class_name ActionSelectionSystem
extends RefCounted

enum SchedulePeriod {
	WORK,
	SLEEP,
	MEAL,
	DISCRETIONARY
}

const SLEEP_BEGIN := 0.88
const SLEEP_END := 0.15
const BREAKFAST_BEGIN := 0.25
const BREAKFAST_END := 0.35
const DINNER_BEGIN := 0.7
const DINNER_END := 0.8
const WORK_BEGIN := 0.28
const WORK_END := 0.85


func select_action(npc: SimNPC, village: SimVillage, time_of_day: float = 0.5) -> ActionSelectionResult:
	if npc.is_dead:
		return null

	var period := _get_period(time_of_day)

	if period == SchedulePeriod.SLEEP:
		if npc.energy < 60.0:
			return ActionSelectionResult.new(
				SimulationIds.ACTION_SLEEP, -1.0, "Night-time sleep; energy is low"
			)
		if npc.hunger > 75.0 and npc.get_inventory_amount(SimulationIds.RESOURCE_FOOD) >= 1.0:
			return ActionSelectionResult.new(
				SimulationIds.ACTION_EAT, -1.0, "Night-time hunger; eating from inventory"
			)
		return ActionSelectionResult.new(
			SimulationIds.ACTION_SLEEP, -1.0, "Night-time; going home"
		)

	if period == SchedulePeriod.MEAL:
		if npc.hunger > 50.0:
			if npc.get_inventory_amount(SimulationIds.RESOURCE_FOOD) >= 1.0:
				return ActionSelectionResult.new(
					SimulationIds.ACTION_EAT, -1.0, "Meal-time hunger; eating from inventory"
				)
			if village.food > 0:
				return ActionSelectionResult.new(
					SimulationIds.ACTION_WITHDRAW_FOOD, -1.0, "Meal-time; pantry has food"
				)
			return ActionSelectionResult.new(
				SimulationIds.ACTION_GATHER_FOOD, -1.0, "Meal-time hunger; pantry is empty"
			)

	if npc.is_starving:
		if npc.get_inventory_amount(SimulationIds.RESOURCE_FOOD) >= 1.0:
			return ActionSelectionResult.new(
				SimulationIds.ACTION_EAT, 1.0, "Starving and carrying food"
			)
		if village.food > 0:
			return ActionSelectionResult.new(
				SimulationIds.ACTION_WITHDRAW_FOOD, 1.0, "Starving; pantry has food"
			)
		return ActionSelectionResult.new(
			SimulationIds.ACTION_GATHER_FOOD, 4.0, "Starving; pantry is empty"
		)
	if npc.hunger > 75.0:
		if npc.get_inventory_amount(SimulationIds.RESOURCE_FOOD) >= 1.0:
			return ActionSelectionResult.new(
				SimulationIds.ACTION_EAT, -1.0, "Hungry and carrying food"
			)
		if village.food > 0:
			return ActionSelectionResult.new(
				SimulationIds.ACTION_WITHDRAW_FOOD, -1.0, "Hungry; pantry has food"
			)
		return ActionSelectionResult.new(
			SimulationIds.ACTION_GATHER_FOOD, -1.0, "Hungry; pantry is empty"
		)
	if npc.get_inventory_amount(SimulationIds.RESOURCE_FOOD) > 0.0:
		return ActionSelectionResult.new(
			SimulationIds.ACTION_DEPOSIT_FOOD, -1.0, "Carrying food for storage"
		)
	if npc.energy < 25.0:
		return ActionSelectionResult.new(
			SimulationIds.ACTION_REST, -1.0, "Energy is below the rest threshold"
		)

	if period == SchedulePeriod.DISCRETIONARY:
		var roll := npc.random_source.randf()
		if roll < 0.3:
			return ActionSelectionResult.new(
				SimulationIds.ACTION_WANDER, -1.0, "Discretionary wander"
			)

	return _choose_best_work_action(npc, village)


func _choose_best_work_action(npc: SimNPC, village: SimVillage) -> ActionSelectionResult:
	var scores := {
		SimulationIds.ACTION_GATHER_FOOD:
		_calculate_score(
			npc,
			SimulationIds.ACTION_GATHER_FOOD,
			village.food_priority,
			village.food,
			15.0,
			30.0,
			3.0,
			1.5
		),
		SimulationIds.ACTION_GATHER_WOOD:
		_calculate_score(
			npc,
			SimulationIds.ACTION_GATHER_WOOD,
			village.wood_priority,
			village.wood,
			10.0,
			20.0,
			2.5,
			1.0
		),
		SimulationIds.ACTION_PATROL:
		_calculate_score(
			npc,
			SimulationIds.ACTION_PATROL,
			village.safety_priority,
			village.safety,
			30.0,
			50.0,
			3.0,
			1.5
		),
		SimulationIds.ACTION_STUDY:
		_calculate_score(
			npc,
			SimulationIds.ACTION_STUDY,
			village.knowledge_priority,
			village.knowledge,
			10.0,
			25.0,
			1.5,
			0.75
		)
	}
	var best_action := SimulationIds.ACTION_GATHER_FOOD
	var best_score: float = scores[best_action]
	for action_id in [
		SimulationIds.ACTION_GATHER_WOOD, SimulationIds.ACTION_PATROL, SimulationIds.ACTION_STUDY
	]:
		var score: float = scores[action_id]
		if score > best_score:
			best_action = action_id
			best_score = score
	return ActionSelectionResult.new(
		best_action, -1.0, "Highest current work utility", scores
	)


func _calculate_score(
	npc: SimNPC,
	action_id: StringName,
	base_priority: float,
	resource_amount: float,
	critical_threshold: float,
	low_threshold: float,
	critical_bonus: float,
	low_bonus: float
) -> float:
	var score := base_priority
	if resource_amount < critical_threshold:
		score += critical_bonus
	elif resource_amount < low_threshold:
		score += low_bonus
	var definition := SimulationDefinitions.get_action(action_id)
	if (
		definition != null
		and not definition.preferred_profession_id.is_empty()
		and npc.profession == definition.preferred_profession_id
	):
		score += 2.0
	if action_id == npc.last_task:
		score -= 1.5
	score += npc.random_source.randf_range(0.0, 0.5)
	if npc.debug_logs:
		print("[ActionSelection] ", npc.npc_name, " score ", action_id, " = ", score)
	return score


static func _get_period(time_of_day: float) -> int:
	if _in_wrap_range(time_of_day, SLEEP_BEGIN, SLEEP_END):
		return SchedulePeriod.SLEEP
	if _in_range(time_of_day, BREAKFAST_BEGIN, BREAKFAST_END):
		return SchedulePeriod.MEAL
	if _in_range(time_of_day, DINNER_BEGIN, DINNER_END):
		return SchedulePeriod.MEAL
	if _in_range(time_of_day, WORK_BEGIN, WORK_END):
		return SchedulePeriod.WORK
	return SchedulePeriod.DISCRETIONARY


static func _in_range(value: float, begin: float, end: float) -> bool:
	return value >= begin and value <= end


static func _in_wrap_range(value: float, begin: float, end: float) -> bool:
	return value >= begin or value <= end