import 'dart:async';

import 'package:flutter/material.dart';
import 'package:video_player/video_player.dart';

import '../core/video_file_cache.dart';

/// 网络视频播放：优先 **稳定 key** 的磁盘缓存（忽略签名 query），遇 ExoPlayer **416**、
/// [UnrecognizedInputFormatException]（坏/HTML 缓存）、[VideoPlayerController] 报错时清缓存并重试
/// （与 [HomeScreen] `_HomeItemVideoBackground` 对齐）。
class ResilientNetworkVideoCover extends StatefulWidget {
  const ResilientNetworkVideoCover({
    super.key,
    required this.url,
    this.isActive = true,
    this.looping = true,
    this.volume = 1.0,
    this.loadingWidget,
    this.failedWidget,
  });

  final String url;
  final bool isActive;
  final bool looping;
  final double volume;
  final Widget? loadingWidget;
  final Widget? failedWidget;

  @override
  State<ResilientNetworkVideoCover> createState() =>
      _ResilientNetworkVideoCoverState();
}

class _ResilientNetworkVideoCoverState extends State<ResilientNetworkVideoCover> {
  VideoPlayerController? _controller;
  bool _failed = false;

  static const int _maxOpenRetries = 6;
  int _openRetries = 0;
  bool _forceNetworkOnly = false;
  Timer? _retryTimer;
  bool _recovering = false;

  String get _playUrl => widget.url.trim();

  @override
  void initState() {
    super.initState();
    if (widget.isActive) {
      unawaited(_startPlaybackAsync());
    }
  }

  @override
  void didUpdateWidget(ResilientNetworkVideoCover oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (oldWidget.isActive != widget.isActive) {
      if (!widget.isActive) {
        _retryTimer?.cancel();
        _retryTimer = null;
        _recovering = false;
        _openRetries = 0;
        _disposePlayback();
        if (mounted) setState(() {});
        return;
      }
      _failed = false;
      _forceNetworkOnly = false;
      unawaited(_startPlaybackAsync());
      return;
    }
    if (oldWidget.url != widget.url) {
      _openRetries = 0;
      _failed = false;
      _recovering = false;
      _forceNetworkOnly = false;
      _disposePlayback();
      if (widget.isActive) {
        unawaited(_startPlaybackAsync());
      }
    }
  }

  @override
  void dispose() {
    _retryTimer?.cancel();
    _disposePlayback();
    super.dispose();
  }

  static Future<void> _pauseThenDispose(VideoPlayerController c) async {
    try {
      await c.pause();
    } catch (_) {}
    try {
      await c.dispose();
    } catch (_) {}
  }

  void _disposePlayback() {
    _retryTimer?.cancel();
    _retryTimer = null;
    final c = _controller;
    if (c != null) {
      c.removeListener(_onVideoValueChanged);
      _controller = null;
      unawaited(_pauseThenDispose(c));
    }
  }

  Future<void> _startPlaybackAsync() async {
    if (!widget.isActive) return;
    final playUrl = _playUrl;
    final uri = Uri.tryParse(playUrl);
    if (uri == null || !(uri.isScheme('http') || uri.isScheme('https'))) {
      if (mounted) setState(() => _failed = true);
      return;
    }
    _disposePlayback();

    final cacheKey = videoCacheKeyForUrl(playUrl);
    VideoPlayerController? controller;
    try {
      if (!_forceNetworkOnly) {
        final cached = await funymeeVideoCacheManager.getFileFromCache(cacheKey);
        if (cached != null &&
            cached.validTill.isAfter(DateTime.now()) &&
            await cached.file.exists() &&
            await videoCachedFileLooksPlayable(cached.file)) {
          controller = VideoPlayerController.file(cached.file);
        } else if (cached != null && await cached.file.exists()) {
          await funymeeVideoCacheManager.removeFile(cacheKey);
        }
      }
      controller ??= VideoPlayerController.networkUrl(uri);
    } catch (_) {
      controller = VideoPlayerController.networkUrl(uri);
    }

    if (!mounted || playUrl != _playUrl || !widget.isActive) {
      unawaited(_pauseThenDispose(controller));
      return;
    }

