from odoo import models, api, Command


class HelpdeskTicket(models.Model):
    _inherit = "helpdesk.ticket"

    @api.onchange("task_id")
    def _onchange_task_id(self):
        for record in self:
            if record.timesheet_ids and record.task_id:
                not_yet_invoiced_timesheet_ids = [t.id for t in record.timesheet_ids if not t.timesheet_invoice_id]
                record.task_id.timesheet_ids = [Command.link(t_id) for t_id in not_yet_invoiced_timesheet_ids]