add redis cache to results

internal/results/repository/postgres/result.go

@@ -16,9 +16,15 @@ import (
 )
 
 const (
-	resultCachePrefix = "result:"
+	resultCachePrefix      = "result:"
+	leaderboardCachePrefix = "leaderboard:"
 )
 
+type leaderboardCache struct {
+	Results    []domain.Result `json:"results"`
+	TotalCount int             `json:"total_count"`
+}
+
 type ResultRepository struct {
 	db           *sql.DB
 	redisClient  *redis.Client
@@ -37,6 +43,21 @@ func (r *ResultRepository) cacheKey(id string) string {
 	return resultCachePrefix + id
 }
 
+func (r *ResultRepository) leaderboardCacheKey(competitionID uuid.UUID, limit, offset int) string {
+	return fmt.Sprintf("%s%s:limit:%d:offset:%d", leaderboardCachePrefix, competitionID.String(), limit, offset)
+}
+
+func (r *ResultRepository) invalidateLeaderboardCache(ctx context.Context, competitionID uuid.UUID) {
+	if !r.cacheEnabled {
+		return
+	}
+	pattern := fmt.Sprintf("%s%s:*", leaderboardCachePrefix, competitionID.String())
+	keys, err := r.redisClient.Keys(ctx, pattern).Result()
+	if err == nil && len(keys) > 0 {
+		r.redisClient.Del(ctx, keys...).Err()
+	}
+}
+
 func (r *ResultRepository) Create(ctx context.Context, result *domain.Result) error {
 	metadataJSON, err := json.Marshal(result.Metadata)
 	if err != nil {
@@ -65,6 +86,7 @@ func (r *ResultRepository) Create(ctx context.Context, result *domain.Result) er
 	}
 
 	if r.cacheEnabled {
+		r.invalidateLeaderboardCache(ctx, result.CompetitionID)
 		data, err := json.Marshal(result)
 		if err == nil {
 			r.redisClient.Set(ctx, r.cacheKey(result.ID.String()), data, 10*time.Minute).Err()
@@ -160,6 +182,7 @@ func (r *ResultRepository) Update(ctx context.Context, result *domain.Result) er
 	}
 
 	if r.cacheEnabled {
+		r.invalidateLeaderboardCache(ctx, result.CompetitionID)
 		r.redisClient.Del(ctx, r.cacheKey(result.ID.String())).Err()
 	}
 
@@ -312,6 +335,16 @@ func (r *ResultRepository) GetByCompetitionAndUser(ctx context.Context, competit
 }
 
 func (r *ResultRepository) GetLeaderboard(ctx context.Context, competitionID uuid.UUID, limit int, offset int) ([]domain.Result, int, error) {
+	if r.cacheEnabled {
+		key := r.leaderboardCacheKey(competitionID, limit, offset)
+		val, err := r.redisClient.Get(ctx, key).Result()
+		if err == nil {
+			var cached leaderboardCache
+			if json.Unmarshal([]byte(val), &cached) == nil {
+				return cached.Results, cached.TotalCount, nil
+			}
+		}
+	}
 	countQuery := `SELECT COUNT(*) FROM results WHERE competition_id = $1 AND status = $2`
 	var total int
 	if err := r.db.QueryRowContext(ctx, countQuery, competitionID, domain.ResultStatusCompleted).Scan(&total); err != nil {
@@ -359,6 +392,15 @@ func (r *ResultRepository) GetLeaderboard(ctx context.Context, competitionID uui
 		results = append(results, result)
 	}
 
+	if r.cacheEnabled {
+		key := r.leaderboardCacheKey(competitionID, limit, offset)
+		cacheData := leaderboardCache{Results: results, TotalCount: total}
+		data, err := json.Marshal(cacheData)
+		if err == nil {
+			r.redisClient.Set(ctx, key, data, 1*time.Minute).Err()
+		}
+	}
+
 	return results, total, nil
 }
 
@@ -382,7 +424,16 @@ func (r *ResultRepository) UpdateStatus(ctx context.Context, id uuid.UUID, statu
 		r.redisClient.Del(ctx, r.cacheKey(id.String())).Err()
 	}
 
-	return r.Get(ctx, id)
+	result, err := r.Get(ctx, id)
+	if err != nil {
+		return nil, err
+	}
+
+	if r.cacheEnabled {
+		r.invalidateLeaderboardCache(ctx, result.CompetitionID)
+	}
+
+	return result, nil
 }
 
 func (r *ResultRepository) RecalculateRanks(ctx context.Context, competitionID uuid.UUID) error {
@@ -425,5 +476,14 @@ func (r *ResultRepository) RecalculateRanks(ctx context.Context, competitionID u
 		}
 	}
 
-	return tx.Commit()
+	err = tx.Commit()
+	if err != nil {
+		return err
+	}
+
+	if r.cacheEnabled {
+		r.invalidateLeaderboardCache(ctx, competitionID)
+	}
+
+	return nil
 }