package actions

import (
	"errors"
	"os"
	"path"
	"strconv"

	"github.com/photoview/photoview/api/graphql/models"
	"github.com/photoview/photoview/api/utils"
	"gorm.io/gorm"
)

func DeleteUser(db *gorm.DB, userID int) (*models.User, error) {

	// make sure the last admin user is not deleted
	var adminUsers []*models.User
	db.Model(&models.User{}).Where("admin = true").Limit(2).Find(&adminUsers)
	if len(adminUsers) == 1 && adminUsers[0].ID == userID {
		return nil, errors.New("deleting sole admin user is not allowed")
	}

	var user models.User
	deletedAlbumIDs := make([]int, 0)

	var err error
	err = db.Transaction(func(tx *gorm.DB) error {
		if err = tx.First(&user, userID).Error; err != nil {
			return err
		}

		userAlbums := user.Albums
		if err = tx.Model(&user).Association("Albums").Find(&userAlbums); err != nil {
			return err
		}

		if err = tx.Model(&user).Association("Albums").Clear(); err != nil {
			return err
		}

		deletedAlbumIDs, err = deleteNotOwnedAlbums(userAlbums, tx, deletedAlbumIDs)
		if err != nil {
			return err
		}

		if err = tx.Delete(&user).Error; err != nil {
			return err
		}

		return nil
	})

	if err != nil {
		return nil, err
	}

	// If there is only one associated user, clean up the cache folder and delete the album row
	return &user, cleanup(deletedAlbumIDs)
}

func cleanup(deletedAlbumIDs []int) error {
	var err error
	for _, deletedAlbumID := range deletedAlbumIDs {
		cachePath := path.Join(utils.MediaCachePath(), strconv.Itoa(int(deletedAlbumID)))
		if err = os.RemoveAll(cachePath); err != nil {
			return err
		}
	}
	return err
}

func deleteNotOwnedAlbums(userAlbums []models.Album, tx *gorm.DB, deletedAlbumIDs []int) ([]int, error) {
	for _, album := range userAlbums {
		var associatedUsers = tx.Model(album).Association("Owners").Count()

		if associatedUsers == 0 {
			deletedAlbumIDs = append(deletedAlbumIDs, album.ID)
			if err := tx.Delete(album).Error; err != nil {
				return nil, err
			}
		}
	}
	return deletedAlbumIDs, nil
}