import 'package:flutter_bloc/flutter_bloc.dart';
import '../../core/utils/app_logger.dart';
import '../../data/models/subject_model.dart';
import '../../data/repositories/curriculum_repository.dart';

abstract class CurriculumState {}

class CurriculumInitial extends CurriculumState {}
class CurriculumLoading extends CurriculumState {}

class CurriculumLoaded extends CurriculumState {
  final List<SubjectModel> subjects;
  final List<SubjectModel> filteredSubjects;
  final List<GradeLevelModel> availableGrades;
  final String selectedGrade;
  final String selectedStream;
  final String searchQuery;
  final SubjectModel? activeSubject;

  CurriculumLoaded({
    required this.subjects,
    required this.filteredSubjects,
    this.availableGrades = const [],
    this.selectedGrade = 'grade_10',
    this.selectedStream = 'scientific',
    this.searchQuery = '',
    this.activeSubject,
  });

  CurriculumLoaded copyWith({
    List<SubjectModel>? subjects,
    List<SubjectModel>? filteredSubjects,
    List<GradeLevelModel>? availableGrades,
    String? selectedGrade,
    String? selectedStream,
    String? searchQuery,
    SubjectModel? activeSubject,
  }) {
    return CurriculumLoaded(
      subjects: subjects ?? this.subjects,
      filteredSubjects: filteredSubjects ?? this.filteredSubjects,
      availableGrades: availableGrades ?? this.availableGrades,
      selectedGrade: selectedGrade ?? this.selectedGrade,
      selectedStream: selectedStream ?? this.selectedStream,
      searchQuery: searchQuery ?? this.searchQuery,
      activeSubject: activeSubject ?? this.activeSubject,
    );
  }
}

class CurriculumError extends CurriculumState {
  final String message;
  CurriculumError(this.message);
}

class CurriculumCubit extends Cubit<CurriculumState> {
  final CurriculumRepository _repo;

  CurriculumCubit({CurriculumRepository? repo})
      : _repo = repo ?? CurriculumRepository(),
        super(CurriculumInitial());

  Future<void> fetchSubjects({String gradeLevel = 'grade_10', String stream = 'scientific'}) async {
    AppLogger.log('CurriculumCubit: Loading subjects for Grade: $gradeLevel ($stream)...', tag: 'CURRICULUM_CUBIT');
    emit(CurriculumLoading());
    try {
      final grades = await _repo.getAvailableGrades();
      final subjects = await _repo.getSubjects(gradeLevel: gradeLevel, stream: stream);
      emit(CurriculumLoaded(
        subjects: subjects,
        filteredSubjects: subjects,
        availableGrades: grades,
        selectedGrade: gradeLevel,
        selectedStream: stream,
      ));
    } catch (e) {
      AppLogger.error('Failed to load curriculum subjects', error: e, tag: 'CURRICULUM_CUBIT');
      emit(CurriculumError(e.toString()));
    }
  }

  void searchSubjects(String query) {
    final currentState = state;
    if (currentState is CurriculumLoaded) {
      final clean = query.trim().toLowerCase();
      if (clean.isEmpty) {
        emit(currentState.copyWith(filteredSubjects: currentState.subjects, searchQuery: ''));
        return;
      }

      final filtered = currentState.subjects.where((s) {
        return s.title.toLowerCase().contains(clean) ||
               s.englishTitle.toLowerCase().contains(clean) ||
               s.id.toLowerCase().contains(clean);
      }).toList();

      emit(currentState.copyWith(filteredSubjects: filtered, searchQuery: query));
    }
  }

  void selectGrade(String gradeKey) {
    AppLogger.log('Switching active grade to $gradeKey...', tag: 'CURRICULUM_CUBIT');
    fetchSubjects(gradeLevel: gradeKey);
  }

  void openSubject(SubjectModel subject) {
    final currentState = state;
    if (currentState is CurriculumLoaded) {
      emit(currentState.copyWith(activeSubject: subject));
    }
  }
}