import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter/widgets.dart';
import 'package:photos/core/configuration.dart';
import 'package:photos/core/event_bus.dart';
import 'package:photos/events/user_authenticated_event.dart';
import 'package:photos/user_authenticator.dart';

class SignInWidget extends StatefulWidget {
  final Function() onReconfigurationRequested;

  const SignInWidget(
    this.onReconfigurationRequested, {
    Key key,
  }) : super(key: key);

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

enum Mode { sign_up, sign_in, unknown }

class _SignInWidgetState extends State<SignInWidget> {
  Mode mode = Mode.unknown;
  final _usernameController = TextEditingController();
  final _passwordController = TextEditingController();
  final _repeatPasswordController = TextEditingController();

  @override
  Widget build(BuildContext context) {
    if (mode == Mode.sign_up) {
      return _getSignUpWidget(context);
    } else {
      return _getSignInWidget(context);
    }
  }

  Widget _getSignUpWidget(BuildContext context) {
    return Container(
        child: SingleChildScrollView(
      child: Column(
        children: <Widget>[
          Padding(
            padding: const EdgeInsets.fromLTRB(0, 16, 0, 0),
            child: Text("Create an account to get started"),
          ),
          TextFormField(
            decoration: InputDecoration(
              hintText: 'username',
              contentPadding: EdgeInsets.all(20),
            ),
            controller: _usernameController,
            autofocus: true,
            autocorrect: false,
          ),
          TextFormField(
            decoration: InputDecoration(
              hintText: 'password',
              contentPadding: EdgeInsets.all(20),
            ),
            autocorrect: false,
            obscureText: true,
            controller: _passwordController,
          ),
          TextFormField(
            decoration: InputDecoration(
              hintText: 'repeat password',
              contentPadding: EdgeInsets.all(20),
            ),
            autocorrect: false,
            obscureText: true,
            controller: _repeatPasswordController,
          ),
          CupertinoButton(
            child: Text("Sign Up"),
            onPressed: () async {
              if (_passwordController.text != _repeatPasswordController.text) {
                _showPasswordMismatchDialog();
              } else {
                try {
                  final userCreated = await UserAuthenticator.instance.create(
                      _usernameController.text, _passwordController.text);
                  if (userCreated) {
                    Navigator.of(context).pop();
                    _showSelectEncryptionLevelDialog();
                  } else {
                    _showGenericErrorDialog();
                  }
                } catch (e) {
                  _showGenericErrorDialog(error: e);
                }
              }
            },
          ),
          CupertinoButton(
            child: Text("Have an account?"),
            onPressed: () {
              setState(() {
                mode = Mode.sign_in;
              });
            },
          ),
        ],
      ),
    ));
  }

  Widget _getSignInWidget(BuildContext context) {
    return Container(
        child: SingleChildScrollView(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          TextFormField(
            // initialValue: Configuration.instance.getUsername(),
            decoration: InputDecoration(
              hintText: 'username',
              contentPadding: EdgeInsets.all(20),
            ),
            autofocus: true,
            autocorrect: false,
            controller: _usernameController,
          ),
          TextFormField(
            // initialValue: Configuration.instance.getPassword(),
            decoration: InputDecoration(
              hintText: 'password',
              contentPadding: EdgeInsets.all(20),
            ),
            autocorrect: false,
            obscureText: true,
            controller: _passwordController,
          ),
          CupertinoButton(
            child: Text("Sign In"),
            onPressed: () async {
              final loggedIn = await UserAuthenticator.instance
                  .login(_usernameController.text, _passwordController.text);
              if (loggedIn) {
                Navigator.of(context).pop();
              } else {
                _showAuthenticationFailedErrorDialog();
              }
            },
          ),
          CupertinoButton(
            child: Text("Don't have an account?"),
            onPressed: () {
              setState(() {
                mode = Mode.sign_up;
              });
            },
          ),
        ],
      ),
    ));
  }

  void _showPasswordMismatchDialog() {
    showDialog<void>(
      context: context,
      barrierDismissible: false, // user must tap button!
      builder: (BuildContext context) {
        return CupertinoAlertDialog(
          title: Text("Passwords don't match"),
          content: Padding(
            padding: const EdgeInsets.fromLTRB(0, 16, 0, 0),
            child: Text("Please make sure that the passwords you enter match."),
          ),
          actions: <Widget>[
            CupertinoDialogAction(
              child: Text('OK'),
              onPressed: () {
                Navigator.of(context).pop();
              },
            ),
          ],
        );
      },
    );
  }

