package scanner

import (
	"database/sql"
	"fmt"
	"log"
	"os"
	"path"
	"strconv"

	"github.com/pkg/errors"
	"github.com/viktorstrate/photoview/api/graphql/models"
	"github.com/viktorstrate/photoview/api/utils"

	// Image decoders
	_ "image/gif"
	_ "image/png"

	_ "golang.org/x/image/bmp"
	_ "golang.org/x/image/tiff"
	_ "golang.org/x/image/webp"
)

// Higher order function used to check if MediaURL for a given MediaPurpose exists
func makePhotoURLChecker(tx *sql.Tx, mediaID int) (func(purpose models.MediaPurpose) (*models.MediaURL, error), error) {
	mediaURLExistsStmt, err := tx.Prepare("SELECT * FROM media_url WHERE media_id = ? AND purpose = ?")
	if err != nil {
		return nil, err
	}

	return func(purpose models.MediaPurpose) (*models.MediaURL, error) {
		row := mediaURLExistsStmt.QueryRow(mediaID, purpose)
		mediaURL, err := models.NewMediaURLFromRow(row)
		if err != nil {
			if err == sql.ErrNoRows {
				return nil, nil
			}
			return nil, err
		}

		return mediaURL, nil
	}, nil
}

func ProcessMedia(tx *sql.Tx, media *models.Media) (bool, error) {
	imageData := EncodeMediaData{
		media: media,
	}

	contentType, err := imageData.ContentType()
	if err != nil {
		return false, errors.Wrapf(err, "get content-type of media (%s)", media.Path)
	}

	// Make sure media cache directory exists
	mediaCachePath, err := makeMediaCacheDir(media)
	if err != nil {
		return false, errors.Wrap(err, "cache directory error")
	}

	if contentType.isVideo() {
		return processVideo(tx, &imageData, mediaCachePath)
	} else {
		return processPhoto(tx, &imageData, mediaCachePath)
	}
}

func processPhoto(tx *sql.Tx, imageData *EncodeMediaData, photoCachePath *string) (bool, error) {

	photo := imageData.media

	log.Printf("Processing photo: %s\n", photo.Path)

	didProcess := false

	photoUrlFromDB, err := makePhotoURLChecker(tx, photo.MediaID)
	if err != nil {
		return false, err
	}

	// original photo url
	origURL, err := photoUrlFromDB(models.MediaOriginal)
	if err != nil {
		return false, err
	}

	// Thumbnail
	thumbURL, err := photoUrlFromDB(models.PhotoThumbnail)
	if err != nil {
		return false, errors.Wrap(err, "error processing photo thumbnail")
	}

	// Highres
	highResURL, err := photoUrlFromDB(models.PhotoHighRes)
	if err != nil {
		return false, errors.Wrap(err, "error processing photo highres")
	}

	var photoDimensions *PhotoDimensions
	var baseImagePath string = photo.Path

	mediaType, err := getMediaType(photo.Path)
	if err != nil {
		return false, errors.Wrap(err, "could determine if media was photo or video")
	}

	if mediaType.isRaw() {
		err = processRawSideCar(tx, imageData, highResURL, thumbURL, photoCachePath)
		if err != nil {
			return false, err
		}
	}

	// Generate high res jpeg
	if highResURL == nil {

		contentType, err := imageData.ContentType()
		if err != nil {
			return false, err
		}

		if !contentType.isWebCompatible() {
			didProcess = true

			highres_name := fmt.Sprintf("highres_%s_%s", path.Base(photo.Path), utils.GenerateToken())
			highres_name = models.SanitizeMediaName(highres_name)
			highres_name = highres_name + ".jpg"

			baseImagePath = path.Join(*photoCachePath, highres_name)

			err = generateSaveHighResJPEG(tx, photo.MediaID, imageData, highres_name, baseImagePath, -1)
			if err != nil {
				return false, err
			}
		}
	} else {
		// Verify that highres photo still exists in cache
		baseImagePath = path.Join(*photoCachePath, highResURL.MediaName)

		if _, err := os.Stat(baseImagePath); os.IsNotExist(err) {
			fmt.Printf("High-res photo found in database but not in cache, re-encoding photo to cache: %s\n", highResURL.MediaName)
			didProcess = true

			err = imageData.EncodeHighRes(tx, baseImagePath)
			if err != nil {
				return false, errors.Wrap(err, "creating high-res cached image")
			}
		}
	}

