pos_reverse_downpayment/README.md

POS Reverse Down Payment

This custom Odoo 17 module implements a special workflow for handling down payments in the Point of Sale (POS) where the cashier creates a sales quotation from the POS UI but leaves the standard products in the cart for printing on the receipt.

Purpose

The module resolves a few standard Odoo limitations for specific workflows:

1. Zero-Priced Quotation Products: Customers can receive a physical POS receipt displaying all ordered standard items (at 0 price) and a "Down Payment" line at normal price.
2. Quotation Generation: A backend Quotation (sale.order) is automatically created via XML-RPC. Standard products are pushed onto this Quotation with their original prices and taxes.
3. No Stock Deductions: Since the standard products remain in the POS cart at $0 price, Odoo normally tries to create zero-value stock moves. This module intercepts these moves (using is_quotation_line flag) to ensure stock doesn't get erroneously deducted before the Quotation is confirmed by backend staff.
4. Kitchen Order Prevention: Quotation items are prevented from printing in the kitchen display by overriding the sendChanges logic (for pos_preparation_display and pos_restaurant).
5. Settlement Stability: Properly resolves Odoo's internal UI when the cashier eventually loads the Quotation and settles the remaining balance.

Dependencies

• Odoo 17.0
• point_of_sale
• pos_sale
• pos_restaurant
• pos_preparation_display

How it works (Technical Flow)

1. POS UI Payment Intercept

When processing a payment (models.js pay() override), the module checks if:

• Standard products exist.
• A down payment product exists with a positive quantity and price. If true, it asks the cashier if they want to create a quotation.

2. Backend RPC Creation

If approved, it sends the original list of standard products via create_quotation_from_pos_lines in pos_order.py. The newly created sale_order_origin_id is linked to the down payment line to ensure tracking and eventual invoice settlements match.

3. POS Clean Up

The cart's standard items are zero-priced and flagged (is_quotation_line = true) so the custom JS won't prompt again during final payment validation.

4. Printing & Preparation

• Kitchen Tickets: Checks for positive down payments in sendChanges. If found, no items go to the kitchen.
• Stock Moves: Odoo's _create_order_picking natively ignores lines with is_quotation_line.

Installation

Clone or copy this repository into your Odoo custom addons path, update the app list, and install the pos_reverse_downpayment module.

No further configurations are required besides the standard Odoo POS Down Payment product settings.