login_screen.dart

import 'package:firebase_crashlytics/firebase_crashlytics.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:mobile/analytics.dart';
import 'package:mobile/auth/password/reset_password_screen.dart';
import 'package:mobile/dimens.dart';
import 'package:mobile/general/extensions/scaffold_extension.dart';
import 'package:mobile/general/utils/biometrics_provider.dart';
import 'package:mobile/general/widgets/progress_button.dart';
import 'package:mobile/keys.dart';
import 'package:mobile/localization.dart';
import 'package:mobile/main/main_screen.dart';
import 'package:mobile/model/user.dart';
import 'package:mobile/repository/api/api_failure_handler.dart';
import 'package:mobile/repository/credentials_store.dart';
import 'package:mobile/repository/user_repository.dart';
import 'package:mobile/styles.dart';
import 'package:tuple/tuple.dart';
import 'package:url_launcher/url_launcher.dart';

import 'input_validation/input_validators_factory.dart';
import 'titled_textfield.dart';

enum LoginButtonState { idle, progress }

const double LOWER_LOGO_INSETS_TRIGGER = 690;

class LoginScreen extends StatefulWidget {
  static const String ANALYTICS_NAME = 'LoginScreen';

  const LoginScreen({Key key}) : super(key: key);

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

class LoginScreenState extends State<LoginScreen>
    with TickerProviderStateMixin {
  LoginButtonState loginButtonState = LoginButtonState.idle;

  final TextEditingController usernameController = TextEditingController();
  final TextEditingController passwordController = TextEditingController();

  final GlobalKey<TitledTextFieldState> usernameKey = GlobalKey();
  final GlobalKey<TitledTextFieldState> passwordKey = GlobalKey();
  final GlobalKey<ProgressButtonState> loginKey = GlobalKey();

  final GlobalKey<ScaffoldState> scaffoldKey = GlobalKey();

  UserRepository get repo => context.repository<UserRepository>();

  BiometricsProvider get biometricsProvider =>
      context.repository<BiometricsProvider>();

  CredentialsStore get credentialsStore =>
      context.repository<CredentialsStore>();

  @override
  void initState() {
    super.initState();
    if (widget.key != null) scheduleAutoLogin();
  }

  scheduleAutoLogin() async {
    await Future.delayed(const Duration(seconds: 2), () {});
    if (mounted) performAutoLogin();
  }

  void resetPassword() {
    analytics.logEvent(name: PASSWORD_RESET);

    Navigator.of(context).push(
      MaterialPageRoute(
        settings: RouteSettings(
          name: ResetPasswordScreen.ANALYTICS_NAME,
        ),
        builder: (_) => ResetPasswordScreen(userRepo: repo),
      ),
    );
  }

  bool useBiometrics = false;

  Future<void> test() async =>
      useBiometrics = await credentialsStore.isAutoLoginActive();

  Future<void> performAutoLogin() async {
    if (useBiometrics) {
      if (await biometricsProvider
          .canCheckBiometrics()) if (await biometricsProvider.authorize()) {
        await _prefillUserData();

        loginKey.currentState.simulateClick();

        final user = await _performLogin();
        if (user != null) await _saveUserData();

        if (user != null) _navigateApp();
      }
    }
  }

  @override
  Widget build(BuildContext context) => Scaffold(
        key: scaffoldKey,
        resizeToAvoidBottomInset: false,
        body: GestureDetector(
          behavior: HitTestBehavior.translucent,
          onTap: _unfocus,
          child: SafeArea(
              child: FutureBuilder<void>(
            future: test(),
            builder: (BuildContext context, AsyncSnapshot<void> snapshot) {
              return _buildBody();
            },
          )),
        ),
      );

  _prefillUserData() async {
    usernameController.text = await credentialsStore.getUsername();
    passwordController.text = await credentialsStore.getPassword();
  }

