package repository

import (
	"context"
	"errors"

	"github.com/cloudprint/cloudprint-backend/internal/model"
	"gorm.io/gorm"
)

type LibraryRepository struct {
	db *gorm.DB
}

func NewLibraryRepository(db *gorm.DB) *LibraryRepository {
	return &LibraryRepository{db: db}
}

// Category operations
func (r *LibraryRepository) CreateCategory(ctx context.Context, category *model.LibraryCategory) error {
	return r.db.WithContext(ctx).Create(category).Error
}

func (r *LibraryRepository) GetCategoryByID(ctx context.Context, id int32) (*model.LibraryCategory, error) {
	var category model.LibraryCategory
	err := r.db.WithContext(ctx).First(&category, id).Error
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, nil
		}
		return nil, err
	}
	return &category, nil
}

func (r *LibraryRepository) GetAllCategories(ctx context.Context) ([]*model.LibraryCategory, error) {
	var categories []*model.LibraryCategory
	err := r.db.WithContext(ctx).Order("sort_order ASC, id ASC").Find(&categories).Error
	return categories, err
}

func (r *LibraryRepository) UpdateCategory(ctx context.Context, category *model.LibraryCategory) error {
	return r.db.WithContext(ctx).Save(category).Error
}

func (r *LibraryRepository) DeleteCategory(ctx context.Context, id int32) error {
	return r.db.WithContext(ctx).Delete(&model.LibraryCategory{}, id).Error
}

// LibraryFile operations
func (r *LibraryRepository) CreateFile(ctx context.Context, file *model.LibraryFile) error {
	return r.db.WithContext(ctx).Create(file).Error
}

func (r *LibraryRepository) GetFileByID(ctx context.Context, id int32) (*model.LibraryFile, error) {
	var file model.LibraryFile
	err := r.db.WithContext(ctx).Preload("File").First(&file, id).Error
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, nil
		}
		return nil, err
	}
	return &file, nil
}

func (r *LibraryRepository) GetFilesByCategory(ctx context.Context, categoryID int32, page, pageSize int) ([]*model.LibraryFile, int64, error) {
	var files []*model.LibraryFile
	var total int64

	query := r.db.WithContext(ctx).Model(&model.LibraryFile{}).Where("category_id = ?", categoryID)
	err := query.Count(&total).Error
	if err != nil {
		return nil, 0, err
	}

	offset := (page - 1) * pageSize
	err = query.Preload("File").Offset(offset).Limit(pageSize).Order("created_at DESC").Find(&files).Error
	if err != nil {
		return nil, 0, err
	}

	return files, total, nil
}

func (r *LibraryRepository) DeleteFile(ctx context.Context, id int32) error {
	return r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		// Get file to delete underlying file record
		var libFile model.LibraryFile
		if err := tx.First(&libFile, id).Error; err != nil {
			return err
		}
		// Delete library file
		if err := tx.Delete(&libFile).Error; err != nil {
			return err
		}
		// Delete underlying file
		if err := tx.Delete(&model.File{}, libFile.FileID).Error; err != nil {
			return err
		}
		return nil
	})
}

func (r *LibraryRepository) IncrementDownloadCount(ctx context.Context, id int32) error {
	return r.db.WithContext(ctx).Model(&model.LibraryFile{}).Where("id = ?", id).
		Update("download_count", gorm.Expr("download_count + 1")).Error
}