// 搜索页面 — 标签+心情筛选日记
//
// 通过 SearchBloc 驱动搜索状态：
// - 标签点击 → SearchByTag event
// - 心情选择 → SearchByMood event
// - 清除按钮 → SearchClear event
// 搜索结果由 BlocBuilder<SearchBloc, SearchState> 响应式渲染。

import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:intl/intl.dart';

import '../../../core/theme/app_colors.dart';
import '../../../data/models/journal_entry.dart';
import '../bloc/search_bloc.dart';

/// 搜索页面 — 标签+心情筛选日记
class SearchPage extends StatefulWidget {
  const SearchPage({super.key});

  @override
  State<SearchPage> createState() => _SearchPageState();
}

class _SearchPageState extends State<SearchPage> {
  final _searchController = TextEditingController();

  // Phase 1 占位标签数据
  final _recentTags = ['日常', '学校', '旅行', '美食', '读书', '心情'];
  final _moodFilters = Mood.values;

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

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

    return BlocBuilder<SearchBloc, SearchState>(
      builder: (context, state) {
        final hasFilter = state is SearchLoaded && state.hasActiveFilter;

        return Scaffold(
          appBar: AppBar(
            title: TextField(
              controller: _searchController,
              decoration: InputDecoration(
                hintText: '搜索日记...',
                hintStyle: theme.textTheme.bodyLarge?.copyWith(
                  color: colorScheme.onSurface.withValues(alpha: 0.4),
                ),
                border: InputBorder.none,
                prefixIcon: const Icon(Icons.search),
                suffixIcon: hasFilter
                    ? IconButton(
                        icon: const Icon(Icons.filter_alt_off),
                        tooltip: '清除筛选',
                        onPressed: _clearSearch,
                      )
                    : (_searchController.text.isNotEmpty
                        ? IconButton(
                            icon: const Icon(Icons.clear),
                            onPressed: () {
                              _searchController.clear();
                              _clearSearch();
                            },
                          )
                        : null),
              ),
              textInputAction: TextInputAction.search,
              onSubmitted: (value) {
                if (value.trim().isNotEmpty) {
                  context.read<SearchBloc>().add(SearchByTag(value.trim()));
                }
              },
            ),
          ),
          body: _buildBody(context, theme, colorScheme, state),
        );
      },
    );
  }

  /// 根据搜索状态构建 body
  Widget _buildBody(
    BuildContext context,
    ThemeData theme,
    ColorScheme colorScheme,
    SearchState state,
  ) {
    return switch (state) {
      SearchInitial() => _buildSuggestions(context, theme, colorScheme),
      SearchLoading() => const Center(child: CircularProgressIndicator()),
      SearchLoaded(:final results, :final activeMood, :final activeTag) =>
        _hasActiveFilter(activeMood, activeTag)
            ? _buildResults(context, theme, colorScheme, results)
            : _buildSuggestions(context, theme, colorScheme),
      SearchError(:final message) => _buildError(colorScheme, message),
    };
  }

  bool _hasActiveFilter(String? mood, String? tag) =>
      mood != null || tag != null;

  /// 建议区域 — 标签云 + 心情选择
  Widget _buildSuggestions(
    BuildContext context,
    ThemeData theme,
    ColorScheme colorScheme,
  ) {
    return SingleChildScrollView(
      padding: const EdgeInsets.all(16),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(
            '常用标签',
            style:
                theme.textTheme.titleSmall?.copyWith(fontWeight: FontWeight.w600),
          ),
          const SizedBox(height: 8),
          Wrap(
            spacing: 8,
            runSpacing: 8,
            children: _recentTags.map((tag) {
              return ActionChip(
                label: Text(tag),
                onPressed: () {
                  _searchController.text = tag;
                  context.read<SearchBloc>().add(SearchByTag(tag));
                },
              );
            }).toList(),
          ),
          const SizedBox(height: 24),
          Text(
            '按心情筛选',
            style:
                theme.textTheme.titleSmall?.copyWith(fontWeight: FontWeight.w600),
          ),
          const SizedBox(height: 12),
          Wrap(
            spacing: 12,
            runSpacing: 12,
            children: _moodFilters.map((mood) {
              final color =
                  AppColors.moodColors[mood.value] ?? colorScheme.primary;
              return GestureDetector(
                onTap: () {
                  _searchController.text = _moodLabel(mood);
                  context.read<SearchBloc>().add(SearchByMood(mood));
                },
                child: Column(
                  children: [
                    Container(
                      width: 48,
                      height: 48,
                      decoration: BoxDecoration(
                        shape: BoxShape.circle,
                        color: color.withValues(alpha: 0.15),
                      ),
                      alignment: Alignment.center,
                      child: Text(_moodEmoji(mood),
                          style: const TextStyle(fontSize: 24)),
                    ),
                    const SizedBox(height: 4),
                    Text(_moodLabel(mood), style: theme.textTheme.labelSmall),
                  ],
                ),
              );
            }).toList(),
          ),
        ],
      ),
    );
  }

