7 files changed, 203 insertions, 33 deletions
diff --git a/utils/format/files.go b/utils/format/files.go
new file mode 100644
index 0000000..82f1546
--- /dev/null
+++ b/utils/format/files.go
@@ -0,0 +1,71 @@
+package format
+
+import (
+	"bytes"
+	"fmt"
+	"image"
+	_ "image/gif"
+	"image/jpeg"
+	"image/png"
+	"strings"
+
+	"golang.org/x/image/webp"
+)
+
+func init() {
+	image.RegisterFormat("webp", "RIFF????WEBP", webp.Decode, webp.DecodeConfig)
+}
+
+func FileSize(size int64) string {
+	const unit = 1024
+	if size < unit {
+		return fmt.Sprintf("%d B", size)
+	}
+	div, exp := int64(unit), 0
+	for n := size / unit; n >= unit; n /= unit {
+		div *= unit
+		exp++
+	}
+
+	val := float64(size) / float64(div)
+	unitStr := "KMGTPE"[exp : exp+1]
+	if val == float64(int64(val)) {
+		return fmt.Sprintf("%d %sB", int64(val), unitStr)
+	}
+	return fmt.Sprintf("%.2f %sB", val, unitStr)
+}
+
+func RemoveExtension(fileName string) string {
+	if fileName == "" {
+		return fileName
+	}
+	parts := strings.Split(fileName, ".")
+	if len(parts) <= 1 {
+		return fileName
+	}
+	return strings.Join(parts[:len(parts)-1], ".")
+}
+
+func DecodeImage(imgData []byte) (image.Image, string, error) {
+	img, formatName, err := image.Decode(bytes.NewReader(imgData))
+	return img, formatName, err
+}
+
+func GetImageFileSize(img image.Image) int64 {
+	var buf bytes.Buffer
+	switch img.(type) {
+	case *image.NRGBA, *image.RGBA, *image.YCbCr:
+		// Use PNG encoding for lossless compression
+		err := png.Encode(&buf, img)
+		if err != nil {
+			return 0
+		}
+	default:
+		// Fallback to JPEG encoding for other formats
+		err := jpeg.Encode(&buf, img, &jpeg.Options{Quality: 85})
+		if err != nil {
+			return 0
+		}
+	}
+	return int64(buf.Len())
+}
diff --git a/utils/format/format.go b/utils/format/format.go
deleted file mode 100644
index e57bc1f..0000000
--- a/utils/format/format.go
+++ /dev/null
@@ -1,32 +0,0 @@
-package format
-
-import "fmt"
-
-func FileSize(size int64) string {
-	const unit = 1024
-	if size < unit {
-		return fmt.Sprintf("%d B", size)
-	}
-	div, exp := int64(unit), 0
-	for n := size / unit; n >= unit; n /= unit {
-		div *= unit
-		exp++
-	}
-
-	val := float64(size) / float64(div)
-	unitStr := "KMGTPE"[exp : exp+1]
-	if val == float64(int64(val)) {
-		return fmt.Sprintf("%d %sB", int64(val), unitStr)
-	}
-	return fmt.Sprintf("%.2f %sB", val, unitStr)
-}
-
-func Count(count int64) string {
-	if count < 1000 {
-		return fmt.Sprintf("%d", count)
-	} else if count < 1000000 {
-		return fmt.Sprintf("%.1fK", float64(count)/1000)
-	} else {
-		return fmt.Sprintf("%.1fM", float64(count)/1000000)
-	}
-}
diff --git a/utils/format/numbers.go b/utils/format/numbers.go
new file mode 100644
index 0000000..8f546f1
--- /dev/null
+++ b/utils/format/numbers.go
@@ -0,0 +1,20 @@
+package format
+
+import "fmt"
+
+func Count(count int64) string {
+	if count < 1000 {
+		return fmt.Sprintf("%d", count)
+	} else if count < 1000000 {
+		return fmt.Sprintf("%.1fK", float64(count)/1000)
+	} else {
+		return fmt.Sprintf("%.1fM", float64(count)/1000000)
+	}
+}
+
+func Int64ToString(value int64) string {
+	if value < 0 {
+		return fmt.Sprintf("-%d", -value)
+	}
+	return fmt.Sprintf("%d", value)
+}
diff --git a/utils/format/time.go b/utils/format/time.go
new file mode 100644
index 0000000..3e65337
--- /dev/null
+++ b/utils/format/time.go
@@ -0,0 +1,7 @@
+package format
+
+import "time"
+
+func GetCurrentTimeAsTimestamp() int64 {
+	return time.Now().Unix()
+}
diff --git a/utils/transformers/image.go b/utils/transformers/image.go
index a88d8bb..e392f7f 100644
--- a/utils/transformers/image.go
+++ b/utils/transformers/image.go
@@ -1,6 +1,77 @@
 package transformers
 
