Reorganize more code

It might make logical sense.  Honestly, I'm just tired of the code for
World being so long.

aoe/costs.py

@@ -5,6 +5,10 @@ from aoe.types import *
 class Costs():
 
 
+    def compute_cost(self, purchase):
+        return self.costs[purchase]
+
+
     def __init__(self):
         self.costs = {
                       Ages.DARK: (0, 0, 0, 0),

aoe/dependencies.py

@@ -1,9 +1,77 @@
 from aoe.types import *
+from aoe.exceptions import *
 
 
 
-class BuildingDependencies():
+class Dependencies():
+
+
+    def check_dependencies(self, world, thing):
+        if type(thing) == Ages:
+            self._check_age_dependencies(world, thing)
+        else:
+            self._check_non_age_dependencies(world, thing)
+
+
+    def _check_non_age_dependencies(self, world, thing):
+        for dep in self.dependencies[thing]:
+            if dep not in world.buildings and \
+                    dep not in world.research and \
+                    not self._is_sufficient_age(world, dep):
+                        raise MissingDependencyException
+
+
+    @staticmethod
+    def _is_sufficient_age(world, age):
+        if type(age) == Ages and world.age >= age:
+            return True
+        return False
+
+
+    def _check_age_dependencies(self, world, age):
+        total_buildings = 0
+        for building in self.age_dependencies[age].keys():
+            if world.has_building(building):
+                total_buildings += self.age_dependencies[age][building]
+        if total_buildings < self.age_dependencies_counts[age]:
+            raise MissingDependencyException
+
+
     def __init__(self):
+        self.age_dependencies = {
+                             Ages.FEUDAL: {
+                                           Buildings.BARRACKS: 1,
+                                           Buildings.MILL: 1,
+                                           Buildings.LUMBERCAMP: 1,
+                                           Buildings.MININGCAMP: 1,
+                                           Buildings.DOCK: 1,
+                                           #Buildings.MULECART: 1,
+                                           #Buildings.FOLWARK: 1,
+                                           #Buildings.SETTLEMENT: 2,
+                                          },
+                             Ages.CASTLE: {
+                                           Buildings.ARCHERYRANGE: 1,
+                                           Buildings.STABLE: 1,
+                                           Buildings.MARKET: 1,
+                                           Buildings.BLACKSMITH: 1,
+                                           Buildings.SIEGEWORKSHOP: 1,
+                                          },
+                             Ages.IMPERIAL: {
+                                             Buildings.MONASTERY: 1,
+                                             #Buildings.FORTIFIEDCHURCH: 1,
+                                             Buildings.UNIVERSITY: 1,
+                                             Buildings.SIEGEWORKSHOP: 1,
+                                             Buildings.CASTLE: 2,
+                                             Buildings.KREPOST: 2,
+                                            },
+                             }
+
+        self.age_dependencies_counts = {
+                                    Ages.FEUDAL: 2,
+                                    Ages.CASTLE: 2,
+                                    Ages.IMPERIAL: 2,
+                                   }
+
         self.dependencies = {
                              Buildings.HOUSE: [Ages.DARK],
                              Buildings.LUMBERCAMP: [Ages.DARK],
@@ -33,56 +101,12 @@ class BuildingDependencies():
                              Buildings.MONASTERY: [Ages.CASTLE],
                              #Buildings.FORTIFIEDCHURCH: [Ages.CASTLE],
                              Buildings.CASTLE: [Ages.CASTLE],
-                             #Buildings.KREPOST: [Ages.CASTLE],
+                             Buildings.KREPOST: [Ages.CASTLE],
                              #Buildings.DONJON: [Ages.DARK],
                              #Buildings.HARBOR: [Ages.CASTLE, Research.THALASSOCRACY],
                              #Buildings.FEITORIA: [Ages.IMPERIAL],
                              Buildings.BOMBARDTOWER: [Ages.IMPERIAL, Research.BOMBARDTOWER],
                              Buildings.WONDER: [Ages.IMPERIAL],
-                            }
-
-
-
-class AgeDependencies():
-    def __init__(self):
-        self.dependencies = {
-                             Ages.FEUDAL: {
-                                           Buildings.BARRACKS: 1,
-                                           Buildings.MILL: 1,
-                                           Buildings.LUMBERCAMP: 1,
-                                           Buildings.MININGCAMP: 1,
-                                           Buildings.DOCK: 1,
-                                           #Buildings.MULECART: 1,
-                                           #Buildings.FOLWARK: 1,
-                                           #Buildings.SETTLEMENT: 2,
-                                          },
-                             Ages.CASTLE: {
-                                           Buildings.ARCHERYRANGE: 1,
-                                           Buildings.STABLE: 1,
-                                           Buildings.MARKET: 1,
-                                           Buildings.BLACKSMITH: 1,
-                                           #Buildings.SIEGEWORKSHOP: 1,
-                                          },
-                             Ages.IMPERIAL: {
-                                             #Buildings.MONASTERY: 1,
-                                             #Buildings.FORTIFIEDCHURCH: 1,
-                                             #Buildings.UNIVERSITY: 1,
-                                             #Buildings.SIEGEWORKSHOP: 1,
-                                             #Buildings.CASTLE: 2,
-                                             #Buildings.KREPOST: 2,
-                                            },
-                             }
-        self.dependencies_counts = {
-                                    Ages.FEUDAL: 2,
-                                    Ages.CASTLE: 2,
-                                    Ages.IMPERIAL: 2,
-                                   }
-
-
-
-class ResearchDependencies():
-    def __init__(self):
-        self.dependencies = {
                              Research.TOWNWATCH: [Ages.FEUDAL,
                                                   Buildings.TOWNCENTER],
                              Research.TOWNPATROL: [Ages.CASTLE,
@@ -237,13 +261,6 @@ class ResearchDependencies():
                              Research.BOMBARDTOWER: [Ages.IMPERIAL,
                                                      Buildings.UNIVERSITY,
                                                      Research.CHEMISTRY],
-                            }
-
-
-
-class UnitDependencies():
-    def __init__(self):
-        self.dependencies = {
                              Units.VILLAGER: [Buildings.TOWNCENTER],
                              Units.TRADECART: [Buildings.MARKET],
                              Units.SPEARMAN: [Ages.FEUDAL, Buildings.BARRACKS],

