Add in-app result viewer and expand Gemini review

backend/services/ranker.go

@@ -3,6 +3,7 @@ package services
 import (
 	"sort"
 	"strings"
+	"sync"
 )
 
 type GeminiBatchStats struct {
@@ -80,42 +81,63 @@ func RankSearchResults(query string, results []SearchResult) []SearchResult {
 }
 
 func GeminiCandidateLimit(total int) int {
-	switch {
-	case total <= 12:
-		return total
-	case total <= 16:
-		return 12
-	default:
-		return 16
-	}
+	return total
 }
 
 func EvaluateAllCandidatesWithGemini(service *GeminiService, query string, ranked []SearchResult) ([]AIRecommendation, GeminiBatchStats) {
 	const chunkSize = 8
+	const maxConcurrentBatches = 2
 	limit := GeminiCandidateLimit(len(ranked))
 	stats := GeminiBatchStats{
 		CandidateCap: limit,
 		Requested:    min(limit, len(ranked)),
 	}
-	merged := make([]AIRecommendation, 0, len(ranked))
-	seen := map[string]bool{}
+	type batchResult struct {
+		index           int
+		recommendations []AIRecommendation
+		err             error
+	}
+	batches := make([][]SearchResult, 0, (limit+chunkSize-1)/chunkSize)
 	for start := 0; start < limit; start += chunkSize {
 		end := start + chunkSize
 		if end > limit {
 			end = limit
 		}
-		batch := ranked[start:end]
-		stats.Batches++
-		recommended, err := service.Recommend(query, batch)
-		if err != nil {
+		batches = append(batches, ranked[start:end])
+	}
+	stats.Batches = len(batches)
+
+	results := make([]batchResult, len(batches))
+	var wg sync.WaitGroup
+	sem := make(chan struct{}, maxConcurrentBatches)
+	for idx, batch := range batches {
+		wg.Add(1)
+		go func(batchIndex int, candidates []SearchResult) {
+			defer wg.Done()
+			sem <- struct{}{}
+			defer func() { <-sem }()
+			recommended, err := service.Recommend(query, candidates)
+			results[batchIndex] = batchResult{
+				index:           batchIndex,
+				recommendations: recommended,
+				err:             err,
+			}
+		}(idx, batch)
+	}
+	wg.Wait()
+
+	merged := make([]AIRecommendation, 0, len(ranked))
+	seen := map[string]bool{}
+	for _, batch := range results {
+		if batch.err != nil {
 			stats.Failed++
 			if len(stats.Errors) < 5 {
-				stats.Errors = append(stats.Errors, err.Error())
+				stats.Errors = append(stats.Errors, batch.err.Error())
 			}
 			continue
 		}
 		stats.Succeeded++
-		for _, item := range recommended {
+		for _, item := range batch.recommendations {
 			if item.Link == "" || seen[item.Link] {
 				continue
 			}
@@ -132,6 +154,9 @@ func MergeRecommendations(recommended []AIRecommendation, ranked []SearchResult,
 	seen := map[string]bool{}
 
 	for _, item := range recommended {
+		if !item.Recommended {
+			continue
+		}
 		if item.Link == "" || seen[item.Link] {
 			continue
 		}
@@ -139,6 +164,14 @@ func MergeRecommendations(recommended []AIRecommendation, ranked []SearchResult,
 		merged = append(merged, item)
 	}
 
+	for _, item := range recommended {
+		if item.Recommended || item.Link == "" || seen[item.Link] || len(merged) >= limit {
+			continue
+		}
+		seen[item.Link] = true
+		merged = append(merged, item)
+	}
+
 	for _, item := range ranked {
 		if len(merged) >= limit || item.Link == "" || seen[item.Link] {
 			continue
@@ -151,8 +184,8 @@ func MergeRecommendations(recommended []AIRecommendation, ranked []SearchResult,
 			ThumbnailURL:    item.ThumbnailURL,
 			PreviewVideoURL: item.PreviewVideoURL,
 			Source:          item.Source,
-			Reason:          "Keyword-ranked result added without extra Gemini vision tokens.",
-			Recommended:     true,
+			Reason:          "Gemini Vision 응답이 부족해 키워드 기준으로 보강된 결과입니다.",
+			Recommended:     false,
 		})
 	}
 	return merged