continue

shifts.py

@@ -2,6 +2,11 @@ import datetime
 import itertools
 from typing import List, Tuple
 
+from workers import Worker
+
+from pyomo.environ import *
+from pyomo.opt import SolverFactory
+
 ShiftName = str
 DayStr = str
 WeekInt = int
@@ -48,7 +53,8 @@ class SingleShift(object):
 
         self.total_shifts = length * len(days) * len(shift_days)
 
-class ShiftCollection(object):
+
+class RotaBuilder(object):
     """Class to hold and manipulate shifts"""
 
     def __init__(self, weeks_to_rota=26):
@@ -64,6 +70,507 @@ class ShiftCollection(object):
 
         self.unavailable_to_work = set()
 
+        self.workers = []
+
+        self.night_blocks = ["weekday", "weekend", "none"]
+
+    def build_model(self):
+        # Initialize model
+        self.model = ConcreteModel()
+
+        # binary variables representing if a worker is scheduled somewhere
+        # NOTE: this will assign to all possible shift combinations (which we probably don't want)
+        self.model.works = Var(
+            (
+                (worker.id, week, day, shift)
+                for worker in self.workers
+                for week, day in self.get_week_day_combinations()
+                for shift in self.get_shift_names()
+            ),
+            within=Binary,
+            initialize=0,
+        )
+
+        # The nights self.model is used to ensure nights are assigned as a block (and limit the number of workers required)
+        self.model.nights = Var(
+            (
+                (worker.id, week, block)
+                for worker in self.workers
+                for week in self.weeks
+                for block in self.night_blocks
+            ),
+            within=Binary,
+            initialize=0,
+        )
+
+        self.model.shift_count = Var(
+            (
+                (worker.id, shift)
+                for worker in self.workers
+                for shift in self.get_shift_names()
+            ),
+            domain=NonNegativeReals,
+            initialize=0,
+        )
+
+        # self.model.shift_count_t1 = Var(((worker.id, shift) for worker in self.workers for shift in self.get_shift_names()), domain=NonNegativeReals, initialize=0)
+        # self.model.shift_count_t2 = Var(((worker.id, shift) for worker in self.workers for shift in self.get_shift_names()), domain=NonNegativeReals, initialize=0)
+
+        self.model.shift_count_t1 = Var(
+            ((worker.id) for worker in self.workers),
+            domain=NonNegativeReals,
+            initialize=0,
+        )
+        self.model.shift_count_t2 = Var(
+            ((worker.id) for worker in self.workers),
+            domain=NonNegativeReals,
+            initialize=0,
+        )
+
+        self.model.shift_count_t3 = Var(
+            (worker.id for worker in self.workers), initialize=0
+        )
+        # self.model.unavailable = Var(((worker, week, day) for worker in self.workers for week in weeks for day in days),
+        #                  within=Binary, initialize=0)
+
+        def availability_init(model, wid, week, day):
+            if (wid, week, day) in self.unavailable_to_work:
+                # print((wid, week, day))
+                return 0
+            return 1
+
+        self.model.available = Param(
+            (
+                (worker.id, week, day)
+                for worker in self.workers
+                for week, day in self.get_week_day_combinations()
+            ),
+            initialize=availability_init,
+        )
+
+        # binary variables representing if a worker is necessary
+        # self.model.needed = Var([worker.id for worker in self.workers], within=Binary, initialize=0)
+
+        # binary variables representing if a worker worked on sunday but not on saturday (avoid if possible)
+        # self.model.no_pref = Var([worker.id for worker in self.workers], within=Binary, initialize=0)
+
+        self.build_model_constraints()
+
+    def build_model_constraints(self):
+        self.model.constraints = ConstraintList()  # Create a set of constraints
+
+        for (
+            week,
+            day,
+            shift,
+            self.workers_required,
+            site_required,
+        ) in self.get_required_workers_and_site_combinations():
+            # print(week, day, shift, self.workers_required, site_required)
+            self.model.constraints.add(
+                self.workers_required
+                == sum(
+                    self.model.works[worker.id, week, day, shift]
+                    for worker in self.workers
+                    if worker.site in site_required
+                )
+            )
+
+        for week, day, shift in self.get_not_required_shifts():
+            self.model.constraints.add(
