[IMP] account: add cumulated balance for general ledger list view

Task 2081612
* Add as an optionnal field "balance" (simple debit -credit)
  - usefull for "group by"
  - usefull when selecting several lines (in the footer total)
  - Hidden by default for journal view
  - Diplayed by default for ledger view
* Cumulative balance only for ledger views

closes odoo/odoo#38174

Related: odoo/enterprise#8024
Signed-off-by: Quentin De Paoli (qdp) <qdp@openerp.com>

addons/account/models/account_move.py

@@ -2440,6 +2440,10 @@ class AccountMoveLine(models.Model):
         currency_field='company_currency_id',
         compute='_compute_balance',
         help="Technical field holding the debit - credit in order to open meaningful graph views from reports")
+    cumulated_balance = fields.Monetary(string='Cumulated Balance', store=False,
+        currency_field='company_currency_id',
+        compute='_compute_cumulated_balance',
+        help="Cumulated balance depending on the domain and the order chosen in the view.")
     amount_currency = fields.Monetary(string='Amount in Currency', store=True, copy=True,
         help="The amount expressed in an optional other currency if it is a multi-currency entry.")
     price_subtotal = fields.Monetary(string='Subtotal', store=True, readonly=True,
@@ -2999,6 +3003,39 @@ class AccountMoveLine(models.Model):
         for line in self:
             line.balance = line.debit - line.credit
 
+    @api.model
+    def search_read(self, domain=None, fields=None, offset=0, limit=None, order=None):
+        def to_tuple(t):
+            return tuple(map(to_tuple, t)) if isinstance(t, (list, tuple)) else t
+        # Make an explicit order because we will need to reverse it
+        order = (order or self._order) + ', id'
+        # Add the domain and order by in order to compute the cumulated balance in _compute_cumulated_balance
+        return super(AccountMoveLine, self.with_context(domain_cumulated_balance=to_tuple(domain or []), order_cumulated_balance=order)).search_read(domain, fields, offset, limit, order)
+
+    @api.depends_context('order_cumulated_balance', 'domain_cumulated_balance')
+    def _compute_cumulated_balance(self):
+        if not self.env.context.get('order_cumulated_balance'):
+            # We do not come from search_read, so we are not in a list view, so it doesn't make any sense to compute the cumulated balance
+            self.cumulated_balance = 0
+            return
+
+        # get the where clause
+        query = self._where_calc(self.env.context.get('domain_cumulated_balance'))
+        order_string = ", ".join(self._generate_order_by_inner(self._table, self.env.context.get('order_cumulated_balance'), query, reverse_direction=True))
+        from_clause, where_clause, where_clause_params = query.get_sql()
+        sql = """
+            SELECT account_move_line.id, SUM(account_move_line.balance) OVER (
+                ORDER BY %(order_by)s
+                ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
+            )
+            FROM %(from)s
+            WHERE %(where)s
+        """ % {'from': from_clause, 'where': where_clause, 'order_by': order_string}
+        self.env.cr.execute(sql, where_clause_params)
+        result = {r[0]: r[1] for r in self.env.cr.fetchall()}
+        for record in self:
+            record.cumulated_balance = result[record.id]
+
     @api.depends('debit', 'credit', 'account_id', 'amount_currency', 'currency_id', 'matched_debit_ids', 'matched_credit_ids', 'matched_debit_ids.amount', 'matched_credit_ids.amount', 'move_id.state', 'company_id')
     def _amount_residual(self):
         """ Computes the residual amount of a move line from a reconcilable account in the company currency and the line's currency.

addons/account/views/account_move_views.xml

@@ -186,6 +186,7 @@
                     <field name="date_maturity" optional="hide"/>
                     <field name="debit" sum="Total Debit" readonly="1"/>
                     <field name="credit" sum="Total Credit" readonly="1"/>
+                    <field name="balance" sum="Total Balance" readonly="1" optional="hide"/>
                     <field name="amount_currency" readonly="1" groups="base.group_multi_currency"/>
                     <field name="currency_id" readonly="1" invisible="1" />
                     <field name="company_currency_id" invisible="1"/>
@@ -254,6 +255,10 @@
                     <attribute name="optional">hide</attribute>
                     <attribute name="readonly">1</attribute>
                 </field>
+                <field name="balance" position="attributes"><attribute name="optional">show</attribute></field>
+                <field name="balance" position="after">
+                    <field name="cumulated_balance" optional="show"/>
+                </field>
             </field>
         </record>
 
@@ -266,6 +271,10 @@
             <field name="arch" type="xml">
                 <field name="partner_id" position="attributes"><attribute name="optional">hide</attribute></field>
                 <field name="date_maturity" position="attributes"><attribute name="optional">show</attribute></field>
+                <field name="balance" position="attributes"><attribute name="optional">show</attribute></field>
+                <field name="balance" position="after">
+                    <field name="cumulated_balance" optional="show"/>
+                </field>
             </field>
         </record>