  /// 搜索结果列表
  Widget _buildResults(
    BuildContext context,
    ThemeData theme,
    ColorScheme colorScheme,
    List<JournalEntry> results,
  ) {
    if (results.isEmpty) {
      return Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(Icons.search_off_rounded,
                size: 48,
                color: colorScheme.onSurface.withValues(alpha: 0.2)),
            const SizedBox(height: 12),
            Text(
              '没有找到匹配的日记',
              style: theme.textTheme.bodyMedium?.copyWith(
                color: colorScheme.onSurface.withValues(alpha: 0.5),
              ),
            ),
            const SizedBox(height: 16),
            FilledButton.tonal(
              onPressed: _clearSearch,
              child: const Text('清除筛选'),
            ),
          ],
        ),
      );
    }

    return ListView.separated(
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
      itemCount: results.length,
      separatorBuilder: (_, _) => const SizedBox(height: 8),
      itemBuilder: (context, index) {
        final entry = results[index];
        return _JournalCard(entry: entry);
      },
    );
  }

  /// 错误提示
  Widget _buildError(ColorScheme colorScheme, String message) {
    return Center(
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          Icon(Icons.error_outline_rounded,
              size: 48,
              color: colorScheme.error.withValues(alpha: 0.6)),
          const SizedBox(height: 12),
          Text(
            message,
            style: TextStyle(
              color: colorScheme.error,
              fontSize: 14,
            ),
          ),
          const SizedBox(height: 16),
          FilledButton.tonal(
            onPressed: _clearSearch,
            child: const Text('重试'),
          ),
        ],
      ),
    );
  }

  void _clearSearch() {
    _searchController.clear();
    context.read<SearchBloc>().add(const SearchClear());
  }

  String _moodEmoji(Mood mood) => switch (mood) {
        Mood.happy => '😊',
        Mood.calm => '😌',
        Mood.sad => '😢',
        Mood.angry => '😠',
        Mood.thinking => '🤔',
      };

  String _moodLabel(Mood mood) => switch (mood) {
        Mood.happy => '开心',
        Mood.calm => '平静',
        Mood.sad => '难过',
        Mood.angry => '生气',
        Mood.thinking => '思考',
      };
}

/// 日记卡片 — 在搜索结果中展示单条日记摘要
class _JournalCard extends StatelessWidget {
  final JournalEntry entry;

  const _JournalCard({required this.entry});

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final colorScheme = theme.colorScheme;
    final moodColor =
        AppColors.moodColors[entry.mood.value] ?? colorScheme.primary;

    return Card(
      elevation: 0,
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(16),
        side: BorderSide(color: colorScheme.outlineVariant),
      ),
      child: InkWell(
        borderRadius: BorderRadius.circular(16),
        onTap: () {
          // TODO: 导航到日记详情页
        },
        child: Padding(
          padding: const EdgeInsets.all(16),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              // 第一行：心情 emoji + 标题 + 日期
              Row(
                children: [
                  Text(
                    _moodEmoji(entry.mood),
                    style: const TextStyle(fontSize: 20),
                  ),
                  const SizedBox(width: 8),
                  Expanded(
                    child: Text(
                      entry.title,
                      style: theme.textTheme.titleSmall?.copyWith(
                        fontWeight: FontWeight.w600,
                      ),
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                    ),
                  ),
                  Text(
                    DateFormat('MM/dd').format(entry.date),
                    style: theme.textTheme.labelSmall?.copyWith(
                      color: colorScheme.onSurfaceVariant,
                    ),
                  ),
                ],
              ),
              // 第二行：标签
              if (entry.tags.isNotEmpty) ...[
                const SizedBox(height: 8),
                Wrap(
                  spacing: 6,
                  runSpacing: 4,
                  children: entry.tags.take(4).map((tag) {
                    return Container(
                      padding: const EdgeInsets.symmetric(
                        horizontal: 8,
                        vertical: 2,
                      ),
                      decoration: BoxDecoration(
                        color: moodColor.withValues(alpha: 0.1),
                        borderRadius: BorderRadius.circular(8),
                      ),
                      child: Text(
                        tag,
                        style: theme.textTheme.labelSmall?.copyWith(
                          color: moodColor,
                          fontSize: 11,
                        ),
                      ),
                    );
                  }).toList(),
                ),
              ],
            ],
          ),
        ),
      ),
    );
  }

  String _moodEmoji(Mood mood) => switch (mood) {
        Mood.happy => '😊',
        Mood.calm => '😌',
        Mood.sad => '😢',
        Mood.angry => '😠',
        Mood.thinking => '🤔',
      };
}