Mobile app initial implementation.

Closes #3 (closed)

lib/src/screens/home.dart

+import 'package:flutter/material.dart';
+import 'package:flutter_web_browser/flutter_web_browser.dart';
+import 'package:flutter_app_auth_wrapper/flutter_app_auth_wrapper.dart';
+import 'package:url_launcher/url_launcher.dart';
+import 'dart:developer';
+import 'dart:convert';
+import 'dart:async';
+import 'package:shared_preferences/shared_preferences.dart';
+
+import '../../config.dart';
+
+class Home extends StatefulWidget {
+  Home({@required this.mode, @required this.invokerURL, @required this.setMode, @required this.host});
+  final String mode;
+  final String invokerURL;
+  final String host;
+  final void Function(String) setMode;
+
+  @override
+  _HomeState createState() => _HomeState();
+}
+
+class _HomeState extends State<Home> {
+  String _host = Config.appFlavor == Flavor.DEVELOPMENT ? Config.HOSTS[0] : Config.DEFAULT_APP_HOST;
+  bool _hidden = true;
+
+  @override
+  initState() {
+    super.initState();
+    if (widget.host != null) {
+      setState(() {
+        _host = widget.host;
+      });
+    }
+
+    showMode(widget.mode);
+
+    FlutterAppAuthWrapper.eventStream().listen((data) {
+      var token = json.decode(data.toString())["access_token"];
+      _showAlert(token);
+      widget.setMode("");
+    }, onError: (error) {
+      log("Err $error");
+      widget.setMode("");
+    });
+
+    Timer(
+        Duration(seconds: 3),
+        () {
+          setState(() {
+            _hidden = false;
+          });
+        }
+    );
+  }
+
+  Future<void> _showAlert(token) {
+    return showDialog<void>(
+      context: context,
+      builder: (BuildContext context) {
+        return AlertDialog(
+          title: Text('Authorization success'),
+          actions: <Widget>[
+            FlatButton(
+              child: Text('Go back'),
+              onPressed: () async {
+                Navigator.of(context).pop();
+
+                log("Open ${widget.invokerURL}");
+                try {
+                  await launch("${widget.invokerURL}?token=$token&host=$_host");
+                } catch (e) {
+                  log("Error launching url ${widget.invokerURL}");
+                }
+              },
+            ),
+          ],
+        );
+      },
+    );
+  }
+
+  @override
+  void didUpdateWidget(Home oldWidget) {
+    // this method IS called when parent widget passes new "props"
+    // unlike React, this method IS called _before_ the build
+    // unlike React, this method ISN'T called after setState()
+
+    if (widget.host != oldWidget.host && widget.host != null) {
+      setState(() {
+        _host = widget.host;
+      });
+    }
+
+    if (widget.mode != oldWidget.mode) {
+      showMode(widget.mode);
+    }
+
+    super.didUpdateWidget(oldWidget);
+  }
+
+  showMode(mode) {
+    if (mode == "app") {
+      openVereign();
+    } else if (mode == "oauth") {
+      startOAuth();
+    }
+  }
+
+  openVereign() {
+    FlutterWebBrowser.openWebPage(url: _host, androidToolbarColor: Color(0xFFd51d32));
+  }
+
+  startOAuth() {
+    var params = Config.getOAuthParams(host: _host);
+
+    FlutterAppAuthWrapper.startAuth(
+      AuthConfig(
+        clientId: params["clientId"],
+        clientSecret: params["clientSecret"],
+        redirectUrl: params["redirectUrl"],
+        state: "login",
+        prompt: "consent",
+        endpoint: AuthEndpoint(
+            auth: params["authEndpoint"], token: params["tokenEndpoint"]),
+        scopes: [
+          "user_account_status",
+          "user_territory",
+          "user_profile"
+        ],
+      ),
+    );
+  }
+
+
+
+  @override
+  Widget build(BuildContext context) {
+    if (_hidden) {
+      return Scaffold();
+    }
+
+    var children = <Widget>[
+      _urlButton(context, "Open Dashboard", openVereign),
+      _urlButton(context, "Authorize with Vereign", startOAuth)
+    ];
+
+    if (Config.appFlavor == Flavor.DEVELOPMENT) {
+      children.add(
+        wrapInContainer(
+          DropdownButton<String>(
+            value: _host,
+            onChanged: (String newValue) async {
+              setState(() {
+                _host = newValue;
+              });
+
+              final prefs = await SharedPreferences.getInstance();
+              prefs.setString("host", newValue);
+            },
+            items: Config.HOSTS
+                .map<DropdownMenuItem<String>>((String value) {
+                  return DropdownMenuItem<String>(
+                    value: value,
+                    child: Text(value),
+                  );
+                })
+                .toList(),
+            )
+        )
+      );
+    }
+
+    return Scaffold(
+        body: SafeArea(
+            child: SingleChildScrollView(
+                child: Column(
+                  mainAxisAlignment: MainAxisAlignment.center,
+                  crossAxisAlignment: CrossAxisAlignment.stretch,
+                  children: children
+                ))));
+  }
+
+  Widget wrapInContainer(Widget widget) {
+    return Container(
+      padding: EdgeInsets.all(10.0),
+      child: widget,
+    );
+  }
+
+  Widget _urlButton(BuildContext context, String title, listener) {
+    return wrapInContainer(
+        FlatButton(
+          color: Theme.of(context).primaryColor,
+          textColor: Colors.white,
+          padding: const EdgeInsets.symmetric(horizontal: 50.0, vertical: 15.0),
+          child: Text(title),
+          onPressed: listener
+        )
+    );
+  }
+}
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