mnemo_cards/mnemo_cards_backend/lib/database/tables/statistics.dart

import 'package:drift/drift.dart';
import 'package:drift_postgres/drift_postgres.dart';
import 'users.dart';
import '../converters.dart' show generateUuid;

/// Таблица StudySessions - сессии изучения
class StudySessions extends Table {
  // ID как String, но фактически UUID (генерируется PostgreSQL на стороне БД)
  TextColumn get id => text()
      .withDefault(const CustomExpression('gen_random_uuid()::text'))();
  TextColumn get userId => text()
      .references(Users, #id, onDelete: KeyAction.cascade)();
  
  TextColumn get sessionId => text().nullable().unique()();
  
  Column<PgDateTime> get startTime => customType(PgTypes.timestampWithTimezone)();
  Column<PgDateTime> get endTime => customType(PgTypes.timestampWithTimezone)
      .nullable()();
  
  IntColumn get wordsLearned => integer().withDefault(const Constant(0))();
  IntColumn get testsCompleted => integer().withDefault(const Constant(0))();
  RealColumn get accuracy => real().withDefault(const Constant(0.0))();
  
  TextColumn get packId => text().nullable()();
  TextColumn get testId => text().nullable()();
  
  // Audit
  Column<PgDateTime> get createdAt => customType(PgTypes.timestampWithTimezone)
      .withDefault(now())();
  Column<PgDateTime> get updatedAt => customType(PgTypes.timestampWithTimezone)
      .withDefault(now())();
  BoolColumn get isDeleted => boolean()
      .customConstraint('NOT NULL DEFAULT FALSE')();
      
  Column<PgDateTime> get deletedAt => customType(PgTypes.timestampWithTimezone)
      .nullable()();
  
  @override
  Set<Column> get primaryKey => {id};
}