) {
+          setCoords(results[0] ?? null);
+          setLoading(false);
+        }
+      } catch (err) {
+        if (isMounted) {
+          setError(err instanceof Error ? err.message : 'Geocoding failed');
+          setLoading(false);
+        }
+      }
+    }, 400);
+
+    return () => {
+      isMounted = false;
+      clearTimeout(timeoutId);
+    };
+  }, [destination]);
+
+  return { coords, loading, error };
+}

apps/mobile/src/hooks/useOriginStationWalk.ts

@@ -0,0 +1,51 @@
+import { useEffect, useState } from 'react';
+import type { Station } from '@timetoleave/core';
+import { api } from '../services/api';
+import { useWalkRoute } from './useWalkRoute';
+
+/**
+ * Resolve the walking leg from the saved origin point to the departure station.
+ *
+ * `origin.lat/lng` may represent the user's real start point while `origin.extId`
+ * identifies the station used for train search. When coordinates are missing or
+ * station resolution fails, callers can safely fall back to zero duration.
+ */
+export function useOriginStationWalk(origin: Station | null) {
+  const [station, setStation] = useState<Station | null>(null);
+  const [lookupError, setLookupError] = useState<string | null>(null);
+
+  useEffect(() => {
+    let isMounted = true;
+
+    const resolveStation = async () => {
+      setStation(null);
+      setLookupError(null);
+
+      if (origin?.lat == null || origin.lng == null) return;
+
+      try {
+        const selectedStation = await api.findStationByExtId(origin.extId);
+        if (!isMounted) return;
+        setStation(selectedStation);
+      } catch (err) {
+        if (!isMounted) return;
+        setLookupError(err instanceof Error ? err.message : 'Origin station lookup failed');
+      }
+    };
+
+    resolveStation();
+
+    return () => {
+      isMounted = false;
+    };
+  }, [origin?.lat, origin?.lng]);
+
+  const walk = useWalkRoute(origin?.lat, origin?.lng, station?.lat, station?.lng);
+
+  return {
+    station,
+    walkRoute: walk.walkRoute,
+    loading: walk.loading,
+    error: lookupError ?? walk.error,
+  };
+}

apps/mobile/src/hooks/useTheme.ts

@@ -0,0 +1,59 @@
+import { useState, useCallback, useEffect, useRef } from 'react';
+import AsyncStorage from '@react-native-async-storage/async-storage';
+
+/** Theme storage key in AsyncStorage. */
+const THEME_KEY = '@timetoleave_theme';
+
+type Theme = 'dark' | 'light';
+
+/** Returns the default theme. Mobile defaults to dark to match the web app. */
+function getDefaultTheme(): Theme {
+  // React Native doesn't have window.matchMedia, but we can use a simple default
+  // The web app uses a dark-first theme, so we match that default
+  return 'dark';
+}
+
+/**
+ * Theme management for the mobile app.
+ *
+ * Persists the user's choice in AsyncStorage and initializes from storage
+ * on mount (guarded by a ref so hot-reload doesn't re-read). Returns a
+ * `dark` boolean and a `toggle` callback for switching themes.
+ *
+ * Mirrors the web app's useTheme hook.
+ */
+export function useTheme() {
+  const [dark, setDark] = useState(false);
+  const initialized = useRef(false);
+
+  // Load theme on mount
+  useEffect(() => {
+    if (initialized.current) return;
+    initialized.current = true;
+
+    (async () => {
+      try {
+        const stored = await AsyncStorage.getItem(THEME_KEY);
+        if (stored === 'dark' || stored === 'light') {
+          setDark(stored === 'dark');
+        } else {
+          setDark(getDefaultTheme() === 'dark');
+        }
+      } catch {
+        setDark(false);
+      }
+    })();
+  }, []);
+
+  const toggle = useCallback(() => {
+    setDark((prev) => {
+      const next = !prev;
+      AsyncStorage.setItem(THEME_KEY, next ? 'dark' : 'light').catch(() => {
+        // Silently fail storage
+      });
+      return next;
+    });
+  }, []);
+
+  return { dark, toggle };
+}

apps/mobile/src/hooks/useWalkRoute.ts

@@ -1,13 +1,19 @@
-import { useState, useEffect } from "react";
-import type { BikeRoute } from "@/types";
+import { useState, useEffect } from 'react';
+import type { WalkRoute } from '@timetoleave/core';
+import { api } from '../services/api';
 
