import 'package:audio_service/audio_service.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

import '../shared/cover.dart';
import '../shared/theme.dart';
import 'audio_handler.dart';

/// Vollbild-Wiedergabe: Cover, Titel, Fortschritt, Transport-Controls.
class NowPlayingScreen extends StatelessWidget {
  const NowPlayingScreen({super.key});

  @override
  Widget build(BuildContext context) {
    final handler = context.read<MeloAudioHandler>();
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Colors.transparent,
        leading: IconButton(
          icon: const Icon(Icons.keyboard_arrow_down),
          onPressed: () => Navigator.of(context).maybePop(),
        ),
      ),
      body: SafeArea(
        child: StreamBuilder<MediaItem?>(
          stream: handler.mediaItem,
          builder: (context, snapshot) {
            final item = snapshot.data;
            if (item == null) {
              return const Center(child: Text('Nichts in Wiedergabe'));
            }
            return Padding(
              padding: const EdgeInsets.symmetric(horizontal: 24),
              child: Column(
                children: [
                  Expanded(child: Center(child: _Cover(item: item))),
                  const SizedBox(height: 24),
                  Text(
                    item.title,
                    style: Theme.of(context).textTheme.headlineSmall,
                    maxLines: 2,
                    overflow: TextOverflow.ellipsis,
                    textAlign: TextAlign.center,
                  ),
                  const SizedBox(height: 8),
                  Text(
                    item.artist ?? 'Unbekannt',
                    style: const TextStyle(color: Colors.white54),
                  ),
                  const SizedBox(height: 24),
                  _ProgressBar(handler: handler),
                  const _Controls(),
                  const SizedBox(height: 16),
                ],
              ),
            );
          },
        ),
      ),
    );
  }
}

class _Cover extends StatelessWidget {
  const _Cover({required this.item});
  final MediaItem item;

  @override
  Widget build(BuildContext context) {
    return AspectRatio(
      aspectRatio: 1,
      child: CoverImage(artUri: item.artUri, radius: 16),
    );
  }
}

class _ProgressBar extends StatelessWidget {
  const _ProgressBar({required this.handler});
  final MeloAudioHandler handler;

  @override
  Widget build(BuildContext context) {
    return StreamBuilder<Duration?>(
      stream: handler.durationStream,
      builder: (context, dSnap) {
        final total = dSnap.data ?? Duration.zero;
        return StreamBuilder<Duration>(
          stream: handler.positionStream,
          builder: (context, pSnap) {
            var position = pSnap.data ?? Duration.zero;
            final hasDuration = total > Duration.zero;
            if (hasDuration && position > total) position = total;
            final maxMs = hasDuration ? total.inMilliseconds.toDouble() : 1.0;
            final valueMs =
                position.inMilliseconds.toDouble().clamp(0.0, maxMs).toDouble();
            return Column(
              children: [
                Slider(
                  value: valueMs,
                  max: maxMs,
                  onChanged: hasDuration
                      ? (v) => handler.seek(Duration(milliseconds: v.round()))
                      : null,
                ),
                Padding(
                  padding: const EdgeInsets.symmetric(horizontal: 8),
                  child: Row(
                    mainAxisAlignment: MainAxisAlignment.spaceBetween,
                    children: [
                      Text(_fmt(position),
                          style: const TextStyle(color: Colors.white54)),
                      Text(_fmt(total),
                          style: const TextStyle(color: Colors.white54)),
                    ],
                  ),
                ),
              ],
            );
          },
        );
      },
    );
  }

  static String _fmt(Duration d) {
    final m = d.inMinutes.remainder(60).toString().padLeft(2, '0');
    final s = d.inSeconds.remainder(60).toString().padLeft(2, '0');
    return '$m:$s';
  }
}

class _Controls extends StatelessWidget {
  const _Controls();

  @override
  Widget build(BuildContext context) {
    final handler = context.read<MeloAudioHandler>();
    return StreamBuilder<PlaybackState>(
      stream: handler.playbackState,
      builder: (context, snapshot) {
        final state = snapshot.data;
        final playing = state?.playing ?? false;
        final shuffle = state?.shuffleMode == AudioServiceShuffleMode.all;
        final repeat = state?.repeatMode ?? AudioServiceRepeatMode.none;
        return Row(
          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
          children: [
            IconButton(
              icon: Icon(Icons.shuffle,
                  color: shuffle ? MeloTheme.red : Colors.white54),
              onPressed: () => handler.setShuffleMode(shuffle
                  ? AudioServiceShuffleMode.none
                  : AudioServiceShuffleMode.all),
            ),
            IconButton(
              iconSize: 40,
              icon: const Icon(Icons.skip_previous),
              onPressed: handler.skipToPrevious,
            ),
            IconButton(
              iconSize: 64,
              icon: Icon(playing ? Icons.pause_circle : Icons.play_circle,
                  color: MeloTheme.red),
              onPressed: playing ? handler.pause : handler.play,
            ),
            IconButton(
              iconSize: 40,
              icon: const Icon(Icons.skip_next),
              onPressed: handler.skipToNext,
            ),
            IconButton(
              icon: Icon(
                repeat == AudioServiceRepeatMode.one
                    ? Icons.repeat_one
                    : Icons.repeat,
                color: repeat == AudioServiceRepeatMode.none
                    ? Colors.white54
                    : MeloTheme.red,
              ),
              onPressed: () => handler.setRepeatMode(switch (repeat) {
                AudioServiceRepeatMode.none => AudioServiceRepeatMode.all,
                AudioServiceRepeatMode.all => AudioServiceRepeatMode.one,
                _ => AudioServiceRepeatMode.none,
              }),
            ),
          ],
        );
      },
    );
  }
}