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

import 'package:flutter/material.dart';
import 'package:flutter_user_agent/flutter_user_agent.dart';
import 'package:webview_flutter/webview_flutter.dart';
import 'package:http/http.dart' as http;
//import 'package:share/share.dart';

void main() => runApp(MaterialApp(home: ForumsScreen()));

class ForumsScreen extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => ForumsScreenState();
}

class ForumsScreenState extends State<ForumsScreen> {
  final _bloc = ForumsBloc();
  Completer<WebViewController> _controller = Completer<WebViewController>();

  // todo: try passing data using an inherited widget-
  @override
  Widget build(BuildContext context) {
    return StreamBuilder<bool>(
        stream: _bloc.loadingStream,
        initialData: true,
        builder: (context, snapshot) {
          return Scaffold(
            appBar: AppBar(
              title: Text("Forums"),
              actions: <Widget>[
                RefreshButton(snapshot.data),
                SharePostButton(_controller, snapshot.data),
              ],
            ),
            body: ForumsWebView(_bloc),
          );
        });
  }
}

class ForumsWebView extends StatefulWidget {
  final ForumsBloc _bloc;
  ForumsWebView(this._bloc);

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

class _ForumsWebViewState extends State<ForumsWebView> {
  Completer<WebViewController> _controller = Completer<WebViewController>();
  String _webViewUserAgent;

  // todo: potentially remove
  @override
  void initState() {
    super.initState();
    getDefaultUserAgent();
  }

  @override
  Widget build(BuildContext context) {
    return WebView(
      initialUrl: 'http://forums.redflagdeals.com',
      onWebViewCreated: (WebViewController webViewController) {
        _controller.complete(webViewController);
      },
      onPageFinished: (String string) {
        widget._bloc.forumsEventSink.add(LoadingEvent());
        final snackBar = SnackBar(
          content: Text(_getNewUserAgent(_webViewUserAgent)),
          duration: Duration(seconds: 2),
        );
        Scaffold.of(context).showSnackBar(snackBar);
      },
      navigationDelegate: (NavigationRequest request) {
        return NavigationDecision.navigate;
      },
    );
  }

  Future<void> getDefaultUserAgent() async {
    String webViewUserAgent;
    try {
      await FlutterUserAgent.init();
      webViewUserAgent = FlutterUserAgent.webViewUserAgent;
    } catch (Exception) {
      webViewUserAgent = '<error>';
    }

    if (!mounted) return;

    setState(() {
      _webViewUserAgent = webViewUserAgent;
    });
  }

  // todo user agent into variables
  // todo format by locale
  String _getNewUserAgent(String oldUserAgent) {
    return oldUserAgent.replaceFirst(
        RegExp(r'^[^(]*'), "RedFlagDealsApp/3.13.9 ");
  }
}

class RefreshButton extends StatefulWidget {
  final bool _loading;
  RefreshButton(this._loading);

  @override
  State<StatefulWidget> createState() => RefreshButtonState();
}

class RefreshButtonState extends State<RefreshButton> {
  @override
  Widget build(BuildContext context) {
    return IconButton(
      icon: Icon(
        Icons.refresh,
        color: widget._loading ? Theme.of(context).disabledColor : Colors.white,
      ),
      onPressed: () {
        _refreshPost();
      },
    );
  }

  _refreshPost() {
    // TODO
  }
}

class SharePostButton extends StatefulWidget {
  final Completer<WebViewController> controller;
  final bool _loading;
  SharePostButton(this.controller, this._loading);

  @override
  State<StatefulWidget> createState() => SharePostButtonState();
}

class SharePostButtonState extends State<SharePostButton> {
  @override
  Widget build(BuildContext context) {
    return IconButton(
        icon: Icon(Icons.share,
            color: widget._loading
                ? Theme
                .of(context)
                .disabledColor
                : Colors.white),
        onPressed: () {
          _sharePost();
        });
  }

  void _sharePost() {}

}


//BLOC Pattern components, move out eventually
abstract class ForumsEvent {}

class LoadingEvent extends ForumsEvent {}

class ForumsBloc {
  // too many loading variables??
  bool _loading = true;

  final _loadingStateController = StreamController<bool>();
  StreamSink<bool> get _loadingSink => _loadingStateController.sink;
  Stream<bool> get loadingStream => _loadingStateController.stream;

  // input events
  final _forumsEventController = StreamController<ForumsEvent>();
  Sink<ForumsEvent> get forumsEventSink => _forumsEventController.sink;

  ForumsBloc() {
    _forumsEventController.stream.listen(_mapEventToState);
  }

  void _mapEventToState(ForumsEvent event) {
    if (event is LoadingEvent) {
      _mapLoadEventToState(event);
    }
  }

  void _mapLoadEventToState(LoadingEvent event) {
    _loading = !_loading;
    _loadingSink.add(_loading);
  }

  void dispose() {
    _loadingStateController.close();
    _forumsEventController.close();
  }
}