라벨 자동할당 로직 임시 커밋

src/main/java/com/kamco/cd/kamcoback/label/service/LabelAllocateService.java

@@ -0,0 +1,90 @@
+package com.kamco.cd.kamcoback.label.service;
+
+import com.kamco.cd.kamcoback.label.dto.LabelAllocateDto.Sheet;
+import com.kamco.cd.kamcoback.label.dto.LabelAllocateDto.TargetUser;
+import java.util.Comparator;
+import java.util.Iterator;
+import java.util.List;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Service;
+
+@Slf4j
+@Service
+public class LabelAllocateService {
+
+  public static void allocate(List<Sheet> sheets, List<TargetUser> targetUsers) {
+
+    // 1️⃣ 실제 도엽 기준 할당
+    allocateSheets(sheets, targetUsers);
+
+    // 2️⃣ 전체 부족분 비율 계산
+    distributeShortage(targetUsers);    //항상 마지막에 한 번만 호출해야함
+
+  }
+
+  public static void allocateSheets(
+    List<Sheet> sheets,
+    List<TargetUser> targets
+  ) {
+    // 도엽 큰 것부터 (선택 사항)
+    sheets.sort(Comparator.comparingInt(Sheet::getCount).reversed());
+
+    for (TargetUser target : targets) {
+      Iterator<Sheet> it = sheets.iterator();
+
+      while (it.hasNext() && target.getRemainDemand() > 0) {
+        Sheet sheet = it.next();
+
+        int assignable = Math.min(
+          sheet.getCount(),
+          target.getRemainDemand()
+        );
+
+        if (assignable > 0) {
+          target.assign(sheet.getSheetId(), assignable);
+          sheet.decrease(assignable);
+        }
+
+        if (sheet.getCount() == 0) {
+          it.remove();
+        }
+      }
+    }
+  }
+
+  public static void distributeShortage(List<TargetUser> targets) {
+
+    int totalDemand = targets.stream()
+      .mapToInt(TargetUser::getDemand)
+      .sum();
+
+    int totalAllocated = targets.stream()
+      .mapToInt(t -> t.getAllocated())
+      .sum();
+
+    int shortage = totalDemand - totalAllocated;
+
+    if (shortage <= 0) {
+      return;
+    }
+
+    int distributed = 0;
+
+    for (int i = 0; i < targets.size(); i++) {
+      TargetUser t = targets.get(i);
+
+      // 마지막 타겟이 나머지 가져가게 (반올림 오차 방지)
+      int share;
+      if (i == targets.size() - 1) {
+        share = shortage - distributed;
+      } else {
+        double ratio = (double) t.getDemand() / totalDemand;
+        share = (int) Math.round(shortage * ratio);
+        distributed += share;
+      }
+
+      t.setShortage(share);
+    }
+  }
+
+}