import 'package:flutter/material.dart';
import 'package:flutter_animate/flutter_animate.dart';
import '../theme.dart';
import '../widgets/s_button.dart';
import 'quiz/quiz_flow.dart';

class IntroScreen extends StatelessWidget {
  const IntroScreen({super.key});

  void _start(BuildContext context) {
    Navigator.of(context).push(PageRouteBuilder(
      pageBuilder: (_, a, __) => const QuizFlow(),
      transitionsBuilder: (_, a, __, child) => SlideTransition(
        position: Tween<Offset>(
          begin: const Offset(1, 0),
          end: Offset.zero,
        ).animate(CurvedAnimation(parent: a, curve: Curves.easeOut)),
        child: child,
      ),
      transitionDuration: const Duration(milliseconds: 300),
    ));
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: SColors.bgSurface,
      body: SafeArea(
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            // Illustration zone (top 42%)
            Expanded(
              flex: 42,
              child: _illustrationZone()
                  .animate()
                  .fadeIn(duration: 500.ms),
            ),

            // Content zone (bottom 58%)
            Expanded(
              flex: 58,
              child: Padding(
                padding: const EdgeInsets.symmetric(horizontal: 24),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    const SizedBox(height: 8),

                    // Trust badge
                    _badge()
                        .animate()
                        .fadeIn(duration: 400.ms, delay: 150.ms),
                    const SizedBox(height: 16),

                    // Headline
                    Text(
                      'Skin that glows,\nroutine that works.',
                      style: SText.headline2(SColors.textHead),
                    )
                        .animate()
                        .fadeIn(duration: 400.ms, delay: 200.ms)
                        .slideY(begin: 0.06, end: 0, duration: 400.ms),
                    const SizedBox(height: 10),

                    // Sub
                    Text(
                      'Answer 5 quick questions and get your\npersonalised skincare plan in 60 seconds.',
                      style: SText.subtitle(SColors.textSub),
                    )
                        .animate()
                        .fadeIn(duration: 400.ms, delay: 280.ms),

                    const Spacer(),

                    // Stats row
                    _statsRow()
                        .animate()
                        .fadeIn(duration: 400.ms, delay: 360.ms),
                    const SizedBox(height: 24),

                    // CTA button
                    SButton(
                      label: 'GET STARTED',
                      onTap: () => _start(context),
                    )
                        .animate()
                        .fadeIn(duration: 400.ms, delay: 440.ms)
                        .slideY(begin: 0.1, end: 0, duration: 400.ms),
                    const SizedBox(height: 16),

                    // Sign in link (plain text, no button)
                    Center(
                      child: GestureDetector(
                        onTap: () {},
                        child: Text(
                          'Already have an account? Sign in',
                          style: SText.caption(SColors.textSub),
                        ),
                      ),
                    )
                        .animate()
                        .fadeIn(duration: 400.ms, delay: 500.ms),
                    const SizedBox(height: 20),
                  ],
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _illustrationZone() {
    return Stack(
      children: [
        // Light tinted background for art area
        Container(color: const Color(0xFFF7F5FF)),
        // Stats visual — abstract feature cards
        Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              _featureChip(Icons.auto_awesome_rounded, 'AI skin analysis'),
              const SizedBox(height: 10),
              _featureChip(Icons.science_rounded, 'Ingredient science'),
              const SizedBox(height: 10),
              _featureChip(Icons.lock_outline_rounded, 'Private & secure'),
            ],
          ),
        ),
      ],
    );
  }

  Widget _featureChip(IconData icon, String label) {
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
      decoration: BoxDecoration(
        color: SColors.bgSurface,
        borderRadius: BorderRadius.circular(14),
        border: Border.all(color: SColors.borderLight, width: 1.5),
      ),
      child: Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          Icon(icon, color: SColors.primary, size: 20),
          const SizedBox(width: 10),
          Text(label, style: SText.cardLabel(SColors.textHead)),
        ],
      ),
    );
  }

  Widget _badge() {
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 5),
      decoration: BoxDecoration(
        color: SColors.primaryLight,
        borderRadius: BorderRadius.circular(20),
      ),
      child: Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          Container(
            width: 7,
            height: 7,
            decoration: const BoxDecoration(
              color: SColors.accent,
              shape: BoxShape.circle,
            ),
          ),
          const SizedBox(width: 6),
          Text(
            'Trusted by 50,000+ women',
            style: SText.caption(SColors.primary).copyWith(fontWeight: FontWeight.w700),
          ),
        ],
      ),
    );
  }

  Widget _statsRow() {
    return Row(
      children: [
        _statBox('50K+', 'Users'),
        const SizedBox(width: 10),
        _statBox('4.9★', 'Rating'),
        const SizedBox(width: 10),
        _statBox('94%', 'Results'),
      ],
    );
  }

  Widget _statBox(String value, String label) {
    return Expanded(
      child: Container(
        padding: const EdgeInsets.symmetric(vertical: 14),
        decoration: BoxDecoration(
          color: SColors.bgSurface,
          borderRadius: BorderRadius.circular(14),
          border: Border.all(color: SColors.borderLight, width: 1.5),
        ),
        child: Column(
          children: [
            Text(value, style: SText.title(SColors.primary)),
            const SizedBox(height: 2),
            Text(label, style: SText.caption(SColors.textSub)),
          ],
        ),
      ),
    );
  }
}