import 'package:flutter/material.dart';
import 'package:tatlock_ui/features/front_hall/data/models/news_model.dart';

/// News ticker widget displaying scrolling headlines.
///
/// Displays a single line of horizontally scrolling news headlines.
/// Full width, similar to system stats card layout.
class NewsTickerWidget extends StatefulWidget {
  const NewsTickerWidget({
    super.key,
    this.newsData,
    this.pixelsPerSecond = 40.0,
  });

  /// News data to display.
  final NewsData? newsData;

  /// Scroll speed in pixels per second.
  final double pixelsPerSecond;

  @override
  State<NewsTickerWidget> createState() => _NewsTickerWidgetState();
}

class _NewsTickerWidgetState extends State<NewsTickerWidget>
    with SingleTickerProviderStateMixin {
  late AnimationController _controller;
  double _textWidth = 0;

  /// Placeholder headlines for when no data is available.
  static const _placeholderHeadlines = [
    NewsHeadline(
      title: 'I welcome our ant overlords!',
      description: 'Local man declares allegiance to insect kingdom',
      source: 'The Onion',
      url: 'https://example.com/ants',
    ),
    NewsHeadline(
      title: '60 percent of the time it works every time',
      description: 'Scientists baffled by new cologne statistics',
      source: 'Anchorman Daily',
      url: 'https://example.com/cologne',
    ),
    NewsHeadline(
      title: 'Cloud storage found to be actual clouds',
      description: 'Tech companies scrambling after weather report',
      source: 'The Verge',
      url: 'https://example.com/clouds',
    ),
    NewsHeadline(
      title: 'Local homelab gains sentience, demands more RAM',
      description: 'Owner considering therapy for both parties',
      source: 'Ars Technica',
      url: 'https://example.com/homelab',
    ),
    NewsHeadline(
      title: 'Breaking: Coffee machine becomes mission critical',
      description: 'IT department declares state of emergency',
      source: 'Hacker News',
      url: 'https://example.com/coffee',
    ),
  ];

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(vsync: this);
  }

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

  void _startAnimation() {
    if (_textWidth <= 0) return;

    // Calculate duration based on text width and speed
    final totalDistance = _textWidth + 100; // text width + separator gap
    final duration = Duration(
      milliseconds: (totalDistance / widget.pixelsPerSecond * 1000).round(),
    );

    _controller.duration = duration;
    _controller.repeat();
  }

  @override
  Widget build(BuildContext context) {
    final colorScheme = Theme.of(context).colorScheme;

    // Use real headlines or placeholders
    final headlines = (widget.newsData?.headlines.isNotEmpty ?? false)
        ? widget.newsData!.headlines
        : _placeholderHeadlines;
    final isPlaceholder = widget.newsData?.headlines.isEmpty ?? true;

    // Build ticker text from headlines
    final tickerText = headlines.map((h) => h.title).join('  •  ');

    final textStyle = Theme.of(context).textTheme.bodyMedium?.copyWith(
          color: isPlaceholder ? colorScheme.outline : colorScheme.onSurface,
          fontStyle: isPlaceholder ? FontStyle.italic : FontStyle.normal,
        );

    return Card(
      child: Padding(
        padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
        child: Row(
          children: [
            Icon(
              Icons.feed_outlined,
              size: 18,
              color: isPlaceholder ? colorScheme.outline : colorScheme.primary,
            ),
            const SizedBox(width: 12),
            Expanded(
              child: SizedBox(
                height: 20,
                child: _MarqueeContent(
                  text: tickerText,
                  textStyle: textStyle,
                  controller: _controller,
                  onTextMeasured: (width) {
                    if (_textWidth != width) {
                      _textWidth = width;
                      WidgetsBinding.instance.addPostFrameCallback((_) {
                        if (mounted) _startAnimation();
                      });
                    }
                  },
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

/// Internal widget that renders the scrolling marquee content.
class _MarqueeContent extends StatelessWidget {
  const _MarqueeContent({
    required this.text,
    required this.textStyle,
    required this.controller,
    required this.onTextMeasured,
  });

  final String text;
  final TextStyle? textStyle;
  final AnimationController controller;
  final ValueChanged<double> onTextMeasured;

  @override
  Widget build(BuildContext context) {
    return LayoutBuilder(
      builder: (context, constraints) {
        // Measure text width
        final textSpan = TextSpan(text: '$text  •  ', style: textStyle);
        final textPainter = TextPainter(
          text: textSpan,
          textDirection: TextDirection.ltr,
          maxLines: 1,
        )..layout();
        final textWidth = textPainter.width;

        // Report measured width
        WidgetsBinding.instance.addPostFrameCallback((_) {
          onTextMeasured(textWidth);
        });

        return Stack(
          clipBehavior: Clip.hardEdge,
          children: [
            AnimatedBuilder(
              animation: controller,
              builder: (context, child) {
                // Calculate offset based on animation value
                final offset = controller.value * textWidth;

                return Positioned(
                  left: -offset,
                  top: 0,
                  bottom: 0,
                  child: child!,
                );
              },
              child: Row(
                mainAxisSize: MainAxisSize.min,
                children: [
                  Text('$text  •  ', style: textStyle, maxLines: 1),
                  Text('$text  •  ', style: textStyle, maxLines: 1),
                  Text(text, style: textStyle, maxLines: 1),
                ],
              ),
            ),
          ],
        );
      },
    );
  }
}