+                0
+                == sum(
+                    self.model.works[worker.id, week, day, shift.name]
+                    for worker in self.workers
+                )
+            )
+
+        # Constraint: total hours worked hours worked
+        # for worker in self.workers:
+        #    self.model.constraints.add(
+        #        1200 >= sum(shift_lengths[shift] * self.model.works[worker, week, day, shift] for week in weeks for day in days for shift in days_shifts[day])
+        #    )
+
+        # for week in weeks:
+        #    for worker in self.workers:
+        #        self.model.constraints.add(
+        #            48 >= sum(shift_lengths[shift] * self.model.works[worker, week, day, shift] for day in days for shift in days_shifts[day])
+        #        )
+
+        def maxHoursPerWeekRule(model, wid, week):
+            return 72 >= sum(
+                shift.length * model.works[wid, week, day, shift.name]
+                for day, shift in self.get_day_shiftclass_products()
+            )
+
+        self.model.max_hours_per_week_constraint = Constraint(
+            [worker.id for worker in self.workers], self.weeks, rule=maxHoursPerWeekRule
+        )
+
+        def maxHoursRule(model, wid):
+            return 8000 >= sum(
+                shift.length * model.works[wid, week, day, shift.name]
+                for week, day, shift in self.get_all_shiftclass_combinations()
+            )
+
+        self.model.max_hours_constraint = Constraint(
+            [worker.id for worker in self.workers], rule=maxHoursRule
+        )
+
+        # self should not be allocated on nwds (excepting night shifts)
+        def nwdRule(model, worker):
+            print(worker, worker.id, worker.nwd)
+            wid = worker.id
+            nwd = worker.nwd
+            return 0 == sum(
+                model.works[wid, week, day, shift.name]
+                for week, day, shift in self.get_all_shiftclass_combinations()
+                if (not shift.rota_on_nwds and day in nwd)
+            )
+
+        # self.model.nwd_constraint = Constraint([(worker) for worker in self.workers if worker.nwd], rule=nwdRule)
+
+        # Set a rule to even twilight shifts:
+        # total_twilight_shifts = len(weeks) * 5 * 1 # One person per site
+
+        # def trurotwilightShiftNumberRule(self.model, wid, fte_adj, site, shift):
+        #    #site, shift = site_and_shift
+        #    max_shifts = total_twilight_shifts / self.full_time_equivalent_sites[site] * fte_adj + twilight_balance_offset
+        #    min_shifts = total_twilight_shifts / self.full_time_equivalent_sites[site] * fte_adj - twilight_balance_offset
+
+        #    return inequality(min_shifts, sum(self.model.works[wid, week, day, shift.GetShift()] for week in weeks for day in days), max_shifts)
+        # self.model.twilight_shifts_truro_constraint = Constraint([(worker.id, worker.fte_adj, ss[0], ss[1]) for ss in site_and_shifts for worker in self.workers if worker.site == ss[0]], rule=trurotwilightShiftNumberRule)
+
+        # def plymouthtwilightShiftNumberRule(self.model, wid, fte_adj):
+        #    max_shifts = total_twilight_shifts / self.full_time_equivalent_sites["plymouth"] * fte_adj + twilight_balance_offset
+        #    min_shifts = total_twilight_shifts / self.full_time_equivalent_sites["plymouth"] * fte_adj - twilight_balance_offset
+        #
+        #    return inequality(min_shifts, sum(self.model.works[wid, week, day, "plymouth_twilight"] for week in weeks for day in days), max_shifts)
+        # self.model.twilight_shifts_plymouth_constraint = Constraint([(worker.id, worker.fte_adj) for worker in self.workers if worker.site == "plymouth"], #rule=plymouthtwilightShiftNumberRule)
+
+        # Limit to 1 ST2 (or below) on a night shift
+        def nightShiftMaxSTRule(model, week, block):
+            """Limits to 1 ST2 (or below) per night"""
+            single_workers = [w for w in self.workers if w.grade < 3]
+            if not single_workers:
+                return Constraint.Skip
+            return sum(model.nights[w.id, week, block] for w in single_workers) <= 1
+
+        self.model.night_shifts_max_st_constraint = Constraint(
+            [week for week in self.weeks],
+            [block for block in ["weekday", "weekend"]],
+            rule=nightShiftMaxSTRule,
+        )
+
+        # Enusre at least 1 ST4+ on a night shift
+        def nightShiftMinST4Rule(model, week, block):
+            single_workers = [w for w in self.workers if w.grade > 3]
+            if not single_workers:
+                return Constraint.Skip
+            return sum(model.nights[w.id, week, block] for w in single_workers) >= 1
+
+        self.model.night_shifts_min_st4_constraint = Constraint(
