[16.0][REF] account_invoice_supplier_self_invoice: enhance self-billing footer and header logic

[nicolas-delbovier-acsone]

1. The self-bill report was incorrectly swapping the positions of the
   issuer and the recipient.

In a self-billing scenario:

• The Company (the recipient of the goods, but the issuer of the document)
  should be in the header/branding area.
• The Vendor (the actual supplier) should be positioned in the
  address window (usually the right side) to ensure the document
  can be mailed correctly in a window envelope.

This change ensures the addresses follow standard commercial letter
formats for self-billing.

2. Improves how footers are handled on self-billing reports and adds more granular configuration options.

Changes:

• Add 'self_invoice_extra_infos' to Company Settings to allow global
  legal mentions etc for self-billing.
• Update report logic to always include the standard Company footer.
• Cumulative footer logic: The report now displays the Company footer, followed by the Company self-billing extra info, and finally the
  Partner-specific self-billing info.
• UI/UX: The "invalid self-bill" warning message is now styled in red to clearly distinguish it from standard document notes.

---

Before

After

Steps to reproduce

Here is some demo data you can load (note that this has to be done after module init otherwise this will not work as some account records might not be setup correctly otherwise):

<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <data>

        <record id="demo_self_invoice_partner" model="res.partner">
            <field name="name">The Mirror Vendor (Self-Bill Vendor)</field>
            <field name="supplier_rank">1</field>
            <field name="self_invoice" eval="True" />
            <field name="self_invoice_partner_prefix">MIRROR</field>
            <field name="self_invoice_report_footer">Custom self invoice footer for Mirror Vendor.</field>
            <field name="email">vendor@mirror.example.com</field>

            <field name="street">Rue du Miroir 123</field>
            <field name="city">Brussels</field>
            <field name="zip">1000</field>
            <field name="country_id" ref="base.be" />
            <field name="phone">+32 2 555 01 23</field>
            <field name="website">www.mirror-vendor.example.com</field>
        </record>

        <record id="demo_delivery_address_mirror" model="res.partner">
            <field name="name">The Mirror Warehouse</field>
            <field name="parent_id" ref="demo_self_invoice_partner" />
            <field name="type">delivery</field>
            <field name="street">Avenue de la Réflexion 45</field>
            <field name="city">Grand-Rosière</field>
            <field name="zip">1367</field>
            <field name="country_id" ref="base.be" />
            <field name="email">warehouse@mirror.example.com</field>
        </record>

        <record id="demo_expense_account" model="account.account">
            <field name="name">Self-Bill Testing Expense</field>
            <field name="code">EXP.SELF.01</field>
            <field name="account_type">expense</field>
            <field name="company_id" ref="base.main_company" />
        </record>

        <record id="demo_self_invoice_move" model="account.move">
            <field name="move_type">in_invoice</field>
            <field name="partner_id" ref="demo_self_invoice_partner" />
            <field name="invoice_date" eval="time.strftime('%Y-%m-01')" />
            <field name="company_id" ref="base.main_company" />
            <field name="journal_id"
                model="account.journal"
                search="[('type', '=', 'purchase'), ('company_id', '=', ref('base.main_company'))]" />
        </record>

        <record id="demo_self_invoice_line" model="account.move.line">
            <field name="move_id" ref="demo_self_invoice_move" />
            <field name="name">Reflective Consultancy Services</field>
            <field name="account_id" ref="demo_expense_account" />
            <field name="quantity">5.0</field>
            <field name="price_unit">120.0</field>
        </record>

    </data>
</odoo>

Alternatively, you can use play this script in an odoo shell:

import datetime

# 1. Resolve External IDs for base data
country_be = env.ref('base.be').id
main_company = env.ref('base.main_company').id

# 2. Create the Vendor Partner
partner = env['res.partner'].create({
    'name': 'The Mirror Vendor (Self-Bill Vendor)',
    'supplier_rank': 1,
    'self_invoice': True,
    'self_invoice_partner_prefix': 'MIRROR',
    'self_invoice_report_footer': 'Custom self invoice footer for Mirror Vendor.',
    'email': 'vendor@mirror.example.com',
    'street': 'Rue du Miroir 123',
    'city': 'Brussels',
    'zip': '1000',
    'country_id': country_be,
    'phone': '+32 2 555 01 23',
    'website': 'www.mirror-vendor.example.com',
})

# 3. Create the Delivery Address
env['res.partner'].create({
    'name': 'The Mirror Warehouse',
    'parent_id': partner.id,
    'type': 'delivery',
    'street': 'Avenue de la Réflexion 45',
    'city': 'Grand-Rosière',
    'zip': '1367',
    'country_id': country_be,
    'email': 'warehouse@mirror.example.com',
})

# 4. Create the Expense Account
account = env['account.account'].create({
    'name': 'Self-Bill Testing Expense',
    'code': 'EXP.SELF.01',
    'account_type': 'expense',
    'company_id': main_company,
})

# 5. Find the Purchase Journal
journal = env['account.journal'].search([
    ('type', '=', 'purchase'), 
    ('company_id', '=', main_company)
], limit=1)

# 6. Create the Invoice (account.move)
move = env['account.move'].create({
    'move_type': 'in_invoice',
    'partner_id': partner.id,
    'invoice_date': datetime.date.today().replace(day=1), # First of current month
    'company_id': main_company,
    'journal_id': journal.id,
})

# 7. Create the Invoice Line
# Note: In Odoo 16, lines can be created directly via 'invoice_line_ids' on the move,
# but to follow your XML structure exactly:
env['account.move.line'].create({
    'move_id': move.id,
    'name': 'Reflective Consultancy Services',
    'account_id': account.id,
    'quantity': 5.0,
    'price_unit': 120.0,
})


print("Demo data created successfully.")

1. Define some company footer:

2. Define some self-billing extra infos

3. Add some customer specific self-billing footer

4. Generate the report using the report endpoint:
   http://localhost:8069/report/pdf/account.report_invoice_with_payments/<move_id>

[nicolas-delbovier-acsone]

@jbaudoux

[jbaudoux]

cc @Shide

[Shide]

Well the position of the partners I think it's correct.
It's a self-invoice, so the invoice generated is like if the partner generated it.
The positions are changed and I'm not sure if it's correct this approach. @rafaelbn please check.

The extra infos can be customized in the footer of the partner. So no need to add an extra infos directly into the report. Maybe if you use the default on the partner to get the company default texts (translated) to the lang of the recipient could be better.

Also, changing Self-Bill for Self-Billed makes no sense to me.

[jbaudoux]

Well the position of the partners I think it's correct. It's a self-invoice, so the invoice generated is like if the partner generated it. The positions are changed and I'm not sure if it's correct this approach. @rafaelbn please check.

The extra infos can be customized in the footer of the partner. So no need to add an extra infos directly into the report. Maybe if you use the default on the partner to get the company default texts (translated) to the lang of the recipient could be better.

Also, changing Self-Bill for Self-Billed makes no sense to me.

It's a self-billed invoice that is generated by the company towards the partner (with agreement from the partner). The document is emitted by the company and needs the header/footer of the company. The company is the legal issuer of the document. Like a customer invoice. The document number is provided by the company corresponding to the sequence in the journal of the company and is the unique document identifier.

You need to send the document to the partner, so you need the partner in the enveloppe window.

As it's managed as a supplier invoice, there is no equivalent of the fiscal position you have on a customer invoice to put the legal required text. That why I asked to add an additional text configurable on the company.

Process is self-billing, document is self-billed invoice / credit note.

This allowed us to be compliant with https://docs.peppol.eu/poacc/self-billing/3.0/bis-sb/