aoe/gather.py

@@ -1,6 +1,7 @@
 import copy
 
 from aoe.types import *
+from aoe.exceptions import *
 
 
 
@@ -136,6 +137,76 @@ class Gather():
     BIG_NUMBER = 1e6
 
 
+    def check_gather(self, world, task, count=1):
+        if task in [Tasks.IDLE, Tasks.BUILD]:
+            return
+
+        required = self.required_gather_buildings[task]
+        have = set(world.buildings)
+
+        match = any(map(have.issuperset, required))
+
+        if not match:
+            raise GatherBuildingNotAvailableException
+
+        if task == task.FARM:
+            if world.villager_tasks[task] + count > len(world.unused_farms):
+                raise GatherBuildingNotAvailableException
+
+
+    def permanently_modify_gather_rate(self, task, rate_multiplier):
+        self.gather_rates[task] *= rate_multiplier
+        self.original_gather_rates[task] *= rate_multiplier
+
+
+    def decrease_gather_rate_by_overuse(self, task):
+        # assumes rate decrease should trigger; does not check
+        new_rate = self.gather_decrease_rates[task]*self.gather_rates[task]
+        self.gather_rates[task] = new_rate
+
+        return new_rate
+
+
+    def improve_gather_rate_by_building(self, building, tasks):
+        if building == Buildings.FARM:
+            raise ValueError('Do not call this routine with a farm')
+
+        if building not in self.buildings_gather_increase.keys():
+            return []
+
+        if not tasks:
+            tasks = self.buildings_gather_increase[building].keys()
+        elif type(tasks) == Tasks:
+            tasks = [tasks]
+
+        for task in tasks:
+            amount = self.buildings_gather_increase[building][task]
+            if self.gather_rates[task] < self.original_gather_rates[task]:
+                self.gather_rates[task] = self.original_gather_rates[task]
+                self.gatherable_amounts[task] = amount
+            else:
+                self.gatherable_amounts[task] += amount
+
+        return tasks
+
+
+    def permanently_modify_consumable_capacity(self, building, task, increase):
+        current_initial_capacity = self.buildings_gather_increase[building]
+        self.buildings_gather_increase[building] += increase
+
+        return increase/current_initial_farm
+
+
+    def compute_gathered_resources_for_duration(self, villager_tasks, duration):
+        all_gathered = [0, 0, 0, 0]
+        for task, count in villager_tasks.items():
+            rate = self.gather_rates[task]
+            gathered = self.gathered_resources[task]
+            for resource, mult in gathered.items():
+                all_gathered[resource] += count*rate*mult*duration
+        return all_gathered
+
+
     def __init__(self):
         self.gather_rates = {
                 Tasks.BERRIES: 18.6/60,

