tercul-backend/internal/repositories/book_repository.go

package repositories

import (
	"context"
	"errors"
	"gorm.io/gorm"
	"tercul/internal/models"
)

// BookRepository defines CRUD methods specific to Book.
type BookRepository interface {
	BaseRepository[models.Book]
	ListByAuthorID(ctx context.Context, authorID uint) ([]models.Book, error)
	ListByPublisherID(ctx context.Context, publisherID uint) ([]models.Book, error)
	ListByWorkID(ctx context.Context, workID uint) ([]models.Book, error)
	FindByISBN(ctx context.Context, isbn string) (*models.Book, error)
}

type bookRepository struct {
	BaseRepository[models.Book]
	db *gorm.DB
}

// NewBookRepository creates a new BookRepository.
func NewBookRepository(db *gorm.DB) BookRepository {
	return &bookRepository{
		BaseRepository: NewBaseRepositoryImpl[models.Book](db),
		db:             db,
	}
}

// ListByAuthorID finds books by author ID
func (r *bookRepository) ListByAuthorID(ctx context.Context, authorID uint) ([]models.Book, error) {
	var books []models.Book
	if err := r.db.WithContext(ctx).Joins("JOIN book_authors ON book_authors.book_id = books.id").
		Where("book_authors.author_id = ?", authorID).
		Find(&books).Error; err != nil {
		return nil, err
	}
	return books, nil
}

// ListByPublisherID finds books by publisher ID
func (r *bookRepository) ListByPublisherID(ctx context.Context, publisherID uint) ([]models.Book, error) {
	var books []models.Book
	if err := r.db.WithContext(ctx).Where("publisher_id = ?", publisherID).Find(&books).Error; err != nil {
		return nil, err
	}
	return books, nil
}

// ListByWorkID finds books by work ID
func (r *bookRepository) ListByWorkID(ctx context.Context, workID uint) ([]models.Book, error) {
	var books []models.Book
	if err := r.db.WithContext(ctx).Joins("JOIN book_works ON book_works.book_id = books.id").
		Where("book_works.work_id = ?", workID).
		Find(&books).Error; err != nil {
		return nil, err
	}
	return books, nil
}

// FindByISBN finds a book by ISBN
func (r *bookRepository) FindByISBN(ctx context.Context, isbn string) (*models.Book, error) {
	var book models.Book
	if err := r.db.WithContext(ctx).Where("isbn = ?", isbn).First(&book).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, ErrEntityNotFound
		}
		return nil, err
	}
	return &book, nil
}