import 'dart:math' as math;

import 'package:flutter/material.dart';
import 'package:lottie/lottie.dart';
import 'package:youtube_player_flutter/youtube_player_flutter.dart';

import '../widgets/entrance.dart';
import '../widgets/tap_bounce.dart';

const Color _pink = Color(0xFFFF55A7);
const Color _teal = Color(0xFF2F9E94);

/// Player do YouTube incorporado (sem AppBar/tela cheia própria) — usado
/// tanto no ecrã intersticial [QuizVideoGuideScreen] como embutido
/// diretamente no ecrã de resultado do quiz.
class QuizGuideVideoCard extends StatefulWidget {
  const QuizGuideVideoCard({super.key, required this.youtubeId, this.onEnded});

  final String youtubeId;

  /// Chamado uma única vez quando o vídeo chega ao fim.
  final VoidCallback? onEnded;

  @override
  State<QuizGuideVideoCard> createState() => _QuizGuideVideoCardState();
}

class _QuizGuideVideoCardState extends State<QuizGuideVideoCard> {
  late final YoutubePlayerController _controller = YoutubePlayerController(
    initialVideoId: widget.youtubeId,
    flags: const YoutubePlayerFlags(autoPlay: true, mute: false),
  );
  bool _endedNotified = false;

  @override
  void initState() {
    super.initState();
    _controller.addListener(_handleValueChange);
  }

  void _handleValueChange() {
    if (_endedNotified) return;
    if (_controller.value.playerState == PlayerState.ended) {
      _endedNotified = true;
      widget.onEnded?.call();
    }
  }

  @override
  void dispose() {
    _controller.removeListener(_handleValueChange);
    _controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return ClipRRect(
      borderRadius: BorderRadius.circular(20),
      child: AspectRatio(
        aspectRatio: 16 / 9,
        child: YoutubePlayer(
          controller: _controller,
          showVideoProgressIndicator: true,
          progressColors: const ProgressBarColors(
            playedColor: _pink,
            handleColor: _pink,
          ),
        ),
      ),
    );
  }
}

/// Ecrã intersticial mostrado a meio do quiz, convidando a ver um vídeo
/// educativo antes de continuar. Tanto "Avançar" como "Pular" seguem para
/// [onAdvance] — o vídeo é um convite, não um bloqueio.
class QuizVideoGuideScreen extends StatefulWidget {
  const QuizVideoGuideScreen({
    super.key,
    required this.youtubeId,
    required this.onAdvance,
    this.caption =
        'Assista para compreender melhor as próximas perguntas do questionário.',
    this.extraHeading,
    this.extraSubtitle,
  });

  final String youtubeId;
  final void Function(BuildContext context) onAdvance;
  final String caption;

  /// Quando definidos, mostram um bloco de destaque extra por baixo da
  /// legenda do vídeo (ex.: um aviso a preparar o utilizador para as
  /// próximas perguntas de observação).
  final String? extraHeading;
  final String? extraSubtitle;

  @override
  State<QuizVideoGuideScreen> createState() => _QuizVideoGuideScreenState();
}

class _QuizVideoGuideScreenState extends State<QuizVideoGuideScreen> {
  // Evita que um duplo-toque (Pular + Avançar, ou o mesmo botão duas vezes
  // seguidas antes da navegação trocar de ecrã) dispare onAdvance duas
  // vezes sobre uma rota que já foi substituída.
  bool _advanced = false;

  // "Avançar" só fica disponível depois de o vídeo chegar ao fim; "Pular"
  // continua livre a qualquer momento.
  bool _videoWatched = false;

  void _advance() {
    if (_advanced) return;
    _advanced = true;
    widget.onAdvance(context);
  }

