[FIX] website_sale: force recompute fiscal position

Fiscal position was setted by onchange before commit #55535a6
Now, we need to call the onchange_shipping_id to set the fiscal position.
In case where the owner of the sale order is the public user, instead to
use the fiscal position from public user, we try to guess it with the
geolocation.

addons/website_sale/models/sale_order.py

@@ -10,6 +10,7 @@ import odoo.addons.decimal_precision as dp
 
 _logger = logging.getLogger(__name__)
 
+
 class SaleOrder(models.Model):
     _inherit = "sale.order"
 
@@ -303,6 +304,20 @@ class Website(models.Model):
                 'partner_shipping_id': addr['delivery'],
                 'user_id': salesperson_id or self.salesperson_id.id,
             })
+
+            # set fiscal position
+            if request.website.partner_id.id != partner.id:
+                sale_order.onchange_partner_shipping_id()
+            else: # For public user, fiscal position based on geolocation
+                country_code = request.session['geoip'].get('country_code')
+                if country_code:
+                    country_id = request.env['res.country'].search([('code', '=', country_code)], limit=1).id
+                    fp_id = request.env['account.fiscal.position'].sudo()._get_fpos_by_region(country_id)
+                    sale_order.fiscal_position_id = fp_id
+                else:
+                    # if no geolocation, use the public user fp
+                    sale_order.onchange_partner_shipping_id()
+
             request.session['sale_order_id'] = sale_order.id
 
             if request.website.partner_id.id != partner.id:
@@ -323,6 +338,7 @@ class Website(models.Model):
                 # change the partner, and trigger the onchange
                 sale_order.write({'partner_id': partner.id})
                 sale_order.onchange_partner_id()
+                sale_order.onchange_partner_shipping_id() # fiscal position
 
                 # check the pricelist : update it if the pricelist is not the 'forced' one
                 values = {}