[IMP] estate: implement only one offer can be accepted and create invoice on property sold, do code cleanup.

This commit improves the usability of the Real Estate module by:
- Making list views for Offers and Tags editable for quick updates.
- Adding row coloring: refused offers appear red, accepted ones green, and the status column has been removed for visual clarity.
- Enabling the ‘Available’ filter by default in property list action to surface active listings.
- Modifying the living_area search input to include properties with an area greater than or equal to the entered value.
- Introducing a stat button on the property type form that shows the number of linked offers.
- Introduced kanban view for the properties that are on sale, grouped by property type.

When a property is marked as sold, automatically create a draft customer invoice containing:
- Selling price of the property.
- 6% commission on the propertly selling price.
- Flat $100 Administrative fees.

Refactored `estate` module:
- Resolved linting and indentation error.
- Corrected XML ID and name for xml files according to Odoo coding guidelines.
- Replaced deprecated 'kanban-box' with 'card' template.
- Deleted unnecessary files.
- Removed unnecessary docstrings and code comments.
- Implemented the logic, that if one offer is accepted for the property then others are automatically marked as refused.
- Replaced direct field assignments with `write()` method for multiple fields.
- Corrected typo errors in the files.
- Removed dead code that wasn't necessary.

Author: aarp-odoo

estate/__manifest__.py

@@ -1,16 +1,21 @@
 {
-    'name': "Real Estate",
-    'description': """Real Estate Application.""",
-    'summary': """Real Estate Application for beginner.""",
+    'name': 'Real Estate',
+    'description': 'Real Estate Application.',
+    'summary': 'Real Estate Application for beginner.',
     'depends': ['base'],
-    'author': "Aaryan Parpyani (aarp)",
-    'category': "Tutorials/RealEstate",
+    'author': 'Aaryan Parpyani (aarp)',
+    'category': 'Tutorials/RealEstate',
     'version': '1.0',
     'application': True,
     'installable': True,
+    'license': 'LGPL-3',
     'data': [
-        'security/ir.model.access.csv',
-        'views/estate_menus_views.xml',
+        'views/estate_property_offer_views.xml',
+        'views/estate_property_type_views.xml',
+        'views/estate_property_tags_views.xml',
+        'views/res_users_views.xml',
         'views/estate_property_views.xml',
+        'views/estate_menus_views.xml',
+        'security/ir.model.access.csv',
     ]
 }

estate/models/__init__.py

@@ -1 +1,5 @@
 from . import estate_property
+from . import estate_property_type
+from . import estate_property_tag
+from . import estate_property_offer
+from . import inherited_user

estate/models/estate_property.py

@@ -1,15 +1,31 @@
-from odoo import fields, models
+# imports of python lib
 from dateutil.relativedelta import relativedelta
 
+# imports of odoo
+from odoo import api, fields, models
+from odoo.exceptions import UserError, ValidationError
+from odoo.tools.float_utils import float_compare, float_is_zero
+
 
 class EstateProperty(models.Model):
-    _name = "estate.property"
-    _description = "Estate Test"
+    # === Private attributes ===
+    _name = 'estate.property'
+    _description = 'Estate Test'
+    _order = 'id desc'
+
+    # SQL Constraints
+    _sql_constraints = [
+        ('check_expected_price_positive', 'CHECK(expected_price > 0)', 'Expected price must be strictly positive.'),
+        ('check_selling_price_positive', 'CHECK(selling_price > 0)', 'Selling price must be strictly positive.'),
+    ]
 
