# Programming Guide: Parallel Deep Miner

> **Basis:** Fourth Example – *Deep Miner* – a parallel mining simulation on a 3-D grid where multiple robots run concurrently in separate threads and compete to accumulate the highest score. All play is automated; there is no manual player mode.
>
> **Scope of this guide:** terminal/C++ implementation, threading, timing, combat, tests, and non-GUI extensions. The SDL2 renderer has been split into `SDL2_GUI_EXTENSION_GUIDE.md`.

---

## Table of Contents

1. [Project Overview](#1-project-overview)
2. [Architecture](#2-architecture)
3. [Core Components](#3-core-components)
   - 3.1 [World](#31-world)
   - 3.2 [Robot Interface](#32-robot-interface)
   - 3.3 [BaseRobot](#33-baserobot)
   - 3.4 [Concrete Robots](#34-concrete-robots)
   - 3.5 [ScopedTimer](#35-scopedtimer)
   - 3.6 [Game](#36-game)
4. [Build and Execution](#4-build-and-execution)
5. [Assignment Levels](#5-assignment-levels)
   - 5.1 [Stufe 1 – Parallel Threads and Conservation Check](#51-stufe-1--parallel-threads-and-conservation-check)
   - 5.2 [Stufe 2 – RAII Thread Timing](#52-stufe-2--raii-thread-timing)
   - 5.3 [Stufe 3 – Robot Combat](#53-stufe-3--robot-combat)
   - 5.4 [Adding SmartBot](#54-adding-smartbot)
   - 5.5 [Adding LookaheadBot](#55-adding-lookaheadbot)
6. [Writing Tests](#6-writing-tests)
7. [Design Principles and Best Practices](#7-design-principles-and-best-practices)
8. [Common Pitfalls and Solutions](#8-common-pitfalls-and-solutions)
9. [Advanced Extension Ideas](#9-advanced-extension-ideas)
10. [Project Structure](#10-project-structure)
11. [Appendix A: Complete Core Source Code](#appendix-a-complete-core-source-code)

---

## 1. Project Overview

**Deep Miner** is a parallel strategy simulation implemented in C++17. A configurable number of robots, usually 5–10, each run in their own `std::thread` on a shared three-dimensional grid. Robots move, trigger effects, fight, and mine blocks to accumulate points.

A single mutex, `turnMutex_`, protects the complete logical turn. This keeps the implementation safe and easy to reason about: only one robot can read or mutate the `World` at a time.

### Grid concept

```text
5 × 5 × 10 grid world (X × Y × Z)

Each column (x, y) has up to 10 layers.
z = 0                 bottom / deepest layer
z = column.size() - 1 surface / top layer

Positive values 1..9  mineable blocks
-1                    blocked turn effect
-2                    teleport effect
-3                    HP damage effect
```

### Assignment levels

| Level | Title | Key feature |
|---|---|---|
| Stufe 1 | Parallel Threads and Conservation Check | One thread per robot, one mutex, point conservation check |
| Stufe 2 | RAII Thread Timing | `ScopedTimer` starts in constructor and stores elapsed time in destructor |
| Stufe 3 | Robot Combat | HP/death system, combat, preserved dead-robot scores |

### Per-thread turn sequence

```text
Thread for robot i wakes up:
 1. Acquire turnMutex_
 2. If this robot is dead: record score, exit thread
 3. If the world is empty: exit thread
 4. decideNextMove(world_)
 5. move(direction, world_)
 6. checkEffects(x, y)
 7. applyEffect(effect), if any
 8. If effect killed this robot: record score, exit thread
 9. fightNearby(robot)
10. If this robot somehow died during the turn: record score, exit thread
11. If effect was not -1: mine(world_)
12. checkRearrange(robot)
13. Release turnMutex_
14. sleep_for(10 ms)
```

The death check must happen **before** the game-over check. A robot may have been killed by another robot on a previous turn. It still needs a chance to record its final score before its thread exits.

---

## 2. Architecture

```text
Robot interface
    ↑
BaseRobot abstract base class
    ↑
SortBot / DigDeepBot / RandomBot / optional extensions

World
    owns the dynamic 3-D grid

Game
    owns World, robots, mutex, score bookkeeping, timing data, and thread lifecycle

ScopedTimer
    small RAII utility used by Game and robot threads for elapsed-time measurement
```

### Main ownership rules

- `Game` owns all robots through `std::vector<std::unique_ptr<Robot>>`.
- The robot threads are launched in `Game::run()` and joined before `Game::run()` returns.
- `World` is accessed only while `turnMutex_` is held.
- Robot HP and score mutations happen only while `turnMutex_` is held.
- Timing slots are pre-sized before threads start; each thread writes only to its own slot.

---

## 3. Core Components

### 3.1 World

The `World` class stores each `(x, y)` column as a dynamic stack:

```cpp
std::vector<std::vector<std::vector<int>>> grid_;
// grid_[x][y] is one vertical column.
// grid_[x][y].back() is the current surface block.
```

This design replaces the older fixed-depth grid that used `0` as a mined-cell sentinel. In the dynamic-column design, mined blocks are removed from the vector. No zero-filled holes should be introduced by robot code.

#### Recommended public API

```cpp
class World {
public:
    World(int x = 5, int y = 5, int z = 10);

    int getSizeX() const;
    int getSizeY() const;
    int getSizeZ() const;

    int getSurfaceLevel(int x, int y) const;       // -1 when empty
    int getSurfaceValue(int x, int y) const;       // 0 when empty
    int getValue(int x, int y, int z) const;       // throws on invalid coordinates

    int mine(int x, int y);                        // pops the surface block
    int checkEffects(int x, int y);                // removes and returns one effect, or 0
    int collectPositiveColumn(int x, int y);       // extension helper; keeps effects

    void setColumn(int x, int y, std::vector<int> values); // tests/examples
    void clear();                                  // tests/examples
    void rearrange();
    void display() const;

private:
    void validateXY(int x, int y) const;
    void validateXYZ(int x, int y, int z) const;

    int sizeX_ = 5;
    int sizeY_ = 5;
    int sizeZ_ = 10;
    std::vector<std::vector<std::vector<int>>> grid_;
};
```

#### Surface level

```cpp
int World::getSurfaceLevel(int x, int y) const {
    validateXY(x, y);
    const auto& col = grid_[x][y];
    return col.empty() ? -1 : static_cast<int>(col.size()) - 1;
}
```

This is O(1), because the column vector already knows its size.

#### Mining

```cpp
int World::mine(int x, int y) {
    validateXY(x, y);
    auto& col = grid_[x][y];
    if (col.empty()) return 0;

    const int value = col.back();
    col.pop_back();
    return value > 0 ? value : 0;
}
```

`mine()` transfers a positive surface value from the world to a robot. It never creates a `0` sentinel.

#### Effect handling

A simple version checks only the current surface. That keeps effects intuitive: a buried effect is triggered only when mining/movement exposes it.

```cpp
int World::checkEffects(int x, int y) {
    validateXY(x, y);
    auto& col = grid_[x][y];
    if (col.empty()) return 0;

    const int value = col.back();
    if (value >= 0) return 0;

    col.pop_back();
    return value;
}
```

If your assignment requires effects to be found anywhere in the column, document that explicitly. Do not mix both interpretations.

#### Extension helper for full-column mining

Some extension robots, such as `SmartBot`, want to mine all positive values in a column. Do not implement that by setting cells to `0`. Add an explicit stack-aware helper:

```cpp
int World::collectPositiveColumn(int x, int y) {
    validateXY(x, y);
    auto& col = grid_[x][y];

    int total = 0;
    std::vector<int> kept;
    kept.reserve(col.size());

    for (int v : col) {
        if (v > 0) {
            total += v;
        } else {
            kept.push_back(v);       // keep effects instead of destroying them
        }
    }

    col = std::move(kept);
    return total;
}
```

#### Test helpers

```cpp
void World::clear() {
    for (auto& row : grid_)
        for (auto& col : row)
            col.clear();
}

void World::setColumn(int x, int y, std::vector<int> values) {
    validateXY(x, y);
    if (static_cast<int>(values.size()) > sizeZ_)
        throw std::out_of_range("column exceeds configured depth");
    grid_[x][y] = std::move(values);
}
```

These helpers solve the test problem cleanly. A dynamic column is empty only when its vector is empty; filling it with zeros is not equivalent.

