import 'dart:async';
import 'dart:convert';
import 'dart:io';

import 'package:flutter/material.dart';
import 'package:quickgui/src/model/operating_system.dart';
import 'package:quickgui/src/model/version.dart';

class Downloader extends StatefulWidget {
  const Downloader({
    Key? key,
    required this.operatingSystem,
    required this.version,
    this.option,
  }) : super(key: key);

  final OperatingSystem operatingSystem;
  final Version version;
  final String? option;

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

class _DownloaderState extends State<Downloader> {
  final pattern = RegExp("( [0-9]+%)");
  late final Stream<double> _progressStream;
  bool _downloadFinished = false;

  @override
  void initState() {
    _progressStream = progressStream();
    super.initState();
  }

  Stream<double> progressStream() {
    var options = [widget.operatingSystem.code, widget.version.version];
    if (widget.option != null) {
      options.add(widget.option!);
    }
    var controller = StreamController<double>();
    Process.start('quickget', options).then((process) {
      process.stderr.transform(utf8.decoder).forEach((line) {
        var matches = pattern.allMatches(line).toList();
        if (matches.isNotEmpty) {
          var percent = matches[0].group(1);
          if (percent != null) {
            var value = double.parse(percent.replaceAll('%', '')) / 100.0;
            controller.add(value);
          }
        }
      });
      process.exitCode.then((value) {
        controller.close();
        setState(() {
          _downloadFinished = true;
        });
      });
    });
    return controller.stream;
  }

  @override
  Widget build(BuildContext context) {
    //process.then((process) {
    //  process.stderr.transform(utf8.decoder).forEach((e) {
    //    var matches = pattern.allMatches(e).toList();
    //    var percent = matches[0].group(1);
    //    if (percent != null) {}
    //  });
    //});

    return Scaffold(
      appBar: AppBar(
        title: Text('Downloading ${widget.operatingSystem.name} ${widget.version.version}' + (widget.option != null ? ' (${widget.option})' : '')),
        automaticallyImplyLeading: false,
      ),
      body: Column(children: [
        Expanded(
          child: StreamBuilder(
            stream: _progressStream,
            builder: (context, AsyncSnapshot<double> snapshot) {
              return Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Padding(
                    padding: const EdgeInsets.all(8.0),
                    child: _downloadFinished
                        ? const Text('Download finished.')
                        : snapshot.hasData
                            ? Text('Downloading...${(snapshot.data! * 100).toInt()}%')
                            : const Text('Waiting for download to start'),
                  ),
                  Padding(
                    padding: const EdgeInsets.all(8.0),
                    child: SizedBox(
                      width: 200,
                      child: LinearProgressIndicator(
                        value: _downloadFinished
                            ? 1
                            : snapshot.hasData
                                ? snapshot.data!
                                : null,
                      ),
                    ),
                  ),
                ],
              );
            },
          ),
        ),
        Padding(
          padding: const EdgeInsets.all(8.0),
          child: Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              ElevatedButton(
                  onPressed: _downloadFinished
                      ? () {
                          Navigator.of(context).pop();
                        }
                      : null,
                  child: _downloadFinished ? const Text('Dimiss') : const Text('Cancel'))
            ],
          ),
        ),
      ]),
    );
  }
}