-    name = fields.Char(string="Name", required=True)
+    # ---------------------
+    # Fields declaration
+    # ---------------------
+    name = fields.Char(string='Name', required=True)
     description = fields.Char()
     postcode = fields.Char()
-    date_availability = fields.Date(String="Available From", copy=False, default=fields.Date.today() + relativedelta(months=3))
+    date_availability = fields.Date(string='Available From', copy=False, default=fields.Date.today() + relativedelta(months=3))
     expected_price = fields.Float(required=True)
     selling_price = fields.Float(readonly=True, copy=False)
     bedrooms = fields.Integer(default=2)
@@ -18,14 +34,17 @@ class EstateProperty(models.Model):
     garage = fields.Boolean()
     garden = fields.Boolean()
     garden_area = fields.Integer()
+    active = fields.Boolean(default=True)
+
+    # Selection fields
     garden_orientation = fields.Selection(
         [
             ('north', 'North'),
             ('south', 'South'),
             ('east', 'East'),
             ('west', 'West')
         ],
-        string="Garden Orientation"
+        string='Garden Orientation'
     )
     state = fields.Selection(
         [
@@ -35,8 +54,89 @@ class EstateProperty(models.Model):
             ('sold', 'Sold'),
             ('cancelled', 'Cancelled')
         ],
-        string="Status",
+        string='Status',
         required=True,
         copy=False,
         default='new'
     )
+
+    # Many2one fields
+    property_type_id = fields.Many2one('estate.property.type', string='Property Type')
+    salesman_id = fields.Many2one('res.users', string='Salesman', default=lambda self: self.env.user)
+    buyer_id = fields.Many2one('res.partner', string='Buyer', copy=False)
+
+    # Many2many fields
+    tag_ids = fields.Many2many('estate.property.tag', string='Tags')
+
+    # One2many fields
+    offer_ids = fields.One2many('estate.property.offer', 'property_id', string='Offers')
+
+    # Computed fields
+    total_area = fields.Integer(string='Total Area', compute='_compute_total_area')
+    best_price = fields.Float(string='Best Offer', compute='_compute_best_price')
+
+    # -----------------------
+    # Compute methods
+    # -----------------------
+    @api.depends('living_area', 'garden_area')
+    def _compute_total_area(self):
+        for record in self:
+            record.total_area = (record.living_area) + (record.garden_area)
+
+    @api.depends('offer_ids.price')
+    def _compute_best_price(self):
+        for record in self:
+            if record.offer_ids:
+                record.best_price = max(record.offer_ids.mapped('price'))
+            else:
+                record.best_price = 0
+
+    # ----------------------------------
+    # Constraints and onchange methods
+    # ----------------------------------
+    @api.constrains('expected_price', 'selling_price')
+    def _check_selling_price(self):
+        for property in self:
+            if not float_is_zero(property.selling_price, precision_digits=2):
+                min_allowed = 0.9 * property.expected_price
+                if float_compare(property.selling_price, min_allowed, precision_digits=2) < 0:
+                    raise ValidationError('Selling price cannot be lower than 90% of the expected price.')
+
+    @api.onchange('garden')
+    def _onchange_garden(self):
+        if self.garden:
+            self.write({
+                'garden_area': 10,
+                'garden_orientation': 'north'
+            })
+        else:
+            self.write({
+                'garden_area': 0,
+                'garden_orientation': False
+            })
+
+    # ----------------------
+    # CRUD methods
+    # -----------------------
+    @api.ondelete(at_uninstall=False)
+    def _unlink_except_new_or_cancelled(self):
+        for record in self:
+            if record.state not in ['new', 'cancelled']:
+                raise UserError('You can only delete properties that are in New or Cancelled state.')
+
+    # ----------------------
+    # Action methods
+    # ----------------------
+    def action_mark_sold(self):
+        for record in self:
+            if record.state == 'cancelled':
+                raise UserError('Cancelled properties cannot be marked as sold.')
+            record.state = 'sold'
+        return True
+
+    def action_mark_cancelled(self):
+        for record in self:
+            if record.state == 'sold':
+                raise UserError('Sold properties cannot be marked as cancelled.')
+            record.state = 'cancelled'
+        return True

estate/models/estate_property_offer.py

@@ -0,0 +1,129 @@
+# imports of python lib
+from datetime import timedelta
+
+# imports of odoo
+from odoo import api, fields, models
+from odoo.exceptions import UserError
+from odoo.tools.float_utils import float_compare
+
+
+class EstatePropertyOffer(models.Model):
+    # === Private attributes ===
+    _name = 'estate.property.offer'
+    _description = 'Offers for all the property listings.'
+    _order = 'price desc'
+
+    # SQL Constraints
+    _sql_constraints = [
+        ('check_price_positive', 'CHECK(price > 0)', 'Offer price must be strictly positive.'),
+    ]
+
+    # ------------------------
+    # Fields declaration
+    # -------------------------
+    price = fields.Float(string='Price')
+    validity = fields.Integer(default=7)
+
+    # Selection fields
+    status = fields.Selection(
+        [
+            ('accepted', 'Accepted'),
+            ('refused', 'Refused')
+        ],
+        string='Status',
+        copy=False
+    )
+
+    # Computed fields
+    date_deadline = fields.Date(compute='_compute_date_deadline', inverse='_inverse_date_deadline', store=True)
+
+    # Many2one fields
+    partner_id = fields.Many2one('res.partner', required=True)
+    property_id = fields.Many2one('estate.property', string='Property Name', required=True)
+    property_type_id = fields.Many2one(related='property_id.property_type_id', store=True)
+
+    # --------------------
+    # Compute methods
+    # --------------------
+    @api.depends('create_date', 'validity', 'date_deadline')
+    def _compute_date_deadline(self):
+        for offer in self:
+            base_date = (offer.create_date or fields.Datetime.now()).date()
+            offer.date_deadline = base_date + timedelta(days=offer.validity or 0)
+
+    def _inverse_date_deadline(self):
+        for offer in self:
+            base_date = (offer.create_date or fields.Datetime.now()).date()
+            if offer.date_deadline:
+                offer.validity = (offer.date_deadline - base_date).days
+
+    # ---------------------
+    # CRUD methods
+    # ---------------------
+    @api.model_create_multi
+    def create(self, vals_list):
+        """Overrided the default create method to enforce business rules when creating an offer.
+
+        Logic implemented:
+        1. Checks if the offer amount is lower than existing offer for the property.
+            - If so raises a UserError to prevent the creation of the offer.
+        2. If the offer is valid, updates the related property's state to 'offer_received'.
+
+        Args:
+            vals (dict): The values used to create the new estate.property.offer record.
+
+        Returns:
+            recordset: the newly created estate.property.offer record.
+
+        Raises:
+            UserError: If the offer amount is lower than an existing offer for the property.
+        """
+        print(vals_list)
+        for vals in vals_list:
+            property_id = vals.get('property_id')
+            offer_price = vals.get('price', 0.0)
+            if not property_id or not offer_price:
+                raise UserError('Both Property and Price must be provided.')
+
+            property_obj = self.env['estate.property'].browse(property_id)
+            for offer in property_obj.offer_ids:
+                if float_compare(offer_price, offer.price, precision_rounding=0.01) < 0:
+                    raise UserError('You cannot create an offer with an amount lower than existing offer.')
+
+            if property_obj.state == 'new':
+                property_obj.state = 'offer_received'
+
+        return super().create(vals_list)
+
+    # -------------------
+    # Action methods
+    # -------------------
+    def action_accept(self):
+        """Accept the offer and update the related property accordingly.
+
+        - Sets the offer's status to 'accepted'.
+        - Sets all the offer's status to 'refused'.
+        - Updates the property's selling price and buyer.
+        - Updates the property's state to 'offer_accepted'.
+
+        Raises:
+            UserError: If the property is already marked as 'sold'.
+        """
+        for offer in self:
+            if offer.property_id.state == 'sold':
+                raise UserError('You cannot accept an offer for a sold property.')
+
+            offer.status = 'accepted'
+            (offer.property_id.offer_ids - offer).write({'status': 'refused'})
+            property = offer.property_id
+            property.write({
+                'selling_price': offer.price,
+                'buyer_id': offer.partner_id,
+                'state': 'offer_accepted'
+            })
+        return True
+
+    def action_refuse(self):
+        for offer in self:
+            offer.status = 'refused'
+        return True

