xianyan/lib/features/classics/classics_pages.dart

// ============================================================
// 闲言APP — 经典名句页面（分类入口 + 列表页）
// 创建时间: 2026-06-12
// 更新时间: 2026-06-12
// 作用: 合并经典名句分类入口页与列表页，统一管理页面组件
// 上次更新: 合并 classics_page.dart + classics_list_page.dart 为单文件
// ============================================================

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../core/theme/app_radius.dart';
import '../../core/theme/app_theme.dart';
import '../../core/theme/app_typography.dart';
import '../../shared/widgets/containers/glass_container.dart';
import '../../shared/widgets/adaptive/adaptive_back_button.dart';
import '../home/feed_model.dart';
import 'classics_core.dart';

// ==================== 分类入口页 ====================

/// 经典名句主页 — 展示古籍分类入口，点击进入对应名句列表
class ClassicsPage extends ConsumerWidget {
  const ClassicsPage({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final ext = Theme.of(context).extension<AppThemeExtension>();

    return CupertinoPageScaffold(
      navigationBar: const CupertinoNavigationBar(
        leading: AdaptiveBackButton(),
        middle: Text('📖 经典名句'),
        previousPageTitle: '返回',
      ),
      child: SafeArea(
        child: GridView.count(
          crossAxisCount: 2,
          padding: const EdgeInsets.all(16),
          mainAxisSpacing: 12,
          crossAxisSpacing: 12,
          childAspectRatio: 1.5,
          children: ClassicsService.categories.map((cat) {
            return _CategoryCard(
              category: cat,
              ext: ext,
              onTap: () => _navigateToList(context, cat),
            );
          }).toList(),
        ),
      ),
    );
  }

  void _navigateToList(BuildContext context, ClassicsCategory cat) {
    Navigator.push<void>(
      context,
      CupertinoPageRoute<void>(builder: (_) => ClassicsListPage(category: cat)),
    );
  }
}

/// 分类卡片组件
class _CategoryCard extends StatelessWidget {
  const _CategoryCard({
    required this.category,
    required this.ext,
    required this.onTap,
  });

  final ClassicsCategory category;
  final AppThemeExtension? ext;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: onTap,
      child: GlassContainer(
        borderRadius: AppRadius.lgBorder,
        child: Padding(
          padding: const EdgeInsets.all(16),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              Row(
                children: [
                  Text(category.emoji, style: const TextStyle(fontSize: 28)),
                  const SizedBox(width: 8),
                  Expanded(
                    child: Text(
                      category.name,
                      style: AppTypography.title3.copyWith(
                        color: ext?.textPrimary ?? CupertinoColors.label,
                        fontWeight: FontWeight.w600,
                      ),
                      overflow: TextOverflow.ellipsis,
                    ),
                  ),
                ],
              ),
              const SizedBox(height: 8),
              Text(
                category.desc,
                style: AppTypography.caption1.copyWith(
                  color: ext?.textSecondary ?? CupertinoColors.secondaryLabel,
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

// ==================== 列表页 ====================

/// 经典名句列表页 — 展示某类古籍的列表，支持搜索和分页
class ClassicsListPage extends ConsumerStatefulWidget {
  const ClassicsListPage({super.key, required this.category});
  final ClassicsCategory category;

  @override
  ConsumerState<ClassicsListPage> createState() => _ClassicsListPageState();
}

class _ClassicsListPageState extends ConsumerState<ClassicsListPage> {
  final _searchController = TextEditingController();

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      ref
          .read(classicsProvider.notifier)
          .loadList(type: widget.category.id, refresh: true);
    });
  }

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

  @override
  Widget build(BuildContext context) {
    final state = ref.watch(classicsProvider);
    final ext = Theme.of(context).extension<AppThemeExtension>();

    return CupertinoPageScaffold(
      navigationBar: CupertinoNavigationBar(
        leading: const AdaptiveBackButton(),
        middle: Text('${widget.category.emoji} ${widget.category.name}'),
        previousPageTitle: '国学',
      ),
      child: SafeArea(
        child: Column(
          children: [
            Padding(
              padding: const EdgeInsets.fromLTRB(16, 8, 16, 4),
              child: CupertinoSearchTextField(
                controller: _searchController,
                placeholder: '搜索${widget.category.name}...',
                onSubmitted: (keyword) {
                  if (keyword.trim().isEmpty) {
                    ref
                        .read(classicsProvider.notifier)
                        .loadList(type: widget.category.id, refresh: true);
                  } else {
                    ref
                        .read(classicsProvider.notifier)
                        .search(keyword: keyword, type: widget.category.id);
                  }
                },
              ),
            ),
            Expanded(
              child: state.isLoading && state.items.isEmpty
                  ? const Center(child: CupertinoActivityIndicator())
                  : state.items.isEmpty
                  ? Center(
                      child: Text(
                        '暂无内容',
                        style: AppTypography.body.copyWith(
                          color:
                              ext?.textHint ?? CupertinoColors.placeholderText,
                        ),
                      ),
                    )
                  : CupertinoScrollbar(
                      child: ListView.builder(
                        padding: const EdgeInsets.symmetric(
                          horizontal: 16,
                          vertical: 8,
                        ),
                        itemCount: state.items.length + 1,
                        itemBuilder: (context, index) {
                          if (index == state.items.length) {
                            if (state.hasMore && !state.isLoading) {
                              ref
                                  .read(classicsProvider.notifier)
                                  .loadList(type: widget.category.id);
                            }
                            return state.isLoading
                                ? const Padding(
                                    padding: EdgeInsets.all(16),
                                    child: Center(
                                      child: CupertinoActivityIndicator(),
                                    ),
                                  )
                                : const SizedBox.shrink();
                          }
                          final item = state.items[index];
                          return _ListItem(item: item, ext: ext);
                        },
                      ),
                    ),
            ),
          ],
        ),
      ),
    );
  }
}

/// 列表项组件
class _ListItem extends StatelessWidget {
  const _ListItem({required this.item, required this.ext});
  final FeedItem item;
  final AppThemeExtension? ext;

  @override
  Widget build(BuildContext context) {
    final title = item.title;
    final content = item.content.isNotEmpty ? item.content : item.summary;

    return Padding(
      padding: const EdgeInsets.only(bottom: 8),
      child: GlassContainer(
        borderRadius: AppRadius.mdBorder,
        child: Padding(
          padding: const EdgeInsets.all(12),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              if (title.isNotEmpty)
                Text(
                  title,
                  style: AppTypography.subhead.copyWith(
                    fontWeight: FontWeight.w600,
                    color: ext?.textPrimary ?? CupertinoColors.label,
                  ),
                  maxLines: 2,
                  overflow: TextOverflow.ellipsis,
                ),
              if (content.isNotEmpty) ...[
                const SizedBox(height: 6),
                Text(
                  content,
                  style: AppTypography.footnote.copyWith(
                    color: ext?.textSecondary ?? CupertinoColors.secondaryLabel,
                  ),
                  maxLines: 4,
                  overflow: TextOverflow.ellipsis,
                ),
              ],
            ],
          ),
        ),
      ),
    );
  }
}