aoe/housing.py

@@ -1,14 +1,26 @@
 from collections import defaultdict
 
 from aoe.types import *
+from aoe.exceptions import *
 
 
 
 class Housing():
 
 
+    def check_housing(self, world, thing):
+        required = self.required[thing]
+
+        if required > 0:
+            pop_space = world.get_population_space()
+            if world.get_effective_population() > pop_space + required:
+                raise YallGotHousedException
+
+
     def __init__(self):
         self.space = defaultdict(int, {
                       Buildings.HOUSE: 5,
                       Buildings.TOWNCENTER: 5,
                      })
+
+        self.required = defaultdict(int, {u: 1 for u in Units})

aoe/production.py

@@ -1,13 +1,22 @@
+from collections import defaultdict
+
 from aoe.types import *
+from aoe.exceptions import *
 
 
 
 class Production():
 
 
+    def check_production(self, world, thing):
+        building = self.building[thing]
+        if world.production_available[building] < 1:
+            raise ProductionBuildingNotAvailableException
+
+
     # assumes for now each unit can be built in only one type of building
     def __init__(self):
-        self.building = {
+        self.building = defaultdict(None, {
                          Units.VILLAGER: Buildings.TOWNCENTER,
                          Units.TRADECART: Buildings.MARKET,
                          Units.SPEARMAN: Buildings.BARRACKS,
@@ -93,4 +102,4 @@ class Production():
                          Research.LOOM: Buildings.TOWNCENTER,
                          Research.SAPPERS: Buildings.CASTLE,
                          Research.BOMBARDTOWER: Buildings.UNIVERSITY,
-                        }
+                        })