-export function useBikeRoute(
+/**
+ * Fetch walk route between two points using the OSRM walking router.
+ * Skips the request if any coordinate is missing, resetting state to null.
+ * Mirrors the web app's useWalkRoute hook.
+ */
+export function useWalkRoute(
   fromLat: number | undefined,
   fromLng: number | undefined,
   toLat: number | undefined,
   toLng: number | undefined,
 ) {
-  const [bikeRoute, setBikeRoute] = useState<BikeRoute | null>(null);
+  const [walkRoute, setWalkRoute] = useState<WalkRoute | null>(null);
   const [loading, setLoading] = useState<boolean>(false);
   const [error, setError] = useState<string | null>(null);
 
@@ -16,6 +22,9 @@ export function useBikeRoute(
 
     const fetchRoute = async () => {
       if (fromLat == null || fromLng == null || toLat == null || toLng == null) {
+        setWalkRoute(null);
+        setLoading(false);
+        setError(null);
         return;
       }
 
@@ -23,25 +32,19 @@ export function useBikeRoute(
       setError(null);
 
       try {
-        const response = await fetch(
-          `/api/bike-route?fromLat=${fromLat}&fromLng=${fromLng}&toLat=${toLat}&toLng=${toLng}`,
-        );
-
-        if (!response.ok) {
-          const errBody = await response.json().catch(() => ({}));
-          throw new Error(errBody.error ?? `Bike route request failed with status ${response.status}`);
-        }
-
-        const data = await response.json();
+        const data = await api.getWalkRoute(fromLat, fromLng, toLat, toLng);
 
         if (isMounted) {
-          setBikeRoute(data);
+          setWalkRoute(data);
           setLoading(false);
         }
       } catch (err: unknown) {
         if (isMounted) {
-          const message = err instanceof Error ? err.message : "Failed to fetch bike route";
+          const message = err instanceof Error ? err.message : 'Failed to fetch walk route';
           setError(message);
+        }
+      } finally {
+        if (isMounted) {
           setLoading(false);
         }
       }
@@ -54,5 +57,5 @@ export function useBikeRoute(
     };
   }, [fromLat, fromLng, toLat, toLng]);
 
-  return { bikeRoute, loading, error };
+  return { walkRoute, loading, error };
 }

