issue #117 - WIP further budget balancing implementation

biweeklybudget/budget_balancer.py

@@ -166,7 +166,7 @@ def plan(self):
             "amount".
           - "budgets" - is a dict describing the budgets before and after
             balancing; keys are budget IDs and values are dicts with keys
-            "before" and "after", to values of the remaining amount.
+            "before" and "after", to values of the remaining amount, and "name"
           - "standing_before" - float, beginning balance of standing budget
           - "standing_after" - float, ending balance of standing budget
 
@@ -196,7 +196,10 @@ def plan(self):
             if data['remaining'] == 0:
                 continue
             to_balance[budg_id] = data['remaining']
-            result['budgets'][budg_id] = {'before': data['remaining']}
+            result['budgets'][budg_id] = {
+                'before': data['remaining'],
+                'name': self._budgets[budg_id].name
+            }
         # @TODO - REMOVE - DEBUGGING
         logger.debug('self._budgets=%s result=%s', self._budgets, result)
         # @TODO - END DEBUGGING
@@ -216,6 +219,14 @@ def plan(self):
         after, transfers, st_bal = self._do_plan_transfers(
             to_balance, [], self._standing.current_balance
         )
+        logger.debug(
+            'Before balancing with standing budget, standing balance=%s '
+            'transfers=%s, budget ending balances=%s', st_bal, transfers, after
+        )
+        # ok, now handle the standing budget stuff...
+        after, transfers, st_bal = self._do_plan_standing_txfr(
+            after, transfers, st_bal
+        )
         result['transfers'] = transfers
         logger.debug(
             'Budget transfers: \n%s',
@@ -237,6 +248,68 @@ def plan(self):
         )
         return result
 
+    def _do_plan_standing_txfr(self, id_to_remain, transfers, standing_bal):
+        """
+        Given a dictionary of budget IDs to remaining amounts, that have already
+        been balanced as much as possible using the remaining amounts of each
+        budget, use the Standing Budget to balance them all to zero.
+
+        The arguments of this function are the final return value from
+        :py:meth:`~._do_plan_transfers`.
+
+        Transfers is a list of lists, each inner list describing a budget
+        transfer and having 3 items: "from_id", "to_id" and "amount".
+
+        :param id_to_remain: Budget ID to remaining balance
+        :type id_to_remain: dict
+        :param transfers: list of transfer dicts for transfers made so far
+        :type transfers: list
+        :param standing_bal: balance of the standing budget
+        :type standing_bal: decimal.Decimal
+        :return: tuple of new id_to_remain, transfers, standing_bal
+        :rtype: tuple
+        """
+        # id_to_remain must be either all >= 0 or all <= 0
+        if min(id_to_remain, key=id_to_remain.get) >= 0:
+            # all positive
+            logger.debug(
+                'Balancing periodic budgets with standing; overall periodic sum'
+                ' is positive'
+            )
+            keyfunc = lambda: max(id_to_remain, key=id_to_remain.get)
+        else:
+            # all negative
+            logger.debug(
+                'Balancing periodic budgets with standing; overall periodic sum'
+                ' is negative'
+            )
+            keyfunc = lambda: min(id_to_remain, key=id_to_remain.get)
+        while sum(id_to_remain.values()) != 0 and standing_bal > 0:
+            logger.debug(
+                'Looping to reconcile periodic with standing; standing bal=%s,'
+                ' id_to_remain=%s, transfers=%s', standing_bal, id_to_remain,
+                transfers
+            )
+            k = keyfunc()
+            v = id_to_remain[k]
+            if v > 0:
+                transfers.append([k, self._standing.id, v])
+                standing_bal += v
+                id_to_remain[k] = 0
+                continue
+            # v < 0; transfer FROM standing TO periodic
+            if abs(v) < standing_bal:
+                # ok, we have enough to cover it
+                transfers.append([self._standing.id, k, abs(v)])
+                standing_bal += v
+                id_to_remain[k] = 0
+                continue
+            # we do NOT have enough in standing to cover it
+            transfers.append([self._standing.id, k, standing_bal])
+            id_to_remain[k] += standing_bal
+            standing_bal = 0
+        return id_to_remain, transfers, standing_bal
+
     def _do_plan_transfers(self, id_to_remain, transfers, standing_bal):
         """
         Given a dictionary of budget IDs to remaining amounts, figure out