  void _showGenericErrorDialog({Exception error}) {
    showDialog<void>(
      context: context,
      barrierDismissible: false, // user must tap button!
      builder: (BuildContext context) {
        return CupertinoAlertDialog(
          title: Text("Ooops."),
          content: Padding(
            padding: const EdgeInsets.fromLTRB(0, 16, 0, 0),
            child: error == null
                ? Text("Something went wrong.")
                : Text(error.toString()),
          ),
          actions: <Widget>[
            CupertinoDialogAction(
              child: Text('OK'),
              onPressed: () {
                Navigator.of(context).pop();
              },
            ),
          ],
        );
      },
    );
  }

  void _showAuthenticationFailedErrorDialog() {
    showDialog<void>(
      context: context,
      barrierDismissible: false, // user must tap button!
      builder: (BuildContext context) {
        return CupertinoAlertDialog(
          title: Text('Login failed'),
          content: Padding(
            padding: const EdgeInsets.fromLTRB(0, 16, 0, 0),
            child: Text(
                'Please make sure that the credentials entered are correct.'),
          ),
          actions: <Widget>[
            CupertinoDialogAction(
              child: Text('Reconfigure'),
              onPressed: () {
                Navigator.of(context).pop();
                Configuration.instance.setEndpoint(null);
                widget.onReconfigurationRequested();
              },
            ),
            CupertinoDialogAction(
              child: Text('OK'),
              onPressed: () {
                Navigator.of(context).pop();
              },
            ),
          ],
        );
      },
    );
  }

  void _showSelectEncryptionLevelDialog() {
    showDialog(
      context: context,
      barrierDismissible: false,
      builder: (BuildContext context) {
        return SelectEncryptionLevelWidget();
      },
    );
  }
}

class SelectEncryptionLevelWidget extends StatelessWidget {
  const SelectEncryptionLevelWidget({
    Key key,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return CupertinoAlertDialog(
      title: Text('Choose encryption level'),
      content: Padding(
        padding: const EdgeInsets.fromLTRB(0, 16, 0, 0),
        child: Column(
          children: [
            Text('Would you like to enable end-to-end encryption?'),
            Padding(padding: EdgeInsets.all(8)),
            Text(
                'This will mean you will not be able to use features like search and sharing.'),
          ],
        ),
      ),
      actions: <Widget>[
        CupertinoDialogAction(
          child: Text('Use E2E encryption'),
          onPressed: () {
            Navigator.of(context).pop();
            _showEnterPassphraseDialog(context);
          },
        ),
        CupertinoDialogAction(
          child: Text("Use encryption at rest"),
          onPressed: () {
            Navigator.of(context).pop();
            Bus.instance.fire(UserAuthenticatedEvent());
          },
        ),
      ],
    );
  }

  void _showEnterPassphraseDialog(BuildContext context) {
    showDialog(
      context: context,
      barrierDismissible: false,
      builder: (BuildContext context) {
        return PassphraseWidget();
      },
    );
  }
}

class PassphraseWidget extends StatefulWidget {
  const PassphraseWidget({
    Key key,
  }) : super(key: key);

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

class _PassphraseWidgetState extends State<PassphraseWidget> {
  String _passphrase = "";

  @override
  Widget build(BuildContext context) {
    return CupertinoAlertDialog(
      title: Text('Enter passphrase'),
      content: Padding(
        padding: const EdgeInsets.fromLTRB(0, 16, 0, 0),
        child: Column(
          children: [
            Text("Do not forget this passphrase!"),
            Padding(padding: EdgeInsets.all(8)),
            CupertinoTextField(
              autofocus: true,
              style: Theme.of(context).textTheme.subtitle1,
              keyboardType: TextInputType.visiblePassword,
              onChanged: (value) {
                _passphrase = value;
              },
            ),
          ],
        ),
      ),
      actions: <Widget>[
        CupertinoDialogAction(
          child: Text('Save'),
          onPressed: () {
            Navigator.of(context).pop();
            Configuration.instance.generateAndSaveKey(_passphrase);
            Bus.instance.fire(UserAuthenticatedEvent());
          },
        )
      ],
    );
  }
}