From 7d0990ca70c17a6e2a3c8c1c1058a7de7d903c5d Mon Sep 17 00:00:00 2001
From: pupat-odoo <pupat@odoo.com>
Date: Fri, 27 Mar 2026 11:25:07 +0530
Subject: [PATCH] [ADD] purchase_global_discount: added global discount on
 purchase order lines.

Purpose :

- Applying global discount to all order lines , avoids the manual setting of indivial discount enrtries.

- Allows discount value to be represented in native monetary values.

Features :

- Added a discount button below the order lines which opens a wizard dialog box.

- Implemented  wizard view for adding the discount value with its specific type.

-  with a single click on  'Apply' button, all the order lines amount get updated with new one.

Technical insights:

1) Added 'purchase_order' model which is implemented using Transient model.

2) 'purchase_order_discount'  wizard view added .
---
 purchase_global_discount/__init__.py          |  4 ++
 purchase_global_discount/__manifest__.py      | 18 +++++++
 purchase_global_discount/models/__init__.py   |  3 ++
 .../models/purchase_order.py                  | 15 ++++++
 .../security/ir.model.access.csv              |  2 +
 .../views/purchase_order_views.xml            | 15 ++++++
 purchase_global_discount/wizard/__init__.py   |  1 +
 .../wizard/purchase_order_discount.py         | 50 +++++++++++++++++++
 .../wizard/purchase_order_discount_views.xml  | 22 ++++++++
 9 files changed, 130 insertions(+)
 create mode 100644 purchase_global_discount/__init__.py
 create mode 100644 purchase_global_discount/__manifest__.py
 create mode 100644 purchase_global_discount/models/__init__.py
 create mode 100644 purchase_global_discount/models/purchase_order.py
 create mode 100644 purchase_global_discount/security/ir.model.access.csv
 create mode 100644 purchase_global_discount/views/purchase_order_views.xml
 create mode 100644 purchase_global_discount/wizard/__init__.py
 create mode 100644 purchase_global_discount/wizard/purchase_order_discount.py
 create mode 100644 purchase_global_discount/wizard/purchase_order_discount_views.xml

