[ADD] account_tax_balance: Compute tax balances based on date range

account_tax_balance/models/__init__.py

@@ -0,0 +1,5 @@
+# -*- coding: utf-8 -*-
+# © 2016 Lorenzo Battistini - Agile Business Group
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+from . import account_tax

account_tax_balance/models/account_tax.py

@@ -0,0 +1,86 @@
+# -*- coding: utf-8 -*-
+# © 2016 Lorenzo Battistini - Agile Business Group
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+from openerp import models, fields
+
+
+class AccountTax(models.Model):
+    _inherit = 'account.tax'
+
+    balance = fields.Float(string="Balance", compute="_compute_balance")
+    base_balance = fields.Float(
+        string="Base Balance", compute="_compute_balance")
+
+    def get_context_values(self):
+        if not self.env.context.get('from_date'):
+            from_date = fields.Date.context_today(self)
+        else:
+            from_date = self.env.context['from_date']
+        if not self.env.context.get('to_date'):
+            to_date = fields.Date.context_today(self)
+        else:
+            to_date = self.env.context['to_date']
+        if not self.env.context.get('target_move'):
+            target_move = 'posted'
+        else:
+            target_move = self.env.context['target_move']
+        if not self.env.context.get('company_id'):
+            company_id = self.env.user.company_id.id
+        else:
+            company_id = self.env.context['company_id']
+        return from_date, to_date, company_id, target_move
+
+    def _compute_balance(self):
+        from_date, to_date, company_id, target_move = self.get_context_values()
+        for tax in self:
+            tax.balance = tax.compute_balance(
+                from_date, to_date, company_id, target_move)
+            tax.base_balance = tax.compute_base_balance(
+                from_date, to_date, company_id, target_move)
+
+    def get_target_state_list(self, target_move="posted"):
+        if target_move == 'posted':
+            state = ['posted']
+        elif target_move == 'all':
+            state = ['posted', 'draft']
+        else:
+            state = []
+        return state
+
+    def get_move_line_domain(self, from_date, to_date, company_id):
+        return [
+            ('date', '<=', to_date),
+            ('date', '>=', from_date),
+            ('company_id', '=', company_id),
+        ]
+
+    def compute_balance(
+        self, from_date, to_date, company_id, target_move="posted"
+    ):
+        self.ensure_one()
+        move_line_model = self.env['account.move.line']
+        state_list = self.get_target_state_list(target_move)
+        domain = self.get_move_line_domain(from_date, to_date, company_id)
+        domain.extend([
+            ('move_id.state', 'in', state_list),
+            ('tax_line_id', '=', self.id),
+        ])
+        move_lines = move_line_model.search(domain)
+        total = sum([l.balance for l in move_lines])
+        return total
+
+    def compute_base_balance(
+        self, from_date, to_date, company_id, target_move="posted"
+    ):
+        self.ensure_one()
+        move_line_model = self.env['account.move.line']
+        state_list = self.get_target_state_list(target_move)
+        domain = self.get_move_line_domain(from_date, to_date, company_id)
+        domain.extend([
+            ('move_id.state', 'in', state_list),
+            ('tax_ids', 'in', self.id),
+        ])
+        move_lines = move_line_model.search(domain)
+        total = sum([l.balance for l in move_lines])
+        return total