---

### 3.2 Robot Interface

`Robot` is a pure virtual interface. `Game` talks to robots only through this interface.

```cpp
class Robot {
public:
    virtual ~Robot() = default;

    virtual void move(int direction, const World& world) = 0;
    virtual int  mine(World& world) = 0;
    virtual int  decideNextMove(const World& world) const = 0;

    virtual void setPosition(int x, int y) = 0;
    virtual int  getScore() const = 0;
    virtual void addScore(int points) = 0;
    virtual int  getX() const = 0;
    virtual int  getY() const = 0;
    virtual std::string getName() const = 0;

    virtual int  getHp() const = 0;
    virtual bool isAlive() const = 0;
    virtual void takeDamage(int dmg) = 0;
};
```

---

### 3.3 BaseRobot

`BaseRobot` implements shared robot state and behavior. It remains abstract because `mine()` is still strategy-specific.

```cpp
class BaseRobot : public Robot {
public:
    BaseRobot(std::string name, int startX, int startY)
        : x_(startX), y_(startY), name_(std::move(name)) {}

    void move(int direction, const World& world) override;
    int decideNextMove(const World& world) const override;

    void setPosition(int x, int y) override { x_ = x; y_ = y; }
    int  getScore() const override { return score_; }
    void addScore(int points) override { score_ += points; }
    int  getX() const override { return x_; }
    int  getY() const override { return y_; }
    std::string getName() const override { return name_; }

    int  getHp() const override { return hp_; }
    bool isAlive() const override { return hp_ > 0; }

    void takeDamage(int dmg) override {
        hp_ -= dmg;
        if (hp_ < 0) hp_ = 0;
    }

protected:
    int x_ = 0;
    int y_ = 0;
    int score_ = 0;
    std::string name_;

    int hp_ = 100;
    static constexpr int kMaxHp = 100;
};
```

Movement uses direction codes:

```text
0 = stay
1 = x + 1
2 = x - 1
3 = y + 1
4 = y - 1
```

Clamp movement to world boundaries:

```cpp
void BaseRobot::move(int direction, const World& world) {
    int nx = x_;
    int ny = y_;

    switch (direction) {
        case 1: ++nx; break;
        case 2: --nx; break;
        case 3: ++ny; break;
        case 4: --ny; break;
        default: break;
    }

    x_ = std::clamp(nx, 0, world.getSizeX() - 1);
    y_ = std::clamp(ny, 0, world.getSizeY() - 1);
}
```

---

### 3.4 Concrete Robots

Each concrete robot implements only its mining strategy.

#### SortBot

Sorts the current column so the highest positive value reaches the surface, then mines one block. With dynamic columns, sorting must not create zeros.

```cpp
int SortBot::mine(World& world) {
    // If you expose a World::sortPositiveColumnToSurface helper, call it here.
    // Then mine the surface once.
    const int points = world.mine(x_, y_);
    score_ += points;
    return points;
}
```

#### DigDeepBot

Mines up to three surface blocks.

```cpp
int DigDeepBot::mine(World& world) {
    int total = 0;
    for (int i = 0; i < 3; ++i) {
        const int points = world.mine(x_, y_);
        if (points <= 0) break;
        total += points;
    }
    score_ += total;
    return total;
}
```

#### RandomBot

Mines a random number of surface blocks from 0 to 9.

```cpp
int RandomBot::mine(World& world) {
    static thread_local std::mt19937 rng{std::random_device{}()};
    std::uniform_int_distribution<int> countDist(0, 9);

    const int n = countDist(rng);
    int total = 0;

    for (int i = 0; i < n; ++i) {
        const int points = world.mine(x_, y_);
        if (points <= 0) break;
        total += points;
    }

    score_ += total;
    return total;
}
```

The caller must **not** call `addScore()` after `mine()`. Each `mine()` implementation credits its own score.

---

### 3.5 ScopedTimer

Stufe 2 uses a small RAII timing class. Its constructor starts the timer. Its destructor stops the timer and writes the elapsed duration into a target variable.

```cpp
// include/ScopedTimer.h
#pragma once

#include <chrono>

class ScopedTimer {
public:
    using Clock = std::chrono::steady_clock;
    using Duration = std::chrono::duration<double>;

    explicit ScopedTimer(Duration& target) noexcept
        : target_(target), start_(Clock::now()) {}

    ~ScopedTimer() noexcept {
        target_ = Clock::now() - start_;
    }

    ScopedTimer(const ScopedTimer&) = delete;
    ScopedTimer& operator=(const ScopedTimer&) = delete;

private:
    Duration& target_;
    Clock::time_point start_;
};
```

Use `std::chrono::steady_clock` for elapsed-time measurement. It is monotonic, so it is not affected by system clock adjustments.

---

### 3.6 Game

`Game` owns the simulation and coordinates all threads.

```cpp
// include/Game.h
#pragma once

#include <chrono>
#include <memory>
#include <mutex>
#include <string>
#include <thread>
#include <vector>

#include "Robot.h"
#include "ScopedTimer.h"
#include "World.h"

class Game {
public:
    Game();
    void run();

private:
    using Duration = ScopedTimer::Duration;

    World world_;
    std::vector<std::unique_ptr<Robot>> robots_;

    std::vector<int> deadRobotScores_;
    std::vector<bool> deathRecorded_;

    std::mutex turnMutex_;
    int lastThreshold_ = 0;

    std::vector<Duration> threadTimes_;
    Duration totalTime_{};

    void setup();
    void robotLoop(int idx);
    void recordDeath(int idx, const std::string& reason);
    void fightNearby(Robot& attacker);

    int computeWorldSum() const;
    int computeLivingScore() const;
    int computeDeadScore() const;

    void checkRearrange(Robot& robot);
    void applyEffect(Robot& robot, int effect);
    bool isGameOver() const;
    void log(const std::string& msg);
    void printScores() const;
    void printResult() const;

    std::unique_ptr<Robot> createRobot(int choice, int x, int y) const;
};
```

`deathRecorded_` prevents accidental double-recording if later code paths call `recordDeath()` more than once for the same robot.

---

## 4. Build and Execution

### Requirements

- C++17-compatible compiler
- CMake 3.15 or newer
- Thread library resolved through CMake's `Threads::Threads`

### CMakeLists.txt

```cmake
cmake_minimum_required(VERSION 3.15)
project(deep_miner)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

find_package(Threads REQUIRED)

include_directories(include)

set(SOURCES
    src/BaseRobot.cpp
    src/SortBot.cpp
    src/DigDeepBot.cpp
    src/RandomBot.cpp
    src/World.cpp
    src/Game.cpp
)

add_executable(deep_miner
    ${SOURCES}
    main.cpp
)

add_executable(deep_miner_tests
    ${SOURCES}
    tests/test_all.cpp
)

target_link_libraries(deep_miner       Threads::Threads)
target_link_libraries(deep_miner_tests Threads::Threads)
```

Build and run:

```bash
mkdir build
cd build
cmake ..
cmake --build .
./deep_miner
./deep_miner_tests
```

Every new `.cpp` file must be added to `SOURCES` so it is compiled into both the game and the test target.

---

## 5. Assignment Levels

### 5.1 Stufe 1 – Parallel Threads and Conservation Check

Stufe 1 replaces the old sequential two-robot loop with one thread per robot.

#### setup()

```cpp
void Game::setup() {
    const int n = validateInput("Number of robots (5-10): ", 5, 10);

    const std::vector<std::pair<int, int>> startTable = {
        {0,0}, {4,4}, {0,4}, {4,0}, {2,2},
        {0,2}, {4,2}, {2,0}, {2,4}, {1,1}
    };

    robots_.reserve(n);
    threadTimes_.resize(n);
    deathRecorded_.assign(n, false);

    for (int i = 0; i < n; ++i) {
        std::cout << "Robot " << (i + 1) << ":\n";
        int type = validateInput(
            "  Type (1=SortBot  2=DigDeepBot  3=RandomBot): ", 1, 3);

        auto [sx, sy] = startTable[i % startTable.size()];
        robots_.push_back(createRobot(type, sx, sy));
    }
}
```

#### run()

```cpp
void Game::run() {
    std::cout << "=== PARALLEL DEEP MINER ===\n\n";
    setup();

    const int initialWorldSum = computeWorldSum();
    std::cout << "Initial world sum: " << initialWorldSum << "\n";
    world_.display();

    {
        ScopedTimer totalTimer(totalTime_);

        std::vector<std::thread> threads;
        threads.reserve(robots_.size());

        for (int i = 0; i < static_cast<int>(robots_.size()); ++i)
            threads.emplace_back(&Game::robotLoop, this, i);

        for (auto& t : threads)
            t.join();
    } // totalTimer destructor stores totalTime_

    printScores();

    const int liveScore = computeLivingScore();
    const int deadScore = computeDeadScore();
    const int remainingWorldSum = computeWorldSum();
    const int conservedTotal = liveScore + deadScore + remainingWorldSum;

    std::cout << "\n--- Conservation Check ---\n"
              << "Initial world sum   : " << initialWorldSum << "\n"
              << "Living robot scores : " << liveScore << "\n"
              << "Dead robot scores   : " << deadScore << "\n"
              << "Remaining world sum : " << remainingWorldSum << "\n"
              << "Conserved total     : " << conservedTotal << "\n"
              << (initialWorldSum == conservedTotal
                    ? "Conservation check: OK\n"
                    : "Conservation check: MISMATCH\n");

    std::cout << "\n--- Thread Timing ---\n";
    for (int i = 0; i < static_cast<int>(robots_.size()); ++i) {
        std::cout << "Thread " << i
                  << " [" << robots_[i]->getName() << "]: "
                  << std::fixed << std::setprecision(3)
                  << threadTimes_[i].count() << " s\n";
    }

    std::cout << "Total wall-clock time: "
              << std::fixed << std::setprecision(3)
              << totalTime_.count() << " s\n";

    printResult();
}
```

This version checks true conservation:

```text
initialWorldSum == livingRobotScores + deadRobotScores + remainingWorldSum
```

If all robots die before the world is depleted, the check can still pass because the remaining world value is counted explicitly.