diff --git a/purchase_global_discount/__init__.py b/purchase_global_discount/__init__.py
new file mode 100644
index 00000000000..3f1aab2085f
--- /dev/null
+++ b/purchase_global_discount/__init__.py
@@ -0,0 +1,4 @@
+from . import (
+    models,  # noqa : F401
+    wizard,  # noqa : F401
+)
diff --git a/purchase_global_discount/__manifest__.py b/purchase_global_discount/__manifest__.py
new file mode 100644
index 00000000000..1762d608944
--- /dev/null
+++ b/purchase_global_discount/__manifest__.py
@@ -0,0 +1,18 @@
+{
+    "name": "purchase_dicount",
+    "description": "Add discount button with its wizard",
+    "author": "odoo-pupat",
+    "website": "https://www.odoo.com/",
+    "category": "Purchase-custom",
+    "version": "0.1",
+    "application": True,
+    "installable": True,
+    "depends": ["purchase"],
+    "data": [
+        "security/ir.model.access.csv",
+        "views/purchase_order_views.xml",
+        "wizard/purchase_order_discount_views.xml",
+    ],
+    "assets": {},
+    "license": "LGPL-3",
+}
diff --git a/purchase_global_discount/models/__init__.py b/purchase_global_discount/models/__init__.py
new file mode 100644
index 00000000000..307a154a11f
--- /dev/null
+++ b/purchase_global_discount/models/__init__.py
@@ -0,0 +1,3 @@
+from . import (
+    purchase_order,  # noqa: F401
+)
diff --git a/purchase_global_discount/models/purchase_order.py b/purchase_global_discount/models/purchase_order.py
new file mode 100644
index 00000000000..c7013a035e8
--- /dev/null
+++ b/purchase_global_discount/models/purchase_order.py
@@ -0,0 +1,15 @@
+from odoo import models
+
+
+class InheritedPurchaseOrder(models.Model):
+    _inherit = "purchase.order"
+
+    def action_open_discount_wizard(self):
+        self.ensure_one()
+        return {
+            "name": "Discount",
+            "type": "ir.actions.act_window",
+            "res_model": "purchase.order.discount",
+            "view_mode": "form",
+            "target": "new",
+        }
diff --git a/purchase_global_discount/security/ir.model.access.csv b/purchase_global_discount/security/ir.model.access.csv
new file mode 100644
index 00000000000..f68ace605d0
--- /dev/null
+++ b/purchase_global_discount/security/ir.model.access.csv
@@ -0,0 +1,2 @@
+id,name,model_id:id,group_id:id,perm_read,perm_write,perm_create,perm_unlink
+access_purchase_discount_wizard,purchase.discount.wizard,model_purchase_order_discount,base.group_user,1,1,1,1
\ No newline at end of file
diff --git a/purchase_global_discount/views/purchase_order_views.xml b/purchase_global_discount/views/purchase_order_views.xml
new file mode 100644
index 00000000000..5352365e4d8
--- /dev/null
+++ b/purchase_global_discount/views/purchase_order_views.xml
@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<odoo>
+    <record id="purchase_view_form" model="ir.ui.view">
+        <field name="name">purchase.view.form.purchase.discount</field>
+        <field name="model">purchase.order</field>
+        <field name="inherit_id" ref="purchase.purchase_order_form"/>
+        <field name="arch" type="xml">
+            <xpath expr="//field[@name='order_line']" position="after">
+                <div class="d-flex justify-content-end mt-2 mb-2">
+                    <button string="Discount" name="action_open_discount_wizard" type="object" class="btn btn-secondary"/>
+                </div>
+            </xpath>
+        </field>
+    </record>
+</odoo>
diff --git a/purchase_global_discount/wizard/__init__.py b/purchase_global_discount/wizard/__init__.py
new file mode 100644
index 00000000000..07afb7cc183
--- /dev/null
+++ b/purchase_global_discount/wizard/__init__.py
@@ -0,0 +1 @@
+from . import purchase_order_discount  # noqa: F401
diff --git a/purchase_global_discount/wizard/purchase_order_discount.py b/purchase_global_discount/wizard/purchase_order_discount.py
new file mode 100644
index 00000000000..a258d8c8083
--- /dev/null
+++ b/purchase_global_discount/wizard/purchase_order_discount.py
@@ -0,0 +1,50 @@
+from odoo import api, fields, models
+from odoo.exceptions import ValidationError
+
+
+class PurchaseOrderDiscount(models.TransientModel):
+    _name = "purchase.order.discount"
+    _description = "Discount Wizard"
+
+    purchase_order_id = fields.Many2one(
+        "purchase.order",
+        default=lambda self: self.env.context.get("active_id"),
+        required=True,
+    )
+    discount_percentage = fields.Float(string="Percentage")
+    discount_type = fields.Selection(
+        selection=[
+            ("percentage", "%"),
+            ("amount", "$"),
+        ],
+        default="percentage",
+    )
+    percentage = fields.Float(compute="_compute_initial_discount")
+
+    @api.depends("discount_type", "discount_percentage")
+    def _compute_initial_discount(self):
+        if self.discount_type == "amount":
+            if self.purchase_order_id.amount_untaxed == 0:
+                raise ValidationError("No more discount possible")
+            self.percentage = (
+                self.discount_percentage * 100 / self.purchase_order_id.amount_untaxed
+            )
+        else:
+            self.percentage = self.discount_percentage
+
+    def action_apply_discount(self):
+        self.ensure_one()
+        if self.discount_type == "amount":
+            self.purchase_order_id.order_line.write(
+                {
+                    "discount": (
+                        self.discount_percentage
+                        * 100
+                        / self.purchase_order_id.amount_untaxed
+                    )
+                }
+            )
+        else:
+            self.purchase_order_id.order_line.write(
+                {"discount": self.discount_percentage}
+            )
diff --git a/purchase_global_discount/wizard/purchase_order_discount_views.xml b/purchase_global_discount/wizard/purchase_order_discount_views.xml
new file mode 100644
index 00000000000..f0acb906e5c
--- /dev/null
+++ b/purchase_global_discount/wizard/purchase_order_discount_views.xml
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<odoo>
+
+    <record id="purchase_order_line_wizard_form" model="ir.ui.view">
+        <field name="name">purchase.order.discount.form</field>
+        <field name="model">purchase.order.discount</field>
+        <field name="arch" type="xml">
+            <form>
+                <sheet>
+                    
+                    <field name="discount_percentage" nolabel="1"/>
+                    <field name="discount_type" nolabel="1"/>
+                    <field name="percentage" class='text-muted' nolabel="1"/>
+                </sheet>
+                <footer>
+                    <button type="object" string="Apply" name="action_apply_discount" class="btn btn-primary"/>
+                    <button special="cancel" string="Cancel" class="btn btn-secondary"/>
+                </footer>
+            </form>
+        </field>
+    </record>
+</odoo>