feat: Adjust loyalty discount calculations to apply before tax and introduce accounting for 100% loyalty discounts.

__init__.py

@@ -1 +1,2 @@
 # -*- coding: utf-8 -*-
+from . import models

__manifest__.py

@@ -9,11 +9,12 @@
     """,
     "depends": ["point_of_sale", "pos_loyalty"],
     "data": [
-        
+        "views/res_config_settings_views.xml",
     ],
     "assets": {
         "point_of_sale._assets_pos": [
             'pos_loyalty_discount_before_tax/static/src/overrides/models/loyalty.js',
+            'pos_loyalty_discount_before_tax/static/src/overrides/models/orderline.js',
         ]
     },
     "installable": True,

models/__init__.py

@@ -0,0 +1,3 @@
+from . import pos_config
+from . import pos_session
+from . import res_config_settings

models/pos_config.py

@@ -0,0 +1,17 @@
+from odoo import fields, models
+
+class PosConfig(models.Model):
+    _inherit = 'pos.config'
+
+    discount_100_income_account_id = fields.Many2one(
+        'account.account',
+        string='100% Discount Income Account',
+        help='Account used for Income when an order has a 100% discount (0 total).',
+        domain="[('deprecated', '=', False)]"
+    )
+    discount_100_expense_account_id = fields.Many2one(
+        'account.account',
+        string='100% Discount Expense Account',
+        help='Account used for Expense/Discount when an order has a 100% discount (0 total).',
+        domain="[('deprecated', '=', False)]"
+    )

models/pos_session.py

@@ -0,0 +1,74 @@
+from odoo import models, _
+from odoo.tools import float_is_zero
+
+class PosSession(models.Model):
+    _inherit = 'pos.session'
+
+    def _create_account_move(self, balancing_account=False, amount_to_balance=0, bank_payment_method_diffs=None):
+        """
+        Extend _create_account_move to generate additional journal entry lines
+        for 100% discount orders (where total amount is 0).
+        """
+        # Call super to generate the standard move
+        data = super(PosSession, self)._create_account_move(balancing_account, amount_to_balance, bank_payment_method_diffs)
+
+        if not self.config_id.discount_100_income_account_id or not self.config_id.discount_100_expense_account_id:
+            return data
+
+        # Identify orders with 0 absolute paid amount but non-zero gross amount
+        # We look for orders where amount_total is near zero.
+        # Note: 100% discount orders have amount_total = 0.
+        
+        MoveLine = data.get('MoveLine')
+        if not MoveLine:
+            # Depending on Odoo 19's internal structure changes, fallback / ensure MoveLine exists. Odoo 17 returns a dict with 'MoveLine'.
+            MoveLine = self.env['account.move.line']
+
+        income_account = self.config_id.discount_100_income_account_id
+        expense_account = self.config_id.discount_100_expense_account_id
+        
+        # Helper to convert amount to company currency if needed, similar to Odoo's internals
+        def _get_amounts(amount, date):
+            return self._update_amounts({'amount': 0, 'amount_converted': 0}, {'amount': amount}, date)
+
+        zero_value_moves = []
+        
+        for order in self._get_closed_orders():
+            if float_is_zero(order.amount_total, precision_rounding=self.currency_id.rounding):
+                # Calculate the exact discount amount applied by loyalty rewards
+                discount_amount = sum(
+                    abs(line.price_subtotal) 
+                    for line in order.lines 
+                    if line.price_subtotal < 0 and (getattr(line, 'is_reward_line', False) or getattr(line, 'reward_id', False))
+                )
+                
+                if float_is_zero(discount_amount, precision_rounding=self.currency_id.rounding):
+                    continue
+
+                amounts = _get_amounts(discount_amount, order.date_order)
+                
+                # Create Credit Line (Income)
+                # We use _credit_amounts helper logic style manually
+                credit_vals = {
+                    'name': _('100%% Discount Income: %s') % order.name,
+                    'account_id': income_account.id,
+                    'move_id': self.move_id.id,
+                    'partner_id': order.partner_id.id or False,
+                }
+                credit_vals.update(self._credit_amounts(credit_vals, amounts['amount'], amounts['amount_converted']))
+                zero_value_moves.append(credit_vals)
+
+                # Create Debit Line (Expense/Discount)
+                debit_vals = {
+                    'name': _('100%% Discount Expense: %s') % order.name,
+                    'account_id': expense_account.id,
+                    'move_id': self.move_id.id,
+                    'partner_id': order.partner_id.id or False,
+                }
+                debit_vals.update(self._debit_amounts(debit_vals, amounts['amount'], amounts['amount_converted']))
+                zero_value_moves.append(debit_vals)
+
+        if zero_value_moves and self.move_id:
+            MoveLine.with_context(check_move_validity=False).create(zero_value_moves)
+
+        return data

models/res_config_settings.py

@@ -0,0 +1,13 @@
+from odoo import fields, models
+
+class ResConfigSettings(models.TransientModel):
+    _inherit = 'res.config.settings'
+
+    pos_discount_100_income_account_id = fields.Many2one(
+        related='pos_config_id.discount_100_income_account_id',
+        readonly=False,
+    )
+    pos_discount_100_expense_account_id = fields.Many2one(
+        related='pos_config_id.discount_100_expense_account_id',
+        readonly=False,
+    )