+            [week for week in self.weeks],
+            [block for block in ["weekday", "weekend"]],
+            rule=nightShiftMinST4Rule,
+        )
+
+        # Constraint (def of self.model.needed)
+        # for worker in self.workers:
+        #    self.model.constraints.add(
+        #        10000 * self.model.needed[worker.id] >= sum(self.model.works[worker.id, week, day, shift] for week in weeks for day in days for shift in days_shifts[day])
+        #    )  # if any self.model.works[worker, ·, ·] non-zero, self.model.needed[worker] must be one; else is zero to reduce the obj function
+        # 10000 is to remark, but 5 was enough since max of 40 hours yields max of 5 shifts, the maximum possible sum
+
+        # Constraint (def of self.model.no_pref)
+        # for worker in self.workers:
+        #    for week in weeks:
+        #        self.model.constraints.add(
+        #            self.model.no_pref[worker.id] >= sum(self.model.works[worker.id, week, 'Sat', shift] for shift in days_shifts['Sat'])
+        #            - sum(self.model.works[worker.id, week, 'Sun', shift] for shift in days_shifts['Sun'])
+        #        )  # if not working on sunday but working saturday self.model.needed must be 1; else will be zero to reduce the obj function
+
+        # def balanceSiteShiftNumberRule(model, wid, fte_adj, shiftClass):
+        #     # TODO: make helper to retrieve
+        #     total_shifts = len(self.weeks) * len(shiftClass.shift_days) * shiftClass.self.workers_required # One person per site
+
+        #     full_time_equivalent_joined = sum([self.full_time_equivalent_sites[i] for i in shiftClass.site])
+
+        #     max_shifts = total_shifts / full_time_equivalent_joined * fte_adj + twilight_balance_offset
+        #     min_shifts = total_shifts / full_time_equivalent_joined * fte_adj - twilight_balance_offset
+
+        #     return inequality(min_shifts, sum(self.model.works[wid, week, day, shiftClass.name] for week, day in self.get_week_day_combinations()), max_shifts)
+
+        # #self.model.balance_site_shift_constraint = Constraint([(worker.id, worker.fte_adj, shift) for shift in self.GetShiftOptions() for worker in self.workers if worker.site in shift.site and shift.balance_by_site], rule=balanceSiteShiftNumberRule)
+
+        # # set a rule to even night shifts (could also be done in blocks, which may be quicker?)
+        # # takes into accound both LTFT, OOP and leaving the training scheme
+        # #total_night_shifts = self.rota_days_length * self.GetShiftByName("night").self.workers_required
+
+        # def nightShiftNumberRule(model, wid, fte_adj): # NOTE no longer used - see generic function below
+        #     target_shifts = total_night_shifts / self.full_time_equivalent * fte_adj
+        #     max_shifts = target_shifts + night_balance_offset
+        #     min_shifts = target_shifts - night_balance_offset
+
+        #     return inequality(min_shifts, sum(model.works[wid, week, day, "night"] for week, day in self.get_week_day_combinations()), max_shifts)
+        # #self.model.night_shifts_constraint = Constraint([(worker.id, worker.fte_adj) for worker in self.workers], rule=nightShiftNumberRule)
+        # twilight_constraints = {}
+
+        # Balance shifts
+        for worker in self.workers:
+            for shift in self.GetShiftOptions():
+                if (
+                    worker.site in shift.site
+                ):  # Each site specfies which sites self.workers can fullfill it
+
+                    # total_shifts = self.rota_days_length * shift.workers_required # One person per site
+                    total_shifts = (
+                        len(self.weeks)
+                        * len(shift.shift_days)
+                        * shift.workers_required
+                    )
+
+                    # if shift.balance_by_site:
+                    full_time_equivalent_joined = sum(
+                        [self.full_time_equivalent_sites[i] for i in shift.site]
+                    )
+
+                    target_shifts = (
+                        total_shifts / full_time_equivalent_joined * worker.fte_adj
+                    )
+
+                    worker.shift_target_number[shift.name] = target_shifts
+
+                    max_shifts = target_shifts + shift.balance_offset
+                    min_shifts = target_shifts - shift.balance_offset
+                    # print(max_shifts, min_shifts)
+
+                    self.model.constraints.add(
+                        inequality(
+                            min_shifts,
+                            sum(
+                                self.model.works[worker.id, week, day, shift.name]
+                                for week, day in self.get_week_day_combinations()
