import 'dart:async';
import 'dart:math';
import 'dart:ui';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:qhd_prevention/tools/tools.dart';
import 'package:video_player/video_player.dart';

class VideoPlayerWidget extends StatefulWidget {
  final VideoPlayerController? controller;
  final String coverUrl;
  final double aspectRatio;
  final bool allowSeek;
  final bool isFullScreen;

  const VideoPlayerWidget({
    Key? key,
    required this.controller,
    required this.coverUrl,
    required this.aspectRatio,
    this.allowSeek = true,
    this.isFullScreen = false,
  }) : super(key: key);

  @override
  _VideoPlayerWidgetState createState() => _VideoPlayerWidgetState();
}

class _VideoPlayerWidgetState extends State<VideoPlayerWidget> {
  bool _visibleControls = true;
  Timer? _hideTimer;
  Timer? _positionTimer;
  Duration _currentPosition = Duration.zero;
  Duration _totalDuration = Duration.zero;
  bool _isPlaying = false;
  final ValueNotifier<double> _sliderValue = ValueNotifier<double>(0.0);

  // Helpers to avoid accessing controller after it's disposed
  bool get _hasController => widget.controller != null;

  /// Safe check whether controller is initialized without throwing.
  bool _controllerInitializedSafe() {
    try {
      final c = widget.controller;
      if (c == null) return false;
      return c.value.isInitialized;
    } catch (e) {
      return false;
    }
  }

  @override
  void initState() {
    super.initState();
    // start hide timer immediately
    _startHideTimer();
    // start position timer only if controller exists and initialized
    _maybeStartPositionTimer();
    // add listener if controller present
    _addControllerListenerSafely();
    // if controller already initialized, fetch values
    if (_controllerInitializedSafe()) {
      _updateControllerValuesSafe();
    }
  }

  @override
  void didUpdateWidget(covariant VideoPlayerWidget oldWidget) {
    super.didUpdateWidget(oldWidget);

    // controller changed -> update listeners and timers
    if (oldWidget.controller != widget.controller) {
      _removeControllerListenerSafely(oldWidget.controller);
      _addControllerListenerSafely();
      _restartPositionTimer();
      _updateControllerValuesSafe();
    }
  }

  void _addControllerListenerSafely() {
    try {
      widget.controller?.addListener(_controllerListener);
    } catch (_) {
      // ignore if controller already disposed
    }
  }

  void _removeControllerListenerSafely([VideoPlayerController? ctrl]) {
    final c = ctrl ?? widget.controller;
    if (c == null) return;
    try {
      c.removeListener(_controllerListener);
    } catch (_) {
      // ignore
    }
  }

  void _controllerListener() {
    if (!mounted) return;
    _updateControllerValuesSafe();
  }

  void _updateControllerValuesSafe() {
    final c = widget.controller;
    if (c == null) {
      // clear values
      if (mounted) {
        setState(() {
          _isPlaying = false;
          _totalDuration = Duration.zero;
          _currentPosition = Duration.zero;
          _sliderValue.value = 0;
        });
      }
      return;
    }

    try {
      final value = c.value;
      if (!value.isInitialized) {
        if (mounted) {
          setState(() {
            _isPlaying = false;
            _totalDuration = Duration.zero;
            _currentPosition = Duration.zero;
            _sliderValue.value = 0;
          });
        }
        return;
      }

      final pos = value.position;
      final dur = value.duration;
      final playing = value.isPlaying;

      if (mounted) {
        setState(() {
          _isPlaying = playing;
          _totalDuration = dur;
          _currentPosition = pos;
          _sliderValue.value = pos.inMilliseconds.toDouble();
        });
      }
    } catch (e) {
      // If controller was disposed between checks, ignore
    }
  }

  void _startHideTimer() {
    _hideTimer?.cancel();
    _hideTimer = Timer(const Duration(seconds: 3), () {
      if (mounted) setState(() => _visibleControls = false);
    });
  }

  void _maybeStartPositionTimer() {
    if (_positionTimer != null && _positionTimer!.isActive) return;
    // only start if controller exists
    if (!_hasController) return;
    _positionTimer = Timer.periodic(const Duration(milliseconds: 300), (_) {
      if (!mounted) return;
      if (!_controllerInitializedSafe()) return;
      try {
        final c = widget.controller!;
        final pos = c.value.position;
        final dur = c.value.duration;
        final playing = c.value.isPlaying;
        setState(() {
          _currentPosition = pos;
          _totalDuration = dur;
          _isPlaying = playing;
          _sliderValue.value = pos.inMilliseconds.toDouble();
        });
      } catch (_) {
        // ignore if controller disposed mid-tick
      }
    });
  }

