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api/database/migration_exif.go

@@ -0,0 +1,214 @@
+package database
+
+import (
+	"fmt"
+	"log"
+	"strconv"
+	"strings"
+
+	"github.com/photoview/photoview/api/graphql/models"
+	"gorm.io/gorm"
+)
+
+type exifModel struct {
+	ID       int `gorm:"primarykey"`
+	Exposure *string
+	Flash    *string
+}
+
+var flashDescriptions = map[int]string{
+	0x0:  "No Flash",
+	0x1:  "Fired",
+	0x5:  "Fired, Return not detected",
+	0x7:  "Fired, Return detected",
+	0x8:  "On, Did not fire",
+	0x9:  "On, Fired",
+	0xD:  "On, Return not detected",
+	0xF:  "On, Return detected",
+	0x10: "Off, Did not fire",
+	0x14: "Off, Did not fire, Return not detected",
+	0x18: "Auto, Did not fire",
+	0x19: "Auto, Fired",
+	0x1D: "Auto, Fired, Return not detected",
+	0x1F: "Auto, Fired, Return detected",
+	0x20: "No flash function",
+	0x30: "Off, No flash function",
+	0x41: "Fired, Red-eye reduction",
+	0x45: "Fired, Red-eye reduction, Return not detected",
+	0x47: "Fired, Red-eye reduction, Return detected",
+	0x49: "On, Red-eye reduction",
+	0x4D: "On, Red-eye reduction, Return not detected",
+	0x4F: "On, Red-eye reduction, Return detected",
+	0x50: "Off, Red-eye reduction",
+	0x58: "Auto, Did not fire, Red-eye reduction",
+	0x59: "Auto, Fired, Red-eye reduction",
+	0x5D: "Auto, Fired, Red-eye reduction, Return not detected",
+	0x5F: "Auto, Fired, Red-eye reduction, Return detected",
+}
+
+// Migrate MediaExif fields "exposure" and "flash" from strings to integers
+func migrateExifFields(db *gorm.DB) error {
+	mediaExifColumns, err := db.Migrator().ColumnTypes(&models.MediaEXIF{})
+	if err != nil {
+		return err
+	}
+
+	return db.Transaction(func(tx *gorm.DB) error {
+		for _, exifCol := range mediaExifColumns {
+			if err := parseExposure(exifCol, db); err != nil {
+				return err
+			}
+
+			if err := parseFlash(exifCol, db); err != nil {
+				return err
+			}
+		}
+
+		if err := db.AutoMigrate(&models.MediaEXIF{}); err != nil {
+			return fmt.Errorf("failed to auto migrate media_exif after exposure conversion: %w", err)
+		}
+
+		return nil
+	})
+}
+
+func parseFlash(exifCol gorm.ColumnType, db *gorm.DB) error {
+	if exifCol.Name() == "flash" {
+		switch exifCol.DatabaseTypeName() {
+		case "double", "numeric", "real", "bigint", "integer":
+			// correct type, do nothing
+		default:
+			// do migration
+			if err := migrateExifFieldsFlash(db); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func parseExposure(exifCol gorm.ColumnType, db *gorm.DB) error {
+	if exifCol.Name() == "exposure" {
+		switch exifCol.DatabaseTypeName() {
+		case "double", "numeric", "real", "bigint", "integer":
+			// correct type, do nothing
+		default:
+			// do migration
+			if err := migrateExifFieldsExposure(db); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func migrateExifFieldsExposure(db *gorm.DB) error {
+	log.Println("Migrating `media_exif.exposure` from string to double")
+
+	err := db.Transaction(func(tx *gorm.DB) error {
+
+		if err := tx.Exec("UPDATE media_exif SET exposure = NULL WHERE exposure = ''").Error; err != nil {
+			return fmt.Errorf("convert flash attribute empty values to NULL: %w", err)
+		}
+
+		var results []exifModel
+
+		return calculateExposure(tx, results)
+	})
+
+	if err != nil {
+		return fmt.Errorf("migrating `media_exif.exposure` failed: %w", err)
+	}
+
+	return nil
+}
+
+func calculateExposure(tx *gorm.DB, results []exifModel) error {
+	return tx.Model(&exifModel{}).Table("media_exif").Where("exposure LIKE '%/%'").FindInBatches(
+		&results, 100, func(tx *gorm.DB, batch int) error {
+			for _, result := range results {
+
+				if result.Exposure == nil {
+					continue
+				}
+
+				frac := strings.Split(*result.Exposure, "/")
+				if len(frac) != 2 {
+					return fmt.Errorf("failed to convert exposure value (%s) expected format x/y", frac)
+				}
+
+				numerator, err := strconv.ParseFloat(frac[0], 64)
+				if err != nil {
+					return err
+				}
+
+				denominator, err := strconv.ParseFloat(frac[1], 64)
+				if err != nil {
+					return err
+				}
+
+				decimalValue := numerator / denominator
+				*result.Exposure = fmt.Sprintf("%f", decimalValue)
+			}
+
+			tx.Save(&results)
+
+			return nil
+		}).Error
+}
+
+func migrateExifFieldsFlash(db *gorm.DB) error {
+	log.Println("Migrating `media_exif.flash` from string to int")
+
+	err := db.Transaction(func(tx *gorm.DB) error {
+
+		var dataType string
+		if err := tx.Raw(
+			"SELECT data_type FROM information_schema.columns WHERE table_name = 'media_exif' AND column_name = 'flash';").
+			Find(&dataType).Error; err != nil {
+
+			return fmt.Errorf("read data_type of column media_exif.flash: %w", err)
+		}
+
+		if dataType == "bigint" {
+			return nil
+		}
+
+		if err := tx.Exec("UPDATE media_exif SET flash = NULL WHERE flash = ''").Error; err != nil {
+			return fmt.Errorf("convert flash attribute empty values to NULL: %w", err)
+		}
+
+		var results []exifModel
+
+		return replaceFlashValues(tx, results)
+	})
+
+	if err != nil {
+		return fmt.Errorf("migrating `media_exif.flash` failed: %w", err)
+	}
+
+	return nil
+}
+
+func replaceFlashValues(tx *gorm.DB, results []exifModel) error {
+	return tx.Model(&exifModel{}).Table("media_exif").Where("flash IS NOT NULL").FindInBatches(
+		&results, 100, func(tx *gorm.DB, batch int) error {
+			for _, result := range results {
+
+				if result.Flash == nil {
+					continue
+				}
+
+				for index, name := range flashDescriptions {
+					if *result.Flash == name {
+						*result.Flash = fmt.Sprintf("%d", index)
+						break
+					}
+				}
+			}
+
+			tx.Save(&results)
+
+			return nil
+		}).Error
+}