+                            ),
+                            max_shifts,
+                        )
+                    )
+                    # return inequality(min_shifts, sum(self.model.works[wid, week, day, shiftClass.name] for week, day in self.get_week_day_combinations()), max_shifts)
+
+        for worker in self.workers:
+            # Define shift_count_t1 and shift_count_t2 constraints for the object
+            # This bypassing the need for a quadratic solver
+            # t1-t2 is the target
+            # As the objective is to minimise t1+t2 and t1 and t2 are positive reals
+            # t1+t2 approximates the absolute target (which otherwise requires a quadratic solver)
+            self.model.constraints.add(
+                # self.model.shift_count_t3[worker.id] == abs(sum(self.model.shift_count[worker.id, shift.name] - worker.shift_target_number[shift.name] for shift in self.GetShiftOptions()))
+                self.model.shift_count_t1[worker.id]
+                - self.model.shift_count_t2[worker.id]
+                == sum(
+                    (
+                        self.model.shift_count[worker.id, shift.name]
+                        - worker.shift_target_number[shift.name]
+                    )
+                    * shift.balance_weighting
+                    for shift in self.GetShiftOptions()
+                )
+            )
+            for shift in self.GetShiftOptions():
+                self.model.constraints.add(
+                    self.model.shift_count[worker.id, shift.name]
+                    == sum(
+                        self.model.works[worker.id, week, day, shift.name]
+                        for week, day in self.get_week_day_combinations()
+                    )
+                )
+                # self.model.constraints.add(
+                #    #self.model.shift_count_t1[worker.id, shift.name]-self.model.shift_count_t2[worker.id, shift.name] == self.model.shift_count[worker.id, shift.name]
+                # self.model.shift_count_t1[worker.id, shift.name]-self.model.shift_count_t2[worker.id, shift.name] == self.model.shift_count[worker.id, shift.name] - worker.shift_target_number[shift.name]
+                # )
+
+            if worker.nwd:
+                for week, day, shift in self.get_all_shiftclass_combinations():
+                    if not shift.rota_on_nwds and day in worker.nwd:
+                        self.model.constraints.add(
+                            0 == self.model.works[worker.id, week, day, shift.name]
+                        )
+
+        # Constraint: rest between two shifts is of 12 hours (i.e., at least two shifts)
+        weeks_days = self.get_week_day_combinations()
+        for worker in self.workers:
+            if "nights" in self.get_shift_names():
+
+                for week_blocks in self.get_week_block_iterator(2):
+                    # Prevent nights more than once every n weeks
+                    self.model.constraints.add(
+                        1
+                        >= sum(
+                            self.model.nights[worker.id, week, block]
+                            for week in week_blocks
+                            for block in ["weekday", "weekend"]
+                        )
+                    )
+
+            for week in self.weeks:
+                if "nights" in self.get_shift_names():
+                    # Force nights to be assigned in blocks
+                    self.model.constraints.add(
+                        1
+                        == sum(
+                            self.model.nights[worker.id, week, block]
+                            for block in self.night_blocks
+                        )
+                    )
+
+                    # if night block is weekday make sure Mon - Thurs is assigned as nights
+                    self.model.constraints.add(
+                        self.model.nights[worker.id, week, "weekday"] * 4
+                        == sum(
+                            self.model.works[worker.id, week, day, "night"]
+                            for day in days[:4]
+                        )
+                    )
+                    self.model.constraints.add(
+                        self.model.nights[worker.id, week, "weekend"] * 3
+                        == sum(
+                            self.model.works[worker.id, week, day, "night"]
+                            for day in days[4:]
+                        )
+                    )
+
+                #
+
+            for n in range(len(weeks_days)):
+
+                week, day = weeks_days[n]
+
+                p1 = 1
+                if n > 0:
+                    pweek, pday = weeks_days[n - 1]
+                else:
