// 模板画廊页面 — 日记模板浏览和选择

import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:go_router/go_router.dart';
import 'package:nuanji_app/core/theme/app_colors.dart';
import 'package:nuanji_app/core/theme/app_radius.dart';
import 'package:nuanji_app/data/remote/api_client.dart';
import '../bloc/template_bloc.dart';

/// 模板画廊页面 — 浏览和选择日记模板
class TemplateGalleryPage extends StatefulWidget {
  const TemplateGalleryPage({super.key});

  @override
  State<TemplateGalleryPage> createState() => _TemplateGalleryPageState();
}

class _TemplateGalleryPageState extends State<TemplateGalleryPage> {
  late final TemplateBloc _bloc;

  @override
  void initState() {
    super.initState();
    _bloc = TemplateBloc(api: context.read<ApiClient>());
    _bloc.load();
  }

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

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

    return Scaffold(
      appBar: AppBar(title: const Text('模板画廊')),
      body: ListenableBuilder(
        listenable: _bloc,
        builder: (context, _) {
          final state = _bloc.state;

          if (state.isLoading) {
            return const Center(child: CircularProgressIndicator());
          }

          if (state.errorMessage != null) {
            return Center(
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Icon(Icons.error_outline, size: 48, color: colorScheme.error),
                  const SizedBox(height: 16),
                  FilledButton.tonal(
                    onPressed: _bloc.load,
                    child: const Text('重试'),
                  ),
                ],
              ),
            );
          }

          final categories = state.categories;

          return Column(
            children: [
              // 分类选择器
              SizedBox(
                height: 48,
                child: ListView(
                  scrollDirection: Axis.horizontal,
                  padding: const EdgeInsets.symmetric(horizontal: 16),
                  children: categories.map((cat) {
                    final isSelected = cat == state.selectedCategory;
                    return Padding(
                      padding: const EdgeInsets.only(right: 8),
                      child: FilterChip(
                        selected: isSelected,
                        label: Text(cat),
                        onSelected: (_) => _bloc.selectCategory(cat),
                        selectedColor: colorScheme.primaryContainer,
                        checkmarkColor: colorScheme.primary,
                      ),
                    );
                  }).toList(),
                ),
              ),
              const SizedBox(height: 8),

              // 模板网格
              Expanded(
                child: state.filteredTemplates.isEmpty
                    ? const Center(child: Text('暂无模板'))
                    : GridView.builder(
                        padding: const EdgeInsets.all(16),
                        gridDelegate:
                            const SliverGridDelegateWithFixedCrossAxisCount(
                          crossAxisCount: 2,
                          mainAxisSpacing: 12,
                          crossAxisSpacing: 12,
                          childAspectRatio: 0.78,
                        ),
                        itemCount: state.filteredTemplates.length,
                        itemBuilder: (context, index) {
                          return _TemplateCard(
                            template: state.filteredTemplates[index],
                          );
                        },
                      ),
              ),
            ],
          );
        },
      ),
    );
  }
}

/// 模板卡片
class _TemplateCard extends StatelessWidget {
  const _TemplateCard({required this.template});

  final Template template;

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

    return Card(
      elevation: 0,
      shape: RoundedRectangleBorder(
        borderRadius: AppRadius.mdBorder,
        side: BorderSide(color: colorScheme.outlineVariant),
      ),
      child: InkWell(
        onTap: () {
          // 使用模板创建日记
          context.push('/editor?template=${template.id}');
        },
        borderRadius: AppRadius.mdBorder,
        child: Padding(
          padding: const EdgeInsets.all(16),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              // 模板预览区
              Container(
                width: 72,
                height: 72,
                decoration: BoxDecoration(
                  gradient: LinearGradient(
                    begin: Alignment.topLeft,
                    end: Alignment.bottomRight,
                    colors: [
                      colorScheme.primaryContainer.withValues(alpha: 0.5),
                      AppColors.tertiary.withValues(alpha: 0.3),
                    ],
                  ),
                  borderRadius: AppRadius.mdBorder,
                ),
                alignment: Alignment.center,
                child: Text(
                  template.emoji,
                  style: const TextStyle(fontSize: 36),
                ),
              ),
              const SizedBox(height: 12),
              // 模板名称
              Text(
                template.name,
                style: theme.textTheme.titleSmall?.copyWith(
                  fontWeight: FontWeight.w600,
                ),
              ),
              const SizedBox(height: 4),
              // 描述
              if (template.description != null)
                Text(
                  template.description!,
                  style: theme.textTheme.bodySmall?.copyWith(
                    color: colorScheme.onSurface.withValues(alpha: 0.5),
                  ),
                  maxLines: 2,
                  overflow: TextOverflow.ellipsis,
                  textAlign: TextAlign.center,
                ),
            ],
          ),
        ),
      ),
    );
  }
}