credit_cash_check/models/purchase_order.py

# -*- encoding: utf-8 -*-
from openerp import models, fields, api, _
from openerp.exceptions import Warning
from pytz import timezone
from openerp.tools import DEFAULT_SERVER_DATETIME_FORMAT, DEFAULT_SERVER_DATE_FORMAT
from datetime import datetime,timedelta

DATE_FORMAT = '%Y-%m-%d'

class purchase_order(models.Model):
    _inherit = 'purchase.order'

    contado = fields.Boolean('Contado')
    credito = fields.Boolean('Crédito')

    @api.one
    @api.onchange('credito')
    def cambiar_estado_credito(self):
        self.contado = not self.credito

    @api.one
    @api.onchange('contado')
    def cambiar_estado_contado(self):
        self.credito = not self.contado
        if self.contado == True:
            self.payment_term = False

    def _convert_str_to_datetime(self, date):
        return datetime.strptime(date,DEFAULT_SERVER_DATETIME_FORMAT)

    @api.model
    def action_invoice_create(self):
        for purchase in self:
            inv_id = super(purchase_order, self).action_invoice_create()
            if inv_id:
                inv = self.env['account.invoice'].browse(inv_id)
                date = self._convert_str_to_datetime(purchase.date_order)
                date = date.strftime(DATE_FORMAT)
                inv.write({
                    'date_invoice':date,
                    'contado':self.contado,
                    'credito':self.credito
                })
                self.update_state()

    @api.multi
    def update_state(self):
        for order in self:
            order.write({'state': 'done'})
        return True