  Widget _buildBody() {
    return Column(
      children: <Widget>[
        _animatedLogoSpacing(
          _shouldShrinkSpacings(context)
              ? _logoSpacing(context).item1
              : INSET_ON_OPEN_KEYBOARD,
        ),
        GestureDetector(
          onDoubleTap: !kReleaseMode
              ? () {
                  usernameController.text = 'brandthuseman@gmail.com';
                  passwordController.text = '21201';
                }
              : null,
          child: Image.asset(
            "images/login/logo.png",
            height: LOGO_HEIGHT,
          ),
        ),
        _animatedLogoSpacing(
          _shouldShrinkSpacings(context)
              ? _logoSpacing(context).item2
              : INSET_ON_OPEN_KEYBOARD,
        ),
        Padding(
          key: ValueKey(Keys.LOGIN_USERNAME_CONTAINER_KEY),
          padding: EdgeInsets.symmetric(horizontal: APP_HORIZONTAL_SPACING),
          child: TitledTextField(
            key: usernameKey,
            title: context.appLocalization.Username,
            hint: context.appLocalization.username_TextField_placeholder,
            inputAction: TextInputAction.next,
            inputType: TextInputType.text,
            nextCallback: _moveToPassword,
            inputValidator:
                InputValidatorsFactory(context).validator(InputType.USERNAME),
            controller: usernameController,
          ),
        ),
        Padding(
          key: ValueKey(Keys.LOGIN_PASSWORD_CONTAINER_KEY),
          padding: EdgeInsets.symmetric(horizontal: APP_HORIZONTAL_SPACING),
          child: TitledTextField(
            key: passwordKey,
            title: context.appLocalization.Password,
            hint: context.appLocalization.password_TextField_placeholder,
            inputAction: TextInputAction.done,
            inputType: TextInputType.visiblePassword,
            // TODO: Proper progress management
            nextCallback: () => loginKey.currentState.simulateClick(),
            inputValidator:
                InputValidatorsFactory(context).validator(InputType.PASSWORD),
            controller: passwordController,
          ),
        ),
        Align(
          alignment: Alignment.centerRight,
          child: FlatButton(
            onPressed: resetPassword,
            materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
            child: Text(
              context.appLocalization.forgot_password_question,
              style: context.textTheme.bodyExtraSmall.copyWith(
                decoration: TextDecoration.underline,
              ),
            ),
          ),
        ),
        SizedBox(height: LOGIN_BUTTON_TOP_INSET),
        Padding(
          padding: EdgeInsets.symmetric(
            horizontal: APP_HORIZONTAL_SPACING,
          ),
          child: ProgressButton(
            key: loginKey,
            width: double.infinity,
            height: LOGIN_BUTTON_HEIGHT,
            type: ProgressButtonType.Raised,
            inProgress: loginButtonState == LoginButtonState.progress,
            borderRadius: APP_HORIZONTAL_SPACING / 2,
            color: context.theme.primaryColor,
            defaultWidget: Text(
              loginButtonState == LoginButtonState.idle
                  ? context.appLocalization.LOG_IN
                  : context.appLocalization.WELCOME_BACK,
              style: context.primaryTextTheme.heading5,
            ),
            progressWidget: const CircularProgressIndicator(
              valueColor: AlwaysStoppedAnimation(
                  AppColors.white // TODO: Proper dark theme color
                  ),
            ),
            onPressed: () async {
              final user = await _performLogin();
              if (user != null) await _saveUserData();

              return user != null ? _navigateApp : () {};
            },
          ),
        ),
        SizedBox(height: HELP_TOP_INSET / 2),
        Align(
          alignment: Alignment.centerRight,
          child: Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Text(
                context.appLocalization.Biometrics_login_hint,
                style: context.textTheme.bodyExtraSmall,
              ),
              Checkbox(
                value: useBiometrics,
                onChanged: (newValue) async {
                  var autologin = false;
                  if (newValue) {
                    autologin = await biometricsProvider.authorize();
                  }

                  await credentialsStore.storeAutologin(autologin.toString());
                  setState(() {});
                },
              ),
            ],
          ),
        ),
        SizedBox(height: HELP_TOP_INSET / 4),
        Visibility(
          // Not for release 1.0
          visible: false,
          child: FlatButton(
            child: Text(
              context.appLocalization.need_help_question,
              style: context.textTheme.bodyExtraSmall.copyWith(
                decoration: TextDecoration.underline,
              ),
            ),
            onPressed: () {
              analytics.logEvent(name: NEED_HELP_LOGGING_IN);