+                    p1 = 0
+                    pweek, pday = weeks_days[n]
+
+                n1 = 1
+                n2 = 1
+                try:
+                    nweek, nday = weeks_days[n + 1]
+                except IndexError:
+                    # print(worker.id, "shit")
+                    nweek, nday = weeks_days[n]
+                    n1 = 0
+
+                try:
+
+                    n2week, n2day = weeks_days[n + 2]
+                except IndexError:
+                    # print(worker.id, "shit2")
+                    n2week, n2day = weeks_days[n]
+                    n2 = 0
+
+                # print(week, day, nweek, nday, n2week, n2day, n1, n2)
+                # Unable to work (hard constraint not preference)
+                self.model.constraints.add(
+                    self.model.available[worker.id, week, day]
+                    >= sum(
+                        self.model.works[worker.id, week, day, shift]
+                        for shift in self.get_shift_namesByDay(day)
+                    )
+                )
+
+                if "nights" in self.get_shift_names():
+                    self.model.constraints.add(
+                        self.model.available[worker.id, week, day]
+                        >= self.model.works[worker.id, pweek, pday, "night"]
+                    )
+
+                # single shift per day
+                self.model.constraints.add(
+                    1
+                    >= sum(
+                        self.model.works[worker.id, week, day, shift]
+                        for shift in self.get_shift_namesByDay(day)
+                    )
+                )
+                ## if working in evening, until next evening (note that after sunday comes next monday)
+                # self.model.constraints.add(
+                #    1 >= sum(self.model.works[worker.id, week, days[j], shift] for shift in ['evening', 'night']) +
+                #    self.model.works[worker.id, nweek, days[(j + 1) % 7], 'truro_twilight']
+                # )
+
+                # if working a night ensure preceeding (1) or subsequent (2) shifts can only be nights
+
+                if "nights" in self.get_shift_names():
+
+                    self.model.constraints.add(
+                        1
+                        >= self.model.works[worker.id, week, day, "night"]
+                        + sum(
+                            n1 * self.model.works[worker.id, nweek, nday, shift]
+                            for shift in self.get_shift_namesByDay(nday)
+                            if shift != "night"
+                        )
+                        + sum(
+                            n2 * self.model.works[worker.id, n2week, n2day, shift]
+                            for shift in self.get_shift_namesByDay(n2day)
+                            if shift != "night"
+                        )
+                        + sum(
+                            p1 * self.model.works[worker.id, pweek, pday, shift]
+                            for shift in self.get_shift_namesByDay(pday)
+                            if shift != "night"
+                        )
+                    )
+
+        self.define_objectives()
+
+    def define_objectives(self):
+        # Define an objective function with model as input, to pass later
+        def obj_rule(m):
+            
+            #c = len(workers)
+
+            #return 1
+            return sum(self.model.shift_count_t1[(worker.id)] + self.model.shift_count_t2[(worker.id)] for worker in self.workers)
+            #return sum(model.shift_count_t3[worker.id] for worker in workers)
+            
+
+
+        # add objective function to the model. rule (pass function) or expr (pass expression directly)
+        self.model.obj = Objective(rule=obj_rule, sense=minimize)
+
+    def add_worker(self, worker: Worker):
+        """Add a worker to the rota
+
+        Args:
+            worker (Worker):
+        """
+        self.workers.append(worker)
+
+    def add_workers(self, workers: List):
+        """Add multiple worker to the rota
+
+        Args:
+            workers (List(Worker)):
+        """
+        self.workers.extend(workers)
+
+    def build_workers(self):
+        """Process loaded workers
+
+        Must be called prior to attempting to solve
+        """
+        self.workers = sorted(self.workers)
+
+        self.full_time_equivalent = sum([w.fte_adj for w in self.workers])
+        self.full_time_equivalent_sites = {}
+
+        for site in sites:
+            self.full_time_equivalent_sites[site] = sum(
+                [w.fte_adj for w in self.workers if w.site == site]
+            )
+
     def add_shift(self, shift):
         """Add a shift to the collection
 
