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 geminiErr != nil && len(recommended) == 0 {
-	if len(recommended) == 0 {
+		warning := geminiErr.Error()
-		err = fmt.Errorf("gemini vision returned no recommended items across all candidate batches")
+		fallback := services.BuildFallbackRecommendations(scored, 20, "")
-	}
-	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()
 		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)
 }

backend/services/gemini.go

@@ -164,16 +164,21 @@ User query: ` + query,
 	}
 
 	maxImages := min(len(candidates), 10)
+	visualCount := 0
 	for idx := 0; idx < maxImages; idx++ {
 		img, mimeType, err := fetchCandidateVisualInlineData(g.Client, candidates[idx])
 		if err != nil {
 			continue
 		}
+		visualCount++
 		parts = append(parts,
 			geminiPart{"text": fmt.Sprintf("Candidate %d: title=%s source=%s link=%s", idx, candidates[idx].Title, candidates[idx].Source, candidates[idx].Link)},
 			geminiPart{"inlineData": map[string]string{"mimeType": mimeType, "data": img}},
 		)
 	}
+	if visualCount == 0 {
+		return nil, fmt.Errorf("no candidate thumbnails or preview frames could be fetched for gemini vision")
+	}
 
 	body := map[string]any{
 		"contents": []map[string]any{
@@ -248,18 +253,7 @@ User query: ` + query,
 	}
 
 	if len(recommendations) == 0 {
-		for _, candidate := range candidates[:min(8, len(candidates))] {
+		recommendations = BuildFallbackRecommendations(candidates, 8, "Gemini Vision 평가를 받지 못해 키워드 기준으로 보강된 결과입니다.")
-			recommendations = append(recommendations, AIRecommendation{
-				Title:           candidate.Title,
-				Link:            candidate.Link,
-				Snippet:         candidate.Snippet,
-				ThumbnailURL:    candidate.ThumbnailURL,
-				PreviewVideoURL: candidate.PreviewVideoURL,
-				Source:          candidate.Source,
-				Reason:          "Gemini Vision 평가를 받지 못해 키워드 기준으로 보강된 결과입니다.",
-				Recommended:     false,
-			})
-		}
 	}
 
 	return recommendations, nil

backend/services/ranker.go

@@ -1,11 +1,14 @@
 package services
 
 import (
+	"fmt"
 	"sort"
 	"strings"
 	"sync"
 )
 
+const GeminiFallbackReason = "Gemini Vision 응답이 부족해 키워드 기준으로 보강된 결과입니다."
+
 type GeminiBatchStats struct {
 	CandidateCap     int      `json:"candidateCap"`
 	Requested        int      `json:"requested"`
@@ -84,9 +87,13 @@ func GeminiCandidateLimit(total int) int {
 	return total
 }
 
-func EvaluateAllCandidatesWithGemini(service *GeminiService, query string, ranked []SearchResult) ([]AIRecommendation, GeminiBatchStats) {
+func EvaluateAllCandidatesWithGemini(service *GeminiService, query string, ranked []SearchResult) ([]AIRecommendation, GeminiBatchStats, error) {
 	const chunkSize = 8
 	const maxConcurrentBatches = 2
+	if service == nil {
+		return nil, GeminiBatchStats{}, fmt.Errorf("gemini service is not configured")
+	}
+
 	limit := GeminiCandidateLimit(len(ranked))
 	stats := GeminiBatchStats{
 		CandidateCap: limit,
@@ -106,6 +113,9 @@ func EvaluateAllCandidatesWithGemini(service *GeminiService, query string, ranke
 		batches = append(batches, ranked[start:end])
 	}
 	stats.Batches = len(batches)
+	if len(batches) == 0 {
+		return []AIRecommendation{}, stats, nil
+	}
 
 	results := make([]batchResult, len(batches))
 	var wg sync.WaitGroup
@@ -146,7 +156,41 @@ func EvaluateAllCandidatesWithGemini(service *GeminiService, query string, ranke
 		}
 	}
 	stats.RecommendedCount = len(merged)
-	return merged, stats
+
+	switch {
+	case len(merged) > 0 && stats.Failed == 0:
+		return merged, stats, nil
+	case len(merged) > 0 && stats.Failed > 0:
+		return merged, stats, fmt.Errorf("gemini vision partially failed on %d of %d batches", stats.Failed, stats.Batches)
+	case stats.Failed == stats.Batches:
+		if len(stats.Errors) > 0 {
+			return nil, stats, fmt.Errorf("gemini vision failed for all batches: %s", strings.Join(stats.Errors, "; "))
+		}
+		return nil, stats, fmt.Errorf("gemini vision failed for all batches")
+	default:
+		return nil, stats, fmt.Errorf("gemini vision returned no candidate evaluations")
+	}
+}
+
+func BuildFallbackRecommendations(ranked []SearchResult, limit int, reason string) []AIRecommendation {
+	if strings.TrimSpace(reason) == "" {
+		reason = GeminiFallbackReason
+	}
+
+	fallback := make([]AIRecommendation, 0, min(limit, len(ranked)))
+	for _, item := range ranked[:min(limit, len(ranked))] {
+		fallback = append(fallback, AIRecommendation{
+			Title:           item.Title,
+			Link:            item.Link,
+			Snippet:         item.Snippet,
+			ThumbnailURL:    item.ThumbnailURL,
+			PreviewVideoURL: item.PreviewVideoURL,
+			Source:          item.Source,
+			Reason:          reason,
+			Recommended:     false,
+		})
+	}
+	return fallback
 }
 
