"""
FocusTrack - Activity Tracker Engine
Detects active window, tracks idle time, logs heartbeats.
Cross-platform: Windows / macOS / Linux
"""

import time
import json
import logging
import platform
import threading
from datetime import datetime
from typing import Optional, Tuple
from pathlib import Path

logger = logging.getLogger("focustrack.tracker")

SYSTEM = platform.system()  # 'Windows', 'Darwin', 'Linux'


# ─── Window Detection ────────────────────────────────────────────────────────

def get_active_window() -> Tuple[str, str]:
    """
    Returns (app_name, window_title) for the currently focused window.
    Cross-platform with graceful fallbacks.
    """
    try:
        if SYSTEM == "Windows":
            return _get_window_windows()
        elif SYSTEM == "Darwin":
            return _get_window_macos()
        else:
            return _get_window_linux()
    except Exception as e:
        logger.debug(f"Window detection error: {e}")
        return ("unknown", "unknown")


def _get_window_windows() -> Tuple[str, str]:
    import ctypes
    import ctypes.wintypes
    user32 = ctypes.windll.user32
    hwnd = user32.GetForegroundWindow()
    length = user32.GetWindowTextLengthW(hwnd)
    buf = ctypes.create_unicode_buffer(length + 1)
    user32.GetWindowTextW(hwnd, buf, length + 1)
    title = buf.value or "unknown"

    # Get process name
    pid = ctypes.wintypes.DWORD()
    user32.GetWindowThreadProcessId(hwnd, ctypes.byref(pid))
    try:
        import psutil
        proc = psutil.Process(pid.value)
        app = proc.name().replace(".exe", "")
    except Exception:
        app = "unknown"
    return (app, title)


def _get_window_macos() -> Tuple[str, str]:
    try:
        from AppKit import NSWorkspace
        ws = NSWorkspace.sharedWorkspace()
        app = ws.activeApplication()
        app_name = app.get("NSApplicationName", "unknown") if app else "unknown"
        title = "unknown"
        try:
            import subprocess
            script = 'tell application "System Events" to get name of first window of (first process whose frontmost is true)'
            result = subprocess.run(
                ["osascript", "-e", script], capture_output=True, text=True, timeout=2
            )
            if result.returncode == 0:
                title = result.stdout.strip()
        except Exception:
            pass
        return (app_name, title)
    except ImportError:
        # Fallback via subprocess
        try:
            import subprocess
            script = """
            tell application "System Events"
                set frontApp to name of first application process whose frontmost is true
                set frontTitle to ""
                try
                    set frontTitle to name of front window of (first process whose frontmost is true)
                end try
                return frontApp & "|" & frontTitle
            end tell
            """
            result = subprocess.run(
                ["osascript", "-e", script], capture_output=True, text=True, timeout=3
            )
            if result.returncode == 0:
                parts = result.stdout.strip().split("|", 1)
                return (parts[0], parts[1] if len(parts) > 1 else "")
        except Exception:
            pass
        return ("unknown", "unknown")


def _get_window_linux() -> Tuple[str, str]:
    try:
        import subprocess
        # Try xdotool
        wid = subprocess.run(
            ["xdotool", "getactivewindow"], capture_output=True, text=True, timeout=2
        )
        if wid.returncode == 0:
            wid_val = wid.stdout.strip()
            name = subprocess.run(
                ["xdotool", "getwindowname", wid_val],
                capture_output=True, text=True, timeout=2
            )
            pid_result = subprocess.run(
                ["xdotool", "getwindowpid", wid_val],
                capture_output=True, text=True, timeout=2
            )
            title = name.stdout.strip() if name.returncode == 0 else "unknown"
            app = "unknown"
            if pid_result.returncode == 0:
                try:
                    import psutil
                    proc = psutil.Process(int(pid_result.stdout.strip()))
                    app = proc.name()
                except Exception:
                    pass
            return (app, title)
    except FileNotFoundError:
        pass

    try:
        # Fallback: wmctrl
        import subprocess
        result = subprocess.run(
            ["wmctrl", "-a", ":ACTIVE:"], capture_output=True, text=True
        )
    except Exception:
        pass

    return ("unknown", "unknown")


# ─── Categorizer ─────────────────────────────────────────────────────────────

class Categorizer:
    """Rule-based app categorization using DB-defined rules."""

    def __init__(self, db):
        self.db = db
        self._cache: dict = {}
        self._reload_interval = 60  # seconds
        self._last_reload = 0.0
        self._load_rules()

    def _load_rules(self):
        cats = self.db.get_categories()
        self._rules = []
        for cat in cats:
            self._rules.append({
                "name": cat["name"],
                "keywords": json.loads(cat["keywords"] or "[]"),
                "apps": json.loads(cat["apps"] or "[]"),
            })
        self._last_reload = time.time()

    def categorize(self, app_name: str, window_title: str, is_idle: bool) -> str:
        if is_idle:
            return "idle"

        # Reload rules periodically
        if time.time() - self._last_reload > self._reload_interval:
            self._load_rules()

        app_lower = app_name.lower()
        title_lower = window_title.lower()

        for rule in self._rules:
            if rule["name"] == "idle":
                continue
            for app_kw in rule["apps"]:
                if app_kw.lower() in app_lower:
                    return rule["name"]
            for kw in rule["keywords"]:
                if kw.lower() in title_lower or kw.lower() in app_lower:
                    return rule["name"]

        return "uncategorized"


