import 'package:flutter/material.dart';
import 'package:url_launcher/url_launcher.dart';

import '../data/models/news_item.dart';

class RssItemMeta {
  final int id;
  final String title;
  final String url;
  final String source;
  final String snippet;
  final DateTime? publishedAt;

  const RssItemMeta({
    required this.id,
    required this.title,
    required this.url,
    required this.source,
    required this.snippet,
    this.publishedAt,
  });

  factory RssItemMeta.fromJson(Map<String, dynamic> json) => RssItemMeta(
        id: json['id'] as int,
        title: json['title'] as String? ?? '',
        url: json['url'] as String? ?? '',
        source: json['source'] as String? ?? '',
        snippet: json['snippet'] as String? ?? '',
        publishedAt: json['published_at'] != null
            ? DateTime.tryParse(json['published_at'] as String)
            : null,
      );

  factory RssItemMeta.fromNewsItem(NewsItem item) => RssItemMeta(
        id: item.id,
        title: item.title,
        url: item.url,
        source: item.source,
        snippet: item.snippet,
        publishedAt: item.publishedAt,
      );

  String get relativeDate {
    if (publishedAt == null) return '';
    final diff = DateTime.now().difference(publishedAt!);
    if (diff.inHours < 24) return '${diff.inHours}h ago';
    if (diff.inHours < 48) return 'Yesterday';
    return '${publishedAt!.month}/${publishedAt!.day}';
  }
}

class NewsCard extends StatelessWidget {
  final RssItemMeta item;
  final String? reaction; // 'up' | 'down' | null
  final void Function(int itemId, String reaction) onReaction;
  final VoidCallback? onDiscuss;
  final int snippetMaxLines;

  const NewsCard({
    super.key,
    required this.item,
    required this.reaction,
    required this.onReaction,
    this.onDiscuss,
    this.snippetMaxLines = 2,
  });

  Future<void> _openUrl() async {
    if (item.url.isEmpty) return;
    final uri = Uri.tryParse(item.url);
    if (uri != null && await canLaunchUrl(uri)) {
      await launchUrl(uri, mode: LaunchMode.externalApplication);
    }
  }

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

    return Card(
      margin: const EdgeInsets.symmetric(vertical: 4),
      elevation: 0,
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(10),
        side: BorderSide(color: scheme.outlineVariant),
      ),
      child: Padding(
        padding: const EdgeInsets.fromLTRB(12, 10, 12, 10),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            // Source + date row
            Row(
              children: [
                if (item.source.isNotEmpty)
                  Text(
                    item.source.toUpperCase(),
                    style: textTheme.labelSmall?.copyWith(
                      color: scheme.primary,
                      fontWeight: FontWeight.w700,
                      letterSpacing: 0.6,
                    ),
                  ),
                if (item.source.isNotEmpty && item.relativeDate.isNotEmpty)
                  Padding(
                    padding: const EdgeInsets.only(left: 8),
                    child: Text(
                      item.relativeDate,
                      style: textTheme.labelSmall?.copyWith(
                        color: scheme.onSurfaceVariant,
                      ),
                    ),
                  ),
              ],
            ),
            const SizedBox(height: 4),
            // Title — tappable if URL present. Text stays in onSurface for
            // contrast; the primary-colored underline carries the "this is a
            // link" signal without tanking readability.
            GestureDetector(
              onTap: item.url.isNotEmpty ? _openUrl : null,
              child: Text(
                item.title,
                style: textTheme.titleSmall?.copyWith(
                  fontWeight: FontWeight.w600,
                  color: scheme.onSurface,
                  height: 1.3,
                  decoration: item.url.isNotEmpty ? TextDecoration.underline : null,
                  decorationColor: scheme.primary.withValues(alpha: 0.7),
                  decorationThickness: 1.5,
                ),
              ),
            ),
            // Snippet
            if (item.snippet.isNotEmpty) ...[
              const SizedBox(height: 4),
              Text(
                item.snippet,
                maxLines: snippetMaxLines,
                overflow: TextOverflow.ellipsis,
                style: textTheme.bodySmall?.copyWith(
                  color: scheme.onSurfaceVariant,
                  height: 1.45,
                ),
              ),
            ],
            const SizedBox(height: 8),
            // Actions row: reactions + discuss
            Row(
              children: [
                _ReactionButton(
                  emoji: '👍',
                  active: reaction == 'up',
                  onTap: () => onReaction(item.id, 'up'),
                ),
                const SizedBox(width: 6),
                _ReactionButton(
                  emoji: '👎',
                  active: reaction == 'down',
                  onTap: () => onReaction(item.id, 'down'),
                ),
                if (onDiscuss != null) ...[
                  const Spacer(),
                  _DiscussButton(onTap: onDiscuss!),
                ],
              ],
            ),
          ],
        ),
      ),
    );
  }
}

class _DiscussButton extends StatelessWidget {
  final VoidCallback onTap;
  const _DiscussButton({required this.onTap});

  @override
  Widget build(BuildContext context) {
    final scheme = Theme.of(context).colorScheme;
    return GestureDetector(
      onTap: onTap,
      child: Container(
        padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 3),
        decoration: BoxDecoration(
          border: Border.all(color: scheme.primary.withValues(alpha: 0.5)),
          borderRadius: BorderRadius.circular(6),
        ),
        child: Text(
          'Discuss',
          style: TextStyle(
            fontSize: 12,
            fontWeight: FontWeight.w600,
            color: scheme.primary,
          ),
        ),
      ),
    );
  }
}

class _ReactionButton extends StatelessWidget {
  final String emoji;
  final bool active;
  final VoidCallback onTap;

  const _ReactionButton({
    required this.emoji,
    required this.active,
    required this.onTap,
  });

  @override
  Widget build(BuildContext context) {
    final scheme = Theme.of(context).colorScheme;
    return GestureDetector(
      onTap: onTap,
      child: AnimatedContainer(
        duration: const Duration(milliseconds: 150),
        padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 3),
        decoration: BoxDecoration(
          color: active ? scheme.primary.withValues(alpha: 0.12) : Colors.transparent,
          border: Border.all(
            color: active ? scheme.primary : scheme.outlineVariant,
          ),
          borderRadius: BorderRadius.circular(6),
        ),
        child: Text(emoji, style: const TextStyle(fontSize: 14)),
      ),
    );
  }
}