    controller
      ..setLooping(widget.looping)
      ..setVolume(widget.volume);
    controller.addListener(_onVideoValueChanged);
    _controller = controller;

    try {
      await controller.initialize().timeout(
        const Duration(seconds: 20),
        onTimeout: () =>
            throw TimeoutException('video init', const Duration(seconds: 20)),
      );
    } catch (_) {
      if (mounted) _scheduleRecoverFromError();
      return;
    }

    if (!mounted ||
        _controller != controller ||
        playUrl != _playUrl ||
        !widget.isActive) {
      return;
    }
    if (controller.value.hasError) {
      if (mounted) _scheduleRecoverFromError();
      return;
    }

    _openRetries = 0;
    try {
      await controller.play();
    } catch (_) {
      if (mounted) _scheduleRecoverFromError();
      return;
    }

    if (!mounted ||
        _controller != controller ||
        playUrl != _playUrl ||
        !widget.isActive) {
      return;
    }
    if (controller.value.hasError) {
      if (mounted) _scheduleRecoverFromError();
      return;
    }

    _forceNetworkOnly = false;
    unawaited(funymeeVideoCacheManager.downloadFile(playUrl, key: cacheKey));
    setState(() {});
  }

  void _onVideoValueChanged() {
    final c = _controller;
    if (c == null || !mounted || _recovering) return;
    if (!c.value.hasError) return;
    c.removeListener(_onVideoValueChanged);
    _scheduleRecoverFromError();
  }

  void _scheduleRecoverFromError() {
    if (!mounted || _failed || !widget.isActive) return;
    if (_recovering) return;
    if (_openRetries >= _maxOpenRetries) {
      setState(() => _failed = true);
      _disposePlayback();
      return;
    }
    _recovering = true;
    _openRetries += 1;
    final cacheKey = videoCacheKeyForUrl(_playUrl);
    unawaited(funymeeVideoCacheManager.removeFile(cacheKey));
    _forceNetworkOnly = true;
    _disposePlayback();
    setState(() {});

    _retryTimer?.cancel();
    _retryTimer = Timer(const Duration(milliseconds: 220), () {
      _retryTimer = null;
      if (!mounted) return;
      _recovering = false;
      unawaited(_startPlaybackAsync());
    });
  }

  @override
  Widget build(BuildContext context) {
    if (!widget.isActive) {
      return SizedBox.expand(
        child: widget.loadingWidget ?? const SizedBox.shrink(),
      );
    }
    if (_failed) {
      return SizedBox.expand(
        child: widget.failedWidget ?? const SizedBox.shrink(),
      );
    }
    final c = _controller;
    return LayoutBuilder(
      builder: (context, constraints) {
        if (c == null || !c.value.isInitialized) {
          return SizedBox.expand(
            child: widget.loadingWidget ??
                const ColoredBox(
                  color: Colors.black,
                  child: Center(
                    child: CircularProgressIndicator(color: Colors.white54),
                  ),
                ),
          );
        }
        final cw = constraints.maxWidth;
        final ch = constraints.maxHeight;
        final w = c.value.size.width;
        final h = c.value.size.height;
        if (w <= 0 ||
            h <= 0 ||
            !cw.isFinite ||
            !ch.isFinite ||
            cw <= 0 ||
            ch <= 0) {
          return SizedBox.expand(
            child: widget.loadingWidget ??
                const ColoredBox(
                  color: Colors.black,
                  child: Center(
                    child: CircularProgressIndicator(color: Colors.white54),
                  ),
                ),
          );
        }
        return Stack(
          fit: StackFit.expand,
          children: [
            Positioned.fill(
              child: ClipRect(
                child: SizedBox(
                  width: cw,
                  height: ch,
                  child: FittedBox(
                    fit: BoxFit.cover,
                    alignment: Alignment.center,
                    clipBehavior: Clip.none,
                    child: SizedBox(
                      width: w,
                      height: h,
                      child: VideoPlayer(c),
                    ),
                  ),
                ),
              ),
            ),
          ],
        );
      },
    );
  }
}