import 'dart:async';

import 'package:flutter/material.dart';

import '../../../core/infra/player_engine/player_engine.dart';
import '../../../shared/utils/format_utils.dart';
import '../../../shared/widgets/app_loading_ring.dart';
import '../services/network_speed_monitor.dart';

class BufferingOverlay extends StatefulWidget {
  final PlayerEngine player;
  final NetworkSpeedMonitor? speedMonitor;
  final ValueChanged<bool>? onBufferingChanged;


  final bool suppress;

  const BufferingOverlay({
    super.key,
    required this.player,
    this.speedMonitor,
    this.onBufferingChanged,
    this.suppress = false,
  });

  @override
  State<BufferingOverlay> createState() => _BufferingOverlayState();
}

class _BufferingOverlayState extends State<BufferingOverlay> {
  bool _isBuffering = false;
  Timer? _debounceTimer;

  Duration _position = Duration.zero;
  Duration _buffer = Duration.zero;
  bool _playing = false;

  StreamSubscription<Duration>? _bufferSub;
  StreamSubscription<Duration>? _positionSub;
  StreamSubscription<bool>? _playingSub;

  @override
  void initState() {
    super.initState();
    _readState(widget.player);
    _subscribe(widget.player);
  }

  @override
  void didUpdateWidget(covariant BufferingOverlay oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (oldWidget.player != widget.player) {
      _cancelSubscriptions();
      _setBuffering(false);
      _readState(widget.player);
      _subscribe(widget.player);
    }
  }

  @override
  void dispose() {
    _debounceTimer?.cancel();
    _cancelSubscriptions();
    super.dispose();
  }

  void _readState(PlayerEngine player) {
    _position = player.state.position;
    _buffer = player.state.buffer;
    _playing = player.state.playing;
  }

  void _subscribe(PlayerEngine player) {
    _positionSub = player.stream.position.listen((p) {
      _position = p;
      _evaluate();
    });
    _bufferSub = player.stream.buffer.listen((b) {
      _buffer = b;
      _evaluate();
    });
    _playingSub = player.stream.playing.listen((playing) {
      _playing = playing;
      _evaluate();
    });
  }

  void _cancelSubscriptions() {
    unawaited(_positionSub?.cancel());
    unawaited(_bufferSub?.cancel());
    unawaited(_playingSub?.cancel());
    _positionSub = null;
    _bufferSub = null;
    _playingSub = null;
  }

  void _setBuffering(bool value) {
    if (_isBuffering == value) return;
    setState(() => _isBuffering = value);
    widget.onBufferingChanged?.call(value);
  }

  void _evaluate() {
    final shouldBuffer =
        _playing && _buffer <= _position && _position > Duration.zero;

    if (shouldBuffer) {
      if (_isBuffering || _debounceTimer != null) return;
      _debounceTimer = Timer(const Duration(milliseconds: 200), () {
        _debounceTimer = null;
        if (!mounted) return;
        if (_playing && _buffer <= _position && _position > Duration.zero) {
          _setBuffering(true);
        }
      });
      return;
    }

    _debounceTimer?.cancel();
    _debounceTimer = null;
    _setBuffering(false);
  }

  @override
  Widget build(BuildContext context) {
    final monitor = widget.speedMonitor;
    return IgnorePointer(
      child: Opacity(
        opacity: widget.suppress ? 0.0 : 1.0,
        child: AnimatedOpacity(
          opacity: _isBuffering ? 1.0 : 0.0,
          duration: const Duration(milliseconds: 100),
          child: Center(
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                const AppLoadingRing(size: 40, color: Colors.white),
                if (monitor != null) ...[
                  const SizedBox(height: 12),
                  ValueListenableBuilder<bool>(
                    valueListenable: monitor.available,
                    builder: (_, available, _) {
                      if (!available) return const SizedBox.shrink();
                      return ValueListenableBuilder<double>(
                        valueListenable: monitor.speed,
                        builder: (_, speed, _) {
                          return Text(
                            formatDownloadSpeed(speed),
                            style: const TextStyle(
                              color: Colors.white70,
                              fontSize: 13,
                              fontFeatures: [FontFeature.tabularFigures()],
                            ),
                          );
                        },
                      );
                    },
                  ),
                ],
              ],
            ),
          ),
        ),
      ),
    );
  }
}