#### robotLoop()

```cpp
void Game::robotLoop(int idx) {
    ScopedTimer threadTimer(threadTimes_[idx]);
    Robot& robot = *robots_[idx];

    while (true) {
        {
            std::lock_guard<std::mutex> lk(turnMutex_);

            if (!robot.isAlive()) {
                recordDeath(idx, "killed earlier");
                break;
            }

            if (isGameOver()) {
                break;
            }

            const int dir = robot.decideNextMove(world_);
            robot.move(dir, world_);

            const int effect = world_.checkEffects(robot.getX(), robot.getY());
            if (effect < 0) {
                applyEffect(robot, effect);
            }

            if (!robot.isAlive()) {
                recordDeath(idx, "killed by effect");
                break;
            }

            fightNearby(robot);

            if (!robot.isAlive()) {
                recordDeath(idx, "killed in combat");
                break;
            }

            if (effect != -1) {
                const int mined = robot.mine(world_);
                log(robot.getName() + " mined " + std::to_string(mined) + " points.");
            }

            checkRearrange(robot);
        }

        std::this_thread::sleep_for(std::chrono::milliseconds(10));
    }
} // threadTimer destructor stores threadTimes_[idx]
```

#### recordDeath()

```cpp
void Game::recordDeath(int idx, const std::string& reason) {
    if (deathRecorded_[idx]) return;

    Robot& robot = *robots_[idx];
    deadRobotScores_.push_back(robot.getScore());
    deathRecorded_[idx] = true;

    log("[DEAD] " + robot.getName() + " " + reason
        + " – final score " + std::to_string(robot.getScore()) + " recorded.");
}
```

`recordDeath()` is called only while `turnMutex_` is held.

#### Score helpers

```cpp
int Game::computeLivingScore() const {
    int sum = 0;
    for (const auto& r : robots_) {
        if (r->isAlive()) sum += r->getScore();
    }
    return sum;
}

int Game::computeDeadScore() const {
    int sum = 0;
    for (int s : deadRobotScores_) sum += s;
    return sum;
}
```

Dead robots remain inside `robots_`, so summing all robot scores plus `deadRobotScores_` would double-count dead robots. Either sum only living robot scores plus dead scores, or skip `deadRobotScores_` and sum every robot directly. The version above is clearer because it documents the death handoff.

---

### 5.2 Stufe 2 – RAII Thread Timing

Stufe 2 uses `ScopedTimer` instead of manually writing start/stop code.

#### Why RAII?

RAII makes timing hard to forget:

```cpp
void someFunction() {
    ScopedTimer timer(durationSlot);

    // Work happens here.
    // All returns and breaks still run the destructor.
}
```

When the scope exits, the destructor writes the elapsed time. This works even if the function leaves through an early `return` or a `break` exits a loop inside the scope.

#### Game data members

```cpp
using Duration = ScopedTimer::Duration;

std::vector<Duration> threadTimes_;
Duration totalTime_{};
```

#### Thread measurement

```cpp
void Game::robotLoop(int idx) {
    ScopedTimer threadTimer(threadTimes_[idx]);
    // full robot loop
}
```

Each thread writes only to `threadTimes_[idx]`. The vector is resized before any thread starts, so this is safe.

#### Total measurement

```cpp
{
    ScopedTimer totalTimer(totalTime_);
    // launch and join all threads
}
```

The braces are intentional. They force the destructor to run before timing is printed.

---

### 5.3 Stufe 3 – Robot Combat

Stufe 3 adds HP, combat, and permanent death.

#### applyEffect()

```cpp
void Game::applyEffect(Robot& robot, int effect) {
    std::ostringstream oss;

    switch (effect) {
        case -1:
            oss << "[EFFECT -1] " << robot.getName()
                << " is blocked and may not mine this turn.";
            break;

        case -2: {
            int bestX = robot.getX();
            int bestY = robot.getY();
            int bestValue = std::numeric_limits<int>::max();

            for (int x = 0; x < world_.getSizeX(); ++x) {
                for (int y = 0; y < world_.getSizeY(); ++y) {
                    const int value = world_.getSurfaceValue(x, y);
                    if (value < bestValue) {
                        bestValue = value;
                        bestX = x;
                        bestY = y;
                    }
                }
            }

            robot.setPosition(bestX, bestY);
            oss << "[EFFECT -2] " << robot.getName()
                << " teleported to (" << bestX << ", " << bestY << ").";
            break;
        }

        case -3:
            robot.takeDamage(30);
            oss << "[EFFECT -3] " << robot.getName()
                << " takes 30 HP damage. HP=" << robot.getHp();
            break;

        default:
            return;
    }

    log(oss.str());
}
```

Effect `-3` damages HP only. It must not subtract score, because score destruction breaks point conservation.

#### fightNearby()

```cpp
void Game::fightNearby(Robot& attacker) {
    static std::mt19937 rng{std::random_device{}()};
    std::uniform_int_distribution<int> dmgDist(5, 25);

    for (auto& targetPtr : robots_) {
        Robot& target = *targetPtr;

        if (&target == &attacker) continue;
        if (!target.isAlive()) continue;

        const int dx = std::abs(attacker.getX() - target.getX());
        const int dy = std::abs(attacker.getY() - target.getY());

        if (dx <= 1 && dy <= 1) {
            const int dmg = dmgDist(rng);
            target.takeDamage(dmg);

            std::ostringstream oss;
            oss << attacker.getName() << " attacked "
                << target.getName() << " for " << dmg
                << " damage. HP=" << target.getHp();

            if (!target.isAlive()) oss << " [DEAD]";
            log(oss.str());
        }
    }
}
```

This function is called while `turnMutex_` is held, so robot HP reads/writes are data-race free.

A target killed in `fightNearby()` records its score when its own thread next acquires the mutex. That is why the top of `robotLoop()` checks `!robot.isAlive()` before checking `isGameOver()`.

---

### 5.4 Adding SmartBot

`SmartBot` mines the entire positive content of a column only when the average positive value exceeds a threshold.

#### include/SmartBot.h

```cpp
#pragma once
#include "BaseRobot.h"

class SmartBot : public BaseRobot {
public:
    explicit SmartBot(int startX, int startY, int threshold = 5);

    int mine(World& world) override;
    int decideNextMove(const World& world) const override;

private:
    int threshold_;
    double columnAverage(const World& world, int x, int y) const;
};
```

#### src/SmartBot.cpp

```cpp
#include "../include/SmartBot.h"
#include "../include/World.h"

SmartBot::SmartBot(int startX, int startY, int threshold)
    : BaseRobot("SmartBot", startX, startY), threshold_(threshold) {}

double SmartBot::columnAverage(const World& world, int x, int y) const {
    int sum = 0;
    int count = 0;

    const int surface = world.getSurfaceLevel(x, y);
    for (int z = 0; z <= surface; ++z) {
        const int v = world.getValue(x, y, z);
        if (v > 0) {
            sum += v;
            ++count;
        }
    }

    return count == 0 ? 0.0 : static_cast<double>(sum) / count;
}

int SmartBot::mine(World& world) {
    if (columnAverage(world, x_, y_) <= threshold_) {
        return 0;
    }

    const int total = world.collectPositiveColumn(x_, y_);
    score_ += total;
    return total;
}

int SmartBot::decideNextMove(const World& world) const {
    int bestDir = 0;
    double bestAvg = -1.0;

    auto check = [&](int dx, int dy, int dir) {
        const int nx = x_ + dx;
        const int ny = y_ + dy;
        if (nx < 0 || nx >= world.getSizeX()) return;
        if (ny < 0 || ny >= world.getSizeY()) return;

        const double avg = columnAverage(world, nx, ny);
        if (avg > bestAvg) {
            bestAvg = avg;
            bestDir = dir;
        }
    };

    check( 0,  0, 0);
    check( 1,  0, 1);
    check(-1,  0, 2);
    check( 0,  1, 3);
    check( 0, -1, 4);

    return bestDir;
}
```

This version does not call `setValue(..., 0)`. It stays compatible with dynamic columns.