apps/mobile/src/hooks/useWienerLinien.ts

@@ -0,0 +1,122 @@
+import { useState, useEffect, useRef, useCallback } from 'react';
+import type { WienerLinienStop, WienerLinienDeparture } from '@timetoleave/core';
+import { api } from '../services/api';
+
+/** Flattened departure row shown in the NearbyStops UI. */
+export interface DepartureRow {
+  stopId: string;
+  lineName: string;
+  direction: string;
+  minutes: number;
+}
+
+const DEBOUNCE_MS = 400;
+const REFRESH_INTERVAL_MS = 60_000;
+
+/** Convert a raw WienerLinien departure to the simplified DepartureRow shape. */
+function transformDeparture(dep: WienerLinienDeparture): DepartureRow {
+  const minutes = Math.max(0, Math.round((dep.departureTime - Date.now()) / 60_000));
+  return {
+    stopId: dep.stopId,
+    lineName: dep.line.name,
+    direction: dep.direction,
+    minutes,
+  };
+}
+
+/**
+ * Fetches nearby WienerLinien stops around given coordinates and their live
+ * departures. Debounces initial lookups (400 ms) and refreshes departures
+ * every 60 seconds. Uses a cancellation ref to prevent stale overwrites when
+ * coordinates change mid-request.
+ *
+ * @param lat - Latitude of the point of interest.
+ * @param lng - Longitude of the point of interest.
+ * @param radius - Search radius in meters (defaults to 500).
+ */
+export function useWienerLinien(
+  lat: number | undefined,
+  lng: number | undefined,
+  radius?: number,
+) {
+  const [stops, setStops] = useState<WienerLinienStop[]>([]);
+  const [departures, setDepartures] = useState<DepartureRow[]>([]);
+  const [loading, setLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  // Stopped by the cleanup effect when coordinates change, so in-flight
+  // monitor requests don't overwrite stale stop lists.
+  const stopIdsRef = useRef<string[]>([]);
+  const cancelledRef = useRef(false);
+
+  /** Fetch live departure data for a batch of stop IDs. Silently ignores errors. */
+  const fetchMonitor = useCallback(async (stopIds: string[]): Promise<void> => {
+    if (stopIds.length === 0 || cancelledRef.current) return;
+    try {
+      const rawDepartures = await api.monitorStops(stopIds);
+      if (!cancelledRef.current) {
+        setDepartures(rawDepartures.map(transformDeparture));
+      }
+    } catch {
+      // Silently ignore monitor errors — stops are still shown
+    }
+  }, []);
+
+  useEffect(() => {
+    cancelledRef.current = false;
+
+    if (lat === undefined || lng === undefined) {
+      setStops([]);
+      setDepartures([]);
+      setError(null);
+      setLoading(false);
+      return;
+    }
+
+    const debounceTimer = setTimeout(async () => {
+      if (cancelledRef.current) return;
+
+      setLoading(true);
+      setError(null);
+
+      try {
+        const stopsList = await api.findNearbyStops(lat, lng, radius ?? 500);
+
+        if (cancelledRef.current) return;
+
+        setStops(stopsList);
+        setLoading(false);
+
+        const ids = stopsList.map((s) => s.id);
+        stopIdsRef.current = ids;
+
+        await fetchMonitor(ids);
+      } catch (err) {
+        if (cancelledRef.current) return;
+        setError(err instanceof Error ? err.message : 'Stops could not be loaded');
+        setLoading(false);
+      }
+    }, DEBOUNCE_MS);
+
+    return () => {
+      cancelledRef.current = true;
+      clearTimeout(debounceTimer);
+    };
+  }, [lat, lng, radius, fetchMonitor]);
+
+  // Periodic departures refresh
+  useEffect(() => {
+    if (stops.length === 0) return;
+
+    const intervalId = setInterval(() => {
+      const ids = stopIdsRef.current;
+      if (ids.length > 0) {
+        fetchMonitor(ids);
+      }
+    }, REFRESH_INTERVAL_MS);
+
+    return () => clearInterval(intervalId);
+  }, [stops.length, fetchMonitor]);
+
+  return { stops, departures, loading, error };
+}