static/src/overrides/models/loyalty.js

@@ -13,6 +13,8 @@ patch(Order.prototype, {
         // For all rewards, we calculate discounts without tax
         let discountable = 0;
         const discountablePerTax = {};
+        const discountableWithTaxPerTax = {};
+        const formattedLines = [];
         const orderLines = this.get_orderlines();
 
         for (const line of orderLines) {
@@ -35,10 +37,13 @@ patch(Order.prototype, {
             discountable += line_total_without_tax;
             if (!discountablePerTax[taxKey]) {
                 discountablePerTax[taxKey] = 0;
+                discountableWithTaxPerTax[taxKey] = 0;
             }
             discountablePerTax[taxKey] += line_total_without_tax;
+            discountableWithTaxPerTax[taxKey] += line.get_price_with_tax();
+            formattedLines.push(line);
         }
-        return { discountable, discountablePerTax };
+        return { discountable, discountablePerTax, discountableWithTaxPerTax, formattedLines };
     },
 
     /**
@@ -53,11 +58,14 @@ patch(Order.prototype, {
 
         // Use price without tax for discount calculation
         const discountableWithoutTax = cheapestLine.get_price_without_tax();
+        const discountableWithTax = cheapestLine.get_price_with_tax();
         const taxKey = cheapestLine.get_taxes().map((t) => t.id);
 
         return {
             discountable: discountableWithoutTax,
             discountablePerTax: Object.fromEntries([[taxKey, discountableWithoutTax]]),
+            discountableWithTaxPerTax: Object.fromEntries([[taxKey, discountableWithTax]]),
+            formattedLines: [cheapestLine],
         };
     },
 
@@ -71,13 +79,16 @@ patch(Order.prototype, {
         const discountLinesPerReward = {};
         const orderLines = this.get_orderlines();
         const remainingAmountPerLine = {};
+        const remainingAmountWithTaxPerLine = {};
 
         for (const line of orderLines) {
             if (!line.get_quantity() || !line.price) {
                 continue;
             }
+
             const product_id = line.get_product().id;
             remainingAmountPerLine[line.cid] = line.get_price_without_tax();
+            remainingAmountWithTaxPerLine[line.cid] = line.get_price_with_tax();
 
             let included = false;
 
@@ -111,16 +122,20 @@ patch(Order.prototype, {
 
         let discountable = 0;
         const discountablePerTax = {};
+        const discountableWithTaxPerTax = {};
         for (const line of linesToDiscount) {
             discountable += remainingAmountPerLine[line.cid];
             const taxKey = line.get_taxes().map((t) => t.id);
             if (!discountablePerTax[taxKey]) {
                 discountablePerTax[taxKey] = 0;
+                discountableWithTaxPerTax[taxKey] = 0;
             }
             discountablePerTax[taxKey] +=
                 remainingAmountPerLine[line.cid];
+            discountableWithTaxPerTax[taxKey] +=
+                remainingAmountWithTaxPerLine[line.cid];
         }
-        return { discountable, discountablePerTax };
+        return { discountable, discountablePerTax, discountableWithTaxPerTax, formattedLines: linesToDiscount };
     },
 
     /**
@@ -145,7 +160,7 @@ patch(Order.prototype, {
             return "Unknown discount type";
         }
 
-        let { discountable, discountablePerTax } = getDiscountable(reward);
+        let { discountable, discountablePerTax, discountableWithTaxPerTax, formattedLines } = getDiscountable(reward);
         // For all rewards, we should use total without tax for comparison
         const totalForComparison = this.get_total_without_tax();
         discountable = Math.min(totalForComparison, discountable);
@@ -191,13 +206,44 @@ patch(Order.prototype, {
 
         const discountFactor = totalDiscountableWithoutTax ? Math.min(1, maxDiscount / totalDiscountableWithoutTax) : 1;
 