	// Save original photo to database
	if origURL == nil {
		didProcess = true

		// Make sure photo dimensions is set
		if photoDimensions == nil {
			photoDimensions, err = GetPhotoDimensions(baseImagePath)
			if err != nil {
				return false, err
			}
		}

		if err = saveOriginalPhotoToDB(tx, photo, imageData, photoDimensions); err != nil {
			return false, errors.Wrap(err, "saving original photo to database")
		}
	}

	// Save thumbnail to cache
	if thumbURL == nil {
		didProcess = true

		thumbnail_name := fmt.Sprintf("thumbnail_%s_%s", path.Base(photo.Path), utils.GenerateToken())
		thumbnail_name = models.SanitizeMediaName(thumbnail_name)
		thumbnail_name = thumbnail_name + ".jpg"

		// thumbnailImage, err := imageData.ThumbnailImage(tx)
		// if err != nil {
		// 	return err
		// }

		err = generateSaveThumbnailJPEG(tx, photo.MediaID, thumbnail_name, photoCachePath, baseImagePath, -1)
		if err != nil {
			return false, err
		}
	} else {
		// Verify that thumbnail photo still exists in cache
		thumbPath := path.Join(*photoCachePath, thumbURL.MediaName)

		if _, err := os.Stat(thumbPath); os.IsNotExist(err) {
			didProcess = true
			fmt.Printf("Thumbnail photo found in database but not in cache, re-encoding photo to cache: %s\n", thumbURL.MediaName)

			_, err := EncodeThumbnail(baseImagePath, thumbPath)
			if err != nil {
				return false, errors.Wrap(err, "could not create thumbnail cached image")
			}
		}
	}

	return didProcess, nil
}

func makeMediaCacheDir(photo *models.Media) (*string, error) {

	// Make root cache dir if not exists
	if _, err := os.Stat(PhotoCache()); os.IsNotExist(err) {
		if err := os.Mkdir(PhotoCache(), os.ModePerm); err != nil {
			return nil, errors.Wrap(err, "could not make root image cache directory")
		}
	}

	// Make album cache dir if not exists
	albumCachePath := path.Join(PhotoCache(), strconv.Itoa(photo.AlbumId))
	if _, err := os.Stat(albumCachePath); os.IsNotExist(err) {
		if err := os.Mkdir(albumCachePath, os.ModePerm); err != nil {
			return nil, errors.Wrap(err, "could not make album image cache directory")
		}
	}

	// Make photo cache dir if not exists
	photoCachePath := path.Join(albumCachePath, strconv.Itoa(photo.MediaID))
	if _, err := os.Stat(photoCachePath); os.IsNotExist(err) {
		if err := os.Mkdir(photoCachePath, os.ModePerm); err != nil {
			return nil, errors.Wrap(err, "could not make photo image cache directory")
		}
	}

	return &photoCachePath, nil
}

func saveOriginalPhotoToDB(tx *sql.Tx, photo *models.Media, imageData *EncodeMediaData, photoDimensions *PhotoDimensions) error {
	photoName := path.Base(photo.Path)
	photoBaseName := photoName[0 : len(photoName)-len(path.Ext(photoName))]
	photoBaseExt := path.Ext(photoName)

	original_image_name := fmt.Sprintf("%s_%s", photoBaseName, utils.GenerateToken())
	original_image_name = models.SanitizeMediaName(original_image_name) + photoBaseExt

	contentType, err := imageData.ContentType()
	if err != nil {
		return err
	}

	fileStats, err := os.Stat(photo.Path)
	if err != nil {
		return errors.Wrap(err, "reading file stats of original photo")
	}

	_, err = tx.Exec("INSERT INTO media_url (media_id, media_name, width, height, purpose, content_type, file_size) VALUES (?, ?, ?, ?, ?, ?, ?)", photo.MediaID, original_image_name, photoDimensions.Width, photoDimensions.Height, models.MediaOriginal, contentType, fileStats.Size())
	if err != nil {
		log.Printf("Could not insert original photo url: %d, %s\n", photo.MediaID, photoName)
		return err
	}

	return nil
}

func generateSaveHighResJPEG(tx *sql.Tx, mediaID int, imageData *EncodeMediaData, highres_name string, imagePath string, urlID int) error {

	err := imageData.EncodeHighRes(tx, imagePath)
	if err != nil {
		return errors.Wrap(err, "creating high-res cached image")
	}

	photoDimensions, err := GetPhotoDimensions(imagePath)
	if err != nil {
		return err
	}

	fileStats, err := os.Stat(imagePath)
	if err != nil {
		return errors.Wrap(err, "reading file stats of highres photo")
	}