aoe/research.py

@@ -43,28 +43,28 @@ class ResearchEffects():
             case Research.HANDCART:
                 cls._modify_rates_with_wheelbarrow_line(world, 1.1, 1.11)
             case Research.DOUBLEBITAXE:
-                world._permanently_modify_gather_rate(Tasks.WOOD, 1.2)
+                world.permanently_modify_gather_rate(Tasks.WOOD, 1.2)
             case Research.BOWSAW:
-                world._permanently_modify_gather_rate(Tasks.WOOD, 1.2)
+                world.permanently_modify_gather_rate(Tasks.WOOD, 1.2)
             case Research.TWOMANSAW:
-                world._permanently_modify_gather_rate(Tasks.WOOD, 1.1)
+                world.permanently_modify_gather_rate(Tasks.WOOD, 1.1)
             case Research.HORSECOLLAR:
-                world._permanently_modify_farm_capacity(75)
+                world.permanently_modify_farm_capacity(75)
             case Research.HEAVYPLOW:
-                world._permanently_modify_farm_capacity(125)
+                world.permanently_modify_farm_capacity(125)
             case Research.CROPROTATION:
-                world._permanently_modify_farm_capacity(175)
+                world.permanently_modify_farm_capacity(175)
             case Research.GOLDMINING:
-                world._permanently_modify_gather_rate(Tasks.GOLD, 1.15)
+                world.permanently_modify_gather_rate(Tasks.GOLD, 1.15)
             case Research.GOLDSHAFTMINING:
-                world._permanently_modify_gather_rate(Tasks.GOLD, 1.15)
+                world.permanently_modify_gather_rate(Tasks.GOLD, 1.15)
             case Research.STONEMINING:
-                world._permanently_modify_gather_rate(Tasks.STONE, 1.15)
+                world.permanently_modify_gather_rate(Tasks.STONE, 1.15)
             case Research.STONESHAFTMINING:
-                world._permanently_modify_gather_rate(Tasks.STONE, 1.15)
+                world.permanently_modify_gather_rate(Tasks.STONE, 1.15)
             case Research.CARAVAN:
-                world._permanently_modify_gather_rate(Tasks.TRADECART, 1.20)
+                world.permanently_modify_gather_rate(Tasks.TRADECART, 1.20)
-                world._permanently_modify_gather_rate(Tasks.TRADECOG, 1.20)
+                world.permanently_modify_gather_rate(Tasks.TRADECOG, 1.20)
             #case Research.FISHINGLINES:
                 # probably looks like wheelbarrow
             #case Research.GILLNETS:
@@ -90,6 +90,6 @@ class ResearchEffects():
                     Tasks.GOLD,
                     Tasks.STONE]
         for task in affected:
-            world._permanently_modify_gather_rate(task, non_farm_rate)
+            world.permanently_modify_gather_rate(task, non_farm_rate)
 
-        world._permanently_modify_gather_rate(Tasks.FARM, farm_rate)
+        world.permanently_modify_gather_rate(Tasks.FARM, farm_rate)

aoe/times.py

@@ -5,6 +5,12 @@ from aoe.types import *
 class Times():
 
 
+    def compute_build_time(self, building, num_builders):
+        solo_build_time = self.build_times[building]
+        build_time = 3*solo_build_time/(num_builders + 2)
+        return build_time
+
+
     def __init__(self):
         self.build_times = {
                              Ages.FEUDAL: 130,
@@ -130,8 +136,3 @@ class Times():
                              Units.SKIRMISHER: 22,
                              Units.ARCHER: 35,
                            }
-
-        self.exist_duration = {
-                               Buildings.FARM: 0,
-                               Buildings.FISHTRAP: 0,
-                              }

aoe/world.py

@@ -54,60 +54,37 @@ class World():
     #     possibly other things
     # TODO gathering boars and hunting
     #     spend villager time in exchange for adding gatherable resource
+    # TODO food spoilage
     # TODO use market for buy/sell
 
 
     MAX_WORLD_TIME = 3*60*60  # 3 hours
 
 
-    def _pay_cost(self, purchase):
+    def add_resources(self, gathered):
         for i in range(len(self.resources)):
-            if self.resources[i] < self.costs.costs[purchase][i]:
+            self.resources[i] += gathered[i]
+
+
+    def pay_cost(self, thing):
+        spent = self.costs.compute_cost(thing)
+
+        for i in range(len(self.resources)):
+            if self.resources[i] < spent[i]:
                 raise NotEnoughResourcesException
+
         for i in range(len(self.resources)):
-            self.resources[i] -= self.costs.costs[purchase][i]
+            self.resources[i] -= spent[i]
 
 
-    def _check_research_dependencies(self, research):
+    def _remove_event_at_time(self, removed_event, scheduled_time):
-        self._check_dependencies(self.research_deps.dependencies[research])
+        if not scheduled_time:
+            return
 
