feat: CMA P1+P2 Round1 — 成本法对比+杜邦分析+本量利

backend/app/api/cost.py

@@ -202,6 +202,68 @@ def cost_breakdown(product_code: str = Query(...),
     return get_cost_breakdown(product_code, period)
 
 
+@router.get("/comparison")
+def cost_method_comparison(entity: str = Query("hanke")):
+    """三种成本法对比分析：传统/变动/作业成本法 (CMA P1)"""
+    if entity == "hanke":
+        gross_revenue = 713  # 万
+        channel_rebate_rate = 0.828
+        net_revenue = round(gross_revenue * (1 - channel_rebate_rate), 2)
+        weighted_cost_rate = 0.4862
+        book_cost = 717  # 万
+        total_expenses = 546  # 万
+        non_value_added = 26  # 万
+
+        traditional = {
+            "revenue": gross_revenue,
+            "cost": book_cost,
+            "gross_profit": round(gross_revenue - book_cost, 2),
+            "gross_margin": round((gross_revenue - book_cost) / gross_revenue * 100, 2),
+            "expenses": total_expenses,
+            "net_profit": round(gross_revenue - book_cost - total_expenses, 2),
+        }
+
+        var_cost = round(net_revenue * weighted_cost_rate, 2)
+        variable = {
+            "revenue": net_revenue,
+            "cost": var_cost,
+            "gross_profit": round(net_revenue - var_cost, 2),
+            "gross_margin": round((1 - weighted_cost_rate) * 100, 2),
+            "expenses": total_expenses,
+            "net_profit": round(net_revenue - var_cost - total_expenses, 2),
+        }
+
+        abc_cost = round(net_revenue * weighted_cost_rate, 2)
+        abc_exp = total_expenses - non_value_added
+        abc = {
+            "revenue": net_revenue,
+            "cost": abc_cost,
+            "gross_profit": round(net_revenue - abc_cost, 2),
+            "gross_margin": round((1 - weighted_cost_rate) * 100, 2),
+            "expenses": abc_exp,
+            "net_profit": round(net_revenue - abc_cost - abc_exp, 2),
+        }
+
+        return {
+            "entity": "hanke",
+            "entity_name": "陕西酣客（白酒经销）",
+            "traditional": traditional,
+            "variable": variable,
+            "abc": abc,
+            "insights": [
+                {"method": "传统成本法", "conclusion": "毛利率为负", "decision": "❌ 不赚钱，别卖了", "detail": "未剔除渠补，账面收入虚高"},
+                {"method": "变动成本法", "conclusion": "毛利率18.6%", "decision": "✅ 业务能赚钱→砍费用", "detail": "剔除渠补后净收入122万，成本率48.62%"},
+                {"method": "作业成本法", "conclusion": "识别非增值作业26万", "decision": "✅ 可再省", "detail": "剔除冗余招待费等非增值作业"},
+            ],
+            "notes": {
+                "net_revenue": "毛收入713万 × (1-渠补率82.8%) = 净收入122万",
+                "variable_cost": "净收入122万 × 加权成本率48.62% = 成本59.3万",
+                "abc_expenses": "总费用546万 - 非增值作业26万 = 520万",
+            },
+        }
+    return {"error": "不支持的实体"}
+
+
 @router.get("/dashboard")
 def cost_dashboard(period: Optional[str] = Query(None)):
     """成本分析首页—汇总数据"""