  @override
  Widget build(BuildContext context) {
    final size = MediaQuery.sizeOf(context);
    return Scaffold(
      body: Stack(
        clipBehavior: Clip.none,
        children: [
          Positioned.fill(
            child: Container(color: const Color(0xFFFAFAF7)),
          ),
          Positioned(
            left: -size.width * 0.40,
            bottom: -size.width * 0.45,
            child: IgnorePointer(
              child: SizedBox(
                width: size.width * 1.05,
                height: size.width * 1.05,
                child: Transform.rotate(
                  angle: 35 * math.pi / 180,
                  child: Opacity(
                    opacity: 0.95,
                    child: Lottie.asset(
                      'lottie/Liquid waves.json',
                      fit: BoxFit.cover,
                      repeat: true,
                    ),
                  ),
                ),
              ),
            ),
          ),
          SafeArea(
            child: Padding(
              padding: const EdgeInsets.fromLTRB(24, 4, 24, 24),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: [
                  Align(
                    alignment: Alignment.topRight,
                    child: TextButton(
                      onPressed: _advance,
                      child: const Text(
                        'Pular',
                        style: TextStyle(
                          color: Colors.black45,
                          fontWeight: FontWeight.w700,
                        ),
                      ),
                    ),
                  ),
                  const SizedBox(height: 4),
                  const FadeSlideIn(
                    child: Text(
                      'Antes de continuar, assista ao vídeo educativo...',
                      style: TextStyle(
                        fontSize: 21,
                        fontWeight: FontWeight.w900,
                        color: Colors.black87,
                        height: 1.25,
                      ),
                    ),
                  ),
                  const SizedBox(height: 24),
                  Expanded(
                    child: Center(
                      child: FadeSlideIn(
                        delay: const Duration(milliseconds: 80),
                        child: QuizGuideVideoCard(
                          youtubeId: widget.youtubeId,
                          onEnded: () => setState(() => _videoWatched = true),
                        ),
                      ),
                    ),
                  ),
                  const SizedBox(height: 16),
                  FadeSlideIn(
                    delay: const Duration(milliseconds: 120),
                    child: Text(
                      widget.caption,
                      textAlign: TextAlign.center,
                      style: TextStyle(
                        fontSize: 13.5,
                        fontWeight: FontWeight.w600,
                        color: Colors.black.withValues(alpha: 0.6),
                        height: 1.4,
                      ),
                    ),
                  ),
                  if (widget.extraHeading != null) ...[
                    const SizedBox(height: 16),
                    FadeSlideIn(
                      delay: const Duration(milliseconds: 140),
                      child: Container(
                        width: double.infinity,
                        padding: const EdgeInsets.all(16),
                        decoration: BoxDecoration(
                          color: _pink.withValues(alpha: 0.08),
                          borderRadius: BorderRadius.circular(16),
                        ),
                        child: Column(
                          children: [
                            Text(
                              widget.extraHeading!,
                              textAlign: TextAlign.center,
                              style: const TextStyle(
                                fontSize: 16,
                                fontWeight: FontWeight.w900,
                                color: _pink,
                                height: 1.25,
                              ),
                            ),
                            if (widget.extraSubtitle != null) ...[
                              const SizedBox(height: 6),
                              Text(
                                widget.extraSubtitle!,
                                textAlign: TextAlign.center,
                                style: TextStyle(
                                  fontSize: 12.5,
                                  fontWeight: FontWeight.w600,
                                  color: Colors.black.withValues(alpha: 0.6),
                                  height: 1.4,
                                ),
                              ),
                            ],
                          ],
                        ),
                      ),
                    ),
                  ],
                  const SizedBox(height: 20),
                  FadeSlideIn(
                    delay: const Duration(milliseconds: 160),
                    child: TapBounce(
                      child: SizedBox(
                        width: double.infinity,
                        height: 52,
                        child: FilledButton(
                          style: FilledButton.styleFrom(
                            backgroundColor: _teal,
                            disabledBackgroundColor: _teal.withValues(
                              alpha: 0.35,
                            ),
                            foregroundColor: Colors.white,
                            shape: const StadiumBorder(),
                            textStyle: const TextStyle(
                              fontWeight: FontWeight.w800,
                              fontSize: 16,
                            ),
                          ),
                          onPressed: _videoWatched ? _advance : null,
                          child: const Text('Avançar'),
                        ),
                      ),
                    ),
                  ),
                ],
              ),
            ),
          ),
        ],
      ),
    );
  }
}