仓储单位成本与费效比KPI — FBA/自营仓单件成本分解与效率提升量化

"""
仓储单位成本与费效比 KPI 体系
功能：FBA vs 自营仓成本对比 / 单件成本分解 / 仓储成本率 / 临界点分析
输入：仓储费用账单数据 + 出入库记录
输出：仓储成本KPI + FBA vs 自营仓对比 + 降本建议
"""
import numpy as np
import pandas as pd
import warnings
warnings.filterwarnings('ignore')


def compute_fba_cost_per_unit(
    monthly_units: int,
    avg_cubic_feet: float = 0.5,
    avg_weight_lbs: float = 2.0,
    avg_months_in_fba: float = 1.5,
    is_q4: bool = False,
):
    """计算FBA单件全成本"""
    # 仓储费
    storage_rate = 2.40 if is_q4 else 0.75
    monthly_storage_per_unit = avg_cubic_feet * storage_rate * avg_months_in_fba / monthly_units * monthly_units
    storage_cost_per_unit = avg_cubic_feet * storage_rate * avg_months_in_fba
    
    # 履约费（按件重量估算）
    if avg_weight_lbs <= 1:
        fulfillment_fee = 3.22
    elif avg_weight_lbs <= 2:
        fulfillment_fee = 3.86
    elif avg_weight_lbs <= 3:
        fulfillment_fee = 4.45
    elif avg_weight_lbs <= 5:
        fulfillment_fee = 5.28
    else:
        fulfillment_fee = 6.10
    
    total_fba = storage_cost_per_unit + fulfillment_fee
    return {
        'storage_cost': round(storage_cost_per_unit, 3),
        'fulfillment_fee': round(fulfillment_fee, 3),
        'total_fba_cpu': round(total_fba, 3),
    }


def compute_self_warehouse_cost(
    monthly_rent: float,
    monthly_labor: float,
    monthly_materials: float,
    monthly_units_handled: int,
    monthly_orders: int,
):
    """计算自营仓单件成本"""
    total_monthly = monthly_rent + monthly_labor + monthly_materials
    cost_per_unit = total_monthly / max(1, monthly_units_handled)
    cost_per_order = total_monthly / max(1, monthly_orders)
    cost_rate = total_monthly / (monthly_units_handled * 150) * 100  # 假设均价150元
    
    return {
        'cost_per_unit': round(cost_per_unit, 2),