Add max days per week block constraint and exclude days for shift constraints

rota/shifts.py

@@ -92,10 +92,12 @@ class NightConstraint(BaseShiftConstraint):
 class PreShiftConstraint(BaseShiftConstraint):
     days: Any = None
     ignore_shifts: List[str] = []
+    exclude_days: List[str] = ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"]
 
 class PostShiftConstraint(BaseShiftConstraint):
     days: Any = None
     ignore_shifts: List[str]  = []
+    exclude_days: List[str] = ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"]
 
 class BalanceAcrossGroupsConstraint(BaseShiftConstraint):
     """"""
@@ -385,6 +387,7 @@ class RotaBuilder(object):
             "max_night_frequency_week_exclusions": [],
             "max_shifts_per_week": 7,
             "max_shifts_per_month": 40,
+            "max_days_per_week_block": [(3, 2)],  # (max_days, week_block)
             # The following will cause an unsolvable problem if a shift
             # is forced as a block and spans the time peroid
             "prevent_monday_after_full_weekends": [],
@@ -1840,6 +1843,17 @@ class RotaBuilder(object):
                     >= -self.constraint_options["maximum_allowed_shift_diff"]
                 )
 
+            for max_days, weeks in self.constraint_options["max_days_per_week_block"]:
+                for week_blocks in self.get_week_block_iterator(weeks):
+                    self.model.constraints.add(
+                        sum(
+                            self.model.works_day[worker.id, week, day]
+                            for week, day in self.get_week_day_combinations()
+                            if week in week_blocks
+                        )
+                        <= max_days
+                    )
+
             for week_blocks in self.get_week_block_iterator(4):
                 # Prevent more than n number shifts per 4 weeks
                 try:
@@ -2922,6 +2936,8 @@ class RotaBuilder(object):
                     if week not in constraint.weeks:
                         continue
                     for n in range(0, constraint.days):
+                        if day in constraint.exclude_days:
+                            continue
                         if day in constraint_shift.days:
                             # Only apply if worker can work this shift
                             if worker.site not in constraint_shift.sites:
@@ -2957,6 +2973,8 @@ class RotaBuilder(object):
                     if week not in constraint.weeks:
                         continue
                     for n in range(0, constraint.days):
+                        if day in constraint.exclude_days:
+                            continue
                         if day in constraint_shift.days:
                             # Only apply if worker can work this shift
                             if worker.site not in constraint_shift.sites: