import 'dart:convert';
import 'dart:isolate';
import 'dart:ui';

import 'package:flutter/material.dart';
import 'package:cached_network_image/cached_network_image.dart';
import 'package:flutter_downloader/flutter_downloader.dart';
import 'package:google_fonts/google_fonts.dart';
import 'class/episodebrief.dart';
import 'episodedetail.dart';
import 'pageroute.dart';

class EpisodeGrid extends StatelessWidget {
  final List<EpisodeBrief> podcast;
  final bool showFavorite;
  final bool showDownload;
  final bool showNumber;
  final String heroTag;
  EpisodeGrid(
      {Key key,
      this.podcast,
      this.showDownload,
      this.showFavorite,
      this.showNumber,
      this.heroTag})
      : super(key: key);
  @override
  Widget build(BuildContext context) {
    return CustomScrollView(
      physics: const AlwaysScrollableScrollPhysics(),
      primary: false,
      slivers: <Widget>[
        SliverPadding(
          padding: const EdgeInsets.all(5.0),
          sliver: SliverGrid(
            gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
              childAspectRatio: 1.0,
              crossAxisCount: 3,
              mainAxisSpacing: 6.0,
              crossAxisSpacing: 6.0,
            ),
            delegate: SliverChildBuilderDelegate(
              (BuildContext context, int index) {
                Color _c;
                var color = json.decode(podcast[index].primaryColor);
                (color[0] > 200 && color[1] > 200 && color[2] > 200)
                    ? _c = Color.fromRGBO(
                        (255 - color[0]), 255 - color[1], 255 - color[2], 1.0)
                    : _c = Color.fromRGBO(color[0], color[1], color[2], 1.0);
                return InkWell(
                  onTap: () {
                    Navigator.push(
                      context,
                      ScaleRoute(
                          page: EpisodeDetail(
                                episodeItem: podcast[index],
                                heroTag: heroTag
                              )),
                    );
                  },
                  child: Container(
                    decoration: BoxDecoration(
                        borderRadius: BorderRadius.all(Radius.circular(5.0)),
                        color: Theme.of(context).scaffoldBackgroundColor,
                        border: Border.all(
                          color: Colors.grey[100],
                          width: 3.0,
                        ),
                        boxShadow: [
                          BoxShadow(
                            color: Colors.grey[100],
                            blurRadius: 1.0,
                            spreadRadius: 0.5,
                          ),
                        ]),
                    alignment: Alignment.center,
                    padding: EdgeInsets.all(8.0),
                    child: Column(
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: <Widget>[
                        Expanded(
                          flex: 2,
                          child: Row(
                            mainAxisAlignment: MainAxisAlignment.start,
                            children: <Widget>[
                              Hero(
                                tag: podcast[index].enclosureUrl + heroTag,
                                child: Container(
                                  child: ClipRRect(
                                    borderRadius:
                                        BorderRadius.all(Radius.circular(15.0)),
                                    child: Container(
                                      height: 30.0,
                                      width: 30.0,
                                      child: CachedNetworkImage(
                                        imageUrl: podcast[index].imageUrl,
                                      ),
                                    ),
                                  ),
                                ),
                              ),
                              Spacer(),
                              showNumber
                                  ? Container(
                                      alignment: Alignment.topRight,
                                      child: Text(
                                        (podcast.length - index).toString(),
                                        style: GoogleFonts.teko(
                                          textStyle: TextStyle(
                                            fontSize: 20.0,
                                            color: _c,
                                          ),
                                        ),
                                      ),
                                    )
                                  : Center(),
                            ],
                          ),
                        ),
                        Expanded(
                          flex: 5,
                          child: Container(
                            alignment: Alignment.topLeft,
                            padding: EdgeInsets.only(top: 2.0),
                            child: Text(
                              podcast[index].title,
                              style: TextStyle(
                                fontSize: 15.0,
                              ),
                              maxLines: 4,
                            ),
                          ),
                        ),
                        Expanded(
                          flex: 1,
                          child: Row(
                            children: <Widget>[
                              Align(
                                alignment: Alignment.bottomLeft,
                                child: Text(
                                  podcast[index].pubDate.substring(4, 16),
                                  style: TextStyle(
                                      color: _c, fontStyle: FontStyle.italic),
                                ),
                              ),
                              Spacer(),
                              showDownload
                                  ? DownloadIcon(episodeBrief: podcast[index])
                                  : Center(),
                              Padding(
                                padding: EdgeInsets.all(1),
                              ),
                              showFavorite
                                  ? Container(
                                      alignment: Alignment.bottomRight,
                                      child: (podcast[index].liked == 0)
                                          ? Center()
                                          : IconTheme(
                                              data: IconThemeData(size: 15),
                                              child: Icon(
                                                Icons.favorite,
                                                color: Colors.red,
                                              ),
                                            ),
                                    )
                                  : Center(),
                            ],
                          ),
                        ),
                      ],
                    ),
                  ),
                );
              },
              childCount: podcast.length,
            ),
          ),
        ),
      ],
    );
  }
}