+        if ((1 - discountFactor) < 0.00001) {
+            // 100% Discount: Generate one reward line per original line to prevent rounding aggregation errors (0.01 issues)
+            // Tags added for UI-level grouping
+            return formattedLines.map((line, index) => {
+                const taxKey = ['ewallet', 'gift_card'].includes(reward.program_id.program_type)
+                    ? line.get_taxes().map((t) => t.id)
+                    : line.get_taxes().filter((t) => t.amount_type !== 'fixed').map((t) => t.id);
+
+                return {
+                    product: reward.discount_line_product_id,
+                    price: -line.get_price_without_tax(),
+                    quantity: 1,
+                    reward_id: reward.id,
+                    is_reward_line: true,
+                    coupon_id: coupon_id,
+                    points_cost: 0,
+                    reward_identifier_code: rewardCode,
+                    tax_ids: taxKey, // Use IDs, not tax objects
+                    merge: false,
+                    is_reward_group_member: true,
+                    reward_group_id: rewardCode,
+                    is_reward_group_head: index === 0,
+                    reward_group_count: formattedLines.length,
+                };
+            });
+        }
+
         const result = Object.entries(discountablePerTax).reduce((lst, entry) => {
             if (!entry[1]) {
                 return lst;
             }
             const taxIds = entry[0] === "" ? [] : entry[0].split(",").map((str) => parseInt(str));
             // Calculate tax-exclusive discount value for display
-            const preliminaryAmount = entry[1] * discountFactor;
+            let preliminaryAmount = entry[1] * discountFactor;
+
+            // Back-calculate logic removed as line-by-line strategy handles 100% case.
+            // Keeping partial discount logic standard for now.
+
             const discountAmount = roundPrecision(preliminaryAmount, this.pos.currency.rounding);
             lst.push({
                 product: reward.discount_line_product_id,
@@ -218,5 +264,15 @@ patch(Order.prototype, {
             result[0]["points_cost"] = pointCost;
         }
         return result;
+    },
+
+    set_orderline_options(line, options) {
+        super.set_orderline_options(...arguments);
+        if (options && options.is_reward_group_member) {
+            line.is_reward_group_member = options.is_reward_group_member;
+            line.reward_group_id = options.reward_group_id;
+            line.is_reward_group_head = options.is_reward_group_head;
+            line.reward_group_count = options.reward_group_count;
         }
+    },
 });

static/src/overrides/models/orderline.js

@@ -0,0 +1,76 @@
+/** @odoo-module **/
+
+import { Order, Orderline } from "@point_of_sale/app/store/models";
+import { patch } from "@web/core/utils/patch";
+
+patch(Order.prototype, {
+    export_for_printing() {
+        const result = super.export_for_printing(...arguments);
+        if (result.orderlines) {
+            result.orderlines = result.orderlines.filter((lineData) => {
+                const line = this.orderlines.find((l) => l.cid === lineData.cid);
+                if (line && line.is_reward_group_member && !line.is_reward_group_head) {
+                    return false;
+                }
+                return true;
+            });
+        }
+        return result;
+    },
+});
+
+patch(Orderline.prototype, {
+    getDisplayClasses() {
+        // Need to ensure we call the original function, might not exist in some versions or might be different
+        let classes = {};
+        if (typeof super.getDisplayClasses === 'function') {
+            classes = super.getDisplayClasses();
+        }
+        if (this.is_reward_group_member && !this.is_reward_group_head) {
+            classes['d-none'] = true;
+        }
+        return classes;
+    },
+    getDisplayData() {
+        const data = super.getDisplayData();
+        data.cid = this.cid;
+        if (this.is_reward_group_head) {
+            // Group and sum all lines in this reward group for display
+            const groupLines = this.order.get_orderlines().filter(
+                line => line.reward_group_id === this.reward_group_id
+            );
+
+            let totalDisplayPrice = 0;
+            let totalQty = 0;
+            for (const line of groupLines) {
+                totalDisplayPrice += line.get_display_price();
+                totalQty += line.get_quantity();
+            }
+
+            // this.env might not exist in Odoo 19 this way, we'll try to use this.pos.env if this.env is absent.
+            const env = this.env || this.pos.env;
+            data.price = env.utils.formatCurrency(totalDisplayPrice, this.pos.currency);
+            data.qty = totalQty.toString();
+        }
+        return data;
+    },
+    export_as_JSON() {
+        const result = super.export_as_JSON(...arguments);
+        if (this.is_reward_group_member) {
+            result.is_reward_group_member = this.is_reward_group_member;
+            result.reward_group_id = this.reward_group_id;
+            result.is_reward_group_head = this.is_reward_group_head;
+            result.reward_group_count = this.reward_group_count;
+        }
+        return result;
+    },
+    init_from_JSON(json) {
+        if (json.is_reward_group_member) {
+            this.is_reward_group_member = json.is_reward_group_member;
+            this.reward_group_id = json.reward_group_id;
+            this.is_reward_group_head = json.is_reward_group_head;
+            this.reward_group_count = json.reward_group_count;
+        }
+        super.init_from_JSON(...arguments);
+    }
+});

views/res_config_settings_views.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<odoo>
+    <record id="res_config_settings_view_form" model="ir.ui.view">
+        <field name="name">res.config.settings.view.form.inherit.pos.loyalty.discount.100</field>
+        <field name="model">res.config.settings</field>
+        <field name="inherit_id" ref="point_of_sale.res_config_settings_view_form"/>
+        <field name="arch" type="xml">
+            <xpath expr="//block[@id='pos_accounting_section']" position="inside">
+                <setting id="discount_100_account" title="Accounting entries for 100% discount orders" string="100% Discount Accounting">
+                    <div class="row">
+                        <label string="Income Account" for="pos_discount_100_income_account_id" class="col-lg-3 o_light_label"/>
+                        <field name="pos_discount_100_income_account_id"/>
+                    </div>
+                    <div class="row">
+                        <label string="Expense/Discount Account" for="pos_discount_100_expense_account_id" class="col-lg-3 o_light_label"/>
+                        <field name="pos_discount_100_expense_account_id"/>
+                    </div>
+                </setting>
+            </xpath>
+        </field>
+    </record>
+</odoo>