#### Register SmartBot

```cpp
// setup() prompt
int type = validateInput(
    "  Type (1=SortBot  2=DigDeepBot  3=RandomBot  4=SmartBot): ", 1, 4);

// createRobot()
case 4:
    return std::make_unique<SmartBot>(x, y);
```

Add `src/SmartBot.cpp` to `SOURCES`.

---

### 5.5 Adding LookaheadBot

`LookaheadBot` chooses a move by estimating the best two-turn yield without mutating the world.

#### include/LookaheadBot.h

```cpp
#pragma once
#include "BaseRobot.h"

class LookaheadBot : public BaseRobot {
public:
    LookaheadBot(int startX, int startY);

    int mine(World& world) override;
    int decideNextMove(const World& world) const override;

private:
    int lookaheadScore(const World& world, int x, int y, int depth) const;
    int columnTopValue(const World& world, int x, int y, int blocks) const;
};
```

#### src/LookaheadBot.cpp

```cpp
#include "../include/LookaheadBot.h"
#include "../include/World.h"

#include <algorithm>

LookaheadBot::LookaheadBot(int startX, int startY)
    : BaseRobot("LookaheadBot", startX, startY) {}

int LookaheadBot::columnTopValue(const World& world, int x, int y, int blocks) const {
    int sum = 0;
    int grabbed = 0;

    for (int z = world.getSurfaceLevel(x, y); z >= 0 && grabbed < blocks; --z) {
        const int v = world.getValue(x, y, z);
        if (v > 0) {
            sum += v;
            ++grabbed;
        }
    }

    return sum;
}

int LookaheadBot::lookaheadScore(const World& world, int x, int y, int depth) const {
    if (depth == 0) {
        return columnTopValue(world, x, y, 3);
    }

    int best = 0;

    auto tryMove = [&](int nx, int ny) {
        if (nx < 0 || nx >= world.getSizeX()) return;
        if (ny < 0 || ny >= world.getSizeY()) return;

        const int score = columnTopValue(world, nx, ny, 3)
                        + lookaheadScore(world, nx, ny, depth - 1);
        best = std::max(best, score);
    };

    tryMove(x,     y);
    tryMove(x + 1, y);
    tryMove(x - 1, y);
    tryMove(x, y + 1);
    tryMove(x, y - 1);

    return best;
}

int LookaheadBot::decideNextMove(const World& world) const {
    int bestDir = 0;
    int bestScore = -1;

    auto check = [&](int dx, int dy, int dir) {
        const int nx = x_ + dx;
        const int ny = y_ + dy;
        if (nx < 0 || nx >= world.getSizeX()) return;
        if (ny < 0 || ny >= world.getSizeY()) return;

        const int score = lookaheadScore(world, nx, ny, 1);
        if (score > bestScore) {
            bestScore = score;
            bestDir = dir;
        }
    };

    check( 0,  0, 0);
    check( 1,  0, 1);
    check(-1,  0, 2);
    check( 0,  1, 3);
    check( 0, -1, 4);

    return bestDir;
}

int LookaheadBot::mine(World& world) {
    int total = 0;

    for (int i = 0; i < 3; ++i) {
        const int points = world.mine(x_, y_);
        if (points <= 0) break;
        total += points;
    }

    score_ += total;
    return total;
}
```

This version estimates using `getValue()` but mutates with `world.mine()`, preserving the dynamic-column model.

---

## 6. Writing Tests

The project uses a small custom test framework in `tests/test_all.cpp`.

### Test macros

```cpp
TEST("Description", {
    ASSERT(condition);
    ASSERT_EQ(actual, expected);
});
```

### Deterministic test worlds

Do not create an empty world by setting every cell to `0`. With dynamic columns, that creates full columns containing zero values. Use `clear()` and `setColumn()`.

```cpp
static World makeEmptyWorld(int x = 5, int y = 5, int z = 10) {
    World w(x, y, z);
    w.clear();
    return w;
}
```

### HP tests

```cpp
static void test_baserobot_combat() {
    TEST("Full HP at construction", {
        SortBot bot(0, 0);
        ASSERT_EQ(bot.getHp(), 100);
        ASSERT_EQ(bot.isAlive(), true);
    });

    TEST("takeDamage reduces HP", {
        SortBot bot(0, 0);
        bot.takeDamage(20);
        ASSERT_EQ(bot.getHp(), 80);
        ASSERT_EQ(bot.isAlive(), true);
    });

    TEST("Fatal damage clamps HP to zero", {
        SortBot bot(0, 0);
        bot.takeDamage(200);
        ASSERT_EQ(bot.getHp(), 0);
        ASSERT_EQ(bot.isAlive(), false);
    });
}
```

### SmartBot tests

```cpp
static void test_smartbot_mine() {
    TEST("Does not mine when average is too low", {
        World w = makeEmptyWorld(3, 3, 5);
        w.setColumn(1, 1, {3});

        SmartBot bot(1, 1, 5);
        ASSERT_EQ(bot.mine(w), 0);
        ASSERT_EQ(bot.getScore(), 0);
        ASSERT_EQ(w.getSurfaceValue(1, 1), 3);
    });

    TEST("Mines positive column when average is high enough", {
        World w = makeEmptyWorld(3, 3, 5);
        w.setColumn(1, 1, {7, 8});

        SmartBot bot(1, 1, 5);
        ASSERT_EQ(bot.mine(w), 15);
        ASSERT_EQ(bot.getScore(), 15);
        ASSERT_EQ(w.getSurfaceLevel(1, 1), -1);
    });

    TEST("Keeps effects when collecting positives", {
        World w = makeEmptyWorld(3, 3, 5);
        w.setColumn(1, 1, {4, -2, 8});

        SmartBot bot(1, 1, 5);
        ASSERT_EQ(bot.mine(w), 12);
        ASSERT_EQ(w.getSurfaceLevel(1, 1), 0);
        ASSERT_EQ(w.getSurfaceValue(1, 1), -2);
    });
}
```

### Timing tests

```cpp
static void test_scoped_timer() {
    TEST("ScopedTimer writes elapsed duration on destruction", {
        ScopedTimer::Duration elapsed{};
        {
            ScopedTimer timer(elapsed);
            std::this_thread::sleep_for(std::chrono::milliseconds(1));
        }
        ASSERT(elapsed.count() > 0.0);
    });
}
```

---

## 7. Design Principles and Best Practices

### Single Responsibility Principle

| Class | Responsibility |
|---|---|
| `World` | Manage grid data and stack operations |
| `Robot` | Define the robot contract |
| `BaseRobot` | Shared robot state, movement, HP/death |
| `*Bot` | Concrete mining and movement strategy |
| `Game` | Thread lifecycle, turns, effects, combat, score/timing output |
| `ScopedTimer` | Elapsed-time measurement through RAII |

### Open/Closed Principle

Adding a robot type should not require changes to `World`, `BaseRobot`, or the thread model. Update only the new robot files, the robot factory, the menu prompt, and CMake.

### RAII

Use RAII for both resource management and timing:

- `std::unique_ptr<Robot>` releases robots automatically.
- `std::lock_guard<std::mutex>` releases the mutex automatically.
- `ScopedTimer` stores elapsed time automatically.

### Const-correctness

Make read-only methods `const`:

```cpp
int getScore() const override;
int decideNextMove(const World& world) const override;
int getHp() const override;
bool isAlive() const override;
```

### Thread safety

The safe rule is simple:

> Every read or write of `world_`, robot score, robot position, or robot HP happens while `turnMutex_` is held.

The 10 ms sleep must stay outside the lock. Otherwise one sleeping thread would block every other robot.

---

## 8. Common Pitfalls and Solutions

### Pitfall 1: Missing `.cpp` file in CMake

**Symptom:** linker error such as `undefined reference to SmartBot::mine`.

**Solution:** add the file to `SOURCES`.

### Pitfall 2: Adding score twice

**Symptom:** scores are too high.

**Cause:** `mine()` already updates `score_`, and `robotLoop()` also calls `addScore()`.

**Solution:** `robotLoop()` should log the returned value only.

```cpp
const int mined = robot.mine(world_);
log(robot.getName() + " mined " + std::to_string(mined) + " points.");
```

### Pitfall 3: Using zero sentinels in dynamic columns

**Symptom:** empty columns are not really empty, surface levels are wrong, and tests behave strangely.

**Solution:** use `clear()`, `setColumn()`, `mine()`, and stack-aware helpers. Do not use `setValue(..., 0)` as a mining operation.

### Pitfall 4: Dead scores are double-counted or lost

**Double-counted:** summing all `robots_` scores and also summing `deadRobotScores_`.

**Lost:** checking `isGameOver()` before checking whether the current robot is dead.

**Solution:** at the top of `robotLoop()`, record death first, then check game over. At the end, compute `livingScore + deadScore + remainingWorldSum`.

