# Part of Odoo. See LICENSE file for full copyright and licensing details.

from odoo import api, fields, models


class ResPartner(models.Model):
    _inherit = 'res.partner'

    membership_level_id = fields.Many2one(
        'loyalty.program',
        string='Membership Level',
        help='Specific multi-level membership assigned to this customer.'
    )

    @api.model
    def _load_pos_data_fields(self, config_id):
        fields_list = super()._load_pos_data_fields(config_id)
        # Add custom field for customer membership level
        fields_list.append('membership_level_id')
        return fields_list

    def write(self, vals):
        """
        When a partner's membership level changes, delete their loyalty cards
        from the OLD level's program so they don't accumulate cards across levels.
        """
        if 'membership_level_id' in vals:
            new_level_id = vals['membership_level_id']
            for partner in self:
                old_level_id = partner.membership_level_id.id if partner.membership_level_id else False
                # Only act when the level is actually changing to a different value
                if old_level_id and old_level_id != new_level_id:
                    old_cards = self.env['loyalty.card'].search([
                        ('partner_id', '=', partner.id),
                        ('program_id', '=', old_level_id),
                    ])
                    if old_cards:
                        # Archive instead of delete — loyalty cards may be referenced
                        # by pos_order_line.coupon_id (FK), so unlink() would fail.
                        old_cards.write({'active': False})
        return super().write(vals)