[ADD] pos_second_uom: Added support for Second Unit of Measure in POS

- Added a new field in product form to set a second UoM
- Backend constraint to prevent primary and secondary UoM being the same
- Loaded second UoM info into POS
- Added custom Add Quantity button in POS control panel(before customer button)
- Clicking the button opens a popup to enter quantity in second UoM
- POS converts the quantity based on UoM ratio
- Added validations in popup:
  - Show error if quantity is zero or negative or empty input
- Optimized validation with translatable error message
- UI improvements with conditional visibility and consistent UX

Author: agir-odoo

Diff for: pos_second_uom/__init__.py

@@ -0,0 +1 @@
+from . import models

Diff for: pos_second_uom/__manifest__.py

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+{
+    'name': 'POS Second UOM',
+    'version': '1.0',
+    'summary': 'Allows products to have a second unit of measure in POS',
+    'description': """
+        Adds the ability to set and use a second unit of measure for products in the Point of Sale.
+        This is useful for businesses that sell products in multiple units.
+        The second UOM is displayed and managed directly within the POS interface for easier sales handling.
+    """,
+    'author': 'Raghav Agiwal',
+    'depends': ['point_of_sale'],
+    'data': [
+        'views/product_template_view.xml',
+    ],
+    'assets': {
+        'point_of_sale._assets_pos': [
+            'pos_second_uom/static/src/**/*',
+        ],
+    },
+    'installable': True,
+    'application': True,
+    'auto_install': True,
+    'license': 'LGPL-3'
+}

Diff for: pos_second_uom/models/__init__.py

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+from . import product
+from . import product_template

Diff for: pos_second_uom/models/product.py

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+from odoo import api, models
+
+
+class Product(models.Model):
+    _inherit = 'product.product'
+
+    @api.model
+    def _load_pos_data_fields(self, config_id):
+        pos_fields = super()._load_pos_data_fields(config_id)
+        pos_fields.extend(['pos_second_uom_id'])
+        return pos_fields

Diff for: pos_second_uom/models/product_template.py

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+from odoo import api, fields, models
+from odoo.exceptions import ValidationError
+
+
+class ProductTemplate(models.Model):
+    _inherit = 'product.template'
+
+    pos_second_uom_id = fields.Many2one(
+        'uom.uom',
+        string="POS Second UoM",
+        domain="[('category_id', '=', uom_category_id)]"
+    )
+
+    uom_category_id = fields.Many2one(
+        'uom.category',
+        string="UoM Category",
+        related='uom_id.category_id',
+    )
+
+    @api.constrains('uom_id', 'pos_second_uom_id')
+    def _check_secondary_uom_not_same_as_primary(self):
+        if self.pos_second_uom_id and self.uom_id == self.pos_second_uom_id:
+            raise ValidationError(
+                f"Configuration Error:\n\n"
+                f'Product "{self.name}" has "{self.uom_id.name}" set as both primary and secondary Unit of Measure.\n'
+                f'These must be different. Please select a different second UoM for POS operations.'
+            )

Diff for: pos_second_uom/static/src/app/control_buttons/control_button.js

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+/** @odoo-module **/
+
+import { AddQuantityDialog } from "./dialog_box/add_quantity_dialog";
+import { ControlButtons } from "@point_of_sale/app/screens/product_screen/control_buttons/control_buttons";
+import { useService } from "@web/core/utils/hooks";
+import { patch } from "@web/core/utils/patch";
+
+patch(ControlButtons.prototype, {
+    setup() {
+        super.setup();
+        this.dialog = useService("dialog");
+        this.pos = this.env.services.pos;
+    },
+
+    get secondUomName() {
+        const line = this.pos.get_order().get_selected_orderline();
+        return line?.get_product()?.pos_second_uom_id?.name;
+    },
+
+    get shouldShowAddQtyButton() {
+        const order = this.pos.get_order();
+        const line = order?.get_selected_orderline();
+        return !!line?.get_product()?.pos_second_uom_id;
+    },
+
+    onAddQuantity() {
+        const order = this.pos.get_order();
+        const line = order.get_selected_orderline();
+
+        if (!line || !line.get_product()?.pos_second_uom_id) {
+            return;
+        }
+
+        this.dialog.add(AddQuantityDialog, {
+            product: line.get_product(),
+            orderline: line,
+            secondUomName: this.secondUomName,
+        });
+    },
+});

