import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:shared_preferences/shared_preferences.dart';
import '../../../core/design/tokens.dart';
import '../../../core/l10n/app_localizations.dart';
import '../../../core/ui/tripz_scaffold.dart';
import '../../../core/ui/tripz_button.dart';

class OnboardingScreen extends StatefulWidget {
  const OnboardingScreen({super.key});

  @override
  State<OnboardingScreen> createState() => _OnboardingScreenState();
}

class _OnboardingScreenState extends State<OnboardingScreen>
    with SingleTickerProviderStateMixin {
  final PageController _pageController = PageController();
  int _currentIndex = 0;

  late final AnimationController _pulseController;
  late final Animation<double> _pulseAnimation;

  static const _onboardingKey = 'onboarding_seen';

  @override
  void initState() {
    super.initState();
    _pulseController = AnimationController(
      vsync: this,
      duration: const Duration(milliseconds: 1400),
    )..repeat(reverse: true);
    _pulseAnimation = Tween<double>(begin: 1.0, end: 1.08).animate(
      CurvedAnimation(parent: _pulseController, curve: Curves.easeInOut),
    );
  }

  @override
  void dispose() {
    _pulseController.dispose();
    _pageController.dispose();
    super.dispose();
  }

  Future<void> _markSeen() async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.setBool(_onboardingKey, true);
  }

  void _nextPage(int pageCount) {
    if (_currentIndex < pageCount - 1) {
      _pageController.nextPage(
        duration: T.slow,
        curve: Curves.easeInOut,
      );
    } else {
      _markSeen();
      context.go('/phone');
    }
  }

  void _skip() {
    _markSeen();
    context.go('/phone');
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final cs = theme.colorScheme;
    final l10n = AppLocalizations.of(context)!;

    final pages = [
      _OnboardingPageData(
        title: l10n.onboardingTitle1,
        subtitle: l10n.onboardingSubtitle1,
        image: 'assets/images/onboarding_1.png',
        fallbackIcon: Icons.touch_app_rounded,
      ),
      _OnboardingPageData(
        title: l10n.onboardingTitle2,
        subtitle: l10n.onboardingSubtitle2,
        image: 'assets/images/onboarding_2.png',
        fallbackIcon: Icons.location_on_rounded,
      ),
      _OnboardingPageData(
        title: l10n.onboardingTitle3,
        subtitle: l10n.onboardingSubtitle3,
        image: 'assets/images/onboarding_3.png',
        fallbackIcon: Icons.payment_rounded,
      ),
    ];

    return TripzScaffold(
      backgroundColor: cs.surface,
      padding: false,
      bottomAction: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          // ── Page Indicators ──
          Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: List.generate(pages.length, (index) {
              final isActive = index == _currentIndex;
              return AnimatedContainer(
                duration: T.medium,
                margin: const EdgeInsets.symmetric(horizontal: T.s4),
                height: T.s8,
                width: isActive ? T.s24 : T.s8,
                decoration: BoxDecoration(
                  color: isActive
                      ? cs.primary
                      : cs.surfaceContainerHighest,
                  borderRadius: BorderRadius.circular(T.rCircle),
                ),
              );
            }),
          ),
          const SizedBox(height: T.s24),

          // ── Primary Button ──
          TripzButton(
            onPressed: () => _nextPage(pages.length),
            label: _currentIndex == pages.length - 1 ? l10n.getStarted : l10n.next,
          ),
        ],
      ),
      child: Column(
        children: [
          // ── Skip Button ──
          Align(
            alignment: AlignmentDirectional.centerEnd,
            child: Padding(
              padding: const EdgeInsets.symmetric(
                horizontal: T.pagePadding,
                vertical: T.s8,
              ),
              child: TripzButton(
                onPressed: _skip,
                style: TripzButtonStyle.text,
                label: l10n.skip,
                fullWidth: false,
              ),
            ),
          ),

          // ── PageView ──
          Expanded(
            child: PageView.builder(
              controller: _pageController,
              itemCount: pages.length,
              onPageChanged: (index) {
                setState(() => _currentIndex = index);
              },
              itemBuilder: (context, index) {
                final data = pages[index];
                return Padding(
                  padding: const EdgeInsets.symmetric(horizontal: T.s24),
                  child: Column(
                    mainAxisAlignment: MainAxisAlignment.center,
                    children: [
                      // ── الرسم التوضيحي (أصل مسجّل) مع نبض خفيف ──
                      AnimatedScale(
                        scale: _pulseAnimation.value,
                        duration: const Duration(milliseconds: 100),
                        child: SizedBox(
                          width: 240,
                          height: 240,
                          child: Image.asset(
                            data.image,
                            fit: BoxFit.contain,
                            errorBuilder: (_, __, ___) => Container(
                              decoration: BoxDecoration(
                                color: cs.primaryContainer,
                                shape: BoxShape.circle,
                              ),
                              child: Icon(
                                data.fallbackIcon,
                                size: 88,
                                color: cs.onPrimaryContainer,
                              ),
                            ),
                          ),
                        ),
                      ),
                      const SizedBox(height: T.s48),

                      // ── Title ──
                      Text(
                        data.title,
                        style: theme.textTheme.headlineMedium?.copyWith(
                          color: cs.onSurface,
                          fontWeight: FontWeight.bold,
                        ),
                        textAlign: TextAlign.center,
                      ),
                      const SizedBox(height: T.s12),

                      // ── Subtitle ──
                      Text(
                        data.subtitle,
                        style: theme.textTheme.bodyLarge?.copyWith(
                          color: cs.onSurfaceVariant,
                        ),
                        textAlign: TextAlign.center,
                      ),
                    ],
                  ),
                );
              },
            ),
          ),
        ],
      ),
    );
  }
}

class _OnboardingPageData {
  final String title;
  final String subtitle;
  final String image;
  final IconData fallbackIcon;

  const _OnboardingPageData({
    required this.title,
    required this.subtitle,
    required this.image,
    required this.fallbackIcon,
  });
}