  void _restartPositionTimer() {
    _positionTimer?.cancel();
    _maybeStartPositionTimer();
  }

  void _stopPositionTimer() {
    try {
      _positionTimer?.cancel();
    } catch (_) {}
    _positionTimer = null;
  }

  void _toggleControls() {
    setState(() => _visibleControls = !_visibleControls);
    if (_visibleControls)
      _startHideTimer();
    else
      _hideTimer?.cancel();
  }

  void _togglePlayPause() {
    final c = widget.controller;
    if (c == null) return;
    try {
      if (_isPlaying) {
        c.pause();
        setState(() => _isPlaying = false);
      } else {
        c.play();
        setState(() => _isPlaying = true);
      }
      _startHideTimer();
    } catch (_) {
      // ignore if controller disposed
    }
  }

  Future<void> _enterFullScreen() async {
    // prepare full screen orientation
    try {
      await SystemChrome.setPreferredOrientations([
        DeviceOrientation.landscapeLeft,
        DeviceOrientation.landscapeRight,
      ]);
      await SystemChrome.setEnabledSystemUIMode(SystemUiMode.immersiveSticky);
      await NativeOrientation.setLandscape();
    } catch (_) {}

    // push a new page with the same widget but isFullScreen = true
    await Navigator.of(context).push(
      MaterialPageRoute(
        builder: (ctx) => Scaffold(
          backgroundColor: Colors.black,
          body: SafeArea(
            top: false,
            bottom: false,
            child: VideoPlayerWidget(
              controller: widget.controller,
              coverUrl: widget.coverUrl,
              aspectRatio: max(
                widget.aspectRatio,
                MediaQuery.of(ctx).size.width / MediaQuery.of(ctx).size.height,
              ),
              allowSeek: widget.allowSeek,
              isFullScreen: true,
            ),
          ),
        ),
      ),
    );

    // on return, restore orientation and UI and force rebuild
    try {
      await NativeOrientation.setPortrait();
      await SystemChrome.setPreferredOrientations([DeviceOrientation.portraitUp]);
      await SystemChrome.setEnabledSystemUIMode(SystemUiMode.edgeToEdge);
    } catch (_) {}

    if (!mounted) return;
    // force a rebuild so parent layouts recalc (fixes overflow after exit)
    setState(() {});
  }

  @override
  void dispose() {
    _hideTimer?.cancel();
    _stopPositionTimer();
    _sliderValue.dispose();
    _removeControllerListenerSafely();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    // Compute constrained size so widget won't try to be infinite height in non-fullscreen usage.
    final media = MediaQuery.of(context);
    final screenW = media.size.width;
    final screenH = media.size.height;

    // Non-fullscreen preferred height: based on aspect ratio but not exceeding a fraction of screen height
    final preferredNonFullHeight = min(screenW / (widget.aspectRatio <= 0 ? (16 / 9) : widget.aspectRatio),
        screenH * 0.5); // at most 50% of screen height

    // If isFullScreen, use available height minus safe areas; otherwise use preferredNonFullHeight
    final containerW = widget.isFullScreen ? screenW : screenW;
    final containerH = widget.isFullScreen
        ? screenH
        : preferredNonFullHeight;

    return Center(
      child: SizedBox(
        width: containerW,
        height: containerH,
        child: GestureDetector(
          behavior: HitTestBehavior.translucent,
          onTap: _toggleControls,
          child: Stack(
            fit: StackFit.expand,
            children: [
              // Video or cover: use AspectRatio to avoid forcing Column to expand
              _buildVideoOrCover(containerW, containerH),
              if (widget.isFullScreen)
                Positioned(
                  top: MediaQuery.of(context).padding.top + 8, // 考虑刘海/状态栏高度
                  left: 8,
                  child: SafeArea(
                    top: true,
                    bottom: false,
                    child: ClipOval(
                      child: Material(
                        color: Colors.black38, // 背景（半透明），可按需调整
                        child: InkWell(
                          onTap: () async {
                            // 可选：在 pop 之前恢复方向与系统 UI（也可以只 pop，让上层的 .then 处理恢复）
                            try {
                              await NativeOrientation.setPortrait();
                            } catch (_) {}
                            try {
                              await SystemChrome.setPreferredOrientations([DeviceOrientation.portraitUp]);
                              await SystemChrome.setEnabledSystemUIMode(SystemUiMode.edgeToEdge);
                            } catch (_) {}
                            Navigator.of(context).maybePop();
                          },
                          child: const Padding(
                            padding: EdgeInsets.all(8.0),
                            child: Icon(
                              Icons.arrow_back,
                              color: Colors.white,
                              size: 22,
                            ),
                          ),
                        ),
                      ),
                    ),
                  ),
                ),
              // Controls overlay
              if (_visibleControls) _buildControls(),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildVideoOrCover(double containerW, double containerH) {
    final c = widget.controller;