-
+        for i, event in enumerate(self.events[scheduled_time]):
-    def _check_building_dependencies(self, building):
+            if event[0] == removed_event:
-        self._check_dependencies(self.building_deps.dependencies[building])
+                del self.events[scheduled_time][i]
-
+                break
-
-    def _check_unit_dependencies(self, unit):
-        self._check_dependencies(self.unit_deps.dependencies[unit])
-
-
-    def _check_dependencies(self, dependencies):
-        for dep in dependencies:
-            if dep not in self.buildings and \
-                    dep not in self.research and \
-                    not self._is_sufficient_age(dep):
-                        raise MissingDependencyException
-
-
-    def _is_sufficient_age(self, age):
-        if type(age) == Ages and self.age >= age:
-            return True
-        return False
-
-
-    def _check_age_dependencies(self, age):
-        total_buildings = 0
-        for building in self.age_deps.dependencies[age].keys():
-            if self.has_building(building):
-                total_buildings += self.age_deps.dependencies[age][building]
-        if total_buildings < self.age_deps.dependencies_counts[age]:
-            raise MissingDependencyException
-
-
-    def queue_research(self, research):
-        self._check_research_dependencies(research)
-        self._pay_cost(research)
-
-        self._start_research(research)
 
 
     def _schedule_next_gather_rate_decrease(self, task):
@@ -115,14 +92,8 @@ class World():
             return
 
         # remove old decrease
-        scheduled_decrease = self.rate_decrease_event_times[task]
+        self._remove_event_at_time(self._decrease_gather_rate_by_overuse,
-        if scheduled_decrease is not None:
+                                   self.rate_decrease_event_times[task])
-            decrease_index = None
-            for i, event in enumerate(self.events[scheduled_decrease]):
-                if event[0] == self._decrease_gather_rate:
-                    decrease_index = i
-                    break
-            del self.events[scheduled_decrease][i]
 
         rate = self.gather.gather_rates[task]
 
@@ -148,53 +119,51 @@ class World():
             if task == Tasks.FARM:
                 self.events[next_decrease].append((self._remove_farm, ()))
             else:
-                self.events[next_decrease].append((self._decrease_gather_rate,
+                self.events[next_decrease].append((self._decrease_gather_rate_by_overuse,
                                                    (task,)))
 
 
-    def _decrease_gather_rate(self, task):
+    def _decrease_gather_rate_by_overuse(self, task):
-        # assumes rate decrease should trigger; does not check
+        new_rate = self.gather.decrease_gather_rate_by_overuse(task)
-        new_rate = self.gather_decrease_rates[task]*self.gather_rates[task]
-        self.gather_rates[task] = new_rate
 
         if new_rate > 0:
             self._schedule_next_gather_rate_decrease(task)
         else:
-            self.assign_villager(task, task.IDLE, self.villager_tasks[task])
+            self.assign_villager(task, Tasks.IDLE, self.villager_tasks[task])
 
 
-    def _improve_gather_rate(self, building, tasks):
+    def _improve_gather_rate_by_building(self, building, tasks):
-        if building == Buildings.FARM:
+        tasks_improved = self.gather.improve_gather_rate_by_building(building,
-            raise ValueError('Do not call this routine with a farm')
+                                                                     tasks)
-
+        for task in tasks_improved:
-        if tasks is None:
-            tasks = self.gather.buildings_gather_increase[building].keys()
-
-        for task in tasks:
-            amount = self.gather.buildings_gather_increase[building][task]
-            if self.gather.gather_rates[task] < self.gather.original_gather_rates[task]:
-                self.gather.gather_rates[task] = self.gather.original_gather_rates[task]
-                self.gather.gatherable_amounts[task] = amount
-            else:
-                self.gather.gatherable_amounts[task] += amount
             self._schedule_next_gather_rate_decrease(task)
 
