freezer/lib/ui/player_bar.dart

import 'package:audio_service/audio_service.dart';
import 'package:flutter/material.dart';
import 'package:freezer/settings.dart';

import '../api/player.dart';
import 'cached_image.dart';
import 'player_screen.dart';

class PlayerBar extends StatelessWidget {
  double get progress {
    if (AudioService.playbackState == null) return 0.0;
    if (AudioService.currentMediaItem == null) return 0.0;
    if (AudioService.currentMediaItem.duration.inSeconds == 0) return 0.0; //Division by 0
    return AudioService.playbackState.currentPosition.inSeconds / AudioService.currentMediaItem.duration.inSeconds;
  }

  double iconSize = 32;

  @override
  Widget build(BuildContext context) {
    return StreamBuilder(
      stream: Stream.periodic(Duration(milliseconds: 250)),
      builder: (BuildContext context, AsyncSnapshot snapshot) {
        if (AudioService.currentMediaItem == null) return Container(width: 0, height: 0,);
        return Column(
          mainAxisSize: MainAxisSize.min,
          children: <Widget>[
            ListTile(
                onTap: () => Navigator.of(context).push(MaterialPageRoute(builder: (BuildContext context) => PlayerScreen())),
                leading: CachedImage(
                  width: 50,
                  height: 50,
                  url: AudioService.currentMediaItem.artUri,
                ),
                title: Text(
                  AudioService.currentMediaItem.displayTitle,
                  overflow: TextOverflow.clip,
                  maxLines: 1,
                ),
                subtitle: Text(
                  AudioService.currentMediaItem.displaySubtitle,
                  overflow: TextOverflow.clip,
                  maxLines: 1,
                ),
                trailing: Row(
                  mainAxisSize: MainAxisSize.min,
                  children: <Widget>[
                    PrevNextButton(iconSize, prev: true, hidePrev: true,),
                    PlayPauseButton(iconSize),
                    PrevNextButton(iconSize)
                  ],
                )
            ),
            Container(
              height: 3.0,
              child: LinearProgressIndicator(
                backgroundColor: Theme.of(context).primaryColor.withOpacity(0.1),
                value: progress,
              ),
            )
          ],
        );
      },
    );
  }
}


class PrevNextButton extends StatelessWidget {

  final double size;
  final bool prev;
  final bool hidePrev;
  int i;
  PrevNextButton(this.size, {this.prev = false, this.hidePrev = false});

  @override
  Widget build(BuildContext context) {
    if (!prev) {
      if (playerHelper.queueIndex == (AudioService.queue??[]).length - 1) {
        return IconButton(
          icon: Icon(Icons.skip_next),
          iconSize: size,
          onPressed: null,
        );
      }
      return IconButton(
        icon: Icon(Icons.skip_next),
        iconSize: size,
        onPressed: () => AudioService.skipToNext(),
      );
    }
    if (prev) {
      if (i == 0) {
        if (hidePrev) {
          return Container(height: 0, width: 0,);
        }
        return IconButton(
          icon: Icon(Icons.skip_previous),
          iconSize: size,
          onPressed: null,
        );
      }
      return IconButton(
        icon: Icon(Icons.skip_previous),
        iconSize: size,
        onPressed: () => AudioService.skipToPrevious(),
      );
    }
    return Container();
  }
}



class PlayPauseButton extends StatelessWidget {

  final double size;
  PlayPauseButton(this.size);

  @override
  Widget build(BuildContext context) {

    //Playing
    if (AudioService.playbackState?.playing??false) {
      return IconButton(
        iconSize: this.size,
        icon: Icon(Icons.pause),
        onPressed: () => AudioService.pause()
      );
    }

    //Paused
    if ((!AudioService.playbackState.playing &&
        AudioService.playbackState.processingState == AudioProcessingState.ready) ||
        //None state (stopped)
        AudioService.playbackState.processingState == AudioProcessingState.none) {
      return IconButton(
        iconSize: this.size,
        icon: Icon(Icons.play_arrow),
        onPressed: () => AudioService.play()
      );
    }

    switch (AudioService.playbackState.processingState) {
      //Stopped/Error
      case AudioProcessingState.error:
      case AudioProcessingState.none:
      case AudioProcessingState.stopped:
        return Container(width: this.size, height: this.size);
      //Loading, connecting, rewinding...
      default:
        return Container(
          width: this.size,
          height: this.size,
          child: CircularProgressIndicator(),
        );
    }
  }
}