[IMP] base: Add compute/inverse methods to manage user groups

Purpose
=======

Allow to define users groups on a res.user with computed fields based on the 'groups_id' field.

Specification
=============

Add compute/inverse methods to manage specific groups on a res.users.

These methods should be used on fields defined like one the following cases:

1. A boolean field with the compute/inverse method and an attribute group_xml_id.
Example:
    has_group_discount_per_so_line = fields.Boolean(
        "Discount on lines",
        compute='_compute_groups_id', inverse='_inverse_groups_id',
        group_xml_id='sale.group_discount_per_so_line')

2. A selection field with the compute/inverse method, the selection got from '_get_group_selection'
   and an attribute 'category_xml_id'
Example:
    group_sales_team_user = fields.Selection(
        selection=lambda self: self._get_group_selection('base.module_category_sales_management'),
        string="Sales", compute='_compute_groups_id', inverse='_inverse_groups_id',
        category_xml_id='base.module_category_sales_management')

The fields will be set according to the groups defined in the 'groups_id' field, and the 'groups_id'
field will be modified according to the modifications made on theses fields when saving the users's
form.

odoo/addons/base/models/res_users.py

@@ -624,6 +624,112 @@ class Users(models.Model):
     def get_company_currency_id(self):
         return self.env.user.company_id.currency_id.id
 
+    def _add_missing_default_values(self, vals):
+        # Remove the default values of 'group_' and 'has_group' fields at the user creation if
+        # 'groups_id' is provided in vals and if the fields value is not explicitely given.
+        res = super(Users, self)._add_missing_default_values(vals)
+        return {
+            key: value for (key, value) in res.items()
+            if 'groups_id' not in vals or key in vals or (not is_boolean_group(key) or not is_selection_groups(key))
+        }
+
+    def _get_group_selection(self, category_xml_id):
+        """Returns the ordered selection for the given ir.module.category xmlid"""
+        category = self.env.ref(category_xml_id, raise_if_not_found=False)
+        selections = []
+        if category:
+            groups = self.env['res.groups'].search([('category_id', '=', category.id)])
+            order = {group: len(group.trans_implied_ids & groups) for group in groups}
+            groups = groups.sorted(key=order.get)
+            selections = [(group.id, group.name) for group in groups]
+        return selections
+
+    @api.depends('groups_id')
+    def _compute_groups_id(self):
+        """Set the value for the group field (Selection of Boolean)
+           according to the user's groups, defined by the field 'groups_id'.
+
+           These methods should be used on fields defined like one the
+           following cases:
+           1. A boolean field with the compute/inverse method and an attribute
+              group_xml_id.
+           Example:
+               has_group_discount_per_so_line = fields.Boolean(
+                   "Discount on lines",
+                   compute='_compute_groups_id', inverse='_inverse_groups_id',
+                   group_xml_id='sale.group_discount_per_so_line')
+           2. A selection field with the compute/inverse method, the selection
+              got from '_get_group_selection' and an attribute
+              'category_xml_id'
+           Example:
+               group_sales_team_user = fields.Selection(
+                   selection=lambda self: self._get_group_selection('base.module_category_sales_management'),
+                   string="Sales", compute='_compute_groups_id', inverse='_inverse_groups_id',
+                   category_xml_id='base.module_category_sales_management')
+           The fields will be set according to the groups defined in the 'groups_id'
+           field, and the 'groups_id' field will be modified according to the
+           modifications made on theses fields when saving the users's form.
+        """
+        computed_group_fields = [field for field in self._field_computed.keys() if field.compute == '_compute_groups_id']
+        all_groups = self.env['res.groups'].search([])
+        category_data = {}
+        # Retrieve groups order for selection fields 
+        for field in computed_group_fields:
+            if getattr(field, 'category_xml_id', None):
+                category = self.env.ref(getattr(field, 'category_xml_id'))
+                category_groups = all_groups.filtered(lambda group: group.category_id == category)
+                order = {group: len(group.trans_implied_ids & category_groups) for group in category_groups}
+                category_data[field] = category_groups.sorted(key=order.get, reverse=True)
+        # Set group fields values according to groups_id 
+        for user in self:
+            for field in computed_group_fields:
+                # Checkbox group
+                if getattr(field, 'group_xml_id', None):
+                    group = self.env.ref(getattr(field, 'group_xml_id'))
+                    user[field.name] = group in user.groups_id
+                # Selection group
+                elif getattr(field, 'category_xml_id', None):
+                    # Take the highest level group the user belongs to
+                    user_groups = [group for group in category_data[field] if group in user.groups_id]
+                    user[field.name] = user_groups[0].id if user_groups else False
+                else:
+                    _logger.warning(_("No 'group_xml_id' or 'category_xml_id' is set on the computed field %s linked to the method _compute_groups_id") % (field.name))
+
+    def _inverse_groups_id(self):
+        """Update 'groups_id' according the group fields values in cache."""
+        computed_group_fields = [field for field in self._field_computed.keys() if field.compute == '_compute_groups_id']
+        all_groups = self.env['res.groups'].search([])
+        for user in self:
+            # we need to read all values in cache before any prefetch
+            field_values = {field: user[field.name] for field in computed_group_fields if field.name in user._cache}
+            groups_id_vals = []
+            for field, value in field_values.items():
+                # Checkbox group
+                if getattr(field, 'group_xml_id', None):
+                    selected_group = self.env.ref(getattr(field, 'group_xml_id'))
+                    if value:
+                        groups_id_vals.append((4, selected_group.id))
+                    else:
+                        groups_id_vals.append((3, selected_group.id))
+                    for group in selected_group.trans_implied_ids:
+                        groups_id_vals.append((4, group.id))
+                # Selection group
+                elif getattr(field, 'category_xml_id', None):
+                    category = self.env.ref(getattr(field, 'category_xml_id'))
+                    category_groups = [group for group in all_groups if group.category_id == category]
+                    selected_group = [group for group in all_groups if group.id == value]
+                    selected_group = selected_group and selected_group[0] or self.env['res.groups']
+                    for group in category_groups:
+                        if group in (selected_group.trans_implied_ids | selected_group):
+                            groups_id_vals.append((4, group.id))
+                        else:
+                            groups_id_vals.append((3, group.id))
+                else:
+                    _logger.warning(_("No 'group_xml_id' or 'category_xml_id' is set on the computed field %s linked to the method _compute_groups_id") % (field.name))
+            if groups_id_vals:
+                user.write({'groups_id': groups_id_vals})
+
+
 #
 # Implied groups
 #