[ADD] estate: Added inheritance to extend the functionality of curren…

…t model

Chapter-12: Implement inheritance for CRUD methods and model extensions

- Added custom business logic to prevent property deletion if the state is not
  'New' or 'Canceled'.
- Modified property state to 'Offer Received' upon offer creation.
- Prevented creation of offers with a lower price than existing ones.
- Extended `res.users` model by adding `property_ids` field to display
  salesperson's properties.
- Implemented view inheritance to include the new field in the user form view.

estate/__manifest__.py

@@ -12,9 +12,10 @@
     "data": [
         "security/ir.model.access.csv",
         "views/estate_property_views.xml",
+        "views/res_user_model_views.xml",
+        "views/estate_property_offer_views.xml",
         "views/estate_property_type_views.xml",
         "views/estate_property_tag_views.xml",
-        "views/estate_property_offer_views.xml",
         "views/estate_menus.xml",
     ],
 }

estate/models/__init__.py

@@ -2,3 +2,4 @@
 from . import estate_property_type
 from . import estate_property_tag
 from . import estate_property_offer
+from . import res_user

estate/models/estate_property.py

@@ -123,3 +123,9 @@ def action_sold_property(self):
             else:
                 self.write({"state": "sold"})
         return True
+
+    @api.ondelete(at_uninstall=False)
+    def _unlink_except_certain_state(self):
+        for record in self:
+            if record.state not in ['new', 'canceled']:
+                raise UserError(_('Only new or canceled property can be deleted.'))

estate/models/estate_property_offer.py

@@ -1,6 +1,6 @@
-from odoo import api, fields, models
+from odoo import api, fields, models, _
 from datetime import timedelta, date
-
+from odoo.exceptions import UserError
 
 class EstatePropertyOffer(models.Model):
     _name = "estate.property.offer"
@@ -18,7 +18,9 @@ class EstatePropertyOffer(models.Model):
         compute="_compute_date_deadline", inverse="_inverse_date_deadline"
     )
 
-    property_type_id = fields.Many2one(related="property_id.property_type_id", store=True)
+    property_type_id = fields.Many2one(
+        related="property_id.property_type_id", store=True
+    )
     _sql_constraints = [
         ("positive_offer_price", "CHECK(price > 0)", "Offer Price Must be Positive")
     ]
@@ -52,3 +54,11 @@ def action_accept_offer(self):
     def action_refuse_offer(self):
         self.write({"status": "refused"})
         return True
+
+    @api.model
+    def create(self, vals):
+        property_id = self.env["estate.property"].browse(vals["property_id"])
+        property_id.state = "offer received"
+        if any(offer.price > vals.get("price", 0) for offer in property_id.offer_ids):
+            raise UserError(_("You cannot create an offer with a lower price than an existing offer."))
+        return super().create(vals)

estate/models/res_user.py

@@ -0,0 +1,11 @@
+from odoo import models, fields
+
+
+class ResUser(models.Model):
+    _inherit = "res.users"
+
+    property_ids = fields.One2many(
+        "estate.property",
+        "salesman_id",
+        domain="['|', ('state', '=', 'new'), ('state', '=', 'offer received')]"
+    )

estate/views/res_user_model_views.xml

@@ -0,0 +1,27 @@
+<?xml version="1.0"?>
+<odoo>
+    <record id="view_users_form_inherited" model="ir.ui.view">
+        <field name="name">res.users.form.inherit.properties</field>
+        <field name="model">res.users</field>
+        <field name="inherit_id" ref="base.view_users_form"/>
+        <field name="arch" type="xml">
+            <xpath expr="//notebook" position="inside">
+                <page string="Properties">
+                    <field name="property_ids">
+                        <tree string="Properties">
+                            <field name="name"/>
+                            <field name="property_type_id"/>
+                            <field name="state" />
+                            <field name="postcode"/>
+                            <field name="tag_ids" widget="many2many_tags" />
+                            <field name="bedrooms"/>
+                            <field name="living_area"/>
+                            <field name="expected_price"/>
+                            <field name="selling_price"/>
+                        </tree>
+                    </field>
+                </page>
+            </xpath>
+        </field>
+    </record>
+</odoo>