import 'dart:convert';

import 'package:equatable/equatable.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:uto_manager/infrastructure/database/app_database.dart';
import 'package:uto_manager/infrastructure/database/daos/template_dao.dart';

// ---------------------------------------------------------------------------
// State
// ---------------------------------------------------------------------------

/// State for the template cubit.
sealed class TemplateState extends Equatable {
  const TemplateState();
}

class TemplateInitial extends TemplateState {
  const TemplateInitial();

  @override
  List<Object?> get props => [];
}

class TemplateLoading extends TemplateState {
  const TemplateLoading();

  @override
  List<Object?> get props => [];
}

class TemplateLoaded extends TemplateState {
  const TemplateLoaded(this.templates);

  final List<Template> templates;

  @override
  List<Object?> get props => [templates];
}

class TemplateError extends TemplateState {
  const TemplateError(this.message);

  final String message;

  @override
  List<Object?> get props => [message];
}

// ---------------------------------------------------------------------------
// Cubit
// ---------------------------------------------------------------------------

/// Manages saved unit tree templates.
class TemplateCubit extends Cubit<TemplateState> {
  TemplateCubit({required this.dao}) : super(const TemplateInitial());

  final TemplateDao dao;

  // ---------------------------------------------------------------------------
  // Loading
  // ---------------------------------------------------------------------------

  /// Loads all saved templates from the database.
  Future<void> loadTemplates() async {
    emit(const TemplateLoading());
    try {
      final templates = await dao.getAllTemplates();
      emit(TemplateLoaded(templates));
    } catch (e) {
      emit(TemplateError(e.toString()));
    }
  }

  // ---------------------------------------------------------------------------
  // Save / Delete
  // ---------------------------------------------------------------------------

  /// Saves a template with [name], [bctType], and [jsonData].
  Future<void> saveTemplate({
    required String templateId,
    required String name,
    required String bctType,
    required Map<String, dynamic> jsonData,
  }) async {
    try {
      final now = DateTime.now();
      await dao.upsertTemplate(
        TemplatesCompanion.insert(
          templateId: templateId,
          name: name,
          bctType: bctType,
          jsonData: jsonEncode(jsonData),
          createdAt: now,
          updatedAt: now,
        ),
      );
      await loadTemplates();
    } catch (e) {
      emit(TemplateError(e.toString()));
    }
  }

  /// Deletes the template with [templateId].
  Future<void> deleteTemplate(String templateId) async {
    try {
      await dao.deleteTemplate(templateId);
      await loadTemplates();
    } catch (e) {
      emit(TemplateError(e.toString()));
    }
  }

  /// Returns the JSON data for [templateId], or null if not found.
  Future<Map<String, dynamic>?> getTemplateJson(String templateId) async {
    try {
      final template = await dao.getTemplateById(templateId);
      if (template == null) return null;
      return jsonDecode(template.jsonData) as Map<String, dynamic>;
    } catch (e) {
      return null;
    }
  }
}