### Pitfall 5: Non-monotonic timing clock

**Symptom:** rare negative or odd elapsed times on systems where wall clock changes.

**Solution:** use `std::chrono::steady_clock` inside `ScopedTimer`.

### Pitfall 6: Holding the lock while sleeping

**Symptom:** one robot monopolizes the game.

**Solution:** keep `sleep_for(10 ms)` after the lock-guard scope.

### Pitfall 7: GUI snippets reference old two-robot state

The GUI has been moved to a separate guide and rewritten to use `std::vector<std::unique_ptr<Robot>>`. The terminal guide should not mention `player_`, `computer_`, `autoMode_`, or `play(Robot&, bool)`.

---

## 9. Advanced Extension Ideas

### Monte Carlo Tree Search

Replace the simple lookahead with Monte Carlo Tree Search. Simulations should operate on copied/snapshot world data, not the shared `world_` object.

### Achievement System

Track milestones such as:

- first 50-point threshold
- three blocks mined in one turn
- first effect triggered
- first robot defeated
- surviving with 1 HP

### Persistent Highscore Table

Save the top 10 results to a local file. Include robot types, total collected score, remaining world sum, and game duration.

### GUI Renderer

Use the separate `SDL2_GUI_EXTENSION_GUIDE.md`. It documents the optional renderer, pimpl interface, CMake target, and integration points for the parallel robot vector.

---

## 10. Project Structure

```text
deep_miner/
|-- CMakeLists.txt
|-- main.cpp
|-- include/
|   |-- Robot.h
|   |-- BaseRobot.h
|   |-- SortBot.h
|   |-- DigDeepBot.h
|   |-- RandomBot.h
|   |-- World.h
|   |-- ScopedTimer.h
|   `-- Game.h
|-- src/
|   |-- BaseRobot.cpp
|   |-- SortBot.cpp
|   |-- DigDeepBot.cpp
|   |-- RandomBot.cpp
|   |-- World.cpp
|   `-- Game.cpp
|-- tests/
|   `-- test_all.cpp
`-- docs/
    |-- PARALLEL_DEEP_MINER_GUIDE.md
    `-- SDL2_GUI_EXTENSION_GUIDE.md
```

The optional GUI target adds:

```text
include/Renderer.h
src/Renderer.cpp
main_gui.cpp
```

Keep GUI dependencies out of the terminal target.

---

*This revised guide documents the fully parallel terminal implementation. It fixes score accounting, dynamic-column examples, deterministic tests, and timing by using an RAII `ScopedTimer` whose constructor starts measurement and destructor stores the elapsed duration.*

---

## Appendix A: Complete Core Source Code

This appendix contains a complete terminal-only version of the project. It uses dynamic stack columns, `ScopedTimer` for RAII timing, living/dead/remaining score conservation, and includes `SmartBot` and `LookaheadBot` so the menu and build file are self-contained.

### `CMakeLists.txt`

```cmake
cmake_minimum_required(VERSION 3.15)
project(deep_miner)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

find_package(Threads REQUIRED)
include_directories(include)

set(SOURCES
    src/BaseRobot.cpp
    src/SortBot.cpp
    src/DigDeepBot.cpp
    src/RandomBot.cpp
    src/SmartBot.cpp
    src/LookaheadBot.cpp
    src/ScopedTimer.cpp
    src/World.cpp
    src/Game.cpp
)

add_executable(deep_miner ${SOURCES} main.cpp)
add_executable(deep_miner_tests ${SOURCES} tests/test_all.cpp)

target_link_libraries(deep_miner Threads::Threads)
target_link_libraries(deep_miner_tests Threads::Threads)
```

### `main.cpp`

```cpp
#include "Game.h"
#include <exception>
#include <iostream>

int main() {
    try {
        Game game;
        game.run();
        return 0;
    } catch (const std::exception& e) {
        std::cerr << "Fatal error: " << e.what() << "\n";
        return 1;
    }
}
```

### `include/Robot.h`

```cpp
#pragma once
#include <string>
class World;

class Robot {
public:
    virtual ~Robot() = default;
    virtual void move(int direction, const World& world) = 0;
    virtual int mine(World& world) = 0;
    virtual int decideNextMove(const World& world) const = 0;
    virtual void setPosition(int x, int y) = 0;
    virtual int getScore() const = 0;
    virtual void addScore(int points) = 0;
    virtual int getX() const = 0;
    virtual int getY() const = 0;
    virtual std::string getName() const = 0;
    virtual int getHp() const = 0;
    virtual bool isAlive() const = 0;
    virtual void takeDamage(int damage) = 0;
};
```

### `include/ScopedTimer.h`

```cpp
#pragma once
#include <chrono>

class ScopedTimer {
public:
    using Clock = std::chrono::steady_clock;
    using Duration = std::chrono::duration<double>;

    explicit ScopedTimer(Duration& output);
    ~ScopedTimer();

    ScopedTimer(const ScopedTimer&) = delete;
    ScopedTimer& operator=(const ScopedTimer&) = delete;

private:
    Duration& output_;
    Clock::time_point start_;
};
```

### `src/ScopedTimer.cpp`

```cpp
#include "ScopedTimer.h"

ScopedTimer::ScopedTimer(Duration& output)
    : output_(output), start_(Clock::now()) {}

ScopedTimer::~ScopedTimer() {
    output_ = Clock::now() - start_;
}
```

### `include/World.h`

```cpp
#pragma once
#include <memory>
#include <vector>
class Robot;

class World {
public:
    World(int x = 5, int y = 5, int z = 10);

    int getSizeX() const { return sizeX_; }
    int getSizeY() const { return sizeY_; }
    int getSizeZ() const { return sizeZ_; }

    int getValue(int x, int y, int z) const;
    void setValue(int x, int y, int z, int value);
    void setColumn(int x, int y, const std::vector<int>& values);
    std::vector<int> getColumn(int x, int y) const;
    void clear();

    int getSurfaceLevel(int x, int y) const;
    int getSurfaceValue(int x, int y) const;
    bool hasPositiveValues() const;
    int remainingPositiveSum() const;

    int checkEffects(int x, int y);
    int mine(int x, int y);
    int mineAllPositive(int x, int y);

    double positiveAverage(int x, int y) const;
    int topPositiveSum(int x, int y, int blocks) const;
    void sortPositiveValuesInColumnAscending(int x, int y);
    void rearrange();

    void display() const;
    void display(const std::vector<std::unique_ptr<Robot>>& robots) const;

private:
    int sizeX_;
    int sizeY_;
    int sizeZ_;
    std::vector<std::vector<std::vector<int>>> grid_;

    void init();
    void validateXY(int x, int y) const;
    void validateZ(int z) const;
};
```

