import 'package:flutter/material.dart';

/// One-line text that scrolls only while [animate] is true.
///
/// Long titles loop with a small gap; short titles (including "Nothing
/// playing") stay static. Pausing stops the animation at its current offset,
/// and resuming continues from there.
class MarqueeText extends StatefulWidget {
  const MarqueeText({
    super.key,
    required this.text,
    this.style,
    this.animate = false,
    this.gap = 48,
  });

  final String text;
  final TextStyle? style;
  final bool animate;
  final double gap;

  @override
  State<MarqueeText> createState() => _MarqueeTextState();
}

class _MarqueeTextState extends State<MarqueeText>
    with SingleTickerProviderStateMixin {
  late final AnimationController _controller;
  bool _needsScroll = false;
  double _textWidth = 0;
  bool _syncScheduled = false;

  bool get _shouldAnimate => widget.animate && _needsScroll;

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(
      vsync: this,
      duration: const Duration(seconds: 10),
    )..addStatusListener(_onStatus);
  }

  void _onStatus(AnimationStatus status) {
    if (status == AnimationStatus.completed && _shouldAnimate) {
      _controller.value = 0;
      _controller.forward();
    }
  }

  @override
  void didUpdateWidget(covariant MarqueeText oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (oldWidget.text != widget.text || oldWidget.style != widget.style) {
      _controller.value = 0;
      _needsScroll = false;
    }
    _scheduleSync();
  }

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

  void _scheduleSync() {
    if (_syncScheduled) return;
    _syncScheduled = true;
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _syncScheduled = false;
      if (mounted) _sync();
    });
  }

  void _sync() {
    if (_shouldAnimate) {
      if (!_controller.isAnimating) {
        if (_controller.value >= 1) _controller.value = 0;
        _controller.forward();
      }
    } else {
      _controller.stop();
    }
  }

  @override
  Widget build(BuildContext context) {
    return LayoutBuilder(
      builder: (context, constraints) {
        final style = widget.style ?? DefaultTextStyle.of(context).style;
        final painter = TextPainter(
          text: TextSpan(text: widget.text, style: style),
          maxLines: 1,
          textDirection: Directionality.of(context),
          textScaler: MediaQuery.textScalerOf(context),
        )..layout();
        final width = painter.width;
        final needsScroll =
            constraints.hasBoundedWidth && width > constraints.maxWidth;
        if (width != _textWidth || needsScroll != _needsScroll) {
          _textWidth = width;
          _needsScroll = needsScroll;
          _scheduleSync();
        }

        if (!needsScroll) {
          return Text(
            widget.text,
            maxLines: 1,
            overflow: TextOverflow.ellipsis,
            style: style,
          );
        }

        final duration = Duration(
          milliseconds: ((width / 28) * 1000).clamp(6000, 18000).round(),
        );
        if (_controller.duration != duration) {
          _controller.duration = duration;
        }

        return ClipRect(
          child: AnimatedBuilder(
            animation: _controller,
            builder: (context, _) {
              final offset = _controller.value * (width + widget.gap);
              return OverflowBox(
                alignment: Alignment.centerLeft,
                maxWidth: double.infinity,
                maxHeight: constraints.maxHeight,
                child: Transform.translate(
                  offset: Offset(-offset, 0),
                  child: SizedBox(
                    width: width * 2 + widget.gap,
                    child: Row(
                      mainAxisSize: MainAxisSize.min,
                      children: [
                        Text(
                          widget.text,
                          maxLines: 1,
                          softWrap: false,
                          style: style,
                        ),
                        SizedBox(width: widget.gap),
                        Text(
                          widget.text,
                          maxLines: 1,
                          softWrap: false,
                          style: style,
                        ),
                      ],
                    ),
                  ),
                ),
              );
            },
          ),
        );
      },
    );
  }
}