quoting automation

pricing.pysimplified rewrite

from __future__ import annotations

from dataclasses import dataclass, field
from decimal import Decimal as D, ROUND_HALF_UP
from enum import Enum

Kind = Enum("Kind", "DISPLAY PLAYER MOUNT INSTALL LICENCE SUPPORT")

HARDWARE = {Kind.DISPLAY, Kind.PLAYER, Kind.MOUNT}
BUNDLE = {Kind.DISPLAY, Kind.PLAYER, Kind.INSTALL, Kind.LICENCE}
VOLUME_FROM, VOLUME_RATE = 10, D("0.05")
BUNDLE_RATE = D("0.08")
DISCOUNT_LIMIT = D("0.10")
MARGIN_FLOOR = D("0.20")
# volume + bundle stack to 13%, so big bundles always need approval


def price(lines: dict[str, int], book: dict[str, Item], months: int) -> Quote:
    unknown = sorted(set(lines) - set(book))
    if unknown:
        raise ValueError(f"not in the price list: {', '.join(unknown)}")
    if months <= 0 or any(qty <= 0 for qty in lines.values()):
        raise ValueError("quantities and term must be positive")
    items = [(book[sku], qty) for sku, qty in lines.items()]

    one_off = sum(i.price * q for i, q in items if not i.recurring)
    hardware = sum(i.price * q for i, q in items if i.kind in HARDWARE)
    monthly = sum(i.price * q for i, q in items if i.recurring)
    cost = sum(i.cost * q * (months if i.recurring else 1) for i, q in items)

    discounts = {}
    if sum(q for i, q in items if i.kind is Kind.DISPLAY) >= VOLUME_FROM:
        discounts["volume"] = cents(hardware * VOLUME_RATE)
    if BUNDLE <= {i.kind for i, _ in items}:
        discounts["bundle"] = cents(hardware * BUNDLE_RATE)
    off = sum(discounts.values())

    one_time = one_off - off
    contract = one_time + monthly * months
    quote = Quote(cents(one_time), cents(monthly), cents(contract), discounts)

    # approval itself happens in HubSpot
    if hardware and off / hardware > DISCOUNT_LIMIT:
        quote.approvals.append(Approval("discount", off / hardware, DISCOUNT_LIMIT))
    margin = (contract - cost) / contract if contract else D(0)
    if margin < MARGIN_FLOOR:
        quote.approvals.append(Approval("margin", margin, MARGIN_FLOOR))
    return quote


@dataclass(frozen=True)
class Item:
    sku: str
    kind: Kind
    price: D  # per screen per month if recurring
    cost: D
    recurring: bool = False


@dataclass(frozen=True)
class Approval:
    rule: str
    actual: D
    limit: D


@dataclass
class Quote:
    one_time: D
    monthly: D
    contract_value: D
    discounts: dict[str, D]
    approvals: list[Approval] = field(default_factory=list)


def cents(x) -> D:
    return D(x).quantize(D("0.01"), ROUND_HALF_UP)