apps/mobile/src/navigation/AppNavigator.tsx

@@ -0,0 +1,148 @@
+import { NavigationContainer } from '@react-navigation/native';
+import { createNativeStackNavigator } from '@react-navigation/native-stack';
+import { FontAwesomeIcon } from '@fortawesome/react-native-fontawesome';
+import { faBars } from '@fortawesome/free-solid-svg-icons/faBars';
+import { Image, Modal, Pressable, StyleSheet, Text, View } from 'react-native';
+import { SafeAreaProvider, SafeAreaView } from 'react-native-safe-area-context';
+import { StatusBar } from 'expo-status-bar';
+import { useState } from 'react';
+import { EventListScreen } from '../screens/EventListScreen';
+import { EventDetailScreen } from '../screens/EventDetailScreen';
+import { AddEventScreen } from '../screens/AddEventScreen';
+import { SettingsScreen } from '../screens/SettingsScreen';
+import { CalendarImportScreen } from '../screens/CalendarImportScreen';
+import type { RootStack } from '../types/navigation';
+import navLogo from '../../assets/nav-logo.png';
+
+// ── Root Stack ──
+
+const Root = createNativeStackNavigator<RootStack>();
+const byPrefixAndName = { fas: { bars: faBars } };
+
+type HeaderMenuProps = {
+  navigation: {
+    navigate: (_screen: 'CalendarImport' | 'Settings') => void;
+  };
+};
+
+function HeaderMenu({ navigation }: HeaderMenuProps) {
+  const [isOpen, setIsOpen] = useState(false);
+
+  const navigateTo = (screen: 'CalendarImport' | 'Settings') => {
+    setIsOpen(false);
+    navigation.navigate(screen);
+  };
+
+  return (
+    <>
+      <Pressable
+        accessibilityLabel="Open menu"
+        accessibilityRole="button"
+        hitSlop={12}
+        onPress={() => setIsOpen(true)}
+        style={({ pressed }) => [styles.menuButton, pressed && styles.menuButtonPressed]}
+      >
+        <FontAwesomeIcon icon={byPrefixAndName.fas['bars']} color="#F4F1EA" size={22} />
+      </Pressable>
+
+      <Modal animationType="fade" transparent visible={isOpen} onRequestClose={() => setIsOpen(false)}>
+        <Pressable style={styles.menuOverlay} onPress={() => setIsOpen(false)}>
+          <View style={styles.menuPanel}>
+            <Pressable
+              accessibilityRole="menuitem"
+              onPress={() => navigateTo('CalendarImport')}
+              style={({ pressed }) => [styles.menuItem, pressed && styles.menuItemPressed]}
+            >
+              <Text style={styles.menuItemText}>Calendar</Text>
+            </Pressable>
+            <Pressable
+              accessibilityRole="menuitem"
+              onPress={() => navigateTo('Settings')}
+              style={({ pressed }) => [styles.menuItem, pressed && styles.menuItemPressed]}
+            >
+              <Text style={styles.menuItemText}>Settings</Text>
+            </Pressable>
+          </View>
+        </Pressable>
+      </Modal>
+    </>
+  );
+}
+
+/**
+ * Root native stack navigator for the app.
+ * Wraps all screens in SafeAreaProvider/SafeAreaView with a dark header bar.
+ */
+export default function AppNavigator() {
+  return (
+    <SafeAreaProvider>
+      <SafeAreaView style={{ flex: 1, backgroundColor: '#090816' }}>
+        <StatusBar style="light" />
+        <NavigationContainer>
+          <Root.Navigator
+            initialRouteName="EventList"
+            screenOptions={({ navigation }) => ({
+              headerStyle: { backgroundColor: '#17112A' },
+              headerTintColor: '#F4F1EA',
+              headerRight: () => <HeaderMenu navigation={navigation} />,
+              headerTitle: () => (
+                <View style={{ flexDirection: 'row', alignItems: 'center', gap: 8 }}>
+                  <Image source={navLogo} style={{ width: 28, height: 28, borderRadius: 6 }} resizeMode="contain" />
+                  <Text style={{ color: '#F4F1EA', fontSize: 18, fontWeight: '600' }}>Time</Text>
+                  <Text style={{ color: '#ea1579', fontSize: 18, fontWeight: '600' }}>To </Text>
+                  <Text style={{ color: '#F4F1EA', fontSize: 18, fontWeight: '600' }}>Leave</Text>
+
+                </View>
+              ),
+            })}
+          >
+            <Root.Screen name="EventList" component={EventListScreen} />
+            <Root.Screen name="AddEvent" component={AddEventScreen} />
+            <Root.Screen name="EventDetail" component={EventDetailScreen} />
+            <Root.Screen name="Settings" component={SettingsScreen} />
+            <Root.Screen name="CalendarImport" component={CalendarImportScreen} />
+          </Root.Navigator>
+        </NavigationContainer>
+      </SafeAreaView>
+    </SafeAreaProvider>
+  );
+}
+
+const styles = StyleSheet.create({
+  menuButton: {
+    alignItems: 'center',
+    height: 40,
+    justifyContent: 'center',
+    width: 40,
+  },
+  menuButtonPressed: {
+    opacity: 0.65,
+  },
+  menuOverlay: {
+    alignItems: 'flex-end',
+    backgroundColor: 'rgba(9, 8, 22, 0.45)',
+    flex: 1,
+    paddingRight: 12,
+    paddingTop: 72,
+  },
+  menuPanel: {
+    backgroundColor: '#17112A',
+    borderColor: '#3B3157',
+    borderRadius: 8,
+    borderWidth: 1,
+    minWidth: 168,
+    overflow: 'hidden',
+  },
+  menuItem: {
+    paddingHorizontal: 18,
+    paddingVertical: 14,
+  },
+  menuItemPressed: {
+    backgroundColor: '#2A2140',
+  },
+  menuItemText: {
+    color: '#F4F1EA',
+    fontSize: 16,
+    fontWeight: '600',
+  },
+});

