feat: RankingFacade 클래스 추가 및 랭킹 조회 기능 구현

Author: rnqhstmd

apps/commerce-api/src/main/java/com/loopers/application/ranking/RankingFacade.java

@@ -0,0 +1,134 @@
+package com.loopers.application.ranking;
+
+import com.loopers.domain.product.Product;
+import com.loopers.domain.product.ProductRepository;
+import com.loopers.domain.ranking.RankingEntry;
+import com.loopers.domain.ranking.RankingInfo;
+import com.loopers.domain.ranking.RankingService;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Component;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.time.Clock;
+import java.time.LocalDate;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+@Slf4j
+@Component
+@RequiredArgsConstructor
+public class RankingFacade {
+
+    private final RankingService rankingService;
+    private final ProductRepository productRepository;
+    private final Clock clock;
+
+    /**
+     * 랭킹 페이지 조회
+     */
+    @Transactional(readOnly = true)
+    public RankingPageInfo getRankingPage(RankingCommand command) {
+        List<RankingEntry> entries = rankingService.getRankingPage(
+                command.date(),
+                command.page(),
+                command.size()
+        );
+
+        if (entries.isEmpty()) {
+            return RankingPageInfo.empty(command.date(), command.page(), command.size());
+        }
+
+        // 상품 정보 조회
+        List<Long> productIds = entries.stream()
+                .map(RankingEntry::productId)
+                .collect(Collectors.toList());
+
+        Map<Long, Product> productMap = productRepository.findAllByIds(productIds).stream()
+                .collect(Collectors.toMap(Product::getId, p -> p));
+
+        // 랭킹 정보 조합
+        List<RankingInfo> rankings = new ArrayList<>();
+        long startRank = (long) command.page() * command.size() + 1;
+
+        for (int i = 0; i < entries.size(); i++) {
+            RankingEntry entry = entries.get(i);
+            Product product = productMap.get(entry.productId());
+
+            if (product != null) {
+                rankings.add(RankingInfo.of(
+                        product.getId(),
+                        product.getName(),
+                        product.getPriceValue(),
+                        product.getBrand().getName(),
+                        startRank + i,
+                        entry.score()
+                ));
+            }
+        }
+
+        Long totalCount = rankingService.getRankingSize(command.date());
+
+        return RankingPageInfo.of(
+                rankings,
+                command.date(),
+                command.page(),
+                command.size(),
+                totalCount
+        );
+    }
+
+    /**
+     * Top-N 랭킹 조회
+     */
+    @Transactional(readOnly = true)
+    public List<RankingInfo> getTopN(LocalDate date, int n) {
+        List<RankingEntry> entries = rankingService.getTopNWithScores(date, n);
+
+        if (entries.isEmpty()) {
+            return List.of();
+        }
+
+        List<Long> productIds = entries.stream()
+                .map(RankingEntry::productId)
+                .collect(Collectors.toList());
+
+        Map<Long, Product> productMap = productRepository.findAllByIds(productIds).stream()
+                .collect(Collectors.toMap(Product::getId, p -> p));
+
+        List<RankingInfo> rankings = new ArrayList<>();
+        for (int i = 0; i < entries.size(); i++) {
+            RankingEntry entry = entries.get(i);
+            Product product = productMap.get(entry.productId());
+
+            if (product != null) {
+                rankings.add(RankingInfo.of(
+                        product.getId(),
+                        product.getName(),
+                        product.getPriceValue(),
+                        product.getBrand().getName(),
+                        (long) (i + 1),
+                        entry.score()
+                ));
+            }
+        }
+
+        return rankings;
+    }
+
+    /**
+     * 특정 상품의 순위 조회
+     */
+    public Long getProductRank(Long productId, LocalDate date) {
+        return rankingService.getRank(productId, date);
+    }
+
+    /**
+     * 특정 상품의 순위 조회 (오늘 기준)
+     */
+    public Long getProductRankToday(Long productId) {
+        return rankingService.getRank(productId, LocalDate.now(clock));
+    }
+}