"""正式核算与试算共用计提规则；比例保持 Fraction，产品覆盖存于参数版本。"""

from fractions import Fraction

from app.services import formula

PERSONAL_FIELDS = ("first", "start", "slope", "floor", "boundary")
BASE_CODES = {
    "first": "salesperson.rate.start",
    "start": "salesperson.rate.start",
    "slope": "salesperson.rate.slope",
    "floor": "salesperson.rate.floor",
    "boundary": "salesperson.days.boundary",
}


def personal_values(snapshot, category):
    """未维护产品专属项时，继续使用同日期的通用参数，不复制初始值。"""
    result = {}
    for field in PERSONAL_FIELDS:
        code = f"coefficient.personal.{field}"
        overrides = snapshot._values.get(code, {})
        result[field] = overrides.get(
            category, overrides.get("", snapshot.get(BASE_CODES[field], role_code="salesperson"))
        )
    return result


def decide(params, *, category, customer_type, role_code, days, prepayment=False):
    """返回纯比例和计算基数类型。经理个人户排除优先于预收／企业户。"""
    if role_code == "sales_manager" or customer_type == "manager_personal":
        return Fraction(0), "converted", "经理本人／经理个人户不单笔计提"
    if role_code == "info_officer":
        return Fraction(str(params.get("info", "1"))) / 1000, "sales", "信息员按销售额计提"
    if prepayment:
        personal = params.get("personal", {}).get(category, params)
        maximum = max(
            Fraction(str(personal.get(key, personal["start"])))
            for key in ("first", "start", "floor")
        )
        return maximum / 1000, "converted", "预收发货后按最高比例计提"
    if customer_type == "enterprise":
        value = params.get("enterprise_by_category", {}).get(category, params["enterprise"])
        return Fraction(str(value)) / 1000, "converted", "企业户按产品分类固定计提"
    values = params.get("personal", {}).get(category, params)
    if days <= 1:
        rate = Fraction(str(values.get("first", values["start"]))) / 1000
    else:
        rate = formula.salesperson_rate(
            days,
            start=Fraction(str(values["start"])),
            slope=Fraction(str(values["slope"])),
            floor=Fraction(str(values["floor"])),
            boundary_days=int(Fraction(str(values.get("boundary", 360)))),
        )
    return rate, "converted", "个人户按产品分类及回款阶段计提"