### `src/World.cpp`

```cpp
#include "World.h"
#include "Robot.h"

#include <algorithm>
#include <iomanip>
#include <iostream>
#include <random>
#include <stdexcept>
#include <utility>

World::World(int x, int y, int z)
    : sizeX_(x), sizeY_(y), sizeZ_(z), grid_(x, std::vector<std::vector<int>>(y)) {
    if (x <= 0 || y <= 0 || z <= 0) throw std::invalid_argument("World dimensions must be positive.");
    init();
}

void World::init() {
    std::mt19937 rng{std::random_device{}()};
    std::uniform_int_distribution<int> valueDist(1, 9);
    std::uniform_int_distribution<int> effectChance(1, 10);
    std::uniform_int_distribution<int> effectDist(1, 3);
    for (int x = 0; x < sizeX_; ++x)
        for (int y = 0; y < sizeY_; ++y) {
            auto& col = grid_[x][y];
            col.clear();
            col.reserve(sizeZ_);
            for (int z = 0; z < sizeZ_; ++z)
                col.push_back(effectChance(rng) == 1 ? -effectDist(rng) : valueDist(rng));
        }
}

void World::validateXY(int x, int y) const {
    if (x < 0 || x >= sizeX_ || y < 0 || y >= sizeY_) throw std::out_of_range("World coordinate out of range.");
}

void World::validateZ(int z) const {
    if (z < 0 || z >= sizeZ_) throw std::out_of_range("World depth out of range.");
}

int World::getValue(int x, int y, int z) const {
    validateXY(x, y); validateZ(z);
    const auto& col = grid_[x][y];
    return z < static_cast<int>(col.size()) ? col[z] : 0;
}

void World::setValue(int x, int y, int z, int value) {
    validateXY(x, y); validateZ(z);
    auto& col = grid_[x][y];
    if (value == 0) {
        if (z < static_cast<int>(col.size())) col.erase(col.begin() + z);
        return;
    }
    if (z > static_cast<int>(col.size())) throw std::logic_error("setValue would create holes; use setColumn instead.");
    if (z == static_cast<int>(col.size())) col.push_back(value);
    else col[z] = value;
}

void World::setColumn(int x, int y, const std::vector<int>& values) {
    validateXY(x, y);
    if (static_cast<int>(values.size()) > sizeZ_) throw std::out_of_range("Column is too deep.");
    grid_[x][y] = values;
}

std::vector<int> World::getColumn(int x, int y) const {
    validateXY(x, y);
    return grid_[x][y];
}

void World::clear() {
    for (auto& row : grid_) for (auto& col : row) col.clear();
}

int World::getSurfaceLevel(int x, int y) const {
    validateXY(x, y);
    const auto& col = grid_[x][y];
    return col.empty() ? -1 : static_cast<int>(col.size()) - 1;
}

int World::getSurfaceValue(int x, int y) const {
    validateXY(x, y);
    const auto& col = grid_[x][y];
    return col.empty() ? 0 : col.back();
}

int World::remainingPositiveSum() const {
    int sum = 0;
    for (const auto& row : grid_) for (const auto& col : row) for (int v : col) if (v > 0) sum += v;
    return sum;
}

bool World::hasPositiveValues() const {
    return remainingPositiveSum() > 0;
}

int World::checkEffects(int x, int y) {
    validateXY(x, y);
    auto& col = grid_[x][y];
    if (!col.empty() && col.back() < 0) {
        int effect = col.back();
        col.pop_back();
        return effect;
    }
    return 0;
}

int World::mine(int x, int y) {
    validateXY(x, y);
    auto& col = grid_[x][y];
    if (col.empty()) return 0;
    int value = col.back();
    col.pop_back();
    return value > 0 ? value : 0;
}

int World::mineAllPositive(int x, int y) {
    validateXY(x, y);
    auto& col = grid_[x][y];
    int total = 0;
    std::vector<int> kept;
    kept.reserve(col.size());
    for (int v : col) {
        if (v > 0) total += v;
        else kept.push_back(v);
    }
    col = std::move(kept);
    return total;
}

double World::positiveAverage(int x, int y) const {
    validateXY(x, y);
    int sum = 0, count = 0;
    for (int v : grid_[x][y]) if (v > 0) { sum += v; ++count; }
    return count == 0 ? 0.0 : static_cast<double>(sum) / count;
}

int World::topPositiveSum(int x, int y, int blocks) const {
    validateXY(x, y);
    int sum = 0, count = 0;
    const auto& col = grid_[x][y];
    for (auto it = col.rbegin(); it != col.rend() && count < blocks; ++it)
        if (*it > 0) { sum += *it; ++count; }
    return sum;
}

void World::sortPositiveValuesInColumnAscending(int x, int y) {
    validateXY(x, y);
    auto& col = grid_[x][y];
    std::vector<int> positives;
    for (int v : col) if (v > 0) positives.push_back(v);
    std::sort(positives.begin(), positives.end());
    auto it = positives.begin();
    for (int& v : col) if (v > 0) v = *it++;
}

void World::rearrange() {
    std::mt19937 rng{std::random_device{}()};
    std::uniform_int_distribution<int> opDist(0, 2);
    for (auto& row : grid_) for (auto& col : row) {
        std::vector<int> positives;
        for (int v : col) if (v > 0) positives.push_back(v);
        int op = opDist(rng);
        if (op == 0) std::shuffle(positives.begin(), positives.end(), rng);
        else if (op == 1) std::sort(positives.begin(), positives.end());
        else std::sort(positives.rbegin(), positives.rend());
        auto it = positives.begin();
        for (int& v : col) if (v > 0) v = *it++;
    }
}

void World::display() const {
    std::cout << "\nWorld surface values:\n";
    for (int y = 0; y < sizeY_; ++y) {
        for (int x = 0; x < sizeX_; ++x) {
            int v = getSurfaceValue(x, y);
            if (v == 0) std::cout << std::setw(4) << "--";
            else std::cout << std::setw(4) << v;
        }
        std::cout << "\n";
    }
}

void World::display(const std::vector<std::unique_ptr<Robot>>& robots) const {
    display();
    std::cout << "Robots:\n";
    for (const auto& r : robots)
        std::cout << "  " << r->getName() << " @ (" << r->getX() << "," << r->getY() << ")"
                  << " score=" << r->getScore() << " hp=" << r->getHp()
                  << (r->isAlive() ? "" : " [DEAD]") << "\n";
}
```

### `include/BaseRobot.h`

```cpp
#pragma once
#include "Robot.h"
#include <string>

class BaseRobot : public Robot {
public:
    BaseRobot(std::string name, int startX, int startY);
    ~BaseRobot() override = default;

    void move(int direction, const World& world) override;
    int decideNextMove(const World& world) const override;
    void setPosition(int x, int y) override;

    int getScore() const override { return score_; }
    void addScore(int points) override { score_ += points; }
    int getX() const override { return x_; }
    int getY() const override { return y_; }
    std::string getName() const override { return name_; }
    int getHp() const override { return hp_; }
    bool isAlive() const override { return hp_ > 0; }
    void takeDamage(int damage) override;

protected:
    int x_ = 0;
    int y_ = 0;
    int score_ = 0;
    std::string name_;
    int hp_ = 100;
    static constexpr int kMaxHp = 100;
};
```

### `src/BaseRobot.cpp`

```cpp
#include "BaseRobot.h"
#include "World.h"
#include <algorithm>
#include <cstdlib>
#include <limits>
#include <utility>

BaseRobot::BaseRobot(std::string name, int startX, int startY)
    : x_(startX), y_(startY), name_(std::move(name)) {}

void BaseRobot::move(int direction, const World& world) {
    int nx = x_, ny = y_;
    if (direction == 1) ++nx;
    else if (direction == 2) --nx;
    else if (direction == 3) ++ny;
    else if (direction == 4) --ny;
    x_ = std::clamp(nx, 0, world.getSizeX() - 1);
    y_ = std::clamp(ny, 0, world.getSizeY() - 1);
}

int BaseRobot::decideNextMove(const World& world) const {
    const int dirs[5][3] = {{0,0,0},{1,0,1},{-1,0,2},{0,1,3},{0,-1,4}};
    int bestDir = 0, bestValue = -1;
    for (const auto& d : dirs) {
        int nx = x_ + d[0], ny = y_ + d[1];
        if (nx < 0 || nx >= world.getSizeX() || ny < 0 || ny >= world.getSizeY()) continue;
        int v = world.getSurfaceValue(nx, ny);
        if (v > bestValue) { bestValue = v; bestDir = d[2]; }
    }
    if (bestValue > 0) return bestDir;

    int bestDistance = std::numeric_limits<int>::max();
    int targetX = x_, targetY = y_;
    for (int x = 0; x < world.getSizeX(); ++x)
        for (int y = 0; y < world.getSizeY(); ++y)
            if (world.topPositiveSum(x, y, 1) > 0) {
                int dist = std::abs(x - x_) + std::abs(y - y_);
                if (dist < bestDistance) { bestDistance = dist; targetX = x; targetY = y; }
            }
    if (bestDistance == std::numeric_limits<int>::max()) return 0;
    if (targetX > x_) return 1;
    if (targetX < x_) return 2;
    if (targetY > y_) return 3;
    if (targetY < y_) return 4;
    return 0;
}

void BaseRobot::setPosition(int x, int y) { x_ = x; y_ = y; }

void BaseRobot::takeDamage(int damage) {
    hp_ -= damage;
    if (hp_ < 0) hp_ = 0;
}
```

### `include/SortBot.h`

```cpp
#pragma once
#include "BaseRobot.h"
class SortBot : public BaseRobot {
public:
    SortBot(int startX, int startY);
    int mine(World& world) override;
};
```

### `src/SortBot.cpp`

```cpp
#include "SortBot.h"
#include "World.h"

SortBot::SortBot(int startX, int startY) : BaseRobot("SortBot", startX, startY) {}

int SortBot::mine(World& world) {
    world.sortPositiveValuesInColumnAscending(x_, y_);
    int mined = world.mine(x_, y_);
    score_ += mined;
    return mined;
}
```

### `include/DigDeepBot.h`

```cpp
#pragma once
#include "BaseRobot.h"
class DigDeepBot : public BaseRobot {
public:
    DigDeepBot(int startX, int startY);
    int mine(World& world) override;
};
```

### `src/DigDeepBot.cpp`

```cpp
#include "DigDeepBot.h"
#include "World.h"

DigDeepBot::DigDeepBot(int startX, int startY) : BaseRobot("DigDeepBot", startX, startY) {}

int DigDeepBot::mine(World& world) {
    int total = 0;
    for (int i = 0; i < 3; ++i) {
        int mined = world.mine(x_, y_);
        if (mined <= 0) break;
        total += mined;
    }
    score_ += total;
    return total;
}
```

