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()

tests/seasonal_rhythm_test.gd

@@ -0,0 +1,127 @@
+extends SceneTree
+
+var failures: Array[String] = []
+
+
+func _initialize() -> void:
+	call_deferred("_run")
+
+
+func _run() -> void:
+	var manager := _create_manager(971)
+	var ticks_per_day: int = manager.get_knowledge_review_interval()
+
+	var berry := ResourceNode.new()
+	berry.name = "SeasonBerry"
+	berry.node_id = &"season_berry"
+	berry.action_id = SimulationIds.ACTION_GATHER_FOOD
+	berry.resource_id = SimulationIds.RESOURCE_FOOD
+	berry.initial_amount = 2.0
+	berry.max_amount = 2.0
+	berry.regrow_rate = 0.1
+	berry.debug_label_enabled = false
+	var interaction_point := Marker3D.new()
+	interaction_point.name = "InteractionPoint"
+	interaction_point.position = Vector3.ZERO
+	berry.add_child(interaction_point)
+	root.add_child(berry)
+	await process_frame
+	_check(
+		manager.register_resource_node(berry), "Season test should bind a real finite ResourceNode"
+	)
+	var state: ResourceStateRecord = manager.get_resource_state(berry.node_id)
+
+	manager.clock.elapsed_ticks = 0 * ticks_per_day + 50
+	_check(
+		(
+			manager.get_season() == &"warm"
+			and is_equal_approx(manager._gather_yield_multiplier(), 1.0)
+		),
+		"The first season days should be warm with full yields"
+	)
+	_check(
+		is_equal_approx(manager.harvest_resource_node(berry), 2.0),
+		"Warm-season gathering should extract the full configured yield"
+	)
+
+	state.set_amount_remaining(2.0)
+	manager.clock.elapsed_ticks = 3 * ticks_per_day + 50
+	_check(
+		(
+			manager.get_season() == &"cold"
+			and is_equal_approx(manager._gather_yield_multiplier(), 0.5)
+		),
+		"Later season days should be cold with reduced yields"
+	)
+	_check(
+		is_equal_approx(manager.harvest_resource_node(berry), 1.0),
+		"Cold-season gathering should extract only half the configured yield"
+	)
+
+	state.set_amount_remaining(0.5)
+	manager.simulate_tick()
+	_check(
+		is_equal_approx(state.get_amount_remaining(), 0.5),
+		"Cold-season regrowth should pause until warmer days"
+	)
+	manager.clock.elapsed_ticks = 4 * ticks_per_day + 50
+	_check(manager.get_season() == &"warm", "The season should return warm after the cold spell")
+	manager.simulate_tick()
+	_check(
+		is_equal_approx(state.get_amount_remaining(), 0.6),
+		"Regrowth should resume once the warm season returns"
+	)
+
+	manager.clock.elapsed_ticks = 3 * ticks_per_day + 50
+	var saved_json: String = manager.serialize_state()
+	var restored := _create_manager(972)
+	_check(
+		restored.restore_state_from_json(saved_json),
+		"Seasonal clock state should survive save and restore"
+	)
+	_check(
+		(
+			restored.get_state_checksum() == manager.get_state_checksum()
+			and restored.get_season() == &"cold"
+			and is_equal_approx(restored._gather_yield_multiplier(), 0.5)
+		),
+		"Restore should re-derive the same cold season and its reduced yields"
+	)
+	restored.free()
+
+	berry.queue_free()
+	manager.free()
+	_finish()
+
+
+func _create_manager(seed_value: int = 971) -> Node:
+	var manager: Node = load("res://simulation/SimulationManager.gd").new()
+	manager.simulation_seed = seed_value
+	manager.debug_logs = false
+	var home_positions: Array[Vector3] = [
+		Vector3(0.0, 0.0, 0.0),
+		Vector3(2.0, 0.0, 0.0),
+		Vector3(10.0, 0.0, 0.0),
+		Vector3(12.0, 0.0, 0.0),
+		Vector3(30.0, 0.0, 30.0),
+		Vector3(40.0, 0.0, 40.0),
+	]
+	manager.home_positions = home_positions
+	root.add_child(manager)
+	manager.set_process(false)
+	return manager
+
+
+func _finish() -> void:
+	if failures.is_empty():
+		print("[TEST] Seasonal rhythm passed: cold yields + paused regrowth")
+		quit(0)
+		return
+	for failure in failures:
+		push_error("[TEST] " + failure)
+	quit(1)
+
+
+func _check(condition: bool, message: String) -> void:
+	if not condition:
+		failures.append(message)

tests/seasonal_rhythm_test.gd.uid

@@ -0,0 +1 @@
+uid://bu0iqfwmmcwsk

world/ui/ui.gd

@@ -86,6 +86,7 @@ func _on_village_changed(village: SimVillage) -> void:
 	if rates["wood_per_day"] > 0.01:
 		wood_rate = "  (−%.0f/d)" % rates["wood_per_day"]
 	var opportunity_text := _build_active_opportunity_display()
+	var season_text := "Cold" if simulation_manager.is_cold_season() else "Warm"
 	village_stats_label.text = (
 		"""
 	Village   [%s]
@@ -95,6 +96,7 @@ func _on_village_changed(village: SimVillage) -> void:
 	Safety: %s
 	Knowledge: %s
 	Starving: %s
+	Season: %s
 
 	Food Mod: %.2f
 	Safety Mod: %.2f
@@ -110,6 +112,7 @@ func _on_village_changed(village: SimVillage) -> void:
 			round(village.safety),
 			round(village.knowledge),
 			simulation_manager.get_starving_count(),
+			season_text,
 			village.food_modifier,
 			village.safety_modifier,
 			village.knowledge_modifier,