import threading
import time
from pathlib import Path
from typing import Callable

from oss.logger.logger import Log


class HotReloadError(Exception):
    pass


class FileWatcher:
    def __init__(self, watch_dirs, extensions, callback):
        self.watch_dirs = watch_dirs
        self.extensions = extensions
        self.callback = callback
        self._running = False
        self._thread = None
        self._file_times = {}
        self._init_file_times()

    def _init_file_times(self):
        for watch_dir in self.watch_dirs:
            p = Path(watch_dir)
            if p.exists():
                for f in p.rglob("*"):
                    if f.is_file() and f.suffix in self.extensions:
                        self._file_times[str(f)] = f.stat().st_mtime

    def start(self):
        self._running = True
        self._thread = threading.Thread(target=self._watch_loop, daemon=True)
        self._thread.start()
        Log.info("Core", "文件监控已启动")

    def stop(self):
        self._running = False
        if self._thread:
            self._thread.join(timeout=5)

    def _watch_loop(self):
        """监控文件变化，触发热重载回调"""
        while self._running:
            try:
                for watch_dir in self.watch_dirs:
                    p = Path(watch_dir)
                    if not p.exists():
                        continue
                    for f in p.rglob("*"):
                        if not f.is_file() or f.suffix not in self.extensions:
                            continue
                        current_mtime = f.stat().st_mtime
                        last_mtime = self._file_times.get(str(f))
                        if last_mtime is not None and current_mtime > last_mtime:
                            self._file_times[str(f)] = current_mtime
                            try:
                                self.callback(str(f))
                            except Exception as e:
                                Log.error("Core", f"热重载回调执行失败: {e}")
                        elif last_mtime is None:
                            self._file_times[str(f)] = current_mtime
            except Exception as e:
                Log.error("Core", f"文件监控异常: {e}")
            time.sleep(2)