# -*- coding: utf-8 -*-
###############################################################################
#
#    Cybrosys Technologies Pvt. Ltd.
#
#    Copyright (C) 2023-TODAY Cybrosys Technologies(<https://www.cybrosys.com>)
#    Author: Cybrosys Techno Solutions (odoo@cybrosys.com)
#
#    You can modify it under the terms of the GNU AFFERO
#    GENERAL PUBLIC LICENSE (AGPL v3), Version 3.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU AFFERO GENERAL PUBLIC LICENSE (AGPL v3) for more details.
#
#    You should have received a copy of the GNU AFFERO GENERAL PUBLIC LICENSE
#    (AGPL v3) along with this program.
#    If not, see <http://www.gnu.org/licenses/>.
#
###############################################################################
import math
from odoo import api, models


class ProductProduct(models.Model):
    """Inherit product_product model for adding EAN13 Standard Barcode"""
    _inherit = 'product.product'

    @api.model
    def create(self, vals):
        """Function to add EAN13 Standard barcode at the time
        create new product"""
        res = super(ProductProduct, self).create(vals)
        ean = generate_ean(str(res.id))
        res.barcode = '21' + ean[2:]
        return res


def ean_checksum(eancode):
    """Returns the checksum of an ean string of length 13, returns -1 if
    the string has the wrong length"""
    if len(eancode) != 13:
        return -1
    odd_sum = 0
    even_sum = 0
    for rec in range(len(eancode[::-1][1:])):
        if rec % 2 == 0:
            odd_sum += int(eancode[::-1][1:][rec])
        else:
            even_sum += int(eancode[::-1][1:][rec])
    total = (odd_sum * 3) + even_sum
    return int(10 - math.ceil(total % 10.0)) % 10


def check_ean(eancode):
    """Returns True if ean code is a valid ean13 string, or null"""
    if not eancode:
        return True
    if len(eancode) != 13:
        return False
    try:
        int(eancode)
    except:
        return False
    return ean_checksum(eancode)


def generate_ean(ean):
    """Creates and returns a valid ean13 from an invalid one"""
    if not ean:
        return "0000000000000"
    product_identifier = '00000000000' + ean
    ean = product_identifier[-11:]
    check_number = check_ean(ean + '00')
    return f'{ean}0{check_number}'