 func MergeRecommendations(recommended []AIRecommendation, ranked []SearchResult, limit int) []AIRecommendation {
@@ -184,7 +228,7 @@ func MergeRecommendations(recommended []AIRecommendation, ranked []SearchResult,
 			ThumbnailURL:    item.ThumbnailURL,
 			PreviewVideoURL: item.PreviewVideoURL,
 			Source:          item.Source,
-			Reason:          "Gemini Vision 응답이 부족해 키워드 기준으로 보강된 결과입니다.",
+			Reason:          GeminiFallbackReason,
 			Recommended:     false,
 		})
 	}

frontend/app.js

@@ -56,6 +56,7 @@ let activeResultItem = null;
 const activePlatforms = new Set(["envato", "artgrid", "google video"]);
 const hlsInstances = new WeakMap();
 const debugEntries = [];
+const PREVIEW_PLACEHOLDER = "https://placehold.co/1280x720/0a0a0a/ffffff?text=Preview";
 
 function setStatus(label, progress) {
   statusLabel.textContent = label;
@@ -63,6 +64,18 @@ function setStatus(label, progress) {
   logEvent("status", { label, progress });
 }
 
+function setHidden(element, hidden, visibleDisplayClass = "flex") {
+  element.classList.toggle("hidden", hidden);
+  if (visibleDisplayClass) {
+    element.classList.toggle(visibleDisplayClass, !hidden);
+  }
+}
+
+function showWarning(message) {
+  searchWarning.textContent = message;
+  setHidden(searchWarning, !message, "");
+}
+
 function logEvent(type, payload) {
   const entry = {
     ts: new Date().toISOString(),
@@ -318,6 +331,20 @@ function detachVideoSource(video) {
   video.load();
 }
 
+function resetPreviewPlayer() {
+  previewVideo.pause();
+  detachVideoSource(previewVideo);
+  previewMediaFrame.style.aspectRatio = "";
+}
+
+function showModal(element) {
+  setHidden(element, false);
+}
+
+function hideModal(element) {
+  setHidden(element, true);
+}
+
 function renderResults(results) {
   searchResults.innerHTML = "";
   if (!results.length) {
@@ -329,7 +356,7 @@ function renderResults(results) {
     const image = node.querySelector("img");
     const previewVideo = node.querySelector(".preview-hover");
     const overlays = node.querySelectorAll(".preview-overlay");
-    image.src = item.thumbnailUrl || "https://placehold.co/1280x720/0a0a0a/ffffff?text=Preview";
+    image.src = item.thumbnailUrl || PREVIEW_PLACEHOLDER;
     image.alt = item.title;
     node.querySelector("h3").textContent = item.title;
     node.querySelector(".result-snippet").textContent = item.snippet || item.reason || item.source || "";
@@ -389,8 +416,7 @@ function openResultModal(item) {
   resultModalOpenExternal.href = item.link || "#";
   const canDirectDownload = item.source === "Google Video" && item.link;
   resultModalDownload.classList.toggle("hidden", !canDirectDownload);
-  resultModal.classList.remove("hidden");
+  showModal(resultModal);
-  resultModal.classList.add("flex");
   logEvent("result:modal:open", { title: item.title, source: item.source, link: item.link });
 }
 
@@ -400,14 +426,13 @@ function closeResultViewer() {
   }
   activeResultItem = null;
   resultModalFrame.src = "about:blank";
-  resultModal.classList.add("hidden");
+  hideModal(resultModal);
-  resultModal.classList.remove("flex");
 }
 
