builder: Reach workable calculation

product/ERP5/mixin/builder.py

@@ -450,7 +450,7 @@ class BuilderMixin(XMLObject, Amount, Predicate):
       )
 
     # Prepare period_list
-    limit_date = getPreviousValidDate(from_date)
+    limit_date = getPreviousValidDate(getPreviousValidDate(from_date) - 0.1)
     limit_date_list = []
     last_date = getPreviousValidDate(history_list[-1][0])
     while limit_date <= last_date:
@@ -460,6 +460,9 @@ class BuilderMixin(XMLObject, Amount, Predicate):
         # Hackish and dangerous
         next_start_date=limit_date)).earliestTime()
 
+    min_stock_value = supply.getMinOrderQuantity() / default_quantity_unit_flow_quantity_unit_conversion_ratio
+    factor = supply.getMinFlow()
+    next_period_history_list = []
     #self.log(limit_date_list)
     # Create a movement per period
     for period_start_date in limit_date_list:
@@ -470,16 +473,46 @@ class BuilderMixin(XMLObject, Amount, Predicate):
         next_start_date=period_start_date)).earliestTime()
       period_history_list = []
 
+      if next_period_history_list and\
+          next_next_period_start_date == next_period_start_date:
+        period_history_list = next_period_history_list[:]
       while history_list and history_list[0][0] < next_period_start_date:
         period_history_list.append(history_list.pop(0))
 
       # Using period history list calculate min stock
-      min_inventory = self.Base_evaluateMinInventoryForSupplyAtDate(
+      # In this iteration we verify that the invetory is always superior
+      # to the min_stock_value
+      min_inventory_end_of_period = min_stock_value
+
+      # Anticipate next period need if a ratio is defined
+      next_period_history_list = []
+      next_next_period_start_date = DateTime(supply.getNextPeriodicalDate(
+        next_period_start_date,
+        next_start_date=next_period_start_date)).earliestTime()
+      if factor and next_next_period_start_date <= last_date:
+        # prepare new hixtory_list
+        while history_list and history_list[0][0] < next_next_period_start_date:
+          next_period_history_list.append(history_list.pop(0))
+
+        # Calculate need with ratio
+        # Here it is actually just a ratio of the next period consumption.
+        min_inventory_end_of_period = self.Base_evaluateMinInventoryForSupplyAtDate(
+          supply=supply,
+          history_list=next_period_history_list,
+          at_date=next_period_start_date,
+          factor=factor,
+          min_stock_value=min_inventory_end_of_period,
+          )
+
+      week_consumption = self.Base_evaluateMinInventoryForSupplyAtDate(
         supply=supply,
         history_list=period_history_list,
         at_date=period_start_date,
-        conversion_ratio=default_quantity_unit_flow_quantity_unit_conversion_ratio,
+        factor=1,
         )
+
+      min_inventory = min_inventory_end_of_period + week_consumption
+
       quantity = 0
 
       if future_inventory_to_date < min_inventory: # SKU