estate/models/estate_property_tag.py

@@ -0,0 +1,18 @@
+# imports of odoo
+from odoo import fields, models
+
+
+class EstatePropertyType(models.Model):
+    # === Private attributes ===
+    _name = 'estate.property.tag'
+    _description = 'Property tags to represent the property.'
+    _order = 'name'
+
+    # SQL Constraints
+    _sql_constraints = [
+        ('unique_tag_name', 'UNIQUE(name)', 'Tag name must be unique.'),
+    ]
+
+    # === Fields declaration ===
+    name = fields.Char('Property Tag', required=True)
+    color = fields.Integer(string="Color")

estate/models/estate_property_type.py

@@ -0,0 +1,38 @@
+# imports of odoo
+from odoo import api, fields, models
+
+
+class EstatePropertyType(models.Model):
+    # === Private attributes ===
+    _name = 'estate.property.type'
+    _description = 'Property types for available in the business.'
+    _order = 'sequence, name'
+
+    # SQL Constraints
+    _sql_constraints = [
+        ('unique_type_name', 'UNIQUE(name)', 'Type name must be unique.')
+    ]
+
+    # === Fields declaration ===
+    name = fields.Char(required=True)
+    sequence = fields.Integer('Sequence', default=10)
+
+    # One2many fields
+    property_ids = fields.One2many('estate.property', 'property_type_id', string='Properties')
+    offer_ids = fields.One2many('estate.property.offer', 'property_type_id', string='Offers')
+
+    # Compute fields
+    offer_count = fields.Integer(string='Number of Offers', compute='_compute_offer_count')
+
+    # === Compute methods ===
+    @api.depends('offer_ids')
+    def _compute_offer_count(self):
+        '''Compute the number of offers linked to each property type.
+
+        This method calculates the total number of related offers (`offer_ids`)
+        for each type in the `estate.property.type` model and stores the count
+        in the `offer_count` field.
+        '''
+        for record in self:
+            record.offer_count = len(record.offer_ids) if hasattr(
+                record, 'offer_ids') else 0

estate/models/inherited_user.py

@@ -0,0 +1,10 @@
+# Imports of odoo
+from odoo import fields, models
+
+
+class InheritedUser(models.Model):
+    # === Private attributes ===
+    _inherit = 'res.users'
+
+    # === Fields declaration ===
+    property_ids = fields.One2many('estate.property', 'salesman_id', string="Properties")

estate/security/ir.model.access.csv

@@ -1,2 +1,5 @@
 id,name,model_id:id,group_id:id,perm_read,perm_write,perm_create,perm_unlink
-estate.access_estate_property,access_estate_property,estate.model_estate_property,base.group_user,1,1,1,1
+estate.access_estate_property,access_estate_property,estate.model_estate_property,base.group_user,1,1,1,1
+estate.access_estate_property_type,access_estate_property_type,estate.model_estate_property_type,base.group_user,1,1,1,1
+estate.access_estate_property_tag,access_estate_property_tag,estate.model_estate_property_tag,base.group_user,1,1,1,1
+estate.access_estate_property_offer,access_estate_property_offer,estate.model_estate_property_offer,base.group_user,1,1,1,1