# ─── Idle Detector ───────────────────────────────────────────────────────────

class IdleDetector:
    """Tracks mouse + keyboard activity to detect idle state."""

    def __init__(self, threshold_seconds: int = 300):
        self.threshold = threshold_seconds
        self._last_event = time.time()
        self._listener = None
        self._running = False

    def start(self):
        self._running = True
        try:
            from pynput import mouse, keyboard

            def on_activity(*args, **kwargs):
                self._last_event = time.time()

            self._mouse_listener = mouse.Listener(
                on_move=on_activity, on_click=on_activity, on_scroll=on_activity
            )
            self._keyboard_listener = keyboard.Listener(on_press=on_activity)
            self._mouse_listener.start()
            self._keyboard_listener.start()
            logger.info("Idle detector started (pynput)")
        except Exception as e:
            logger.warning(f"pynput unavailable ({e}), idle detection disabled")

    def stop(self):
        self._running = False
        try:
            if self._mouse_listener:
                self._mouse_listener.stop()
            if self._keyboard_listener:
                self._keyboard_listener.stop()
        except Exception:
            pass

    @property
    def is_idle(self) -> bool:
        return (time.time() - self._last_event) > self.threshold

    @property
    def idle_seconds(self) -> float:
        elapsed = time.time() - self._last_event
        return max(0.0, elapsed - self.threshold) if self.is_idle else 0.0

    def update_threshold(self, seconds: int):
        self.threshold = seconds


# ─── Main Tracker ────────────────────────────────────────────────────────────

class ActivityTracker:
    """
    Background activity tracking service.
    Logs heartbeats every N seconds to SQLite.
    """

    def __init__(self, db):
        self.db = db
        self._running = False
        self._paused = False
        self._lock = threading.Lock()

        idle_threshold = int(db.get_setting("idle_threshold_seconds", 300))
        self.heartbeat_interval = int(db.get_setting("heartbeat_interval", 5))

        self.idle_detector = IdleDetector(idle_threshold)
        self.categorizer = Categorizer(db)

        # Current session state
        self.current_app = ""
        self.current_title = ""
        self.current_category = ""
        self.session_start = datetime.now()
        self.is_idle = False

    def run(self):
        """Main tracking loop. Runs in a background thread."""
        self._running = True
        self.idle_detector.start()
        logger.info(f"Tracker started (heartbeat: {self.heartbeat_interval}s)")

        ignored_raw = self.db.get_setting("ignored_apps", "[]")
        try:
            ignored_apps = [a.lower() for a in json.loads(ignored_raw)]
        except Exception:
            ignored_apps = []

        while self._running:
            try:
                if not self._paused:
                    self._tick(ignored_apps)
                time.sleep(self.heartbeat_interval)
            except Exception as e:
                logger.error(f"Tracker error: {e}", exc_info=True)
                time.sleep(self.heartbeat_interval)

    def _tick(self, ignored_apps: list):
        """One heartbeat: detect window, log activity."""
        app_name, window_title = get_active_window()
        is_idle = self.idle_detector.is_idle

        # Skip ignored apps
        if any(ig in app_name.lower() for ig in ignored_apps):
            return

        category = self.categorizer.categorize(app_name, window_title, is_idle)

        with self._lock:
            self.current_app = app_name
            self.current_title = window_title
            self.current_category = category
            self.is_idle = is_idle

            # Check if session changed
            if (app_name != self.current_app or
                    abs((datetime.now() - self.session_start).total_seconds()) > 30):
                self.session_start = datetime.now()

        self.db.log_activity(
            timestamp=datetime.now(),
            app_name=app_name,
            window_title=window_title,
            duration_seconds=self.heartbeat_interval,
            category=category,
            is_idle=is_idle,
        )

    # ─── Controls ────────────────────────────────────────────────────────────

    def pause(self):
        self._paused = True
        self.db.set_setting("tracker_running", "paused")
        logger.info("Tracker paused")

    def resume(self):
        self._paused = False
        self.db.set_setting("tracker_running", "true")
        logger.info("Tracker resumed")

    def stop(self):
        self._running = False
        self.idle_detector.stop()
        self.db.set_setting("tracker_running", "false")
        logger.info("Tracker stopped")

    @property
    def status(self) -> str:
        if not self._running:
            return "stopped"
        if self._paused:
            return "paused"
        return "running"

    def get_current_state(self) -> dict:
        with self._lock:
            return {
                "app": self.current_app,
                "title": self.current_title,
                "category": self.current_category,
                "is_idle": self.is_idle,
                "status": self.status,
                "session_start": self.session_start.isoformat(),
            }

    def reload_settings(self):
        """Reload settings from DB (called after settings change)."""
        idle_threshold = int(self.db.get_setting("idle_threshold_seconds", 300))
        self.heartbeat_interval = int(self.db.get_setting("heartbeat_interval", 5))
        self.idle_detector.update_threshold(idle_threshold)
        logger.info("Tracker settings reloaded")