library/library_app/models/library_book.py

from odoo import api,fields,models
from odoo.exceptions import Warning
from odoo.exceptions import ValidationError


class Book(models.Model):

    @api.depends('publisher_id.country_id')
    def _compute_publisher_country(self):
        for book in self:
            book.publisher_country_id = book.publisher_id.country_id

    def _inverse_publisher_country(self):
        for book in self:
            book.publisher_id.country_id = book.publisher_country_id

    def _search_publisher_country(self, operator, value):
        return [('publisher_id.country_id', operator, value)]

    @api.constrains('isbn')
    def _constrain_isbn_valid(self):
        for book in self:
            if book.isbn and not book._check_isbn():
                raise ValidationError('%s is an invalid ISBN' % book.isbn)

    _name = 'library.book'
    _description = 'Book'
    _sql_constraints = [
        ('library_book_name_date_uq','UNIQUE (name, date_published)', 'Book title and publication date must be unique'),
        ('library_book_check_date','CHECK (date_published <= current_date)', 'Publication date must not be in the future.')
    ]

    name = fields.Char('Title', required=True)
    isbn = fields.Char('ISBN')
    book_type = fields.Selection([
        ('paper', 'Paperback'),
        ('hard', 'Hardcover'),
        ('electronic', 'Electronic'),
        ('other', 'Other')
    ],'Type')
    notes = fields.Text()
    descr = fields.Html('Description')

    # Numeric fields:
    copies = fields.Integer(default=1)
    avg_rating = fields.Float('Average Rating', (3,2))
    price = fields.Monetary('Price', 'currency_id')
    currency_id = fields.Many2one('res.currency')

    # Date and time fields:
    date_published = fields.Date()
    last_borrow_date = fields.Datetime(
        'Last Borrowed On',
        default = lambda self: fields.Datetime.now()
    )

    # Other fields:
    active = fields.Boolean('Active?', default=True)
    image = fields.Binary('Cover')

    # Relational fields:
    publisher_id = fields.Many2one('res.partner', string='Publisher')
    author_ids = fields.Many2many('res.partner', string='Authors')

    # Compute fields:
    publisher_country_id = fields.Many2one(
        'res.country',
        string='Publisher Country',
        compute='_compute_publisher_country',
        inverse='_inverse_publisher_country',
        search='_search_publisher_country'
    )

    def _check_isbn(self):
        self.ensure_one()
        isbn=self.isbn.replace('-','')
        digits=[int(x) for x in isbn if x.isdigit()]
        if len(digits) == 13:
            ponderations = [1 , 3] * 6
            terms = [a * b for a,b in zip(digits[:13], ponderations)]
            remain = sum(terms) % 10
            check = 10 - remain if remain != 0 else 0
            return digits[-1] == check

    def button_check_isbn(self):
        for book in self:
            if not book.isbn:
                raise Warning('Please provide an ISBN for %s' % book.name)
            if book.isbn and not book._check_isbn():
                raise Warning('%s is an invalid ISBN' % book.isbn)
            return True