apps/mobile/src/polyfills/sharedArrayBuffer.ts

@@ -0,0 +1,94 @@
+/**
+ * Polyfills for newer JavaScript features that React Native's Hermes engine
+ * doesn't provide out of the box.
+ *
+ * - `String.prototype.toWellFormed` / `isWellFormed` — handles lone surrogates
+ *   by replacing them with the Unicode replacement character (U+FFFD).
+ * - `ArrayBuffer.prototype.resizable` — required by newer Intl APIs.
+ * - `SharedArrayBuffer` — stubbed so that libraries which check for its
+ *   presence (e.g. the Intl locale data) don't crash at runtime.
+ */
+
+const globalScope = globalThis as Record<string, unknown>;
+const stringPrototype = String.prototype as typeof String.prototype & {
+  isWellFormed?: () => boolean;
+  toWellFormed?: () => string;
+};
+
+const arrayBufferByteLength = Object.getOwnPropertyDescriptor(ArrayBuffer.prototype, 'byteLength')?.get;
+
+/**
+ * Replace lone surrogates (U+D800…U+DBFF without a partner, or U+DC00…U+DFFF
+ * without a lead) with the Unicode replacement character U+FFFD. Valid
+ * surrogate pairs are kept as-is. Used by both `toWellFormed` and `isWellFormed`.
+ */
+function toWellFormedString(value: string): string {
+  let result = '';
+
+  for (let index = 0; index < value.length; index += 1) {
+    const code = value.charCodeAt(index);
+
+    if (code >= 0xd800 && code <= 0xdbff) {
+      const next = value.charCodeAt(index + 1);
+      if (next >= 0xdc00 && next <= 0xdfff) {
+        result += value[index] + value[index + 1];
+        index += 1;
+      } else {
+        result += '\uFFFD';
+      }
+    } else if (code >= 0xdc00 && code <= 0xdfff) {
+      result += '\uFFFD';
+    } else {
+      result += value[index];
+    }
+  }
+
+  return result;
+}
+
+if (typeof stringPrototype.toWellFormed !== 'function') {
+  Object.defineProperty(String.prototype, 'toWellFormed', {
+    configurable: true,
+    value() {
+      return toWellFormedString(String(this));
+    },
+  });
+}
+
+if (typeof stringPrototype.isWellFormed !== 'function') {
+  Object.defineProperty(String.prototype, 'isWellFormed', {
+    configurable: true,
+    value() {
+      const value = String(this);
+      return toWellFormedString(value) === value;
+    },
+  });
+}
+
+if (!Object.getOwnPropertyDescriptor(ArrayBuffer.prototype, 'resizable')) {
+  Object.defineProperty(ArrayBuffer.prototype, 'resizable', {
+    configurable: true,
+    get() {
+      return false;
+    },
+  });
+}
+
+if (typeof globalScope.SharedArrayBuffer === 'undefined') {
+  class SharedArrayBufferPolyfill extends ArrayBuffer {
+    get byteLength() {
+      return arrayBufferByteLength?.call(this) ?? 0;
+    }
+
+    get growable() {
+      return false;
+    }
+  }
+
+  Object.defineProperty(SharedArrayBufferPolyfill.prototype, Symbol.toStringTag, {
+    configurable: true,
+    value: 'SharedArrayBuffer',
+  });
+
+  globalScope.SharedArrayBuffer = SharedArrayBufferPolyfill;
+}