@@ -71,7 +578,7 @@ class ShiftCollection(object):
 
         """
         self.shifts.append(shift)
-        self.BuildShifts()
+        self.BuildShift()
 
     def add_shifts(self, *shifts: SingleShift):
         """Add multiple shifts
@@ -80,9 +587,9 @@ class ShiftCollection(object):
             None
         """
         self.shifts.extend(shifts)
-        self.BuildShifts()
+        self.BuildShift()
 
-    def GetShiftNamesByDay(self, day: DayStr):
+    def get_shift_namesByDay(self, day: DayStr):
         """Returns the shifts required for a specific day
 
         Returns:
@@ -110,7 +617,7 @@ class ShiftCollection(object):
         """
         return self.shifts_by_name[name].length
 
-    def BuildShifts(self):
+    def BuildShift(self):
         """ """
         self.shifts_by_name = {}
         self.shift_names = []  # type: List[ShiftName]
@@ -140,7 +647,7 @@ class ShiftCollection(object):
                     self.day_shift_product.append((day, s.name))
                     self.day_shiftclass_product.append((day, s))
 
-    def GetAllDayShiftsAsNames(self):
+    def GetAllDayShiftAsNames(self):
         """Returns a list of all required day / shift combinations
         
         Returns:
@@ -148,7 +655,7 @@ class ShiftCollection(object):
         """
         return self.day_shift_product
 
-    def GetAllDayShiftsAsClass(self) -> List[Tuple[DayStr, SingleShift]]:
+    def get_day_shiftclass_products(self) -> List[Tuple[DayStr, SingleShift]]:
         """Returns a list of all required day / shift combinations
         
         Returns:
@@ -156,7 +663,7 @@ class ShiftCollection(object):
         """
         return self.day_shiftclass_product
 
-    def GetAllShiftsAsNames(self) -> List[Tuple[WeekInt, DayStr, ShiftName]]:
+    def GetAllShiftAsNames(self) -> List[Tuple[WeekInt, DayStr, ShiftName]]:
         """Returns a list of all possible week / day / shift combinations
         
         Returns:
@@ -164,7 +671,7 @@ class ShiftCollection(object):
         """
         return self.week_day_shift_product
 
-    def GetAllShiftsAsClass(self) -> List[Tuple[WeekInt, DayStr, SingleShift]]:
+    def get_all_shiftclass_combinations(self) -> List[Tuple[WeekInt, DayStr, SingleShift]]:
         """Returns a list of all possible week / day / shift combinations
         
         Returns:
@@ -172,7 +679,7 @@ class ShiftCollection(object):
         """
         return self.week_day_shiftclass_product
 
-    def GetAllWeeksDays(self) -> list:
+    def get_week_day_combinations(self) -> list:
         """Returns a list of all week / day tuple combinations
 
         Returns:
@@ -189,7 +696,7 @@ class ShiftCollection(object):
         """
         return self.shifts
 
-    def GetShiftNames(self) -> List[ShiftName]:
+    def get_shift_names(self) -> List[ShiftName]:
         """Returns a list of all the registered shift names
         
         Returns:
@@ -197,7 +704,7 @@ class ShiftCollection(object):
         """ """ """
         return self.shift_names
 
-    def GetWeeksInBlocks(self, block_length):
+    def get_week_block_iterator(self, block_length):
         """Gets a two dimensional list of week blocks in specified length
 
         e.g. block_length = 4
@@ -218,7 +725,7 @@ class ShiftCollection(object):
             blocks.append(self.weeks[i : i + block_length])
         return blocks
 
-    def GetRequiredShiftsWorkersAndSites(self):
+    def get_required_workers_and_site_combinations(self):
         """Returns a list of all possible shifts, the workers required and site
         
         Returns:
@@ -227,11 +734,13 @@ class ShiftCollection(object):
         l = []
         for week, day, shift in self.week_day_shiftclass_product:
             if day in shift.shift_days:
-                l.append((week, day, shift.name, shift.workers_required, shift.site))
+                l.append(
+                    (week, day, shift.name, shift.workers_required, shift.site)
+                )
 
         return l
 
-    def GetNotRequiredShifts(self):
+    def get_not_required_shifts(self):
         """Returns a set of all possible shifts combinations that are not required
 
