library/library_checkout/models/library_checkout.py

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


class Checkout(models.Model):
    _name = 'library.checkout'
    _description = 'Library Checkout'
    _inherit = ['mail.thread', 'mail.activity.mixin']

    @api.onchange('member_id')
    def onchange_member_id(self):
        today = fields.Date.today()
        if self.request_date != today:
            self.request_date = today
            return {
                'warning': {
                    'title': 'Changed Request Date',
                    'message': 'Request date changed to today'
                }
            }

    @api.model
    def create(self, vals):
        if 'stage_id' in vals:
            Stage = self.env['library.checkout.stage']
            new_state = Stage.browse(vals['stage_id']).state
            if new_state == 'open':
                vals['checkout_date'] = fields.Date.today()
        new_record = super().create(vals)

        if new_record.state == 'done':
            raise UserError(
                'Not allowed to create a checkout in the done state.'
            )
        return new_record

    def write(self, vals):
        if 'stage_id' in vals:
            Stage = self.env['library.checkout.stage']
            new_state = Stage.browse(vals['stage_id']).state
            if new_state == 'open' and self.state != 'open':
                vals['checkout_date'] = fields.Date.today()
            if new_state == 'done' and self.state != 'done':
                vals['closed_date'] = fields.Date.today()
        super().write(vals)
        return True

    def _compute_num_other_checkouts(self):
        for rec in self:
            domain = [
                ('member_id', '=', rec.member_id.id),
                ('state', '!=', ['open']),
                ('id', '!=', rec.id)
            ]
            rec.num_other_checkouts = self.search_count(domain)

    num_other_checkouts = fields.Integer(
        compute='_compute_num_other_checkouts'
    )

    def _compute_num_books(self):
        for rec in self:
            rec.num_books = len(self.line_ids)

    num_books = fields.Integer(
        compute='_compute_num_books'
    )

    member_id = fields.Many2one(
        'library.member',
        required=True
    )
    user_id = fields.Many2one(
        'res.users',
        'Librarian',
        default=lambda s: s.env.uid
    )
    request_date = fields.Date(
        default=lambda s: fields.Date.today()
    )
    line_ids = fields.One2many(
        'library.checkout.line',
        'checkout_id',
        string='Borrowed Books'
    )

    @api.model
    def _default_stage(self):
        Stage = self.env['library.checkout.stage']
        return Stage.search([], limit=1)

    @api.model
    def _group_expand_stage_id(self, stages, domain, order):
        return stages.search([], order=order)

    stage_id = fields.Many2one(
        'library.checkout.stage',
        default=_default_stage,
        group_expand='_group_expand_stage_id'
    )
    state = fields.Selection(related='stage_id.state')
    checkout_date = fields.Date(readonly=True)
    closed_date = fields.Date(readonly=True)

    priority = fields.Selection(
        [('0', 'Low'),
         ('1', 'Normal'),
         ('2', 'High')],
        'Priority',
        default = '1'
    )
    kanban_state = fields.Selection(
        [('normal', 'In Progress'),
         ('blocked', 'Blocked'),
         ('done', 'Ready for next stage')],
        'Kanban State',
        default='normal'
    )
    color = fields.Char('Color')


class CheckoutLine(models.Model):
    _name = 'library.checkout.line'
    _description = 'Borrow Request Line'
    checkout_id = fields.Many2one('library.checkout')
    book_id = fields.Many2one('library.book')