Refactor search fallback and preview flows

backend/handlers/api.go

@@ -321,27 +321,11 @@ func (a *App) searchMedia(c *gin.Context) {
 	scored := services.RankSearchResults(rankQuery, results)
 	a.debug("search ranked summary", summarizeSearchResults(scored, time.Since(started), services.GeminiCandidateLimit(len(scored)), ""))
 	a.Hub.Broadcast("progress", gin.H{"type": "search", "status": "analyzing all candidate visuals with Gemini Vision", "progress": 75})
-	recommended, geminiStats := services.EvaluateAllCandidatesWithGemini(a.GeminiService, req.Query, scored)
+	recommended, geminiStats, geminiErr := services.EvaluateAllCandidatesWithGemini(a.GeminiService, req.Query, scored)
 	a.debug("search gemini evaluation", geminiStats)
-	err = nil
-	if len(recommended) == 0 {
-		err = fmt.Errorf("gemini vision returned no recommended items across all candidate batches")
-	}
-	if err != nil {
-		fallback := make([]services.AIRecommendation, 0, min(20, len(scored)))
-		for _, result := range scored[:min(20, len(scored))] {
-			fallback = append(fallback, services.AIRecommendation{
-				Title:           result.Title,
-				Link:            result.Link,
-				Snippet:         result.Snippet,
-				ThumbnailURL:    result.ThumbnailURL,
-				PreviewVideoURL: result.PreviewVideoURL,
-				Source:          result.Source,
-				Reason:          "Gemini Vision 응답이 부족해 키워드 기준으로 보강된 결과입니다.",
-				Recommended:     false,
-			})
-		}
-		warning := err.Error()
+	if geminiErr != nil && len(recommended) == 0 {
+		warning := geminiErr.Error()
+		fallback := services.BuildFallbackRecommendations(scored, 20, "")
 		a.debug("search fallback summary", summarizeRecommendationResults(fallback, time.Since(started), warning))
 		a.Hub.Broadcast("progress", gin.H{"type": "search", "status": "Gemini Vision fallback to ranked results", "progress": 90, "message": warning})
 		c.JSON(http.StatusOK, gin.H{"results": fallback, "warning": warning, "queries": queryVariants})
@@ -349,8 +333,15 @@ func (a *App) searchMedia(c *gin.Context) {
 	}
 
 	merged := services.MergeRecommendations(recommended, scored, 20)
-	a.debug("search complete summary", summarizeRecommendationResults(merged, time.Since(started), ""))
+	warning := ""
+	if geminiErr != nil {
+		warning = geminiErr.Error()
+	}
+	a.debug("search complete summary", summarizeRecommendationResults(merged, time.Since(started), warning))
 	response := gin.H{"results": merged, "queries": queryVariants}
+	if warning != "" {
+		response["warning"] = warning
+	}
 	a.Hub.Broadcast("progress", gin.H{"type": "search", "status": "search complete", "progress": 100})
 	c.JSON(http.StatusOK, response)
 }