mnemo_cards/mnemo_cards_backend/lib/database/converters.dart

import 'package:drift/drift.dart';
import 'dart:convert';
import 'package:uuid/uuid.dart';

const _uuid = Uuid();

// Конвертеры для JSON полей - общие для всех таблиц

class JsonMapConverter extends TypeConverter<Map<String, dynamic>?, String?> {
  const JsonMapConverter();
  
  @override
  Map<String, dynamic>? fromSql(String? fromDb) {
    if (fromDb == null || fromDb.isEmpty || fromDb == '{}') return null;
    try {
      return json.decode(fromDb) as Map<String, dynamic>;
    } catch (e) {
      return null;
    }
  }
  
  @override
  String toSql(Map<String, dynamic>? value) {
    if (value == null || value.isEmpty) return '{}';
    return json.encode(value);
  }
}

class JsonListConverter extends TypeConverter<List<dynamic>, String> {
  const JsonListConverter();
  
  @override
  List<dynamic> fromSql(String? fromDb) {
    if (fromDb == null || fromDb.isEmpty || fromDb == '[]') return [];
    try {
      return json.decode(fromDb) as List<dynamic>;
    } catch (e) {
      return [];
    }
  }
  
  @override
  String toSql(List<dynamic>? value) {
    if (value == null || value.isEmpty) return '[]';
    return json.encode(value);
  }
}

class StringListConverter extends TypeConverter<List<String>, String> {
  const StringListConverter();
  
  @override
  List<String> fromSql(String fromDb) {
    if (fromDb.isEmpty || fromDb == '[]') return [];
    try {
      final decoded = json.decode(fromDb);
      return (decoded as List).map((e) => e as String).toList();
    } catch (e) {
      return [];
    }
  }
  
  @override
  String toSql(List<String> value) {
    if (value.isEmpty) return '[]';
    return json.encode(value);
  }
}

class DateTimeListConverter extends TypeConverter<List<DateTime>?, String> {
  const DateTimeListConverter();
  
  @override
  List<DateTime>? fromSql(String? fromDb) {
    if (fromDb == null || fromDb.isEmpty || fromDb == '[]') return null;
    try {
      final decoded = json.decode(fromDb) as List;
      return decoded.map((e) {
        if (e is String) {
          return DateTime.parse(e);
        }
        return DateTime.now();
      }).toList();
    } catch (e) {
      return null;
    }
  }
  
  @override
  String toSql(List<DateTime>? value) {
    if (value == null || value.isEmpty) return '[]';
    return json.encode(value.map((e) => e.toIso8601String()).toList());
  }
}

class IntListConverter extends TypeConverter<List<int>, String> {
  const IntListConverter();
  
  @override
  List<int> fromSql(String fromDb) {
    if (fromDb.isEmpty || fromDb == '[]') return [];
    try {
      final decoded = json.decode(fromDb);
      return (decoded as List).map((e) => e as int).toList();
    } catch (e) {
      return [];
    }
  }
  
  @override
  String toSql(List<int> value) {
    if (value.isEmpty) return '[]';
    return json.encode(value);
  }
}

/// Helper function for UUID generation
String generateUuid() {
  return _uuid.v4();
}