Adds Death and Sickness systems

systems.py

@@ -1,5 +1,5 @@
-from components import Health, Hydration, Hygiene, Satiety
-from ecs import World
+from components import Health, Hydration, Hygiene, Satiety, Tag, Tags
+from libs.ecs import World
 
 
 class SatietySystem:
@@ -39,3 +39,28 @@ class HygieneSystem:
                 hygiene.value = 0
             else:
                 hygiene.value -= 1
+
+
+class SicknessSystem:
+    @classmethod
+    def process(cls, world: World):
+        for _, component_map in world.query(Health, Tags):
+            health = component_map[Health]
+            tags = component_map[Tags]
+            if Tag.SICK in tags.values and health.value > 0:
+                health.value -= 1
+            if health.value <= 0:
+                health.value = 0
+                tags.values.add(Tag.DEAD)
+
+
+class DeathSystem:
+    @classmethod
+    def process(cls, world: World):
+        marked = set()
+        for entity, component_map in world.query(Health, Tags):
+            tags = component_map[Tags]
+            if Tag.DEAD in tags.values:
+                marked.add(entity)
+        for entity in marked:
+            world.get_components(entity, pop=True)