import 'package:flutter/material.dart';
import 'package:vikunja_app/global.dart';
import 'package:vikunja_app/pages/register_page.dart';
import 'package:vikunja_app/theme/button.dart';
import 'package:vikunja_app/theme/buttonText.dart';
import 'package:vikunja_app/theme/constants.dart';
import 'package:vikunja_app/utils/validator.dart';

class LoginPage extends StatefulWidget {
  @override
  _LoginPageState createState() => _LoginPageState();
}

class _LoginPageState extends State<LoginPage> {
  final _formKey = GlobalKey<FormState>();
  String _server, _username, _password;
  bool _loading = false;

  @override
  Widget build(BuildContext ctx) {
    return Scaffold(
      body: Center(
        child: SingleChildScrollView(
          padding: const EdgeInsets.all(16.0),
          child: Builder(
            builder: (BuildContext context) => Form(
                  autovalidate: true,
                  key: _formKey,
                  child: Center(
                    child: Column(
                      mainAxisAlignment: MainAxisAlignment.center,
                      crossAxisAlignment: CrossAxisAlignment.center,
                      children: <Widget>[
                        Padding(
                          padding: EdgeInsets.symmetric(vertical: 30),
                          child: Image(
                            image: AssetImage('assets/vikunja_logo_full.png'),
                            height: 85.0,
                            semanticLabel: 'Vikunja Logo',
                          ),
                        ),
                        Padding(
                          padding: vStandardVerticalPadding,
                          child: TextFormField(
                            enabled: !_loading,
                            onSaved: (serverAddress) => _server = serverAddress,
                            validator: (address) {
                              return isUrl(address) ? null : 'Invalid URL';
                            },
                            decoration: new InputDecoration(
                                border: OutlineInputBorder(),
                                labelText: 'Server Address'),
                          ),
                        ),
                        Padding(
                          padding: vStandardVerticalPadding,
                          child: TextFormField(
                            enabled: !_loading,
                            onSaved: (username) => _username = username,
                            decoration: new InputDecoration(
                                border: OutlineInputBorder(),
                                labelText: 'Username'),
                          ),
                        ),
                        Padding(
                          padding: vStandardVerticalPadding,
                          child: TextFormField(
                            enabled: !_loading,
                            onSaved: (password) => _password = password,
                            decoration: new InputDecoration(
                                border: OutlineInputBorder(),
                                labelText: 'Password'),
                            obscureText: true,
                          ),
                        ),
                        Builder(
                            builder: (context) => FancyButton(
                                  onPressed: !_loading
                                      ? () {
                                          if (_formKey.currentState
                                              .validate()) {
                                            Form.of(context).save();
                                            _loginUser(context);
                                          }
                                        }
                                      : null,
                                  child: _loading
                                      ? CircularProgressIndicator()
                                      : VikunjaButtonText('Login'),
                                )),
                        Builder(
                            builder: (context) => FancyButton(
                                  onPressed: () => Navigator.push(
                                      context,
                                      MaterialPageRoute(
                                          builder: (context) =>
                                              RegisterPage())),
                                  child: VikunjaButtonText('Register'),
                                )),
                      ],
                    ),
                  ),
                ),
          ),
        ),
      ),
    );
  }

  _loginUser(BuildContext context) async {
    setState(() => _loading = true);
    try {
      var vGlobal = VikunjaGlobal.of(context);
      var newUser =
          await vGlobal.newUserService(_server).login(_username, _password);
      vGlobal.changeUser(newUser.user, token: newUser.token, base: _server);
    } catch (ex) {
      showDialog(
          context: context,
          builder: (context) => new AlertDialog(
                title: Text(
                    'Login failed! Please check your server url and credentials. ' +
                        ex.toString()),
                actions: <Widget>[
                  FlatButton(
                      onPressed: () => Navigator.pop(context),
                      child: const Text('Close'))
                ],
              ));
    } finally {
      setState(() {
        _loading = false;
      });
    }
  }
}