package services

import (
	"context"

	"github.com/breakpilot/school-service/internal/models"
)

// Class- and room-scoped constraint CRUD. Ownership is via tt_class /
// tt_subject / tt_room.created_by_user_id.

// ---------- Class Max Hours / Day ----------

func (s *TimetableService) CreateClassMaxHoursDay(ctx context.Context, userID string, req *models.CreateClassMaxHoursDayRequest) (*models.ClassMaxHoursDay, error) {
	var c models.ClassMaxHoursDay
	err := s.db.QueryRow(ctx, `
		INSERT INTO tt_constraint_class_max_hours_day
			(created_by_user_id, class_id, max_hours, is_hard, weight, active, note)
		SELECT $1, $2, $3, $4, $5, $6, $7
		WHERE EXISTS (SELECT 1 FROM tt_class WHERE id = $2 AND created_by_user_id = $1)
		RETURNING id, created_by_user_id, class_id, max_hours, is_hard, weight, active, COALESCE(note,''), created_at
	`, userID, req.ClassID, req.MaxHours, req.IsHard, req.Weight, req.Active, req.Note).Scan(
		&c.ID, &c.CreatedByUserID, &c.ClassID, &c.MaxHours, &c.IsHard, &c.Weight, &c.Active, &c.Note, &c.CreatedAt,
	)
	return &c, err
}

func (s *TimetableService) ListClassMaxHoursDay(ctx context.Context, userID string) ([]models.ClassMaxHoursDay, error) {
	rows, err := s.db.Query(ctx, `
		SELECT id, created_by_user_id, class_id, max_hours, is_hard, weight, active, COALESCE(note,''), created_at
		FROM tt_constraint_class_max_hours_day WHERE created_by_user_id = $1 ORDER BY class_id
	`, userID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []models.ClassMaxHoursDay
	for rows.Next() {
		var c models.ClassMaxHoursDay
		if err := rows.Scan(&c.ID, &c.CreatedByUserID, &c.ClassID, &c.MaxHours, &c.IsHard, &c.Weight, &c.Active, &c.Note, &c.CreatedAt); err != nil {
			return nil, err
		}
		out = append(out, c)
	}
	return out, nil
}

func (s *TimetableService) DeleteClassMaxHoursDay(ctx context.Context, id, userID string) error {
	_, err := s.db.Exec(ctx, `DELETE FROM tt_constraint_class_max_hours_day WHERE id = $1 AND created_by_user_id = $2`, id, userID)
	return err
}

// ---------- Class No Gaps ----------

func (s *TimetableService) CreateClassNoGaps(ctx context.Context, userID string, req *models.CreateClassNoGapsRequest) (*models.ClassNoGaps, error) {
	var c models.ClassNoGaps
	err := s.db.QueryRow(ctx, `
		INSERT INTO tt_constraint_class_no_gaps
			(created_by_user_id, class_id, is_hard, weight, active, note)
		SELECT $1, $2, $3, $4, $5, $6
		WHERE EXISTS (SELECT 1 FROM tt_class WHERE id = $2 AND created_by_user_id = $1)
		RETURNING id, created_by_user_id, class_id, is_hard, weight, active, COALESCE(note,''), created_at
	`, userID, req.ClassID, req.IsHard, req.Weight, req.Active, req.Note).Scan(
		&c.ID, &c.CreatedByUserID, &c.ClassID, &c.IsHard, &c.Weight, &c.Active, &c.Note, &c.CreatedAt,
	)
	return &c, err
}

func (s *TimetableService) ListClassNoGaps(ctx context.Context, userID string) ([]models.ClassNoGaps, error) {
	rows, err := s.db.Query(ctx, `
		SELECT id, created_by_user_id, class_id, is_hard, weight, active, COALESCE(note,''), created_at
		FROM tt_constraint_class_no_gaps WHERE created_by_user_id = $1 ORDER BY class_id
	`, userID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []models.ClassNoGaps
	for rows.Next() {
		var c models.ClassNoGaps
		if err := rows.Scan(&c.ID, &c.CreatedByUserID, &c.ClassID, &c.IsHard, &c.Weight, &c.Active, &c.Note, &c.CreatedAt); err != nil {
			return nil, err
		}
		out = append(out, c)
	}
	return out, nil
}

func (s *TimetableService) DeleteClassNoGaps(ctx context.Context, id, userID string) error {
	_, err := s.db.Exec(ctx, `DELETE FROM tt_constraint_class_no_gaps WHERE id = $1 AND created_by_user_id = $2`, id, userID)
	return err
}

