# -*- coding: utf-8 -*-
from openerp import models, fields, api
import math


class AccountVoucher(models.Model):
    _inherit = 'account.voucher'

    comision = fields.Integer(
        string='Comisión',
        compute='_compute_comision',
        store=True
    )

    @api.depends('amount', 'state')
    def _compute_comision(self):

        param = self.env['ir.config_parameter'].get_param(
            'voucher_comision.porcentaje', '2'
        )

        porcentaje = float(param)

        for rec in self:
            if rec.state == 'posted' and rec.amount:

                valor = rec.amount * porcentaje / 100

                # ✔ redondeo sin decimal estable
                rec.comision = int(valor + 0.5)

            else:
                rec.comision = 0