### `include/RandomBot.h`

```cpp
#pragma once
#include "BaseRobot.h"
class RandomBot : public BaseRobot {
public:
    RandomBot(int startX, int startY);
    int mine(World& world) override;
};
```

### `src/RandomBot.cpp`

```cpp
#include "RandomBot.h"
#include "World.h"
#include <random>

RandomBot::RandomBot(int startX, int startY) : BaseRobot("RandomBot", startX, startY) {}

int RandomBot::mine(World& world) {
    static thread_local std::mt19937 rng{std::random_device{}()};
    std::uniform_int_distribution<int> countDist(0, 9);
    int attempts = countDist(rng);
    int total = 0;
    for (int i = 0; i < attempts; ++i) {
        int mined = world.mine(x_, y_);
        if (mined <= 0) break;
        total += mined;
    }
    score_ += total;
    return total;
}
```

### `include/SmartBot.h`

```cpp
#pragma once
#include "BaseRobot.h"
class SmartBot : public BaseRobot {
public:
    explicit SmartBot(int startX, int startY, int threshold = 5);
    int mine(World& world) override;
    int decideNextMove(const World& world) const override;
private:
    int threshold_;
};
```

### `src/SmartBot.cpp`

```cpp
#include "SmartBot.h"
#include "World.h"

SmartBot::SmartBot(int startX, int startY, int threshold)
    : BaseRobot("SmartBot", startX, startY), threshold_(threshold) {}

int SmartBot::mine(World& world) {
    if (world.positiveAverage(x_, y_) <= threshold_) return 0;
    int total = world.mineAllPositive(x_, y_);
    score_ += total;
    return total;
}

int SmartBot::decideNextMove(const World& world) const {
    const int dirs[5][3] = {{0,0,0},{1,0,1},{-1,0,2},{0,1,3},{0,-1,4}};
    int bestDir = 0;
    double bestAverage = -1.0;
    for (const auto& d : dirs) {
        int nx = x_ + d[0], ny = y_ + d[1];
        if (nx < 0 || nx >= world.getSizeX() || ny < 0 || ny >= world.getSizeY()) continue;
        double avg = world.positiveAverage(nx, ny);
        if (avg > bestAverage) { bestAverage = avg; bestDir = d[2]; }
    }
    return bestDir;
}
```

### `include/LookaheadBot.h`

```cpp
#pragma once
#include "BaseRobot.h"
class LookaheadBot : public BaseRobot {
public:
    LookaheadBot(int startX, int startY);
    int mine(World& world) override;
    int decideNextMove(const World& world) const override;
private:
    int lookaheadScore(const World& world, int x, int y, int depth) const;
};
```

### `src/LookaheadBot.cpp`

```cpp
#include "LookaheadBot.h"
#include "World.h"
#include <algorithm>

LookaheadBot::LookaheadBot(int startX, int startY) : BaseRobot("LookaheadBot", startX, startY) {}

int LookaheadBot::lookaheadScore(const World& world, int x, int y, int depth) const {
    int here = world.topPositiveSum(x, y, 3);
    if (depth == 0) return here;
    int bestNext = 0;
    const int moves[5][2] = {{0,0},{1,0},{-1,0},{0,1},{0,-1}};
    for (const auto& m : moves) {
        int nx = x + m[0], ny = y + m[1];
        if (nx < 0 || nx >= world.getSizeX() || ny < 0 || ny >= world.getSizeY()) continue;
        bestNext = std::max(bestNext, lookaheadScore(world, nx, ny, depth - 1));
    }
    return here + bestNext;
}

int LookaheadBot::decideNextMove(const World& world) const {
    const int dirs[5][3] = {{0,0,0},{1,0,1},{-1,0,2},{0,1,3},{0,-1,4}};
    int bestDir = 0, bestScore = -1;
    for (const auto& d : dirs) {
        int nx = x_ + d[0], ny = y_ + d[1];
        if (nx < 0 || nx >= world.getSizeX() || ny < 0 || ny >= world.getSizeY()) continue;
        int score = lookaheadScore(world, nx, ny, 1);
        if (score > bestScore) { bestScore = score; bestDir = d[2]; }
    }
    return bestDir;
}

int LookaheadBot::mine(World& world) {
    int total = 0;
    for (int i = 0; i < 3; ++i) {
        int mined = world.mine(x_, y_);
        if (mined <= 0) break;
        total += mined;
    }
    score_ += total;
    return total;
}
```

### `include/Game.h`

```cpp
#pragma once
#include <memory>
#include <mutex>
#include <string>
#include <vector>
#include "Robot.h"
#include "ScopedTimer.h"
#include "World.h"

class Game {
public:
    Game();
    void run();

private:
    World world_;
    std::vector<std::unique_ptr<Robot>> robots_;
    std::vector<int> deadRobotScores_;
    std::mutex turnMutex_;
    int lastThreshold_ = 0;
    int round_ = 0;
    ScopedTimer::Clock::time_point programStart_;
    std::vector<ScopedTimer::Duration> threadTimes_;

    void setup();
    void robotLoop(int idx);
    void fightNearby(Robot& attacker);
    int computeWorldSum() const;
    bool isGameOver() const;
    void log(const std::string& message) const;
    void checkRearrange(Robot& robot);
    void applyEffect(Robot& robot, int effect);
    void printScores() const;
    void printResult() const;
    std::unique_ptr<Robot> createRobot(int choice, int x, int y) const;
};
```