// ---------- Room Requires Type ----------

func (s *TimetableService) CreateRoomRequiresType(ctx context.Context, userID string, req *models.CreateRoomRequiresTypeRequest) (*models.RoomRequiresType, error) {
	var c models.RoomRequiresType
	err := s.db.QueryRow(ctx, `
		INSERT INTO tt_constraint_room_requires_type
			(created_by_user_id, subject_id, room_type, is_hard, weight, active, note)
		SELECT $1, $2, $3, $4, $5, $6, $7
		WHERE EXISTS (SELECT 1 FROM tt_subject WHERE id = $2 AND created_by_user_id = $1)
		RETURNING id, created_by_user_id, subject_id, room_type, is_hard, weight, active, COALESCE(note,''), created_at
	`, userID, req.SubjectID, req.RoomType, req.IsHard, req.Weight, req.Active, req.Note).Scan(
		&c.ID, &c.CreatedByUserID, &c.SubjectID, &c.RoomType, &c.IsHard, &c.Weight, &c.Active, &c.Note, &c.CreatedAt,
	)
	return &c, err
}

func (s *TimetableService) ListRoomRequiresTypes(ctx context.Context, userID string) ([]models.RoomRequiresType, error) {
	rows, err := s.db.Query(ctx, `
		SELECT id, created_by_user_id, subject_id, room_type, is_hard, weight, active, COALESCE(note,''), created_at
		FROM tt_constraint_room_requires_type WHERE created_by_user_id = $1 ORDER BY subject_id
	`, userID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []models.RoomRequiresType
	for rows.Next() {
		var c models.RoomRequiresType
		if err := rows.Scan(&c.ID, &c.CreatedByUserID, &c.SubjectID, &c.RoomType, &c.IsHard, &c.Weight, &c.Active, &c.Note, &c.CreatedAt); err != nil {
			return nil, err
		}
		out = append(out, c)
	}
	return out, nil
}

func (s *TimetableService) DeleteRoomRequiresType(ctx context.Context, id, userID string) error {
	_, err := s.db.Exec(ctx, `DELETE FROM tt_constraint_room_requires_type WHERE id = $1 AND created_by_user_id = $2`, id, userID)
	return err
}

// ---------- Room Unavailable ----------

func (s *TimetableService) CreateRoomUnavailable(ctx context.Context, userID string, req *models.CreateRoomUnavailableRequest) (*models.RoomUnavailable, error) {
	var c models.RoomUnavailable
	err := s.db.QueryRow(ctx, `
		INSERT INTO tt_constraint_room_unavailable
			(created_by_user_id, room_id, day_of_week, period_index, is_hard, weight, active, note)
		SELECT $1, $2, $3, $4, $5, $6, $7, $8
		WHERE EXISTS (SELECT 1 FROM tt_room WHERE id = $2 AND created_by_user_id = $1)
		RETURNING id, created_by_user_id, room_id, day_of_week, period_index, is_hard, weight, active, COALESCE(note,''), created_at
	`, userID, req.RoomID, req.DayOfWeek, req.PeriodIndex, req.IsHard, req.Weight, req.Active, req.Note).Scan(
		&c.ID, &c.CreatedByUserID, &c.RoomID, &c.DayOfWeek, &c.PeriodIndex, &c.IsHard, &c.Weight, &c.Active, &c.Note, &c.CreatedAt,
	)
	return &c, err
}

func (s *TimetableService) ListRoomUnavailable(ctx context.Context, userID string) ([]models.RoomUnavailable, error) {
	rows, err := s.db.Query(ctx, `
		SELECT id, created_by_user_id, room_id, day_of_week, period_index, is_hard, weight, active, COALESCE(note,''), created_at
		FROM tt_constraint_room_unavailable WHERE created_by_user_id = $1 ORDER BY room_id, day_of_week, period_index
	`, userID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []models.RoomUnavailable
	for rows.Next() {
		var c models.RoomUnavailable
		if err := rows.Scan(&c.ID, &c.CreatedByUserID, &c.RoomID, &c.DayOfWeek, &c.PeriodIndex, &c.IsHard, &c.Weight, &c.Active, &c.Note, &c.CreatedAt); err != nil {
			return nil, err
		}
		out = append(out, c)
	}
	return out, nil
}

func (s *TimetableService) DeleteRoomUnavailable(ctx context.Context, id, userID string) error {
	_, err := s.db.Exec(ctx, `DELETE FROM tt_constraint_room_unavailable WHERE id = $1 AND created_by_user_id = $2`, id, userID)
	return err
}