-import "imageboard/config"
+import (
+	"image"
+	"imageboard/config"
+	"imageboard/models"
+	"imageboard/utils/format"
+	"imageboard/utils/validators"
+	"strings"
+)
+
+func TransformImageToVariant(img image.Image, variant config.ImageSizeType) (models.ImageSize, image.Image, error) {
+	variantSizeMap := map[config.ImageSizeType]int{
+		config.ImageSizeTypeIcon:      64,
+		config.ImageSizeTypeThumbnail: 256,
+		config.ImageSizeTypeSmall:     512,
+		config.ImageSizeTypeMedium:    1024,
+		config.ImageSizeTypeLarge:     2048,
+		config.ImageSizeTypeOriginal:  0, // Original size, no resizing
+	}
+
+	maxWidth := variantSizeMap[variant]
+	if maxWidth > 0 {
+		img = ResizeImage(img, maxWidth)
+	}
+
+	fileSize := format.GetImageFileSize(img)
+
+	return models.ImageSize{
+		SizeType: variant,
+		Width:    img.Bounds().Dx(),
+		Height:   img.Bounds().Dy(),
+		FileSize: fileSize,
+	}, img, nil
+}
+
+func ResizeImage(img image.Image, maxWidth int) image.Image {
+	if maxWidth <= 0 || img.Bounds().Dx() <= maxWidth {
+		return img
+	}
+
+	ratio := float64(maxWidth) / float64(img.Bounds().Dx())
+	newWidth := int(float64(img.Bounds().Dx()) * ratio)
+	newHeight := int(float64(img.Bounds().Dy()) * ratio)
+	newImg := image.NewRGBA(image.Rect(0, 0, newWidth, newHeight))
+	for y := 0; y < newHeight; y++ {
+		for x := 0; x < newWidth; x++ {
+			srcX := int(float64(x) / ratio)
+			srcY := int(float64(y) / ratio)
+			if srcX < img.Bounds().Dx() && srcY < img.Bounds().Dy() {
+				newImg.Set(x, y, img.At(srcX, srcY))
+			}
+		}
+	}
+	return newImg
+}
+
+func CreateUniqueFileName(sourceURLOrOriginalName, imageFormat string) string {
+	fileName := sourceURLOrOriginalName
+	if validators.IsValidURL(sourceURLOrOriginalName) {
+		parts := strings.Split(sourceURLOrOriginalName, "/")
+		fileName = parts[len(parts)-1]
+	}
+
+	currentTime := format.GetCurrentTimeAsTimestamp()
+	fileNameWithoutExtension := format.RemoveExtension(fileName)
+	fileName = GenerateTokenFromString(fileNameWithoutExtension + "_" + format.Int64ToString(currentTime))
+
+	if len(fileName) > 32 {
+		mid := len(fileName) / 2
+		fileName = fileName[mid-16 : mid+16]
+	}
+	return fileName + "." + imageFormat
+}
 
 func ConvertStringRatingToType(rating string) (config.Rating, error) {
 	switch rating {
diff --git a/utils/transformers/tokens.go b/utils/transformers/tokens.go
index 7ad36ed..f2f2e0b 100644
--- a/utils/transformers/tokens.go
+++ b/utils/transformers/tokens.go
@@ -1,6 +1,7 @@
 package transformers
 
 import (
+	"crypto"
 	"crypto/rand"
 	"encoding/hex"
 )
@@ -12,3 +13,9 @@ func GenerateRandomToken() (string, error) {
 	}
 	return hex.EncodeToString(bytes), nil
 }
+
+func GenerateTokenFromString(input string) string {
+	hasher := crypto.SHA256.New()
+	hasher.Write([]byte(input))
+	return hex.EncodeToString(hasher.Sum(nil))
+}
diff --git a/utils/validators/url.go b/utils/validators/url.go
new file mode 100644
index 0000000..b85eca7
--- /dev/null
+++ b/utils/validators/url.go
@@ -0,0 +1,26 @@
+package validators
+
+import (
+	"regexp"
+	"strings"
+)
+
+func IsValidURL(url string) bool {
+	if url == "" {
+		return false
+	}
+	if len(url) > 2048 { // Common max URL length
+		return false
+	}
+	if !strings.HasPrefix(url, "http://") && !strings.HasPrefix(url, "https://") {
+		return false
+	}
+
+	pattern := `^(http|https)://[a-zA-Z0-9\-._~:/?#\[\]@!$&'()*+,;=]+$`
+	matched, err := regexp.MatchString(pattern, url)
+	if err != nil {
+		return false
+	}
+
+	return matched
+}