feat: get similar images function

backend/models/image.go

@@ -196,6 +196,44 @@ func (m ImageModel) UpdateEmbedding(ctx context.Context, imageId uuid.UUID, embe
 	return err
 }
 
+const SIMILARITY_THRESHOLD = 0.9
+
+func (m ImageModel) GetSimilar(ctx context.Context, imageId uuid.UUID) ([]model.Image, error) {
+	stmt, err := m.dbPool.PrepareContext(ctx, `
+		WITH similarities AS (
+			SELECT 1 - (embedding <=> (
+				SELECT embedding
+				FROM haystack.image
+				WHERE ID = $1
+			)) AS cosine_similarity, id, image_name FROM haystack.image
+			WHERE embedding IS NOT NULL
+		)
+		SELECT id, image_name 
+		FROM similatiries 
+		WHERE cosine_similarity > $2
+	`)
+
+	if err != nil {
+		return []model.Image{}, err
+	}
+
+	images := []model.Image{}
+
+	rows, err := stmt.QueryContext(ctx, imageId, SIMILARITY_THRESHOLD)
+
+	for rows.Next() {
+		image := model.Image{}
+		err := rows.Scan(&image)
+		if err != nil {
+			return []model.Image{}, err
+		}
+
+		images = append(images, image)
+	}
+
+	return images, nil
+}
+
 func NewImageModel(db *sql.DB) ImageModel {
 	return ImageModel{dbPool: db}
 }