car-interface-android/lib/features/lock/pin_setup_screen.dart

import 'dart:math' as math;

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

import '../../core/theme/app_colors.dart';
import '../../core/widgets/app_icon.dart';
import '../../core/widgets/pressable.dart';
import 'lock_controller.dart';
import 'pin_pad.dart';

enum PinSetupMode { set, change, remove }

/// Set, change or remove the four-digit PIN. The PIN is only used when the
/// launcher is cold-started; this screen never locks the current session.
class PinSetupScreen extends StatefulWidget {
  const PinSetupScreen({super.key, required this.mode});

  final PinSetupMode mode;

  @override
  State<PinSetupScreen> createState() => _PinSetupScreenState();
}

class _PinSetupScreenState extends State<PinSetupScreen>
    with SingleTickerProviderStateMixin {
  String _pin = '';
  int _step = 0;
  String? _firstPin;
  String? _currentPin;
  bool _busy = false;
  String? _error;

  late final AnimationController _shake = AnimationController(
    vsync: this,
    duration: const Duration(milliseconds: 380),
  );

  @override
  void dispose() {
    _shake.dispose();
    super.dispose();
  }

  int get _stepCount {
    switch (widget.mode) {
      case PinSetupMode.set:
        return 2;
      case PinSetupMode.change:
        return 3;
      case PinSetupMode.remove:
        return 1;
    }
  }

  String get _title {
    switch (widget.mode) {
      case PinSetupMode.set:
        return _step == 0 ? 'Choose a PIN' : 'Confirm your PIN';
      case PinSetupMode.change:
        return switch (_step) {
          0 => 'Enter current PIN',
          1 => 'Choose a new PIN',
          _ => 'Confirm your new PIN',
        };
      case PinSetupMode.remove:
        return 'Enter current PIN';
    }
  }

  String get _description {
    switch (widget.mode) {
      case PinSetupMode.set:
        return _step == 0
            ? 'Four digits. You will be asked for this the next time CarDash starts.'
            : 'Enter the same four digits again.';
      case PinSetupMode.change:
        return switch (_step) {
          0 => 'Confirm your current PIN before choosing a new one.',
          1 => 'Four digits. The new PIN is used the next time CarDash starts.',
          _ => 'Enter the new four digits again.',
        };
      case PinSetupMode.remove:
        return 'Confirm your current PIN. PIN protection will be turned off.';
    }
  }

  void _onDigit(String digit) {
    if (_busy || _pin.length >= 4) return;
    final lock = context.read<LockController>();
    if (lock.isCoolingDown) return;
    setState(() {
      _error = null;
      _pin += digit;
    });
    if (_pin.length == 4) {
      setState(() => _busy = true);
      Future<void>.delayed(const Duration(milliseconds: 110), _advance);
    }
  }

  void _onBackspace() {
    if (_busy || _pin.isEmpty) return;
    setState(() => _pin = _pin.substring(0, _pin.length - 1));
  }

  void _fail(String message) {
    setState(() {
      _pin = '';
      _busy = false;
      _error = message;
    });
    _shake.forward(from: 0);
  }

  Future<void> _advance() async {
    if (!mounted) return;
    final lock = context.read<LockController>();

    switch (widget.mode) {
      case PinSetupMode.set:
        if (_step == 0) {
          setState(() {
            _firstPin = _pin;
            _pin = '';
            _step = 1;
            _busy = false;
            _error = null;
          });
          return;
        }
        if (_pin != _firstPin) {
          _fail('PINs do not match.');
          return;
        }
        final error = await lock.setPin(_firstPin!);
        if (!mounted) return;
        if (error != null) {
          _fail(error);
          return;
        }
        Navigator.of(context).pop(true);

      case PinSetupMode.change:
        if (_step == 0) {
          final valid = await lock.verifyPin(_pin);
          if (!mounted) return;
          if (!valid) {
            _fail(lock.errorMessage ?? 'Current PIN is incorrect.');
            return;
          }
          setState(() {
            _currentPin = _pin;
            _pin = '';
            _step = 1;
            _busy = false;
            _error = null;
          });
          return;
        }
        if (_step == 1) {
          setState(() {
            _firstPin = _pin;
            _pin = '';
            _step = 2;
            _busy = false;
            _error = null;
          });
          return;
        }
        if (_pin != _firstPin) {
          _fail('PINs do not match.');
          return;
        }
        final error = await lock.changePin(
          currentPin: _currentPin!,
          newPin: _firstPin!,
        );
        if (!mounted) return;
        if (error != null) {
          _fail(error);
          return;
        }
        Navigator.of(context).pop(true);

      case PinSetupMode.remove:
        final error = await lock.removePin(_pin);
        if (!mounted) return;
        if (error != null) {
          _fail(error);
          return;
        }
        Navigator.of(context).pop(true);
    }
  }

  @override
  Widget build(BuildContext context) {
    final colors = context.colors;
    final theme = Theme.of(context);
    final lock = context.watch<LockController>();
    final error = lock.isCoolingDown
        ? 'Too many attempts. Try again in ${lock.cooldownSecondsRemaining}s.'
        : _error;

    return Scaffold(
      backgroundColor: colors.canvas,
      body: Container(
        decoration: BoxDecoration(
          gradient: LinearGradient(
            begin: Alignment.topLeft,
            end: Alignment.bottomRight,
            colors: Theme.of(context).brightness == Brightness.dark
                ? [colors.canvas, colors.canvasDeep]
                : [colors.canvas, const Color(0xFFF7F5EF)],
          ),
        ),
        child: SafeArea(
          child: Padding(
            padding: const EdgeInsets.fromLTRB(32, 22, 32, 22),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Row(
                  children: [
                    Pressable(
                      onTap: () => Navigator.of(context).pop(),
                      semanticLabel: 'Back',
                      pressedScale: 0.92,
                      child: Container(
                        width: 46,
                        height: 46,
                        decoration: BoxDecoration(
                          color: colors.surface,
                          shape: BoxShape.circle,
                          border: Border.all(color: colors.border),
                        ),
                        alignment: Alignment.center,
                        child: AppIcon(
                          'assets/icons/arrow-left.svg',
                          size: 20,
                          color: colors.ink,
                        ),
                      ),
                    ),
                    const SizedBox(width: 16),
                    Text(
                      'PIN',
                      style: theme.textTheme.titleLarge?.copyWith(
                        color: colors.inkMuted,
                      ),
                    ),
                    const Spacer(),
                    if (_stepCount > 1)
                      Text(
                        '${_step + 1} of $_stepCount',
                        style: theme.textTheme.labelMedium?.copyWith(
                          color: colors.inkFaint,
                        ),
                      ),
                  ],
                ),
                Expanded(
                  child: Center(
                    child: SingleChildScrollView(
                      child: ConstrainedBox(
                        constraints: const BoxConstraints(maxWidth: 420),
                        child: Column(
                          mainAxisSize: MainAxisSize.min,
                          children: [
                            const BrandMark(size: 7, gap: 6),
                            const SizedBox(height: 26),
                            Text(
                              _title,
                              textAlign: TextAlign.center,
                              style: theme.textTheme.headlineLarge,
                            ),
                            const SizedBox(height: 8),
                            Text(
                              _description,
                              textAlign: TextAlign.center,
                              style: theme.textTheme.bodyMedium?.copyWith(
                                color: colors.inkMuted,
                              ),
                            ),
                            const SizedBox(height: 28),
                            AnimatedBuilder(
                              animation: _shake,
                              builder: (context, child) {
                                final progress = _shake.value;
                                final offset =
                                    math.sin(progress * math.pi * 6) *
                                    9 *
                                    (1 - progress);
                                return Transform.translate(
                                  offset: Offset(offset, 0),
                                  child: child,
                                );
                              },
                              child: PinDots(
                                length: 4,
                                filled: _pin.length,
                                error: error != null,
                              ),
                            ),
                            const SizedBox(height: 14),
                            SizedBox(
                              height: 42,
                              child: Text(
                                error ?? 'Four digits',
                                textAlign: TextAlign.center,
                                style: theme.textTheme.bodySmall?.copyWith(
                                  color: error == null
                                      ? colors.inkFaint
                                      : colors.danger,
                                ),
                              ),
                            ),
                            const SizedBox(height: 6),
                            PinKeypad(
                              enabled: !_busy && !lock.isCoolingDown,
                              onDigit: _onDigit,
                              onBackspace: _onBackspace,
                            ),
                          ],
                        ),
                      ),
                    ),
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}