library/library_app/models/library_book.py

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

class Book(models.Model):
    _name = 'library.book'
    _description = 'Book'
    # String fields
    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('Internal Notes')
    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') # price helper

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

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


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

    # Relational Fields

    publisher_country_id = fields.Many2one(
        'res.country', string='Publisher Country',
        compute='_compute_publisher_country'
    )

    @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 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