	if urlID < 0 {
		_, err = tx.Exec("INSERT INTO media_url (media_id, media_name, width, height, purpose, content_type, file_size) VALUES (?, ?, ?, ?, ?, ?, ?)",
			mediaID, highres_name, photoDimensions.Width, photoDimensions.Height, models.PhotoHighRes, "image/jpeg", fileStats.Size())
	} else {
		_, err = tx.Exec("UPDATE media_url SET width = ?, height = ?,  file_size= ? WHERE url_id = ?",
			photoDimensions.Width, photoDimensions.Height, fileStats.Size(), urlID)
	}
	if err != nil {
		return errors.Wrapf(err, "could not insert highres media url (%d, %s)", mediaID, highres_name)
	}

	return nil
}

func generateSaveThumbnailJPEG(tx *sql.Tx, mediaID int, thumbnail_name string, photoCachePath *string, baseImagePath string, urlID int) error {
	thumbOutputPath := path.Join(*photoCachePath, thumbnail_name)

	thumbSize, err := EncodeThumbnail(baseImagePath, thumbOutputPath)
	if err != nil {
		return errors.Wrap(err, "could not create thumbnail cached image")
	}

	fileStats, err := os.Stat(thumbOutputPath)
	if err != nil {
		return errors.Wrap(err, "reading file stats of thumbnail photo")
	}

	if urlID < 0 {
		_, err = tx.Exec("INSERT INTO media_url (media_id, media_name, width, height, purpose, content_type, file_size) VALUES (?, ?, ?, ?, ?, ?, ?)",
			mediaID, thumbnail_name, thumbSize.Width, thumbSize.Height, models.PhotoThumbnail, "image/jpeg", fileStats.Size())
	} else {
		_, err = tx.Exec("UPDATE media_url SET width = ?, height = ?,  file_size= ? WHERE url_id = ?",
			thumbSize.Width, thumbSize.Height, fileStats.Size(), urlID)
	}
	if err != nil {
		return err
	}
	return nil
}

func processRawSideCar(tx *sql.Tx, imageData *EncodeMediaData, highResURL *models.MediaURL, thumbURL *models.MediaURL, photoCachePath *string) error {
	photo := imageData.media
	sideCarFileHasChanged := false
	var currentFileHash *string
	currentSideCarPath := scanForSideCarFile(photo.Path)

	if currentSideCarPath != nil {
		currentFileHash = hashSideCarFile(currentSideCarPath)
		if photo.SideCarHash == nil || *photo.SideCarHash != *currentFileHash {
			sideCarFileHasChanged = true
		}
	} else if photo.SideCarPath != nil { // sidecar has been deleted since last scan
		sideCarFileHasChanged = true
	}
	if sideCarFileHasChanged {
		fmt.Printf("Detected changed sidecar file for %s recreating JPG's to reflect changes\n", photo.Path)

		// update high res image may be cropped so dimentions and file size can change
		baseImagePath := path.Join(*photoCachePath, highResURL.MediaName) // update base image path for thumbnail
		tempHighResPath := baseImagePath + ".hold"
		os.Rename(baseImagePath, tempHighResPath)
		err := generateSaveHighResJPEG(tx, photo.MediaID, imageData, highResURL.MediaName, baseImagePath, highResURL.UrlID)
		if err != nil {
			os.Rename(tempHighResPath, baseImagePath)
			return errors.Wrap(err, "recreating high-res cached image")
		}
		os.Remove(tempHighResPath)

		// update thumbnail image may be cropped so dimentions and file size can change
		thumbPath := path.Join(*photoCachePath, thumbURL.MediaName)
		tempThumbPath := thumbPath + ".hold" // hold onto the original image incase for some reason we fail to recreate one with the new settings
		os.Rename(thumbPath, tempThumbPath)
		err = generateSaveThumbnailJPEG(tx, photo.MediaID, thumbURL.MediaName, photoCachePath, baseImagePath, thumbURL.UrlID)
		if err != nil {
			os.Rename(tempThumbPath, thumbPath)
			return errors.Wrap(err, "recreating thumbnail cached image")
		}
		os.Remove(tempThumbPath)

		// save new side car hash
		_, err = tx.Exec("UPDATE media SET side_car_hash = ?, side_car_path = ? WHERE media_id = ?", currentFileHash, currentSideCarPath, photo.MediaID)
		if err != nil {
			return errors.Wrapf(err, "could not update side car hash for media: %s", photo.Path)
		}
	}
	return nil
}