import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter_webview_plugin/flutter_webview_plugin.dart';

//白名单
const CATCH_URLS = ['m.ctrip.com/', 'm.ctrip.com/html5/', 'm.ctrip.com/html5','dp.ctrip.com/','m.ctrip.com/webapp/you/','www.chromestatus.com/'];
class WebView extends StatefulWidget {
  final String url;
  final String statusBarColor;
  final String title;
  final bool hideAppBar;
  final bool backForbid;

  WebView(
      {this.url,
      this.statusBarColor,
      this.title,
      this.hideAppBar,
      this.backForbid = false});

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

class _WebViewState extends State<WebView> {
  final webviewReference = FlutterWebviewPlugin();
  StreamSubscription<String> _onUrlChanged;

  StreamSubscription<WebViewStateChanged> _onStateChanged;
  StreamSubscription<WebViewHttpError> _onHttpError;
  bool exiting = false;

  @override
  void initState() {
    // TODO: implement initState
    super.initState();
    webviewReference.close(); //防止页面重新打开
    _onUrlChanged =
        webviewReference.onUrlChanged.listen((String url) {}); // url 变化的监听
    _onStateChanged =
        webviewReference.onStateChanged.listen((WebViewStateChanged state) {
      // h5 页面状态变化的监听
      switch (state.type) {
        case WebViewState.startLoad:
          if (_isToMain(state.url)&&!exiting) {
            if (widget.backForbid) {
              webviewReference.launch(widget.url);
            } else {
                Navigator.pop(context);
                exiting = true;
            }
          }
          break;
        default:
          print(widget.url);
          break;
      }
    });
    _onHttpError =
        webviewReference.onHttpError.listen((WebViewHttpError error) {
      // h5 加载网络错误的监听
      print(error);
    });
  }

  _isToMain(String url) {
    bool contain = false;
    for (final value in CATCH_URLS) {
      if (url?.endsWith(value) ?? false) {
        //  url 存在 才会调用endsWith
        contain = true;
        break;
      }
    }
    return contain;
  }

  @override
  void dispose() {
    // TODO: implement dispose
    super.dispose();
    _onUrlChanged.cancel();
    _onStateChanged.cancel();
    _onHttpError.cancel();
    webviewReference.dispose();
  }

  @override
  Widget build(BuildContext context) {
    String statusBarColorStr = widget.statusBarColor ?? 'ffffff';
    Color backButtonColor;
    if (statusBarColorStr == 'ffffff') {
      backButtonColor = Colors.black;
    } else {
      backButtonColor = Colors.white;
    }
    return Scaffold(
      body: Column(
        children: <Widget>[
          _appBar(
              Color(int.parse('0xff' + statusBarColorStr)), backButtonColor),
          Expanded(
              child: WebviewScaffold(
            url: widget.url,
            withZoom: true,
            withLocalStorage: true,
            hidden: true,
            initialChild: Container(
              //加载等待的界面
              color: Colors.white,
              child: Center(
                child: Text('Waiting...'),
              ),
            ),
          ))
        ],
      ),
    );
  }

  _appBar(Color backgroundColor, Color backButtonColor) {
    if (widget.hideAppBar ?? false) {
      return Container(
        color: backgroundColor,
        height: 30,
      );
    }
    return Container(
      child: FractionallySizedBox(
        widthFactor: 1,
        child: Stack(
          children: <Widget>[
            GestureDetector(
              child: Container(
                margin: EdgeInsets.only(left: 10),
                child: Icon(
                  Icons.close,
                  color: backButtonColor,
                  size: 26,
                ),
              ),
            ),
            Positioned(
              left: 0,
              right: 0,
              child: Center(
                child: Text(
                  widget.title ?? '',
                  style: TextStyle(color: backButtonColor, fontSize: 20),
                ),
              ),
            )
          ],
        ),
      ),
    );
  }
}