[IMP] l10n_in: autofill PAN from GST number

Previously, users were required to enter their PAN number even after manually
inputting their GSTIN, even though the PAN is inherently part of the
GSTIN (spanning from the 3rd to the 12th character). Furthermore, there was
no mechanism to alert users if the manually entered PAN did not match the PAN
segment within the GSTIN.

This commit automates the filling of the PAN based on the entered GSTIN. Now
upon entering a GSTIN, the corresponding PAN is auto-filled.

task-3767627

closes odoo/odoo#157689

X-original-commit: ffd2274498f1fbf0205e60f1b125134e4fede16e
Signed-off-by: Quentin De Paoli <qdp@odoo.com>
Signed-off-by: Earth Patel (eapa) <eapa@odoo.com>

addons/l10n_in/models/res_partner.py

@@ -27,6 +27,12 @@ class ResPartner(models.Model):
              "Thus, PAN acts as an identifier for the person with the tax department."
     )
 
+    display_pan_warning = fields.Boolean(string="Display pan warning", compute="_compute_display_pan_warning")
+
+    @api.depends('l10n_in_pan')
+    def _compute_display_pan_warning(self):
+        self.display_pan_warning = self.vat and self.l10n_in_pan and self.l10n_in_pan != self.vat[2:12]
+
     @api.onchange('company_type')
     def onchange_company_type(self):
         res = super().onchange_company_type()
@@ -49,6 +55,8 @@ class ResPartner(models.Model):
             state_id = self.env['res.country.state'].search([('l10n_in_tin', '=', self.vat[:2])], limit=1)
             if state_id:
                 self.state_id = state_id
+            if self.vat[2].isalpha():
+                self.l10n_in_pan = self.vat[2:12]
 
     @api.model
     def _commercial_fields(self):

addons/l10n_in/views/res_partner_views.xml

@@ -16,6 +16,13 @@
             <xpath expr="//field[@name='vat']" position="after">
                 <field name="l10n_in_pan" placeholder="e.g. ABCTY1234D" invisible="'IN' not in fiscal_country_codes" />
             </xpath>
+            <xpath expr="//sheet" position="before">
+                <field name="display_pan_warning" invisible="1"/>
+                <div class="alert alert-warning" role="alert"
+                        invisible="not display_pan_warning">
+                        PAN number is not same as the 3rd to 12th characters of the GST number.
+                </div>
+            </xpath>
         </field>
     </record>
 </odoo>