import 'package:flutter/material.dart';

/// Animação de entrada (fade + leve deslize para cima) para dar vida a
/// cards e listas quando aparecem em ecrã. Suporta [delay] para permitir
/// efeito "staggered" (itens surgindo em sequência) em listas/grades.
class FadeSlideIn extends StatefulWidget {
  const FadeSlideIn({
    super.key,
    required this.child,
    this.delay = Duration.zero,
    this.duration = const Duration(milliseconds: 420),
    this.offset = const Offset(0, 0.08),
  });

  final Widget child;
  final Duration delay;
  final Duration duration;
  final Offset offset;

  @override
  State<FadeSlideIn> createState() => _FadeSlideInState();
}

class _FadeSlideInState extends State<FadeSlideIn>
    with SingleTickerProviderStateMixin {
  late final AnimationController _controller = AnimationController(
    vsync: this,
    duration: widget.duration,
  );
  late final Animation<double> _fade = CurvedAnimation(
    parent: _controller,
    curve: Curves.easeOut,
  );
  late final Animation<Offset> _slide = Tween<Offset>(
    begin: widget.offset,
    end: Offset.zero,
  ).animate(CurvedAnimation(parent: _controller, curve: Curves.easeOutCubic));

  @override
  void initState() {
    super.initState();
    if (widget.delay == Duration.zero) {
      _controller.forward();
    } else {
      Future.delayed(widget.delay, () {
        if (mounted) _controller.forward();
      });
    }
  }

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

  @override
  Widget build(BuildContext context) {
    return FadeTransition(
      opacity: _fade,
      child: SlideTransition(position: _slide, child: widget.child),
    );
  }
}