class DownloadIcon extends StatefulWidget {
  final EpisodeBrief episodeBrief;
  DownloadIcon({this.episodeBrief, Key key}) : super(key: key);
  @override
  _DownloadIconState createState() => _DownloadIconState();
}

class _DownloadIconState extends State<DownloadIcon> {
  _TaskInfo _task;
  bool _isLoading;
  ReceivePort _port = ReceivePort();

  @override
  void initState() {
    super.initState();
    _bindBackgroundIsolate();

    FlutterDownloader.registerCallback(downloadCallback);

    _isLoading = true;
    _prepare();
  }

  @override
  void dispose() {
    _unbindBackgroundIsolate();
    super.dispose();
  }

  void _bindBackgroundIsolate() {
    bool isSuccess = IsolateNameServer.registerPortWithName(
        _port.sendPort, 'downloader_send_port');
    if (!isSuccess) {
      _unbindBackgroundIsolate();
      _bindBackgroundIsolate();
      return;
    }

    _port.listen((dynamic data) {
      print('UI isolate callback: $data');
      String id = data[0];
      DownloadTaskStatus status = data[1];
      int progress = data[2];
      if (_task.taskId == id) {
        setState(() {
          _task.status = status;
          _task.progress = progress;
        });
      }
    });
  }

  void _unbindBackgroundIsolate() {
    IsolateNameServer.removePortNameMapping('downloader_send_port');
  }

  static void downloadCallback(
      String id, DownloadTaskStatus status, int progress) {
    print('Background callback task in $id  status ($status) $progress');
    final SendPort send =
        IsolateNameServer.lookupPortByName('downloader_send_port');
    send.send([id, status, progress]);
  }

  Future<Null> _prepare() async {
    final tasks = await FlutterDownloader.loadTasks();

    _task = _TaskInfo(
        name: widget.episodeBrief.title,
        link: widget.episodeBrief.enclosureUrl);

    tasks?.forEach((task) {
      if (_task.link == task.url) {
        _task.taskId = task.taskId;
        _task.status = task.status;
        _task.progress = task.progress;
      }
    });
    setState(() {
      _isLoading = false;
    });
  }

  @override
  Widget build(BuildContext context) {
    return _downloadButton(_task);
  }

  Widget _downloadButton(_TaskInfo task) {
    if (_isLoading)
      return Center();
    else if (task.status == DownloadTaskStatus.running) {
      return SizedBox(
        height: 12,
        width: 12,
        child: CircularProgressIndicator(
          backgroundColor: Colors.grey[200],
          strokeWidth: 1,
          valueColor: AlwaysStoppedAnimation<Color>(Colors.blue),
          value: task.progress / 100,
        ),
      );
    } else if (task.status == DownloadTaskStatus.paused) {
      return SizedBox(
        height: 12,
        width: 12,
        child: CircularProgressIndicator(
          backgroundColor: Colors.grey[200],
          strokeWidth: 1,
          valueColor: AlwaysStoppedAnimation<Color>(Colors.red),
          value: task.progress / 100,
        ),
      );
    } else if (task.status == DownloadTaskStatus.complete) {
      return IconTheme(
        data: IconThemeData(size: 15),
        child: Icon(
          Icons.done_all,
          color: Colors.blue,
        ),
      );
    } else if (task.status == DownloadTaskStatus.failed) {
      return IconTheme(
        data: IconThemeData(size: 15),
        child: Icon(Icons.refresh, color: Colors.red),
      );
    }
    return Center();
  }
}

class _TaskInfo {
  final String name;
  final String link;

  String taskId;
  int progress = 0;
  DownloadTaskStatus status = DownloadTaskStatus.undefined;

  _TaskInfo({this.name, this.link});
}