photoplaces/backend/internal/repository/reviews.go

package repository

import (
	"context"
	"fmt"

	"github.com/jackc/pgx/v5/pgxpool"
	"github.com/photoplaces/backend/internal/models"
)

type ReviewRepo struct {
	pool *pgxpool.Pool
}

func NewReviewRepo(pool *pgxpool.Pool) *ReviewRepo {
	return &ReviewRepo{pool: pool}
}

func (r *ReviewRepo) Create(ctx context.Context, review *models.Review) error {
	tx, err := r.pool.Begin(ctx)
	if err != nil {
		return err
	}
	defer tx.Rollback(ctx)

	err = tx.QueryRow(ctx,
		`INSERT INTO reviews (user_id, target_type, target_id, rating, text)
		 VALUES ($1, $2, $3, $4, $5)
		 RETURNING id, created_at, updated_at`,
		review.UserID, review.TargetType, review.TargetID, review.Rating, review.Text,
	).Scan(&review.ID, &review.CreatedAt, &review.UpdatedAt)
	if err != nil {
		if isUniqueViolation(err) {
			return fmt.Errorf("you already reviewed this")
		}
		return fmt.Errorf("create review: %w", err)
	}

	tableName := "places"
	if review.TargetType == "service" {
		tableName = "services"
	}

	_, err = tx.Exec(ctx,
		fmt.Sprintf(`UPDATE %s SET
			reviews_count = (SELECT COUNT(*) FROM reviews WHERE target_type = $1 AND target_id = $2 AND deleted_at IS NULL),
			rating = (SELECT COALESCE(AVG(rating), 0) FROM reviews WHERE target_type = $1 AND target_id = $2 AND deleted_at IS NULL)
			WHERE id = $2`, tableName),
		review.TargetType, review.TargetID)
	if err != nil {
		return fmt.Errorf("update rating: %w", err)
	}

	return tx.Commit(ctx)
}

func (r *ReviewRepo) List(ctx context.Context, targetType, targetID string) ([]*models.Review, error) {
	rows, err := r.pool.Query(ctx,
		`SELECT r.id, r.user_id, r.target_type, r.target_id, r.rating, r.text,
		        r.created_at, r.updated_at,
		        u.name, u.avatar_url
		 FROM reviews r
		 JOIN users u ON u.id = r.user_id
		 WHERE r.target_type = $1 AND r.target_id = $2 AND r.deleted_at IS NULL
		 ORDER BY r.created_at DESC`, targetType, targetID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var reviews []*models.Review
	for rows.Next() {
		var rev models.Review
		var userName, userAvatar *string
		if err := rows.Scan(
			&rev.ID, &rev.UserID, &rev.TargetType, &rev.TargetID, &rev.Rating, &rev.Text,
			&rev.CreatedAt, &rev.UpdatedAt,
			&userName, &userAvatar,
		); err != nil {
			return nil, err
		}
		rev.User = &models.User{Name: userName, AvatarURL: userAvatar}
		reviews = append(reviews, &rev)
	}
	return reviews, nil
}

func isUniqueViolation(err error) bool {
	return err != nil && contains(err.Error(), "unique")
}

func contains(s, substr string) bool {
	return len(s) >= len(substr) && searchString(s, substr)
}

func searchString(s, sub string) bool {
	for i := 0; i <= len(s)-len(sub); i++ {
		if s[i:i+len(sub)] == sub {
			return true
		}
	}
	return false
}