 
-    def _permanently_modify_farm_capacity(self, increase):
+    def permanently_modify_gather_rate(self, task, multiplier):
-        current_initial_farm = self.gather.buildings_gather_increase[Buildings.FARM]
+        self.gather.permanently_modify_gather_rate(task, multiplier)
-        for i in range(len(farms)):
+        self._schedule_next_gather_rate_decrease(task)
-            farms[i] += (farms[i]/current_initial_farm)*increase
-        for i in range(len(unused_farms)):
-            unused_farms[i] += (unused_farms[i]/current_initial_farm)*increase
-
-        self.gather.buildings_gather_increase[Buildings.FARM] += increase
-
-        self._schedule_next_gather_rate_decrease(Task.FARM)
 
 
-    def _permanently_modify_gather_rate(self, task, rate_multiplier):
+    def permanently_modify_farm_capacity(self, increase):
-        self.gather.gather_rates[tasks] *= rate_multiplier
+        self._permanently_modify_consumable_capacity(Buildings.FARM,
-        self.gather.original_gather_rates[tasks] *= rate_multiplier
+                                                     Tasks.FARM,
+                                                     increase)
+
+
+    def _permanently_modify_consumable_capacity(self, building, task, increase):
+        multiplier = self.gather.permanently_modify_consumable_capacity(building,
+                                                                        task,
+                                                                        increase)
+
+        if building == Buildings.FARM:
+            used = self.farms
+            unused = self.unused_farms
+
+        for i in range(len(used)):
+            used[i] += used[i]*multiplier
+        for i in range(len(unused)):
+            unused[i] += unused[i]*multiplier
+
         self._schedule_next_gather_rate_decrease(task)
 
 
@@ -207,7 +176,7 @@ class World():
             raise IllegalVillagerMoveException
 
         if new_task:
-            self._check_gather(new_task, count)
+            self.gather.check_gather(self, new_task, count)
             self.villager_tasks[new_task] += count
         else:
             self.villagers -= 1
@@ -254,16 +223,16 @@ class World():
         villagers_from_count = Counter(villagers_from)
 
         self._check_villager_move(villagers_from_count)
-        self._check_building_dependencies(building)
 
-        self._pay_cost(building)
+        self.dependencies.check_dependencies(self, building)
+
+        self.pay_cost(building)
         self._move_villagers_to_build(villagers_from_count)
 
         villagers_to_count = Counter(villagers_to)
 
-        num_villagers_building = len(villagers_from)
+        num_builders = len(villagers_from)
-        solo_build_time = self.build_times.build_times[building]
+        build_time = self.build_times.compute_build_time(building, num_builders)
-        build_time = 3*solo_build_time/(num_villagers_building + 2)
         update_time = self.current_time + build_time
 
         self.events[update_time].append((self._add_building,
@@ -281,8 +250,8 @@ class World():
 
         if building == Buildings.FARM:
             self._add_farm()
-        elif building in self.gather.buildings_gather_increase.keys():
+        else:
-            self._improve_gather_rate(building, tasks_improved)
+            self._improve_gather_rate_by_building(building, tasks_improved)
 
         for task, count in villagers_to.items():
             self.assign_villager(Tasks.BUILD, task, count)
@@ -320,7 +289,12 @@ class World():
 
 
     def _run_clock_without_events(self, end_time):
-        self._gather_resources_for_duration(end_time - self.current_time)
+        duration = end_time - self.current_time
+
+        gathered = self.gather.compute_gathered_resources_for_duration(self.villager_tasks,
+                                                                       duration)
+        self.add_resources(gathered)
+
         self.current_time = end_time
 
 
@@ -331,135 +305,72 @@ class World():
             self._handle_events()
 
 
-    def _get_population_space(self):
+    def get_population_space(self):
         space = sum([self.housing.space[building] for building in self.buildings])
         return min(space, 200)
 
 
-    def _get_effective_population(self):
+    def get_effective_population(self):
         return self.population + self.units_being_built
 
 
     def _free_housing(self):
-        pop_space = self._get_population_space()
+        pop_space = self.get_population_space()
-        original_queue_len = len(self.production_queue)
 
-        # Assumes each unit costs 1 pop
-        new_builds = []
         i = 0
-        while (self._get_effective_population() < pop_space and
+        while (self.get_effective_population() < pop_space and
-               i < original_queue_len):
+               i < len(self.production_queue)):
 
