[FIX] point_of_sale: fix price computation for tax included

When you hava a fiscal position that that map one tax included into the
price to another, the new amount is wrong.

I we have a fiscal position that map a tax of 10% included to 20%
included, and a product at 110$ having 10% included. When we map the tax
from 10% to 20%, the new price is 100$ but should be 120$.

This is because for now, the price is fixed to get the amount without
tax, which perfectly works when destination tax is tax excluded. But
when you call compute_all from a price with a tax included (20%) it keep
the price and compute the tax amount out of this price.

So to fix this issue, whent the origin tax and destination tax are
included, we are computing the base amount (like before) and then we
compute the new tax amount wihtout trying to find the tax amount out of
the price.

This will lead to have the same behavior between accounting and POS

closes odoo/odoo#60237

X-original-commit: a0baa3751e1d8825c657464097f77f1957149065
Signed-off-by: pimodoo <pimodoo@users.noreply.github.com>

1 files changed, 40 insertions, 29 deletions

diff --git a/addons/point_of_sale/static/src/js/models.js b/addons/point_of_sale/static/src/js/models.js
index aff04017b64..a7d826eacd9 100644
--- a/addons/point_of_sale/static/src/js/models.js
+++ b/addons/point_of_sale/static/src/js/models.js
@@ -1849,13 +1849,15 @@ exports.Orderline = Backbone.Model.extend({
     // in the orderline. This returns true if it makes sense to merge the two
     can_be_merged_with: function(orderline){
         var price = parseFloat(round_di(this.price || 0, this.pos.dp['Product Price']).toFixed(this.pos.dp['Product Price']));
+        var order_line_price = orderline.get_product().get_price(orderline.order.pricelist, this.get_quantity());
+        order_line_price = orderline.compute_fixed_price(order_line_price);
         if( this.get_product().id !== orderline.get_product().id){    //only orderline of the same product can be merged
             return false;
         }else if(!this.get_unit() || !this.get_unit().is_pos_groupable){
             return false;
         }else if(this.get_discount() > 0){             // we don't merge discounted orderlines
             return false;
-        }else if(!utils.float_is_zero(price - orderline.get_product().get_price(orderline.order.pricelist, this.get_quantity()) - orderline.get_price_extra(),
+        }else if(!utils.float_is_zero(price - order_line_price - orderline.get_price_extra(),
                     this.pos.currency.decimals)){
             return false;
         }else if(this.product.tracking == 'lot') {
@@ -2102,7 +2104,7 @@ exports.Orderline = Backbone.Model.extend({
      *
      * Read comments in the python side method for more details about each sub-methods.
      */
-    compute_all: function(taxes, price_unit, quantity, currency_rounding) {
+    compute_all: function(taxes, price_unit, quantity, currency_rounding, handle_price_include=true) {
         var self = this;
 
         // 1) Flatten the taxes.
@@ -2169,34 +2171,35 @@ exports.Orderline = Backbone.Model.extend({
         var incl_division_amount = 0.0;
 
         var cached_tax_amounts = {};
-
-        _(taxes.reverse()).each(function(tax){
-            if(tax.include_base_amount){
-                base = recompute_base(base, incl_fixed_amount, incl_percent_amount, incl_division_amount);
-                incl_fixed_amount = 0.0;
-                incl_percent_amount = 0.0;
-                incl_division_amount = 0.0;
-                store_included_tax_total = true;
-            }
-            if(tax.price_include){
-                if(tax.amount_type === 'percent')
-                    incl_percent_amount += tax.amount;
-                else if(tax.amount_type === 'division')
-                    incl_division_amount += tax.amount;
-                else if(tax.amount_type === 'fixed')
-                    incl_fixed_amount += quantity * tax.amount
-                else{
-                    var tax_amount = self._compute_all(tax, base, quantity);
-                    incl_fixed_amount += tax_amount;
-                    cached_tax_amounts[i] = tax_amount;
+        if (handle_price_include){
+            _(taxes.reverse()).each(function(tax){
+                if(tax.include_base_amount){
+                    base = recompute_base(base, incl_fixed_amount, incl_percent_amount, incl_division_amount);
+                    incl_fixed_amount = 0.0;
+                    incl_percent_amount = 0.0;
+                    incl_division_amount = 0.0;
+                    store_included_tax_total = true;
                 }
-                if(store_included_tax_total){
-                    total_included_checkpoints[i] = base;
-                    store_included_tax_total = false;
+                if(tax.price_include){
+                    if(tax.amount_type === 'percent')
+                        incl_percent_amount += tax.amount;
+                    else if(tax.amount_type === 'division')
+                        incl_division_amount += tax.amount;
+                    else if(tax.amount_type === 'fixed')
+                        incl_fixed_amount += quantity * tax.amount
+                    else{
+                        var tax_amount = self._compute_all(tax, base, quantity);
+                        incl_fixed_amount += tax_amount;
+                        cached_tax_amounts[i] = tax_amount;
+                    }
+                    if(store_included_tax_total){
+                        total_included_checkpoints[i] = base;
+                        store_included_tax_total = false;
+                    }
                 }
-            }
-            i -= 1;
-        });
+                i -= 1;
+            });
+        }
 
         var total_excluded = round_pr(recompute_base(base, incl_fixed_amount, incl_percent_amount, incl_division_amount), initial_currency_rounding);
         var total_included = total_excluded;
@@ -2284,16 +2287,24 @@ exports.Orderline = Backbone.Model.extend({
         if(order.fiscal_position) {
             var taxes = this.get_taxes();
             var mapped_included_taxes = [];
+            var new_included_taxes = [];
             var self = this;
             _(taxes).each(function(tax) {
                 var line_taxes = self._map_tax_fiscal_position(tax);
+                new_included_taxes = new_included_taxes.concat(line_taxes)
                 if(tax.price_include && !_.contains(line_taxes, tax)){
                     mapped_included_taxes.push(tax);
                 }
             });
 
             if (mapped_included_taxes.length > 0) {
-                return this.compute_all(mapped_included_taxes, price, 1, order.pos.currency.rounding, true).total_excluded;
+                if (new_included_taxes.length > 0) {
+                    var price_without_taxes = this.compute_all(mapped_included_taxes, price, 1, order.pos.currency.rounding, true).total_excluded
+                    return this.compute_all(new_included_taxes, price_without_taxes, 1, order.pos.currency.rounding, false).total_included
+                }
+                else{
+                    return this.compute_all(mapped_included_taxes, price, 1, order.pos.currency.rounding, true).total_excluded;
+                }
             }
         }
         return price;