Diff for: pos_second_uom/static/src/app/control_buttons/control_button.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<templates id="template" xml:space="preserve">
+  <t t-name="pos_second_uom.ControlButtons"
+     t-inherit="point_of_sale.ControlButtons"
+     t-inherit-mode="extension">
+    <xpath expr="//SelectPartnerButton" position="before">
+      <button
+        t-if="shouldShowAddQtyButton"
+        t-attf-class="{{ buttonClass }}"
+        t-on-click="onAddQuantity"
+        title="Add quantity using Secondary UoM"
+      >
+        <i class="fa fa-plus"/> Add Quantity
+      </button>
+    </xpath>
+  </t>
+</templates>

Diff for: pos_second_uom/static/src/app/control_buttons/dialog_box/add_quantity_dialog.js

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+/** @odoo-module **/
+
+import { Component, useRef } from "@odoo/owl";
+import { usePos } from "@point_of_sale/app/store/pos_hook";
+import { AlertDialog } from "@web/core/confirmation_dialog/confirmation_dialog";
+import { useService } from "@web/core/utils/hooks";
+import { _t } from "@web/core/l10n/translation";
+import { Dialog } from "@web/core/dialog/dialog";
+
+export class AddQuantityDialog extends Component {
+    static template = "pos_second_uom.AddQuantityDialog";
+    static components = { Dialog };
+    static props = {
+        close: { type: Function },
+        product: { type: Object },
+        orderline: { type: Object },
+        secondUomName: { type: String, optional: true },
+    };
+
+    setup() {
+        this.pos = usePos();
+        this.input_qty = useRef("quantityInput");
+        this.uom_ratio = this.computeUomRatio(this.props.product);
+        this.dialog = useService("dialog");
+    }
+
+    computeUomRatio(product) {
+        if (product.uom_id && product.pos_second_uom_id) {
+            return product.uom_id.factor / product.pos_second_uom_id.factor;
+        }
+        return 1;
+    }
+
+    confirm() {
+        const quantity = parseFloat(this.input_qty.el.value);
+        if (!quantity || quantity <= 0) {
+            this.pos.dialog.add(AlertDialog, {
+                title: _t("Error"),
+                body: _t("Oops!!!!! Quantity cannot be negative, zero, or empty. Please enter a valid positive number !!"),
+            });
+            return;
+        }
+        this.props.orderline.set_quantity(quantity * this.uom_ratio);
+        this.props.close();
+    }
+}

Diff for: pos_second_uom/static/src/app/control_buttons/dialog_box/add_quantity_dialog.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<templates xml:space="preserve">
+    <t t-name="pos_second_uom.AddQuantityDialog">
+      <Dialog size="'sm'" title="'Enter Quantity in Second UoM'">
+        <t t-set-slot="default">
+          <div class="mb-3">
+            <label for="quantityInput" class="form-label">
+              Enter Quantity in <b><t t-out="props.secondUomName"/></b>
+            </label>
+            <input type="number" min="0.01" step="0.01" class="form-control"
+                   id="quantityInput" placeholder="Enter quantity" t-ref="quantityInput"/>
+          </div>
+        </t>
+        <t t-set-slot="footer">
+          <button class="btn btn-primary" t-on-click="confirm">Confirm</button>
+          <button class="btn btn-secondary" t-on-click="props.close">Cancel</button>
+        </t>
+      </Dialog>
+    </t>
+</templates>

Diff for: pos_second_uom/views/product_template_view.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<odoo>
+    <record id="view_product_template_form_inherit_uom" model="ir.ui.view">
+        <field name="name">product.template.form.inherit.uom</field>
+        <field name="model">product.template</field>
+        <field name="inherit_id" ref="product.product_template_form_view"/>
+        <field name="arch" type="xml">
+            <xpath expr="//field[@name='pos_categ_ids']" position="after">
+                <field name="pos_second_uom_id"/>
+            </xpath>
+        </field>
+    </record>
+</odoo>