add placeholders for subject of booking

planner.py

@@ -5,6 +5,7 @@
 
 from decimal import Decimal
 from datetime import date, timedelta
+from string import Template
 from dateutil.rrule import (
     rrule, YEARLY, MONTHLY, WEEKLY, DAILY, MO, TU, WE, TH, FR, SA, SU)
 from trytond.model import ModelSQL, ModelView, fields, Index, DeactivableMixin
@@ -430,6 +431,60 @@ class ScheduledBooking(DeactivableMixin, ModelSQL, ModelView):
         IrDate = Pool().get('ir.date')
         return IrDate.today()
 
+    @classmethod
+    def fill_placeholder(cls, linedata):
+        """ replace placeholder in description
+
+        Args:
+            description (str): booking text of planned booking
+        allowed substitution strings:
+            ${date}, ${month}, ${year}, ${amount}, ${quantity}
+
+        Returns:
+            str: booking text
+        """
+        pool = Pool()
+        IrDate = pool.get('ir.date')
+        Cashbook = pool.get('cashbook.book')
+
+        line_date = linedata.get('date', IrDate.today())
+        amount = linedata.get('amount', None)
+        from_book = linedata.get('cashbook', None)
+        if from_book:
+            from_book = Cashbook(from_book)
+        to_book = linedata.get('booktransf', None)
+        if to_book:
+            to_book = Cashbook(to_book)
+
+        quantity_txt = '-'
+        quantity = linedata.get('quantity', None)
+        if quantity is not None:
+            uom = (
+                to_book.quantity_uom if to_book and to_book.quantity_uom
+                else from_book.quantity_uom
+                if from_book and from_book.quantity_uom else None)
+            uom_digits = (
+                to_book.quantity_digits
+                if to_book and to_book.quantity_digits is not None
+                else from_book.quantity_digits
+                if from_book and from_book.quantity_digits is not None
+                else 2)
+            if uom:
+                quantity_txt = Report.format_number_symbol(
+                    quantity, lang=None, symbol=uom, digits=uom_digits)
+            else:
+                quantity_txt = Report.format_number(
+                    quantity, lang=None, digits=uom_digits)
+
+        return Template(linedata.get('description')).safe_substitute({
+            'date': Report.format_date(line_date, lang=None),
+            'month': line_date.month,
+            'year': line_date.year,
+            'amount': Report.format_currency(
+                amount, lang=None, currency=from_book.currency)
+            if (amount is not None) and from_book else '-',
+            'quantity': quantity_txt})
+
     @classmethod
     def update_next_occurence(cls, records, query_date=None):
         """ compute date of next execution, create/update nextrun-record,
@@ -573,6 +628,7 @@ class ScheduledBooking(DeactivableMixin, ModelSQL, ModelView):
                     if record.booktransf.feature == 'asset':
                         line.update(add_asset_values(
                             line, record.cashbook, record.booktransf))
+            line['description'] = cls.fill_placeholder(line)
 
             if record.wfcheck:
                 to_create_check.append(line)