feat: add cold-season scarcity that halves yields and pauses regrowth

simulation/SimulationManager.gd

@@ -68,6 +68,10 @@ var _population_view := SimulationPopulationView.new()
 var speed_index := 2
 const SPEED_LEVELS := [0.25, 0.5, 1.0, 2.0, 4.0, 10.0]
 const KNOWLEDGE_COMMUNICATION_RADIUS := 2.5
+const SEASON_DAYS := 4
+const COLD_DAYS := 3
+const SEASON_COLD := &"cold"
+const SEASON_WARM := &"warm"
 signal speed_changed(multiplier: float)
 
 const NPC_NAMES := ["Amina", "Tarik", "Jasmin", "Elma", "Mirza", "Lejla"]
@@ -337,7 +341,9 @@ func _complete_resource_gather(npc: SimNPC, completed_task: StringName) -> void:
 		release_npc_reservation(npc.id)
 		return
 
-	var extracted := resource_state.extract()
+	var extracted := resource_state.extract(
+		resource_state.get_yield_per_action() * _gather_yield_multiplier()
+	)
 	if extracted > 0.0:
 		var resource_id := resource_state.get_resource_id()
 		npc.add_inventory(resource_id, extracted)
@@ -1019,7 +1025,9 @@ func harvest_resource_node(node: ResourceNode) -> float:
 	var resource_state := get_resource_state(node.node_id)
 	if resource_state == null or not resource_state.can_player_use_resource():
 		return 0.0
-	var extracted := resource_state.extract(resource_state.get_yield_per_action())
+	var extracted := resource_state.extract(
+		resource_state.get_yield_per_action() * _gather_yield_multiplier()
+	)
 	if extracted <= 0.0:
 		return 0.0
 	var resource_id := resource_state.get_resource_id()
@@ -1066,7 +1074,23 @@ func advance_player_needs() -> void:
 	player_system.advance_needs(village.food_modifier)
 
 
+func get_season() -> StringName:
+	var ticks_per_day := maxi(get_knowledge_review_interval(), 1)
+	var season_day := int(clock.elapsed_ticks / ticks_per_day)
+	return SEASON_COLD if season_day % SEASON_DAYS >= COLD_DAYS else SEASON_WARM
+
+
+func is_cold_season() -> bool:
+	return get_season() == SEASON_COLD
+
+
+func _gather_yield_multiplier() -> float:
+	return 0.5 if is_cold_season() else 1.0
+
+
 func _advance_resource_regrowth() -> void:
+	if is_cold_season():
+		return
 	for resource_id in resource_states:
 		var resource_state := resource_states[resource_id] as ResourceStateRecord
 		resource_state.regrow()