# Copyright (c) 2018, Frappe Technologies Pvt. Ltd. and contributors
# For license information, please see license.txt


import frappe
from dateutil import relativedelta
from frappe import _
from frappe.model.document import Document
from frappe.utils import date_diff, flt, get_first_day, get_last_day, getdate

from erpnext.utilities.product import get_price


class SubscriptionPlan(Document):
	def validate(self):
		self.validate_interval_count()

	def validate_interval_count(self):
		if self.billing_interval_count < 1:
			frappe.throw(_("Billing Interval Count cannot be less than 1"))


@frappe.whitelist()
def get_plan_rate(
	plan, quantity=1, customer=None, start_date=None, end_date=None, prorate_factor=1
):
	plan = frappe.get_doc("Subscription Plan", plan)
	if plan.price_determination == "Fixed Rate":
		return plan.cost * prorate_factor

	elif plan.price_determination == "Based On Price List":
		if customer:
			customer_group = frappe.db.get_value("Customer", customer, "customer_group")
		else:
			customer_group = None

		price = get_price(
			item_code=plan.item,
			price_list=plan.price_list,
			customer_group=customer_group,
			company=None,
			qty=quantity,
		)
		if not price:
			return 0
		else:
			return price.price_list_rate * prorate_factor

	elif plan.price_determination == "Monthly Rate":
		start_date = getdate(start_date)
		end_date = getdate(end_date)

		no_of_months = relativedelta.relativedelta(end_date, start_date).months + 1
		cost = plan.cost * no_of_months

		# Adjust cost if start or end date is not month start or end
		prorate = frappe.db.get_single_value("Subscription Settings", "prorate")

		if prorate:
			prorate_factor = flt(
				date_diff(start_date, get_first_day(start_date))
				/ date_diff(get_last_day(start_date), get_first_day(start_date)),
				1,
			)

			prorate_factor += flt(
				date_diff(get_last_day(end_date), end_date)
				/ date_diff(get_last_day(end_date), get_first_day(end_date)),
				1,
			)

			cost -= plan.cost * prorate_factor

		return cost