-            unit = self.production_queue[i]
+            thing = self.production_queue[i]
-            if self._check_production(unit):
+            if self.housing.check_housing(self, thing) and \
-                if unit in Units:
+                    self.production.check_production(self, thing):
-                    self._build_unit(unit)
+                self._start_producing(thing)
-                elif unit in Research:
+                del self.production_queue[i]
-                    self._start_research(unit)
+            else:
-                new_builds.append(i)
+                i += 1
-
-            i += 1
-
-        self.production_queue = [self.production_queue[i]
-                                 for i in range(original_queue_len)
-                                 if i not in new_builds]
 
 
-    def _free_production_building_of_unit(self, unit):
+    def _free_production_building_of_thing(self, thing):
-        building = self.production.building[unit]
+        building = self.production.building[thing]
         self._free_production_building(building)
 
 
     def _free_production_building(self, building):
+        # This will not respect the order of a queue in a particular building.
+        # For example, if there is a TC with the queue [villager, loom] and
+        # there is no available housing, the TC will research loom. In the
+        # actual game, the villager would block the researching of loom.
+        # There is no easy way around this as long as we are treating the
+        # production queue as a shared pool, and I don't really care.
         self.production_available[building] += 1
 
-        # Start the next queued unit if one exists
+        i = 0
-        ready_index = None
+        while i < len(self.production_queue):
-        ready_unit = None
+            thing = self.production_queue[i]
-        for i in range(len(self.production_queue)):
+            if self.production.building[thing] == building and \
-            unit = self.production_queue[i]
+                    self.housing.check_housing(self, thing):
-            if self.production.building[unit] == building:
+                self._start_producing(thing)
-                ready_index = i
+                del self.production_queue[i]
-                ready_unit = unit
                 break
-
+            i += 1
-        if ready_index:
-            self.production_queue.remove(i)
-            if unit in Units:
-                self._build_unit(unit)
-            elif unit in Research:
-                self._start_research(unit)
 
 
-    def _check_housing(self, unit):
+    def _use_housing_and_production(self, thing):
-        # assumes for now that all units cost 1 pop
+        self.housing.check_housing(self, thing)
-        pop_space = sum([self.housing.space[building] for building in self.buildings])
+        self.production.check_production(self, thing)
-        if self._get_effective_population() >= pop_space:
-            raise YallGotHousedException
 
+        building = self.production.building[thing]
+        if building is not None:
+            self.production_available[building] -= 1
 
-    def _check_gather(self, task, count=1):
+        self.units_being_built += self.housing.required[thing]
-        if task in [Tasks.IDLE, Tasks.BUILD]:
-            return
-
-        required = self.gather.required_gather_buildings[task]
-        have = set(self.buildings)
-
-        match = any(map(have.issuperset, required))
-
-        if not match:
-            raise GatherBuildingNotAvailableException
-
-        if task == task.FARM:
-            if self.villager_tasks[task] + count > len(self.unused_farms):
-                raise GatherBuildingNotAvailableException
-
-
-    def _check_production(self, unit):
-        building = self.production.building[unit]
-        if self.production_available[building] < 1:
-            raise ProductionBuildingNotAvailableException
-
-
-    def _use_production_for_research(self, research):
-        self._check_production(research)
-
-        building = self.production.building[research]
-        self.production_available[building] -= 1
-
-
-    def _add_research(self, research):
-        self.research.append(research)
-        ResearchEffects.complete_research(self, research)
-        self._free_production_building_of_unit(research)
-
-
-    def _start_research(self, research):
-        try:
-            self._use_production_for_research(research)
-        except ProductionBuildingNotAvailableException:
-            self.production_queue.append(research)
-        else:
-            update_time = self.current_time + self.build_times.build_times[research]
-            self.events[update_time].append((self._add_research, (research,)))
-
-
-    def _use_housing_and_production(self, unit):
-        self._check_housing(unit)
-        self._check_production(unit)
-
-        building = self.production.building[unit]
-
-        self.production_available[building] -= 1
-        self.units_being_built += 1
 
 
     def _kill_unit(self, unit, task=None):
         if unit == Units.VILLAGER and not task:
                 raise IllegalVillagerMoveException
 
