107 lines
3.5 KiB
Python
107 lines
3.5 KiB
Python
"""往来单位服务：开单取价 + 信用额度。
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取价优先级（quote_price）：
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1. 客户专属价 CustomerProductPrice
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2. 价格等级价 PriceLevel.discount_rate × 默认售价（rate>0 且 <1 时生效）
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3. 最近成交价（该客户+商品最近一张已过账销售单行单价）
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4. 默认售价 Product.sale_price
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"""
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from __future__ import annotations
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from decimal import Decimal
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from .models import Customer, CustomerProductPrice, PriceLevel
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def quote_price(*, tenant, customer: Customer, product) -> dict:
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"""返回 {price, source, last_price, min_price, max_price}。
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price 为基本单位价；last/min/max 为该客户历史成交参考（基本单位口径）。
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"""
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# 1. 客户专属价
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cpp = CustomerProductPrice.objects.filter(
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tenant=tenant, customer=customer, product=product
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).first()
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if cpp is not None:
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price, source = cpp.price, "customer"
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else:
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# 2. 价格等级价
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level: PriceLevel | None = customer.price_level
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rate = level.discount_rate if level else Decimal("0")
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if rate and Decimal("0") < rate < Decimal("1"):
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price, source = product.sale_price * rate, "level"
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else:
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# 3. 最近成交价
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last = _history(tenant, customer, product).first()
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if last is not None:
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price, source = last.unit_price, "last"
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else:
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price, source = product.sale_price, "default"
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hist = list(_history(tenant, customer, product).values_list(
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"unit_price", flat=True
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)[:50])
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return {
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"price": price,
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"source": source,
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"last_price": hist[0] if hist else None,
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"min_price": min(hist) if hist else None,
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"max_price": max(hist) if hist else None,
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}
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def _history(tenant, customer: Customer, product):
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"""该客户+商品的已过账销售行（新→旧）。"""
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from apps.sales.models import SalesBillLine
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return (
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SalesBillLine.objects.filter(
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tenant=tenant,
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bill__customer=customer,
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bill__state="confirmed",
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product=product,
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)
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.order_by("-bill_id", "-id")
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)
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def credit_usage(*, tenant, customer: Customer) -> dict:
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"""客户信用额度占用：{limit, outstanding, available}。
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limit=0 表示未启用管控；available = limit - outstanding（未启用时为 None）。
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"""
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from django.db.models import Sum
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from apps.finance.models import Receivable
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agg = Receivable.objects.filter(
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tenant=tenant,
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customer=customer,
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status__in=["open", "partial"],
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is_deleted=False,
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).aggregate(total=Sum("total_amount"), paid=Sum("paid_amount"))
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outstanding = ((agg["total"] or Decimal("0")) - (agg["paid"] or Decimal("0"))).quantize(
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Decimal("0.0001")
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)
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limit = customer.credit_limit or Decimal("0")
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return {
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"limit": limit,
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"outstanding": outstanding,
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"available": (limit - outstanding) if limit > 0 else None,
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}
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def check_credit(*, tenant, customer: Customer, extra_amount: Decimal) -> dict:
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"""下单/过账前检查额度。返回 usage；超限抛 CreditLimitExceeded。"""
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from apps.sales.services import CreditLimitExceeded
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usage = credit_usage(tenant=tenant, customer=customer)
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if usage["limit"] <= 0:
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return usage
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if usage["outstanding"] + extra_amount > usage["limit"]:
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raise CreditLimitExceeded(
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customer.code, usage["outstanding"], usage["limit"], extra_amount
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)
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return usage
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