         Includes those on days
@@ -246,4 +755,4 @@ class ShiftCollection(object):
                 for shift in self.shifts:
                     l.add((week, day, shift))
 
-        return l - set(self.GetAllShiftsAsClass())
+        return l - set(self.get_all_shiftclass_combinations())

workers.py

@@ -1,11 +1,13 @@
 import datetime
 from collections import defaultdict
 
-from shifts import SingleShift, ShiftCollection, days, sites
+#from shifts import RotaBuilder, days, sites
 
 
 class Worker:
-    def __init__(self, Shifts, id, name, site, grade, fte=100, nwd=None, end_date=None, oop=None):
+    def __init__(
+        self, Rota, id, name, site, grade, fte=100, nwd=None, end_date=None, oop=None
+    ):
         self.id = id
         self.name = name
         self.site = site
@@ -16,48 +18,53 @@ class Worker:
 
         self.shift_target_number = defaultdict(int)
 
-        days_to_work = Shifts.rota_days_length
+        days_to_work = Rota.rota_days_length
 
         if end_date is None:
             self.end_date = None
         else:
-            self.end_date = datetime.datetime.strptime(end_date, '%Y/%m/%d').date()
+            self.end_date = datetime.datetime.strptime(end_date, "%Y/%m/%d").date()
 
-            if self.end_date > Shifts.rota_end_date:
-                self.end_date = Shifts.rota_end_date
+            if self.end_date > Rota.rota_end_date:
+                self.end_date = Rota.rota_end_date
             else:
-                days_to_work = (self.end_date - Shifts.start_date).days
+                days_to_work = (self.end_date - Rota.start_date).days
 
                 # add unavalabilities
-                for weeks_days in Shifts.weeks_days_product[days_to_work:]:
+                for weeks_days in Rota.weeks_days_product[days_to_work:]:
                     week, day = weeks_days
-                    Shifts.unavailable_to_work.add((self.id, week, day))
-        
+                    Rota.unavailable_to_work.add((self.id, week, day))
+
         if oop is not None:
             start_oop, end_oop = oop
-            start_oop_date = datetime.datetime.strptime(start_oop, '%Y/%m/%d').date()
-            end_oop_date = datetime.datetime.strptime(end_oop, '%Y/%m/%d').date()
+            start_oop_date = datetime.datetime.strptime(start_oop, "%Y/%m/%d").date()
+            end_oop_date = datetime.datetime.strptime(end_oop, "%Y/%m/%d").date()
+
+            if end_oop_date > Rota.rota_end_date:
+                end_oop_date = Rota.rota_end_date
 
-            if end_oop_date > Shifts.rota_end_date:
-                end_oop_date = Shifts.rota_end_date
-            
             oop_length = (end_oop_date - start_oop_date).days
             days_to_work = days_to_work - oop_length
 
-            days_until_oop = (start_oop_date - Shifts.start_date).days
+            days_until_oop = (start_oop_date - Rota.start_date).days
 
-            for weeks_days in Shifts.weeks_days_product[days_until_oop:days_until_oop+oop_length]:
+            for weeks_days in Rota.weeks_days_product[
+                days_until_oop : days_until_oop + oop_length
+            ]:
                 week, day = weeks_days
-                Shifts.unavailable_to_work.add((self.id, week, day))
+                Rota.unavailable_to_work.add((self.id, week, day))
 
-        
-        self.proportion_rota_to_work = days_to_work / Shifts.rota_days_length
+        self.proportion_rota_to_work = days_to_work / Rota.rota_days_length
 
         # We had to adjust the full time equivalent for people who CCT / leave the rota early
         self.fte_adj = self.fte * self.proportion_rota_to_work
 
     def __lt__(self, other):
-        return (self.site, self.grade, self.name) < (other.site, other.grade, other.name)
-    
+        return (self.site, self.grade, self.name) < (
+            other.site,
+            other.grade,
+            other.name,
+        )
+
     def get_details(self):
-        return "{} {} {}".format(self.id, self.site[0], self.grade)
+        return "{} {} {}".format(self.id, self.site[0], self.grade)