    // If controller exists and is initialized (safe check), show video in AspectRatio
    if (c != null) {
      try {
        if (c.value.isInitialized) {
          // Use video's natural aspect ratio if available, otherwise widget.aspectRatio
          final vidAspect = (c.value.size.height > 0) ? (c.value.size.width / c.value.size.height) : widget.aspectRatio;
          return Center(
            child: AspectRatio(
              aspectRatio: vidAspect > 0 ? vidAspect : widget.aspectRatio,
              child: VideoPlayer(c),
            ),
          );
        }
      } catch (_) {
        // controller may be disposed; fall through to show cover
      }
    }

    // Fallback: show cover image (fills the container)
    if (widget.coverUrl.isNotEmpty) {
      return Image.network(
        widget.coverUrl,
        width: containerW,
        height: containerH,
        fit: BoxFit.cover,
        errorBuilder: (_, __, ___) => Container(color: Colors.black),
      );
    }

    // final fallback: black box
    return Container(color: Colors.black);
  }

  Widget _buildControls() {
    // Use local copies to avoid repeated reads that might throw if ctrl disposed
    final totalMs = _totalDuration.inMilliseconds.toDouble();
    final sliderMax = totalMs > 0 ? totalMs : 1.0;
    final sliderValue = _sliderValue.value.clamp(0.0, sliderMax).toDouble();

    return Positioned(
      bottom: 0,
      left: 0,
      right: 0,
      child: Container(
        height: 50,
        decoration: BoxDecoration(
          gradient: LinearGradient(
            begin: Alignment.bottomCenter,
            end: Alignment.topCenter,
            colors: [
              Colors.black.withOpacity(0.7),
              Colors.transparent,
            ],
          ),
        ),
        padding: const EdgeInsets.symmetric(horizontal: 12),
        child: Row(
          children: [
            IconButton(
              padding: EdgeInsets.zero,
              icon: Icon(
                _isPlaying ? Icons.pause : Icons.play_arrow,
                size: 28,
                color: Colors.white,
              ),
              onPressed: _togglePlayPause,
            ),
            Expanded(
              child: ValueListenableBuilder<double>(
                valueListenable: _sliderValue,
                builder: (_, value, __) => SliderTheme(
                  data: SliderTheme.of(context).copyWith(
                    activeTrackColor: Colors.white,
                    inactiveTrackColor: Colors.white54,
                    thumbColor: Colors.white,
                    overlayColor: Colors.white24,
                    trackHeight: 2,
                    thumbShape: RoundSliderThumbShape(enabledThumbRadius: 8),
                  ),
                  child: Slider(
                    value: sliderValue,
                    min: 0,
                    max: sliderMax,
                    onChanged: (v) {
                      if (widget.allowSeek && widget.controller != null) {
                        try {
                          widget.controller!.seekTo(Duration(milliseconds: v.toInt()));
                          setState(() => _currentPosition = Duration(milliseconds: v.toInt()));
                          _sliderValue.value = v;
                          _startHideTimer();
                        } catch (_) {}
                      }
                    },
                  ),
                ),
              ),
            ),
            SizedBox(
              width: 110,
              child: Text(
                '${_formatDuration(_currentPosition)} / ${_formatDuration(_totalDuration)}',
                style: TextStyle(
                  color: Colors.white,
                  fontSize: 12,
                  fontFeatures: [FontFeature.tabularFigures()],
                ),
              ),
            ),
            IconButton(
              padding: EdgeInsets.zero,
              icon: Icon(
                widget.isFullScreen ? Icons.fullscreen_exit : Icons.fullscreen,
                size: 28,
                color: Colors.white,
              ),
              onPressed: () {
                if (widget.isFullScreen) {
                  // if this widget is used inside a full screen route, popping will exit fullscreen
                  Navigator.of(context).maybePop();
                } else {
                  _enterFullScreen();
                }
              },
            ),
          ],
        ),
      ),
    );
  }

  String _formatDuration(Duration d) {
    String twoDigits(int n) => n.toString().padLeft(2, '0');
    final h = d.inHours, m = d.inMinutes.remainder(60), s = d.inSeconds.remainder(60);
    if (h > 0) return '${twoDigits(h)}:${twoDigits(m)}:${twoDigits(s)}';
    return '${twoDigits(m)}:${twoDigits(s)}';
  }
}