X-Git-Url: https://git.giacomolli.uk/onechat/blobdiff_plain/36229ef68a30c5a117599037d79fa1fc708fbfef..add3cf6416e33c24331fd1e90e99284f44d2aae2:/image.go?ds=inline

diff --git a/image.go b/image.go
index d6a0b20..4b23f7c 100644
--- a/image.go
+++ b/image.go
@@ -22,6 +22,11 @@ const (
 	imageMaxBytes = 20 << 20
 )
 
+var (
+	errImageSize   = errors.New("image exceeds 20 MB")
+	errImageFormat = errors.New("use a JPEG, PNG, or WebP image")
+)
+
 // ImageStore holds immutable images shared by the root, children, and
 // subagents. Names are the SHA-256 of the bytes with the decoded format as
 // extension. Publication is atomic and does not replace an existing image.
@@ -97,12 +102,12 @@ func (s *ImageStore) Read(name string) ([]byte, error) {
 
 func imageFormat(data []byte) (string, error) {
 	if len(data) > imageMaxBytes {
-		return "", errors.New("image exceeds 20 MB")
+		return "", errImageSize
 	}
 
 	config, format, err := image.DecodeConfig(bytes.NewReader(data))
 	if err != nil || config.Width <= 0 || config.Height <= 0 {
-		return "", errors.New("use a JPEG, PNG, or WebP image")
+		return "", errImageFormat
 	}
 
 	switch format {
@@ -111,7 +116,7 @@ func imageFormat(data []byte) (string, error) {
 	case "png", "webp":
 		return format, nil
 	default:
-		return "", errors.New("use a JPEG, PNG, or WebP image")
+		return "", errImageFormat
 	}
 }
 
@@ -136,7 +141,7 @@ func imageReadFile(path string) (data []byte, err error) {
 	}
 
 	if len(data) > imageMaxBytes {
-		return nil, errors.New("image exceeds 20 MB")
+		return nil, errImageSize
 	}
 
 	return data, nil
@@ -162,13 +167,14 @@ func imageFiles(text string) []string {
 }
 
 func imageText(names []string, caption string) string {
-	var text strings.Builder
-
+	lines := make([]string, 0, len(names)+1)
 	for _, name := range names {
-		text.WriteString("[image " + name + "]\n")
+		lines = append(lines, "[image "+name+"]")
 	}
 
-	text.WriteString(caption)
+	if caption != "" {
+		lines = append(lines, caption)
+	}
 
-	return strings.TrimSuffix(text.String(), "\n")
+	return strings.Join(lines, "\n")
 }