 searchForm.addEventListener("submit", async (event) => {
   event.preventDefault();
   setStatus("preparing search", 5);
-  searchWarning.classList.add("hidden");
+  showWarning("");
   try {
     const data = await api("/api/search", {
       method: "POST",
@@ -416,15 +441,11 @@ searchForm.addEventListener("submit", async (event) => {
     });
     renderResults(data.results || []);
     renderQueryVariants(data.queries || []);
-    if (data.warning) {
+    showWarning(data.warning || "");
-      searchWarning.textContent = data.warning;
-      searchWarning.classList.remove("hidden");
-    }
     logEvent("search:completed", { results: data.results?.length || 0, queries: data.queries || [] });
     setStatus("search complete", 100);
   } catch (error) {
-    searchWarning.textContent = error.message;
+    showWarning(error.message);
-    searchWarning.classList.remove("hidden");
     renderQueryVariants([]);
     setStatus("search failed", 100);
   }
@@ -445,18 +466,16 @@ async function uploadFile(file) {
 function openPreviewModal(preview) {
   logEvent("preview:modal:open", preview);
   previewTitle.textContent = preview.title;
-  previewThumbnail.src = preview.thumbnail;
+  previewThumbnail.src = preview.thumbnail || PREVIEW_PLACEHOLDER;
   previewThumbnail.alt = preview.title;
-  previewVideo.pause();
+  resetPreviewPlayer();
-  detachVideoSource(previewVideo);
-  previewMediaFrame.style.aspectRatio = "";
   if (preview.previewStreamUrl) {
     attachVideoSource(previewVideo, preview.previewStreamUrl);
-    previewVideo.classList.remove("hidden");
+    setHidden(previewVideo, false, "");
-    previewThumbnail.classList.add("hidden");
+    setHidden(previewThumbnail, true, "");
   } else {
-    previewVideo.classList.add("hidden");
+    setHidden(previewVideo, true, "");
-    previewThumbnail.classList.remove("hidden");
+    setHidden(previewThumbnail, false, "");
   }
   previewDuration.textContent = preview.duration;
   qualitySelect.innerHTML = "";
@@ -470,17 +489,13 @@ function openPreviewModal(preview) {
   cropStart = 0;
   cropEnd = cropMax;
   syncRanges();
-  previewModal.classList.remove("hidden");
+  showModal(previewModal);
-  previewModal.classList.add("flex");
 }
 
 function closeModal() {
   logEvent("preview:modal:close", { title: previewTitle.textContent });
-  previewVideo.pause();
+  resetPreviewPlayer();
-  detachVideoSource(previewVideo);
+  hideModal(previewModal);
-  previewMediaFrame.style.aspectRatio = "";
-  previewModal.classList.add("hidden");
-  previewModal.classList.remove("flex");
   cropStart = 0;
   cropEnd = 0;
   cropMax = 0;

worker/downloader.py

@@ -36,12 +36,6 @@ def parse_duration(value):
     return f"{hours:02d}:{minutes:02d}:{seconds:02d}"
 
 
-def format_label(height, ext):
-    if height:
-        return f"{height}p ({ext})"
-    return f"Best ({ext})"
-
-
 def build_quality_options(formats: List[dict]):
     heights = []
     for item in formats:
@@ -99,6 +93,45 @@ def probe(url):
     print(json.dumps(preview), flush=True)
 
 
+def parse_timestamp(value: str) -> int:
+    text = (value or "").strip()
+    if not text:
+        return 0
+    parts = text.split(":")
+    try:
+        if len(parts) == 3:
+            hours, minutes, seconds = parts
+            return int(hours) * 3600 + int(minutes) * 60 + int(float(seconds))
+        if len(parts) == 2:
+            minutes, seconds = parts
+            return int(minutes) * 60 + int(float(seconds))
+        return int(float(text))
+    except ValueError:
+        return 0
+
+
+def resolve_source_file(tmpdir: str) -> str:
+    files = [os.path.join(tmpdir, name) for name in os.listdir(tmpdir)]
+    media_files = [path for path in files if os.path.isfile(path)]
+    if not media_files:
+        raise RuntimeError("yt-dlp did not produce an output file")
+    return sorted(media_files)[0]
+
+
+def should_trim(start: str, end: str) -> bool:
+    start_seconds = parse_timestamp(start)
+    end_seconds = parse_timestamp(end)
+    return end_seconds > start_seconds
+
+
+def build_ffmpeg_cmd(source_file: str, output_path: str, start: str, end: str) -> List[str]:
+    cmd = ["ffmpeg", "-y"]
+    if should_trim(start, end):
+        cmd.extend(["-ss", start, "-to", end])
+    cmd.extend(["-i", source_file, "-c", "copy", output_path])
+    return cmd
+
+
 def main():
     parser = argparse.ArgumentParser()
     parser.add_argument("--mode", choices=["probe", "download"], default="download")
@@ -132,25 +165,10 @@ def main():
         run(download_cmd)
         emit("downloaded", 55, "Source downloaded")
 
-        files = [os.path.join(tmpdir, name) for name in os.listdir(tmpdir)]
+        source_file = resolve_source_file(tmpdir)
-        if not files:
+        ffmpeg_cmd = build_ffmpeg_cmd(source_file, args.output, args.start, args.end)
-            raise RuntimeError("yt-dlp did not produce an output file")
+        message = "Cropping requested segment" if should_trim(args.start, args.end) else "Saving downloaded media"
-        source_file = sorted(files)[0]
+        emit("cropping", 75, message)
-
-        ffmpeg_cmd = [
-            "ffmpeg",
-            "-y",
-            "-ss",
-            args.start,
-            "-to",
-            args.end,
-            "-i",
-            source_file,
-            "-c",
-            "copy",
-            args.output,
-        ]
-        emit("cropping", 75, "Cropping requested segment")
         run(ffmpeg_cmd)
 
     emit("completed", 100, "Download complete", args.output)