nj/app/lib/features/search/bloc/search_bloc.dart

// 搜索 BLoC — 关键词+标签+心情筛选日记
//
// 状态机: SearchInitial → SearchLoading → SearchLoaded/SearchError
// 支持关键词搜索、标签筛选、心情筛选、结果分类 tab。

import 'package:flutter_bloc/flutter_bloc.dart';

import '../../../data/models/journal_entry.dart';
import '../../../data/repositories/journal_repository.dart';

part 'search_event.dart';
part 'search_state.dart';

/// 搜索 BLoC
class SearchBloc extends Bloc<SearchEvent, SearchState> {
  final JournalRepository _journalRepo;

  /// 内存搜索历史（最多 10 条）
  final List<String> _searchHistory = [];

  SearchBloc({required JournalRepository journalRepository})
      : _journalRepo = journalRepository,
        super(const SearchInitial()) {
    on<SearchByMood>(_onSearchByMood);
    on<SearchByTag>(_onSearchByTag);
    on<SearchByKeyword>(_onSearchByKeyword);
    on<SearchClear>(_onSearchClear);
    on<SearchTabChanged>(_onSearchTabChanged);
  }

  /// 按心情筛选日记
  Future<void> _onSearchByMood(
    SearchByMood event,
    Emitter<SearchState> emit,
  ) async {
    emit(const SearchLoading());
    try {
      if (event.mood == null) {
        emit(SearchLoaded(searchHistory: List.unmodifiable(_searchHistory)));
        return;
      }
      final results = await _journalRepo.getJournals(
        mood: event.mood!.value,
        page: 1,
        pageSize: 50,
      );
      emit(SearchLoaded(
        results: results,
        activeMood: event.mood!.value,
        searchHistory: List.unmodifiable(_searchHistory),
      ));
    } catch (e) {
      emit(const SearchError('搜索失败，请重试'));
    }
  }

  /// 按标签筛选日记
  Future<void> _onSearchByTag(
    SearchByTag event,
    Emitter<SearchState> emit,
  ) async {
    emit(const SearchLoading());
    try {
      _addToHistory(event.tag);
      final results = await _journalRepo.getJournals(
        tag: event.tag,
        page: 1,
        pageSize: 50,
      );
      emit(SearchLoaded(
        results: results,
        activeTag: event.tag,
        searchHistory: List.unmodifiable(_searchHistory),
      ));
    } catch (e) {
      emit(const SearchError('搜索失败，请重试'));
    }
  }

  /// 关键词搜索 — 在标题中匹配关键词
  Future<void> _onSearchByKeyword(
    SearchByKeyword event,
    Emitter<SearchState> emit,
  ) async {
    final keyword = event.keyword.trim();
    if (keyword.isEmpty) {
      emit(SearchLoaded(searchHistory: List.unmodifiable(_searchHistory)));
      return;
    }

    emit(const SearchLoading());
    try {
      _addToHistory(keyword);
      // 获取所有日记并在客户端按关键词过滤
      final allJournals = await _journalRepo.getJournals(
        page: 1,
        pageSize: 200,
      );
      final lowerKeyword = keyword.toLowerCase();
      final results = allJournals.where((j) {
        final titleMatch = j.title.toLowerCase().contains(lowerKeyword);
        final excerptMatch = (j.contentExcerpt ?? '')
            .toLowerCase()
            .contains(lowerKeyword);
        final tagMatch =
            j.tags.any((t) => t.toLowerCase().contains(lowerKeyword));
        return titleMatch || excerptMatch || tagMatch;
      }).toList();

      emit(SearchLoaded(
        results: results,
        activeKeyword: keyword,
        searchHistory: List.unmodifiable(_searchHistory),
      ));
    } catch (e) {
      emit(const SearchError('搜索失败，请重试'));
    }
  }

  /// 清除搜索结果
  void _onSearchClear(
    SearchClear event,
    Emitter<SearchState> emit,
  ) {
    emit(SearchLoaded(searchHistory: List.unmodifiable(_searchHistory)));
  }

  /// 切换结果分类 tab
  void _onSearchTabChanged(
    SearchTabChanged event,
    Emitter<SearchState> emit,
  ) {
    final current = state;
    if (current is SearchLoaded) {
      emit(current.copyWith(activeTab: event.tab));
    }
  }

  /// 添加到搜索历史（去重，最多 10 条）
  void _addToHistory(String keyword) {
    _searchHistory.remove(keyword);
    _searchHistory.insert(0, keyword);
    if (_searchHistory.length > 10) {
      _searchHistory.removeLast();
    }
  }
}