fix: adjust BOM cost calculation SQL and refactor for consistency

Co-authored-by: aider (openai/DeepSeek-V3.2-Thinking) <aider@aider.chat>

inventory-backend/app/services/inbound/semi_service.py

@@ -458,45 +458,47 @@ class SemiInboundService:
     @staticmethod
     def calculate_bom_cost(bom_no, bom_version):
         """
-        【防崩修正版】查询物理字段：采购的税前价 / 半成品和成品的 manual_cost(映射后的单件成本)
+        根据 BOM 编号和版本计算原材料总成本
+        遍历 BOM 子件，使用原生 SQL 查物理表 bom_table，取每个子件在采购、半成品、成品三个表中的最高单价，乘以用量后累加
         """
-        from app.models.bom import bom_table  # 假设这可能是 SQLAlchemy 表对象或类
         from app.models.inbound.buy import StockBuy
         from app.models.inbound.semi import StockSemi
         from app.models.inbound.product import StockProduct
-        from sqlalchemy import func
-
+        from sqlalchemy import func, text
         try:
-            # 兼容你的表名
-            bom_lines = db.session.execute(
-                text("SELECT child_id, dosage FROM bom_table WHERE bom_no = :bom_no AND version = :version"),
-                {'bom_no': bom_no, 'version': bom_version}
-            ).fetchall()
-
+            # 使用原生 SQL 精准查询 bom_table，避免模型映射错误
+            sql = text("""
+                SELECT child_id, dosage 
+                FROM bom_table 
+                WHERE bom_no = :bom_no AND version = :version
+            """)
+            bom_lines = db.session.execute(sql, {'bom_no': bom_no, 'version': bom_version}).fetchall()
+            
             total_cost = 0.0
             for line in bom_lines:
-                component_base_id = line[0]
-                usage_qty = float(line[1] or 1.0)
-
-                # 查采购表最高价
+                component_base_id = line[0]  # child_id
+                usage_qty = float(line[1] or 1.0)  # dosage
+                
+                # 1. 查采购表最高价 (不含税)
                 buy_price = db.session.query(func.max(StockBuy.pre_tax_unit_price)).filter(
                     StockBuy.base_id == component_base_id
                 ).scalar() or 0.0
-
-                # 查半成品表最高价 (直接查 manual_cost，因为它存的就是单件成本)
+                
+                # 2. 查半成品表最高价 (单件成本映射存在 manual_cost 里了)
                 semi_price = db.session.query(func.max(StockSemi.manual_cost)).filter(
                     StockSemi.base_id == component_base_id
                 ).scalar() or 0.0
-
-                # 查成品表最高价
+                
+                # 3. 查成品表最高价 (同样存储在 manual_cost 字段里)
                 product_price = db.session.query(func.max(StockProduct.manual_cost)).filter(
                     StockProduct.base_id == component_base_id
                 ).scalar() or 0.0
-
-                max_price = max(buy_price, semi_price, product_price)
+                
+                # 4. 取三个表中的最大值，乘以用量 (dosage)
+                max_price = max(float(buy_price), float(semi_price), float(product_price))
                 total_cost += max_price * usage_qty
-
+                
             return round(total_cost, 2)
         except Exception as e:
             traceback.print_exc()
-            raise e
+            raise e