biweeklybudget/flaskapp/static/js/balance_budgets_modal.js

@@ -124,12 +124,12 @@ function balanceBudgetsConfirmationDivForm(data) {
     content += '<div class="panel panel-info">' + "\n";
     content += '<div class="panel-heading">Budget Balances</div>' + "\n";
     content += '<div class="table-responsive">' + "\n";
-    content += '<table class="table table-bordered">' + "\n";
+    content += '<table class="table table-bordered" id="budg_bal_modal_budgets">' + "\n";
     content += "<thead><tr><th>Budget</th><th>Before</th><th>After</th></tr></thead>\n";
     content += "<tbody>\n";
     Object.keys(data.budgets).forEach(function (budg_id) {
         content += '<tr>';
-        content += '<td>' + budg_id + '</td>';
+        content += '<td>' + data.budgets[budg_id]['name'] + ' (' + budg_id + ')</td>';
         content += '<td>' + fmt_currency(data.budgets[budg_id]['before']) + '</td>';
         content += '<td>' + fmt_currency(data.budgets[budg_id]['after']) + '</td>';
         content += "</tr>\n";
@@ -146,7 +146,7 @@ function balanceBudgetsConfirmationDivForm(data) {
     content += '<div class="panel panel-info" style="padding-top: 1em;">' + "\n";
     content += '<div class="panel-heading">Transfers</div>' + "\n";
     content += '<div class="table-responsive">' + "\n";
-    content += '<table class="table table-bordered">' + "\n";
+    content += '<table class="table table-bordered" id="budg_bal_modal_transfers">' + "\n";
     content += "<thead><tr><th>Amount</th><th>From</th><th>To</th></tr></thead>\n";
     content += "<tbody>\n";
     for (var txfr in data.transfers) {

biweeklybudget/tests/acceptance/flaskapp/views/test_payperiods.py

@@ -1638,6 +1638,34 @@ def test_10_do_balance(self, base_url, selenium, testdb):
         budg_sel.select_by_value('4')
         selenium.find_element_by_id('modalSaveButton').click()
         self.wait_for_jquery_done(selenium)
+        modal, title, body = self.get_modal_parts(selenium)
+        self.assert_modal_displayed(modal, title, body)
+        assert title.text == 'Confirm Balance Budgets (%s)' % p_date_str
+        table = selenium.find_element_by_id('budg_bal_modal_budgets')
+        elems = self.tbody2elemlist(table)
+        htmls = []
+        for row in elems:
+            htmls.append(
+                [x.get_attribute('innerHTML') for x in row]
+            )
+        assert htmls == [
+            ['Periodic1 (1)', '-$75.00', '$0.00'],
+            ['Periodic8 (8)', '$350.00', '$0.00'],
+            ['Periodic9 (9)', '-$25.00', '$0.00'],
+            ['<strong>Standing1 (4)</strong>', '$1,284.23', '$1,384.23']
+        ]
+        table = selenium.find_element_by_id('budg_bal_modal_transfers')
+        elems = self.tbody2elemlist(table)
+        htmls = []
+        for row in elems:
+            htmls.append(
+                [x.get_attribute('innerHTML') for x in row]
+            )
+        assert htmls == [
+            ['$75.00', 'Periodic8 (8)', 'Periodic1 (1)'],
+            ['$25.00', 'Periodic8 (8)', 'Periodic9 (9)'],
+            ['$250.00', 'Periodic8 (8)', 'Standing1 (4)']
+        ]
 
 
 @pytest.mark.acceptance