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};
}