feat(artwork): add SetAvatar to the image uploader

core/artwork/uploader.go

@@ -1,6 +1,7 @@
 package artwork
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	"io"
@@ -31,6 +32,9 @@ func parseSize(value, fallback string) int64 {
 // Uploader stores a user-uploaded entity image and invalidates that entity's artwork state.
 type Uploader interface {
 	SetImage(ctx context.Context, entityType string, entityID string, name string, oldPath string, reader io.Reader, ext string) (filename string, err error)
+	// SetAvatar resizes a user avatar to consts.MaxAvatarSize (aspect ratio preserved,
+	// no square padding) and stores it under the avatar folder.
+	SetAvatar(ctx context.Context, userID, username, oldPath string, reader io.Reader, ext string) (filename string, err error)
 	RemoveImage(ctx context.Context, path string) error
 	// EnqueueArtwork re-resolves the item's artwork. Call it AFTER persisting the new
 	// filename, or the worker resolves the old one.
@@ -77,6 +81,22 @@ func (s *uploader) SetImage(ctx context.Context, entityType string, entityID str
 	return filename, nil
 }
 
+func (s *uploader) SetAvatar(ctx context.Context, userID, username, oldPath string, reader io.Reader, ext string) (string, error) {
+	data, err := io.ReadAll(io.LimitReader(reader, MaxImageUploadSize()))
+	if err != nil {
+		return "", fmt.Errorf("reading avatar: %w", err)
+	}
+	// square=false: square padding would put transparent bars around a non-square photo.
+	resized, _, err := resizeStaticImage(data, consts.MaxAvatarSize, false)
+	if err != nil {
+		return "", fmt.Errorf("resizing avatar: %w", err)
+	}
+	if resized == nil {
+		resized = bytes.NewReader(data) // already within bounds: resizeStaticImage returns nil, not the original
+	}
+	return s.SetImage(ctx, consts.EntityUser, userID, username, oldPath, resized, ext)
+}
+
 func (s *uploader) EnqueueArtwork(ctx context.Context, entityType, id string) {
 	kind, ok := uploadEntityKind[entityType]
 	if !ok {

core/artwork/uploader_test.go

@@ -1,7 +1,10 @@
 package artwork
 
 import (
+	"bytes"
 	"context"
+	"image"
+	"image/png"
 	"os"
 	"path/filepath"
 	"strings"
@@ -93,6 +96,65 @@ var _ = Describe("Uploader", func() {
 		})
 	})
 
+	Describe("SetAvatar", func() {
+		It("writes into the avatar folder, named after id and username", func() {
+			ctx := context.Background()
+			big := makePNG(1024, 1024)
+			filename, err := svc.SetAvatar(ctx, "u1", "deluan", "", bytes.NewReader(big), ".png")
+			Expect(err).ToNot(HaveOccurred())
+			Expect(filename).To(Equal("u1_deluan.png"))
+			Expect(filepath.Join(tmpDir, "avatar", filename)).To(BeAnExistingFile())
+		})
+
+		It("shrinks a large image to MaxAvatarSize, preserving aspect ratio", func() {
+			ctx := context.Background()
+			big := makePNG(1024, 768)
+			filename, err := svc.SetAvatar(ctx, "u1", "deluan", "", bytes.NewReader(big), ".png")
+			Expect(err).ToNot(HaveOccurred())
+
+			f, err := os.Open(filepath.Join(tmpDir, "avatar", filename))
+			Expect(err).ToNot(HaveOccurred())
+			defer f.Close()
+			cfg, _, err := image.DecodeConfig(f)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(cfg.Width).To(Equal(consts.MaxAvatarSize))
+			Expect(cfg.Height).To(Equal(384)) // aspect ratio kept, not padded to a square
+		})
+
+		It("keeps a small image intact instead of writing an empty file", func() {
+			ctx := context.Background()
+			small := makePNG(64, 64)
+			filename, err := svc.SetAvatar(ctx, "u1", "deluan", "", bytes.NewReader(small), ".png")
+			Expect(err).ToNot(HaveOccurred())
+
+			data, err := os.ReadFile(filepath.Join(tmpDir, "avatar", filename))
+			Expect(err).ToNot(HaveOccurred())
+			Expect(data).ToNot(BeEmpty())
+
+			cfg, _, err := image.DecodeConfig(bytes.NewReader(data))
+			Expect(err).ToNot(HaveOccurred())
+			Expect(cfg.Width).To(Equal(64))
+			Expect(cfg.Height).To(Equal(64))
+		})
+
+		It("removes the previous file", func() {
+			ctx := context.Background()
+			old := filepath.Join(tmpDir, "avatar", "u1_old.png")
+			Expect(os.MkdirAll(filepath.Dir(old), 0755)).To(Succeed())
+			Expect(os.WriteFile(old, []byte("x"), 0600)).To(Succeed())
+
+			_, err := svc.SetAvatar(ctx, "u1", "deluan", old, bytes.NewReader(makePNG(64, 64)), ".png")
+			Expect(err).ToNot(HaveOccurred())
+			Expect(old).ToNot(BeAnExistingFile())
+		})
+
+		It("rejects a body that is not a decodable image", func() {
+			ctx := context.Background()
+			_, err := svc.SetAvatar(ctx, "u1", "deluan", "", strings.NewReader("not an image"), ".png")
+			Expect(err).To(HaveOccurred())
+		})
+	})
+
 	Describe("EnqueueArtwork", func() {
 		It("clears artwork state and enqueues a Bump", func() {
 			ctx := context.Background()
@@ -172,3 +234,10 @@ var _ = Describe("MaxImageUploadSize", func() {
 		Expect(MaxImageUploadSize()).To(Equal(int64(52_428_800)))
 	})
 })
+
+func makePNG(w, h int) []byte {
+	img := image.NewRGBA(image.Rect(0, 0, w, h))
+	var buf bytes.Buffer
+	Expect(png.Encode(&buf, img)).To(Succeed())
+	return buf.Bytes()
+}