              scaffoldKey.currentState.showSnackBar(SnackBar(
                content: Text('Sending email'),
                duration: Duration(seconds: 1),
              ));
            },
          ),
        ),
        Expanded(
          child: Align(
            alignment: Alignment.bottomCenter,
            child: Container(
              height: BOTTOM_MENU_INSET,
              margin: EdgeInsets.only(
                bottom: BOTTOM_MENU_BOTTOM_INSET,
                left: APP_HORIZONTAL_SPACING,
                right: APP_HORIZONTAL_SPACING,
              ),
              child: Column(
                children: <Widget>[
                  Text(
                    context.appLocalization.policy_conditions_title,
                    style: context.textTheme.bodyExtraSmall,
                  ),
                  RichText(
                    text: TextSpan(
                      style: context.textTheme.bodyExtraSmall,
                      children: <TextSpan>[
                        TextSpan(
                          text: context.appLocalization.Privacy_Policy,
                          style: context.textTheme.heading6,
                          recognizer: TapGestureRecognizer()
                            ..onTap = () => _openPrivacy(),
                        ),
                        TextSpan(
                          text: ' ${context.appLocalization.and} ',
                        ),
                        TextSpan(
                          text: context.appLocalization.Terms_and_Conditions,
                          style: context.textTheme.heading6,
                          recognizer: TapGestureRecognizer()
                            ..onTap = () => _openTerms(),
                        ),
                      ],
                    ),
                  ),
                ],
              ),
            ),
          ),
        ),
      ],
    );
  }

  _saveUserData() async {
    if (!useBiometrics) return;

    var u = useBiometrics ? usernameController.text : null;
    var p = useBiometrics ? passwordController.text : null;

    await credentialsStore.storeUsername(u);
    await credentialsStore.storePassword(p);
  }

  void _moveToPassword() => passwordKey.currentState.becomeFocused();

  void _unfocus() {
    usernameKey.currentState.becomeUnfocused();
    passwordKey.currentState.becomeUnfocused();
  }

  bool _validateInput() {
    _unfocus();

    final usernameValid = usernameKey.currentState.validate();
    final passwordValid = passwordKey.currentState.validate();

    return usernameValid && passwordValid;
  }

  Future<User> _performLogin() async {
    analytics.logEvent(name: LOG_IN);

    final isValidInput = _validateInput();
    if (!isValidInput) return null;

    setState(() => loginButtonState = LoginButtonState.progress);

    try {
      final user = await repo.logIn(
        username: usernameController.text,
        password: passwordController.text,
      );

      analytics.logLogin();
      reportUser(user);

      return user;
    } catch (e, s) {
      setState(() => loginButtonState = LoginButtonState.idle);
      Crashlytics.instance.recordError(e, s, context: 'User login failure');

      _showLoginError(e);

      return null;
    }
  }

  void _showLoginError(error) => scaffoldKey.currentState.showErrorSnackBar(
        error: error is ApiMessageException &&
                error.statusCode != null &&
                error.statusCode >= 400 &&
                error.statusCode < 500
            ? context.appLocalization.loginErrorMessage
            : context.appLocalization.unexpectedErrorMessage,
      );

  void _navigateApp() {
    Navigator.of(context).pushReplacement(MaterialPageRoute(
      settings: RouteSettings(name: MainScreen.ANALYTICS_NAME),
      builder: (_) => MainScreen(),
    ));
  }

  _openPrivacy() {
    analytics.logEvent(name: PRIVACY_POLICY);
    return _launchURL('https://banyanhill.com/privacy-policy/');
  }

  _openTerms() {
    analytics.logEvent(name: TERMS_AND_CONDITIONS);
    return _launchURL('https://banyanhill.com/disclaimer/');
  }

  _launchURL(String url) async {
    if (await canLaunch(url)) {
      await launch(url);
    } else {
      logCantOpenUrl();
      Scaffold.of(context).showErrorSnackBar(
        error: context.appLocalization.Cant_open_url,
      );
    }
  }

  Tuple2<double, double> _logoSpacing(BuildContext context) =>
      MediaQuery.of(context).size.height > LOWER_LOGO_INSETS_TRIGGER
          ? Tuple2(TOP_INSET, LOGO_BOTTOM_INSET)
          : Tuple2(INSET_ON_OPEN_KEYBOARD, INSET_ON_OPEN_KEYBOARD);

  bool _shouldShrinkSpacings(BuildContext context) =>
      MediaQuery.of(context).viewInsets.bottom < KEYBOARD_TRIGGER_HEIGHT;

  Widget _animatedLogoSpacing(double height) => AnimatedSize(
        vsync: this,
        duration: Duration(milliseconds: 150),
        child: SizedBox(
          height: height,
        ),
      );
}