### `src/Game.cpp`

```cpp
#include "Game.h"
#include "DigDeepBot.h"
#include "LookaheadBot.h"
#include "RandomBot.h"
#include "SmartBot.h"
#include "SortBot.h"

#include <chrono>
#include <cstdlib>
#include <iomanip>
#include <iostream>
#include <limits>
#include <numeric>
#include <random>
#include <sstream>
#include <stdexcept>
#include <thread>
#include <utility>

namespace {
int validateInput(const std::string& prompt, int min, int max) {
    int value = 0;
    while (true) {
        std::cout << prompt;
        if (std::cin >> value && value >= min && value <= max) return value;
        std::cout << "Please enter a number from " << min << " to " << max << ".\n";
        std::cin.clear();
        std::cin.ignore(10000, '\n');
    }
}
}

Game::Game() : world_(5, 5, 10) {}

void Game::run() {
    std::cout << "=== PARALLEL DEEP MINER ===\n\n";
    setup();
    int initialSum = computeWorldSum();
    std::cout << "Initial world sum: " << initialSum << "\n";
    world_.display(robots_);

    programStart_ = ScopedTimer::Clock::now();
    std::vector<std::thread> threads;
    threads.reserve(robots_.size());
    for (int i = 0; i < static_cast<int>(robots_.size()); ++i)
        threads.emplace_back(&Game::robotLoop, this, i);
    for (auto& t : threads) t.join();

    printScores();
    printResult();

    int livingScore = 0;
    for (const auto& r : robots_) if (r->isAlive()) livingScore += r->getScore();
    int deadScore = std::accumulate(deadRobotScores_.begin(), deadRobotScores_.end(), 0);
    int remainingWorld = computeWorldSum();
    int conservedTotal = livingScore + deadScore + remainingWorld;

    std::cout << "\n--- Conservation Check ---\n"
              << "Initial world sum     : " << initialSum << "\n"
              << "Living robot scores   : " << livingScore << "\n"
              << "Dead robot scores     : " << deadScore << "\n"
              << "Remaining world sum   : " << remainingWorld << "\n"
              << "Conserved total       : " << conservedTotal << "\n"
              << (initialSum == conservedTotal ? "Conservation check: OK\n" : "Conservation check: MISMATCH\n");
}

void Game::setup() {
    int n = validateInput("Number of robots (5-10): ", 5, 10);
    const std::vector<std::pair<int,int>> starts = {
        {0,0}, {4,4}, {0,4}, {4,0}, {2,2}, {0,2}, {4,2}, {2,0}, {2,4}, {1,1}
    };
    robots_.reserve(n);
    threadTimes_.resize(n);
    for (int i = 0; i < n; ++i) {
        std::cout << "Robot " << (i + 1) << ":\n";
        int type = validateInput("  Type (1=SortBot  2=DigDeepBot  3=RandomBot  4=SmartBot  5=LookaheadBot): ", 1, 5);
        auto [x, y] = starts[i % starts.size()];
        robots_.push_back(createRobot(type, x, y));
    }
}

void Game::robotLoop(int idx) {
    ScopedTimer timer(threadTimes_[idx]);
    Robot& robot = *robots_[idx];
    while (true) {
        {
            std::lock_guard<std::mutex> lock(turnMutex_);
            if (!robot.isAlive()) {
                deadRobotScores_.push_back(robot.getScore());
                log("[DEAD] " + robot.getName() + " final score " + std::to_string(robot.getScore()) + " recorded.");
                break;
            }
            if (isGameOver()) break;

            ++round_;
            int dir = robot.decideNextMove(world_);
            robot.move(dir, world_);

            int effect = world_.checkEffects(robot.getX(), robot.getY());
            if (effect < 0) applyEffect(robot, effect);
            if (!robot.isAlive()) {
                deadRobotScores_.push_back(robot.getScore());
                log("[DEAD] " + robot.getName() + " killed by effect; score recorded.");
                break;
            }

            fightNearby(robot);

            if (effect != -1) {
                int mined = robot.mine(world_);
                log(robot.getName() + " mined " + std::to_string(mined) + " points.");
            } else {
                log(robot.getName() + " is blocked and cannot mine this turn.");
            }
            checkRearrange(robot);
        }
        std::this_thread::sleep_for(std::chrono::milliseconds(10));
    }
}

void Game::fightNearby(Robot& attacker) {
    static std::mt19937 rng{std::random_device{}()};
    std::uniform_int_distribution<int> damageDist(5, 25);
    for (auto& targetPtr : robots_) {
        Robot& target = *targetPtr;
        if (&target == &attacker || !target.isAlive()) continue;
        int dx = std::abs(attacker.getX() - target.getX());
        int dy = std::abs(attacker.getY() - target.getY());
        if (dx <= 1 && dy <= 1) {
            int damage = damageDist(rng);
            target.takeDamage(damage);
            std::ostringstream oss;
            oss << attacker.getName() << " attacked " << target.getName()
                << " for " << damage << " dmg. HP=" << target.getHp()
                << (target.isAlive() ? "" : " [DEAD]");
            log(oss.str());
        }
    }
}

int Game::computeWorldSum() const { return world_.remainingPositiveSum(); }
bool Game::isGameOver() const { return !world_.hasPositiveValues(); }
void Game::log(const std::string& message) const { std::cout << message << "\n"; }

void Game::checkRearrange(Robot& robot) {
    int threshold = robot.getScore() / 50;
    if (threshold > lastThreshold_) {
        lastThreshold_ = threshold;
        world_.rearrange();
        log("*** " + robot.getName() + " reached a 50-point threshold. World rearranged. ***");
    }
}

void Game::applyEffect(Robot& robot, int effect) {
    std::ostringstream oss;
    if (effect == -1) {
        oss << "[EFFECT -1] " << robot.getName() << " is blocked this turn.";
    } else if (effect == -2) {
        int bestX = robot.getX(), bestY = robot.getY();
        int lowest = std::numeric_limits<int>::max();
        for (int x = 0; x < world_.getSizeX(); ++x)
            for (int y = 0; y < world_.getSizeY(); ++y)
                if (world_.getSurfaceValue(x, y) < lowest) {
                    lowest = world_.getSurfaceValue(x, y);
                    bestX = x; bestY = y;
                }
        robot.setPosition(bestX, bestY);
        oss << "[EFFECT -2] " << robot.getName() << " teleported to (" << bestX << "," << bestY << ").";
    } else if (effect == -3) {
        robot.takeDamage(30);
        oss << "[EFFECT -3] " << robot.getName() << " takes 30 HP damage. HP=" << robot.getHp();
    }
    log(oss.str());
}

void Game::printScores() const {
    std::cout << "\n--- Scores ---\n";
    for (const auto& r : robots_)
        std::cout << r->getName() << " score=" << r->getScore() << " hp=" << r->getHp()
                  << (r->isAlive() ? "" : " [DEAD]") << "\n";
}

void Game::printResult() const {
    ScopedTimer::Duration total = ScopedTimer::Clock::now() - programStart_;
    std::cout << "\n--- Thread Timing ---\n";
    for (int i = 0; i < static_cast<int>(robots_.size()); ++i)
        std::cout << "Thread " << i << " [" << robots_[i]->getName() << "]: "
                  << std::fixed << std::setprecision(3) << threadTimes_[i].count() << " s\n";
    std::cout << "Total wall-clock time: " << std::fixed << std::setprecision(3) << total.count() << " s\n";
}

std::unique_ptr<Robot> Game::createRobot(int choice, int x, int y) const {
    if (choice == 1) return std::make_unique<SortBot>(x, y);
    if (choice == 2) return std::make_unique<DigDeepBot>(x, y);
    if (choice == 3) return std::make_unique<RandomBot>(x, y);
    if (choice == 4) return std::make_unique<SmartBot>(x, y);
    if (choice == 5) return std::make_unique<LookaheadBot>(x, y);
    throw std::invalid_argument("Unknown robot type.");
}
```

### `tests/test_all.cpp`

```cpp
#include "DigDeepBot.h"
#include "LookaheadBot.h"
#include "SmartBot.h"
#include "SortBot.h"
#include "World.h"

#include <exception>
#include <iostream>
#include <sstream>
#include <stdexcept>
#include <string>

namespace {
int s_passed = 0;
int s_failed = 0;

void assertTrue(bool value, const std::string& expr, int line) {
    if (!value) throw std::runtime_error("Assertion failed at line " + std::to_string(line) + ": " + expr);
}

template <typename A, typename B>
void assertEq(const A& actual, const B& expected, const std::string& expr, int line) {
    if (!(actual == expected)) {
        std::ostringstream oss;
        oss << "Assertion failed at line " << line << ": " << expr
            << " actual=" << actual << " expected=" << expected;
        throw std::runtime_error(oss.str());
    }
}

#define ASSERT(expr) assertTrue((expr), #expr, __LINE__)
#define ASSERT_EQ(actual, expected) assertEq((actual), (expected), #actual " == " #expected, __LINE__)
#define TEST(name, body) do { try { body; ++s_passed; std::cout << "[PASS] " << name << "\n"; } catch (const std::exception& e) { ++s_failed; std::cout << "[FAIL] " << name << ": " << e.what() << "\n"; } } while (false)

World makeEmptyWorld(int x = 5, int y = 5, int z = 10) {
    World world(x, y, z);
    world.clear();
    return world;
}

void test_world_stack_model() {
    TEST("mine pops surface values", {
        World world = makeEmptyWorld(2, 2, 5);
        world.setColumn(0, 0, {1, 2, 3});
        ASSERT_EQ(world.mine(0, 0), 3);
        ASSERT_EQ(world.mine(0, 0), 2);
        ASSERT_EQ(world.mine(0, 0), 1);
        ASSERT_EQ(world.mine(0, 0), 0);
    });
    TEST("surface effect is removed by checkEffects", {
        World world = makeEmptyWorld(2, 2, 5);
        world.setColumn(0, 0, {5, -3});
        ASSERT_EQ(world.checkEffects(0, 0), -3);
        ASSERT_EQ(world.getSurfaceValue(0, 0), 5);
    });
}

void test_hp_and_movement() {
    TEST("damage clamps at zero", {
        SortBot bot(0, 0);
        bot.takeDamage(200);
        ASSERT_EQ(bot.getHp(), 0);
        ASSERT(!bot.isAlive());
    });
    TEST("movement clamps to boundaries", {
        World world = makeEmptyWorld(3, 3, 3);
        SortBot bot(0, 0);
        bot.move(2, world);
        bot.move(4, world);
        ASSERT_EQ(bot.getX(), 0);
        ASSERT_EQ(bot.getY(), 0);
    });
}

void test_robot_mining() {
    TEST("SortBot mines highest after sorting", {
        World world = makeEmptyWorld(3, 3, 5);
        world.setColumn(1, 1, {2, 9, 4});
        SortBot bot(1, 1);
        ASSERT_EQ(bot.mine(world), 9);
        ASSERT_EQ(bot.getScore(), 9);
    });
    TEST("DigDeepBot mines up to three blocks", {
        World world = makeEmptyWorld(3, 3, 5);
        world.setColumn(1, 1, {1, 2, 3, 4});
        DigDeepBot bot(1, 1);
        ASSERT_EQ(bot.mine(world), 9);
    });
    TEST("SmartBot uses average threshold", {
        World world = makeEmptyWorld(3, 3, 5);
        world.setColumn(1, 1, {8, -1, 7});
        SmartBot bot(1, 1, 5);
        ASSERT_EQ(bot.mine(world), 15);
    });
}

void test_lookahead() {
    TEST("LookaheadBot moves toward best yield", {
        World world = makeEmptyWorld(3, 3, 5);
        world.setColumn(2, 1, {9});
        LookaheadBot bot(1, 1);
        ASSERT_EQ(bot.decideNextMove(world), 1);
    });
}
}

int main() {
    std::cout << "=== Deep Miner Tests ===\n";
    test_world_stack_model();
    test_hp_and_movement();
    test_robot_mining();
    test_lookahead();
    std::cout << "\n=== Results: " << s_passed << " passed, " << s_failed << " failed ===\n";
    return s_failed > 0 ? 1 : 0;
}
```