# 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, transfer points, history,
        and archive their loyalty cards from the OLD level's program.
        """
        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'].sudo().search([
                        ('partner_id', '=', partner.id),
                        ('program_id', '=', old_level_id),
                        ('active', '=', True),
                    ])
                    if old_cards and new_level_id:
                        new_card = self.env['loyalty.card'].sudo().search([
                            ('partner_id', '=', partner.id),
                            ('program_id', '=', new_level_id),
                        ], limit=1)

                        if not new_card:
                            new_card = self.env['loyalty.card'].sudo().create({
                                'partner_id': partner.id,
                                'program_id': new_level_id,
                                'points': 0,
                            })

                        # 1. Transfer points
                        for old_card in old_cards:
                            pts = old_card.points
                            if abs(pts) > 0.0001:
                                new_card.points += pts
                                old_card.points = 0.0

                        # 2. Transfer loyalty history (point transactions)
                        old_histories = self.env['loyalty.history'].sudo().search([
                            ('card_id', 'in', old_cards.ids)
                        ])
                        if old_histories:
                            old_histories.write({'card_id': new_card.id})

                        # 3. Transfer POS order line references
                        old_pos_lines = self.env['pos.order.line'].sudo().search([
                            ('coupon_id', 'in', old_cards.ids)
                        ])
                        if old_pos_lines:
                            old_pos_lines.write({'coupon_id': new_card.id})

                        # 4. Transfer Sales order line references
                        old_sale_lines = self.env['sale.order.line'].sudo().search([
                            ('coupon_id', 'in', old_cards.ids)
                        ])
                        if old_sale_lines:
                            old_sale_lines.write({'coupon_id': new_card.id})

                    # Archive old-level cards
                    if old_cards:
                        old_cards.write({'active': False, 'points': 0.0})
        return super().write(vals)