-        # assumes population of 1 for every unit
+        self.population -= self.housing.required(unit)
-        self.population -= 1
 
         if unit == Units.VILLAGER:
             self.assign_villager(task, None)
@@ -467,47 +378,50 @@ class World():
         self._free_housing()
 
 
-    def _add_unit(self, unit, initial_task):
+    def _add_thing(self, thing, initial_task):
-        # assumes population of 1 for every unit
+        self.units_being_built -= self.housing.required[thing]
-        self.units_being_built -= 1
+        self.population += self.housing.required[thing]
-        self.population += 1
-        self._free_production_building_of_unit(unit)
 
-        if unit == Units.VILLAGER:
+        if thing in Research:
+            self.research.append(thing)
+            ResearchEffects.complete_research(self, thing)
+
+        self._free_production_building_of_thing(thing)
+
+        if thing == Units.VILLAGER:
             self.villagers += 1
             self.villager_tasks[Tasks.IDLE] += 1
             self.assign_villager(Tasks.IDLE, initial_task)
 
 
-    def _build_unit(self, unit, initial_task):
+    def _start_producing(self, thing, initial_task):
         try:
-            self._use_housing_and_production(unit)
+            self._use_housing_and_production(thing)
         except ProductionBuildingNotAvailableException:
-            self.production_queue.append(unit)
+            self.production_queue.append(thing)
-        except YallGotHousedException:
-            pass
         else:
-            update_time = self.current_time + self.build_times.build_times[unit]
+            update_time = self.current_time + self.build_times.build_times[thing]
-            self.events[update_time].append((self._add_unit, (unit, initial_task,)))
+            self.events[update_time].append((self._add_thing, (thing, initial_task,)))
 
 
-    def queue_unit(self, unit, initial_task=None):
+    def _queue_thing(self, thing, initial_task=None):
-        self._check_unit_dependencies(unit)
+        self.dependencies.check_dependencies(self, thing)
-        self._pay_cost(unit)
+        self.costs.compute_cost(thing)
+        self.pay_cost(thing)
 
-        self._build_unit(unit, initial_task)
+        self._start_producing(thing, initial_task)
+
+
+    def queue_research(self, research):
+        self._queue_thing(research)
+
+
+    def queue_unit(self, unit):
+        self._queue_thing(unit)
 
 
     def queue_villager(self, initial_task):
-        self.queue_unit(Units.VILLAGER, initial_task)
+        self._queue_thing(Units.VILLAGER, initial_task)
-
-
-    def _gather_resources_for_duration(self, duration):
-        for task, count in self.villager_tasks.items():
-            rate = self.gather.gather_rates[task]
-            gathered = self.gather.gathered_resources[task]
-            for resource, mult in gathered.items():
-                self.resources[resource] += count*rate*mult*duration
 
 
     def _handle_events(self):
@@ -526,8 +440,8 @@ class World():
 
         new_age = self.age + 1
 
-        self._check_age_dependencies(new_age)
+        self.dependencies.check_dependencies(new_age)
-        self._pay_cost(new_age)
+        self.pay_cost(new_age)
 
         update_time = self.current_time + self.build_times.build_times[new_age]
         self.events[update_time].append((self._update_age, (new_age,)))
@@ -564,10 +478,7 @@ class World():
 
         self.build_times = Times()
         self.costs = Costs()
-        self.building_deps = BuildingDependencies()
+        self.dependencies = Dependencies()
-        self.age_deps = AgeDependencies()
-        self.research_deps = ResearchDependencies()
-        self.unit_deps = UnitDependencies()
         self.housing = Housing()
         self.production = Production()
         self.gather = Gather()