import 'package:drift/drift.dart';
import 'package:drift_postgres/drift_postgres.dart';
import '../database.dart';
import '../tables/statistics.dart';
import '../tables/users.dart';

part 'statistics_dao.g.dart';

@DriftAccessor(tables: [StudySessions])
class StatisticsDao extends DatabaseAccessor<AppDatabase> with _$StatisticsDaoMixin {
  StatisticsDao(super.db);
  
  /// Получить сессию по ID
  Future<StudySession?> getSessionById(String id) {
    return (select(studySessions)..where((s) => s.id.equals(id))).getSingleOrNull();
  }
  
  /// Получить сессию по sessionId
  Future<StudySession?> getSessionBySessionId(String sessionId) {
    return (select(studySessions)
      ..where((s) => s.sessionId.equals(sessionId))
    ).getSingleOrNull();
  }
  
  /// Получить активные сессии пользователя
  Future<List<StudySession>> getActiveSessions(String userId) {
    return (select(studySessions)
      ..where((s) => s.userId.equals(userId))
      ..where((s) => s.endTime.isNull())
      ..orderBy([(s) => OrderingTerm.desc(s.startTime)])
    ).get();
  }
  
  /// Получить сессии пользователя
  Future<List<StudySession>> getSessionsByUserId(String userId, {
    int? limit,
    int? offset,
    DateTime? fromDate,
    DateTime? toDate,
  }) {
    final query = select(studySessions)
      ..where((s) => s.userId.equals(userId))
      ..orderBy([(s) => OrderingTerm.desc(s.startTime)]);
    
    if (fromDate != null) {
      query.where((s) => s.startTime.isBiggerOrEqualValue(PgDateTime(fromDate)));
    }
    if (toDate != null) {
      query.where((s) => s.startTime.isSmallerOrEqualValue(PgDateTime(toDate)));
    }
    
    if (limit != null) {
      query.limit(limit, offset: offset);
    }
    
    return query.get();
  }
  
  /// Создать сессию
  Future<String> createSession(StudySessionsCompanion session) async {
    final inserted = await into(studySessions).insertReturning(session);
    return inserted.id;
  }
  
  /// Обновить сессию
  Future<bool> updateSession(StudySession session) {
    return update(studySessions).replace(session);
  }
  
  /// Завершить сессию
  Future<void> endSession(String sessionId, {
    int? wordsLearned,
    int? testsCompleted,
    double? accuracy,
  }) {
    final updates = StudySessionsCompanion(
      id: Value(sessionId),
      endTime: Value(PgDateTime(DateTime.now())),
      updatedAt: Value(PgDateTime(DateTime.now())),
      wordsLearned: wordsLearned != null ? Value(wordsLearned) : const Value.absent(),
      testsCompleted: testsCompleted != null ? Value(testsCompleted) : const Value.absent(),
      accuracy: accuracy != null ? Value(accuracy) : const Value.absent(),
    );
    
    return (update(studySessions)..where((s) => s.id.equals(sessionId)))
        .write(updates);
  }
  
  /// Подсчитать сессии пользователя
  Future<int> countSessionsByUserId(String userId) async {
    final countExpr = studySessions.id.count();
    final query = selectOnly(studySessions)
      ..addColumns([countExpr])
      ..where(studySessions.userId.equals(userId));
    
    return await query.map((row) => row.read(countExpr)!).getSingle();
  }
}