// Author: fruit.com.cn

import 'package:flutter/material.dart';

import '../../../core/config/app_config.dart';
import '../../../core/data/models/drama.dart';
import '../../../core/formatting/count_format.dart';
import '../../../core/theme/app_colors.dart';
import '../../../core/theme/app_dimens.dart';
import '../../../core/widgets/remote_image.dart';
import '../../../l10n/app_localizations.dart';

const double _columnGap = 8;
const double _cardGap = 14;
const double _gridHorizontalPadding = 12;
const double _coverAspectRatio = 3 / 4;
const double _coverRadius = AppDimens.coverRadius;
const double _titleGap = 8;
const double _tagsGap = 6;
const double _titleFontSize = 15;
const double _tagChipRadius = 6;
const double _tagChipFontSize = 11;
const double _heatFontSize = 9;
const double _heatIconSize = 11;
const int _maxTags = 3;
const Color _heatBackground = AppColors.overlayMedium;
const Color _tagChipBackground = AppColors.raised;
final RegExp _tagSplitter = RegExp(r'[,/、·]');

/// 剧场/分类页共用的双列剧目网格。
///
/// 按行懒加载：翻到第 N 页时只构建当前可见的几张卡，长列表不会把整本目录都留在树上。
class SliverDramaGrid extends StatelessWidget {
  const SliverDramaGrid({
    super.key,
    required this.l10n,
    required this.dramas,
    required this.onOpen,
  });

  final AppLocalizations l10n;
  final List<Drama> dramas;
  final ValueChanged<Drama> onOpen;

  @override
  Widget build(BuildContext context) {
    final rowCount = (dramas.length + 1) ~/ 2;
    return SliverPadding(
      padding: const EdgeInsets.symmetric(horizontal: _gridHorizontalPadding),
      sliver: SliverList(
        delegate: SliverChildBuilderDelegate((context, row) {
          final left = dramas[row * 2];
          final rightIndex = row * 2 + 1;
          final right = rightIndex < dramas.length ? dramas[rightIndex] : null;
          return Padding(
            // 行间距沿用卡片间距，首行不需要。
            padding: EdgeInsets.only(top: row == 0 ? 0 : _cardGap),
            child: Row(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Expanded(child: _card(left)),
                const SizedBox(width: _columnGap),
                Expanded(
                  child: right == null
                      ? const SizedBox.shrink()
                      : _card(right),
                ),
              ],
            ),
          );
        }, childCount: rowCount),
      ),
    );
  }

  Widget _card(Drama drama) {
    return DramaGridCard(
      l10n: l10n,
      drama: drama,
      onTap: () => onOpen(drama),
    );
  }
}

/// 双列网格中的剧目卡片：海报 + 标题 + 题材标签。
class DramaGridCard extends StatelessWidget {
  const DramaGridCard({
    super.key,
    required this.l10n,
    required this.drama,
    required this.onTap,
  });

  final AppLocalizations l10n;
  final Drama drama;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      key: Key('home-drama-card-${drama.id}'),
      behavior: HitTestBehavior.opaque,
      onTap: onTap,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          _cover(),
          const SizedBox(height: _titleGap),
          _title(context),
          const SizedBox(height: _tagsGap),
          _tags(context),
        ],
      ),
    );
  }

  Widget _cover() {
    return ClipRRect(
      key: Key('home-drama-cover-${drama.id}'),
      borderRadius: BorderRadius.circular(_coverRadius),
      child: AspectRatio(
        aspectRatio: _coverAspectRatio,
        child: Stack(
          fit: StackFit.expand,
          children: [
            _DiscoverCoverImage(path: drama.posterUrl),
            Positioned(left: 8, bottom: 8, child: _heatBadge()),
          ],
        ),
      ),
    );
  }

  Widget _heatBadge() {
    return Container(
      key: Key('drama-heat-${drama.id}'),
      padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 3),
      decoration: BoxDecoration(
        color: _heatBackground,
        borderRadius: BorderRadius.circular(AppDimens.pillRadius),
      ),
      child: Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          const Icon(
            Icons.local_fire_department_rounded,
            color: AppColors.onPrimary,
            size: _heatIconSize,
          ),
          const SizedBox(width: 2),
          Text(
            l10n.heatLabel(formatInteractionCount(drama.viewCount)),
            style: const TextStyle(
              color: AppColors.onPrimary,
              fontSize: _heatFontSize,
              fontWeight: FontWeight.w600,
            ),
          ),
        ],
      ),
    );
  }

  Widget _title(BuildContext context) {
    return Text(
      drama.localizedTitle(Localizations.localeOf(context).languageCode),
      key: Key('home-drama-title-${drama.id}'),
      maxLines: 2,
      overflow: TextOverflow.ellipsis,
      style: const TextStyle(
        color: AppColors.onSurface,
        fontSize: _titleFontSize,
        fontWeight: FontWeight.w700,
        height: 1.25,
      ),
    );
  }

  Widget _tags(BuildContext context) {
    final tags = _tagValues(context);
    if (tags.isEmpty) return const SizedBox.shrink();
    return Wrap(
      spacing: 6,
      runSpacing: 4,
      children: [
        for (var index = 0; index < tags.length; index++)
          Container(
            key: Key('drama-tag-chip-${drama.id}-$index'),
            padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
            decoration: BoxDecoration(
              color: _tagChipBackground,
              borderRadius: BorderRadius.circular(_tagChipRadius),
            ),
            child: Text(
              tags[index],
              style: const TextStyle(
                color: AppColors.muted,
                fontSize: _tagChipFontSize,
              ),
            ),
          ),
      ],
    );
  }

  List<String> _tagValues(BuildContext context) {
    final localized = drama.localizedTypeLabels(Localizations.localeOf(context).languageCode);
    if (localized.isNotEmpty) return localized.take(3).toList(growable: false);
    final result = <String>[];
    for (final value in [drama.genre, drama.category]) {
      for (final part in value.split(_tagSplitter)) {
        final tag = part.trim();
        if (tag.isEmpty || result.contains(tag)) continue;
        result.add(tag);
        if (result.length == _maxTags) return result;
      }
    }
    return result;
  }
}

class _DiscoverCoverImage extends StatelessWidget {
  const _DiscoverCoverImage({required this.path});

  final String path;

  @override
  Widget build(BuildContext context) {
    final url = AppConfig.mediaUrl(path);
    if (url.isEmpty) return _placeholder();
    return LayoutBuilder(
      builder: (context, constraints) {
        // 卡片只有半屏宽，按原图解码一张竖版海报就是数 MB，按布局宽度限一下。
        final decodeWidth = constraints.hasBoundedWidth
            ? resolveImageDecodePixels(
                constraints.maxWidth,
                MediaQuery.devicePixelRatioOf(context),
              )
            : null;
        return Image.network(
          url,
          width: double.infinity,
          height: double.infinity,
          fit: BoxFit.cover,
          cacheWidth: decodeWidth,
          loadingBuilder: (context, child, progress) {
            if (progress == null) return child;
            return _placeholder();
          },
          errorBuilder: (_, _, _) => _placeholder(),
        );
      },
    );
  }

  Widget _placeholder() {
    return const ColoredBox(
      color: AppColors.raised,
      child: Center(
        child: Icon(
          Icons.image_not_supported_outlined,
          color: AppColors.subtle,
          size: 32,
        ),
      ),
    );
  }
}