#!/usr/bin/env python3
"""Install the Zed Hours Tracker git hook and config for the current project."""

import json
import os
import stat
import subprocess
from pathlib import Path


def get_project_root() -> Path:
    """Return the git project root, falling back to the script's project directory."""
    try:
        root = subprocess.check_output(
            ["git", "rev-parse", "--show-toplevel"],
            text=True,
            stderr=subprocess.DEVNULL,
        ).strip()
        return Path(root).resolve()
    except (subprocess.CalledProcessError, FileNotFoundError):
        pass
    # Fallback 1: directory containing this script's grandparent (<project>/tools/time_tracking/install.py)
    script_project = Path(__file__).resolve().parents[2]
    if (script_project / ".git").exists() or (script_project / ".zed-hours").exists():
        return script_project
    # Fallback 2: current working directory
    return Path.cwd().resolve()


def ensure_log_dir(project_root: Path) -> Path:
    log_dir = project_root / ".zed-hours"
    log_dir.mkdir(parents=True, exist_ok=True)
    return log_dir


def write_config(log_dir: Path, project_root: Path) -> Path:
    config = {
        "project_root": str(project_root),
        "log_dir": str(log_dir.relative_to(project_root)),
        "heartbeat_interval_seconds": 60,
        "idle_threshold_seconds": 300,
        "max_inactive_gap_seconds": 600,
    }
    config_path = log_dir / "config.json"
    if not config_path.exists():
        config_path.write_text(json.dumps(config, indent=2) + "\n", encoding="utf-8")
        print(f"Created config: {config_path}")
    else:
        print(f"Config already exists: {config_path}")
    return config_path


def install_git_hook(project_root: Path) -> None:
    hook_path = project_root / ".git" / "hooks" / "post-commit"
    if not hook_path.parent.exists():
        print("No .git directory found; skipping git hook install.")
        return

    script_dir = project_root / "tools" / "time_tracking"
    log_commit_script = script_dir / "log_commit.py"

    hook_content = f"""#!/bin/sh
# Zed Hours Tracker - post-commit hook
python3 "{log_commit_script}" "$@"
"""
    if hook_path.exists():
        existing = hook_path.read_text(encoding="utf-8")
        if "Zed Hours Tracker" in existing:
            print(f"Hook already installed: {hook_path}")
            return
        # Append to existing hook
        hook_path.write_text(existing.rstrip("\n") + "\n\n" + hook_content, encoding="utf-8")
    else:
        hook_path.write_text(hook_content, encoding="utf-8")

    # Make executable
    hook_path.chmod(hook_path.stat().st_mode | stat.S_IXUSR | stat.S_IXGRP | stat.S_IXOTH)
    print(f"Installed git hook: {hook_path}")


def write_systemd_service(project_root: Path, script_dir: Path) -> None:
    """Write a sample systemd user service file for background tracking."""
    systemd_dir = Path.home() / ".config" / "systemd" / "user"
    service_name = f"zed-hours-{project_root.name}.service"
    service_path = systemd_dir / service_name

    tracker_script = script_dir / "zed_tracker.py"

    service_content = f"""[Unit]
Description=Zed Hours Tracker for {project_root.name}
After=graphical-session.target

[Service]
Type=simple
WorkingDirectory={project_root}
ExecStart=/usr/bin/python3 {tracker_script} --project-root {project_root}
Restart=on-failure
RestartSec=10
Environment="PYTHONUNBUFFERED=1"

[Install]
WantedBy=default.target
"""
    systemd_dir.mkdir(parents=True, exist_ok=True)
    service_path.write_text(service_content, encoding="utf-8")
    print(f"Wrote systemd user service: {service_path}")
    print(f"Enable with: systemctl --user daemon-reload && systemctl --user enable --now {service_name}")


def main() -> None:
    project_root = get_project_root()
    script_dir = Path(__file__).resolve().parent

    log_dir = ensure_log_dir(project_root)
    write_config(log_dir, project_root)
    install_git_hook(project_root)
    write_systemd_service(project_root, script_dir)

    print(f"\nZed Hours Tracker installed for project: {project_root}")
    print(f"Data directory: {log_dir}")
    print("\nNext steps:")
    print("  1. Start the tracker: python3 tools/time_tracking/zed_tracker.py")
    print("  2. Or enable the systemd service shown above.")
    print("  3. Make a commit to test the git hook.")
    print("  4. Generate a report: python3 tools/time_tracking/generate_report.py --today")


if __name__ == "__main__":
    main()