修正

backend/app/payroll/bonus/service.py

@@ -11,20 +11,22 @@ class BonusCalculationService:
     """賞与計算サービス"""
     
     @staticmethod
-    def get_insurance_rate(rate_type: str, target_date: date) -> Dict[str, Any]:
-        """保険料率を取得"""
+    def get_insurance_rate(rate_type: str, target_date: date, calculation_target: str = '賞与') -> Dict[str, Any]:
+        """保険料率を取得（賞与用）"""
         with get_connection() as conn:
             with conn.cursor() as cur:
+                # rate_yearで年度を判定
+                target_year = target_date.year
                 cur.execute(
                     """
                     SELECT * FROM insurance_rates 
                     WHERE rate_type = %s
-                    AND valid_from <= %s
-                    AND (valid_to IS NULL OR valid_to >= %s)
-                    ORDER BY valid_from DESC
+                    AND rate_year = %s
+                    AND calculation_target = %s
+                    ORDER BY rate_id DESC
                     LIMIT 1
                     """,
-                    (rate_type, target_date, target_date)
+                    (rate_type, target_year, calculation_target)
                 )
                 return cur.fetchone()
     
@@ -134,10 +136,15 @@ class BonusCalculationService:
                 )
                 employee_info = cur.fetchone()
         
-        # 年齢を計算
+        # 年齢を計算（介護保険は40歳以上65歳未満が対象）
         age = 0
         if employee_info and employee_info["birth_date"]:
-            age = (payment_date - employee_info["birth_date"]).days // 365
+            birth_date = employee_info["birth_date"]
+            # より正確な年齢計算
+            age = payment_date.year - birth_date.year
+            # 誕生日がまだ来ていない場合は-1
+            if (payment_date.month, payment_date.day) < (birth_date.month, birth_date.day):
+                age -= 1
         
         # 健康保険（賞与額の1/1000で計算）
         health_insurance_rate = BonusCalculationService.get_insurance_rate("健康保険", payment_date)