contract/contract_variable_qty_prorated/models/contract_line.py

# Copyright 2018 ACSONE SA/NV
# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).

from odoo import api, models


class ContractLine(models.Model):
    _inherit = "contract.line"

    @api.model
    def _compute_prorated(
        self, real_next_date, real_last_date, therical_next_date,
            therical_last_date):
        def _invoiced_days(next_date, last_date):
            return (next_date - last_date).days + 1

        return _invoiced_days(real_next_date, real_last_date) / _invoiced_days(
            therical_next_date, therical_last_date
        )

    @api.multi
    def compute_prorated(self, period_first_date, period_last_date,
                         invoice_date):
        self.ensure_one()
        relative_delta = self.get_relative_delta(
            self.recurring_rule_type, self.recurring_interval
        )
        theoretical_next_date = invoice_date
        if self.recurring_rule_type == "monthlylastday":
            relative_delta = self.get_relative_delta("monthly",
                                                     self.recurring_interval)
            theoretical_next_date += self.get_relative_delta("daily", 1)
        if (
            self.recurring_invoicing_type == "pre-paid"
            and self.recurring_rule_type != "monthlylastday"
        ):
            theoretical_next_date += relative_delta
        theoretical_last_date = theoretical_next_date - relative_delta
        theoretical_next_date -= self.get_relative_delta("daily", 1)
        real_last_date = period_first_date
        real_next_date = period_last_date
        return self._compute_prorated(
            real_next_date, real_last_date, theoretical_next_date,
            theoretical_last_date
        )