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

class PosOrder(models.Model):
    _inherit = 'pos.order'

    payer_id = fields.Many2one('hr.employee', string='Cashier', help='Employee who processed the payment')
    
    # Existing Odoo/POS fields renamed for clarity
    user_id = fields.Many2one('res.users', string='Session User', help='Odoo user who opened the session')
    employee_id = fields.Many2one('hr.employee', string='Order Taker', help='Employee who uses the cash register')

    def _refund(self):
        for order in self:
            if order.state == 'cancel':
                raise UserError(_("You cannot refund a cancelled order."))
        return super()._refund()