class_name SimNPC
extends RefCounted

const TASK_STATE_IDLE := &"idle"
const TASK_STATE_TRAVELING := &"traveling"
const TASK_STATE_WORKING := &"working"
const TASK_STATE_COMPLETE := &"complete"

var id: int
var npc_name: String
var profession: StringName
var hunger: float
var energy: float
var strength: float
var intelligence: float
var current_task: StringName = SimulationIds.ACTION_IDLE
var task_state: StringName = TASK_STATE_IDLE
var position: Vector3

var is_starving := false
var starvation_ticks := 0
var starvation_death_threshold := 20
var is_dead := false

var task_duration := 0.0
var task_progress := 0.0
var task_complete := true
var target_id: StringName = &""
var last_task: StringName
var random_source: RandomNumberGenerator
var debug_logs := true

func _init(
	_id: int,
	_npc_name: String,
	_profession: StringName,
	_strength: float,
	_intelligence: float,
	_random_source: RandomNumberGenerator = null
) -> void:
	id = _id
	npc_name = _npc_name
	profession = _profession
	strength = _strength
	intelligence = _intelligence
	random_source = _random_source
	if random_source == null:
		random_source = RandomNumberGenerator.new()
		random_source.seed = id + 1
	hunger = random_source.randf_range(20.0, 80.0)
	energy = random_source.randf_range(40.0, 100.0)
	position = Vector3(
		random_source.randf_range(-8.0, 8.0),
		0.0,
		random_source.randf_range(-8.0, 8.0)
	)

func simulate_tick(village: SimVillage) -> void:
	if is_dead:
		return

	update_needs(village)

	if is_dead:
		return

	if task_state == TASK_STATE_IDLE or task_state == TASK_STATE_COMPLETE:
		choose_new_task(village)
		return

	if task_state == TASK_STATE_TRAVELING:
		return

	if task_state == TASK_STATE_WORKING:
		task_progress += 1.0

		if task_progress >= task_duration:
			task_complete = true
			task_state = TASK_STATE_COMPLETE
			
func update_needs(village: SimVillage) -> void:
	hunger += 3.0 * village.food_modifier

	match task_state:
		TASK_STATE_IDLE:
			energy -= 0.5
		TASK_STATE_TRAVELING:
			energy -= 2.0
		TASK_STATE_WORKING:
			if current_task != SimulationIds.ACTION_REST:
				energy -= 3.0
		TASK_STATE_COMPLETE:
			energy -= 0.25

	hunger = clamp(hunger, 0.0, 100.0)
	energy = clamp(energy, 0.0, 100.0)

	is_starving = hunger >= 90.0

	if is_starving:
		starvation_ticks += 1
	else:
		starvation_ticks = 0

	if starvation_ticks >= starvation_death_threshold:
		die_from_starvation()

func die_from_starvation() -> void:
	is_dead = true
	current_task = SimulationIds.ACTION_DEAD
	task_state = TASK_STATE_IDLE
	task_progress = 0.0
	task_duration = 0.0
	task_complete = true

	if debug_logs:
		print("[SimNPC] ", npc_name, " died from starvation.")
		
func choose_new_task(village: SimVillage) -> void:
	if is_dead:
		return

	if is_starving:
		if village.food > 0:
			set_task(SimulationIds.ACTION_EAT, 1.0)
		else:
			set_task(SimulationIds.ACTION_GATHER_FOOD, 4.0)
		return

	if hunger > 75.0:
		if village.food > 0:
			set_task(SimulationIds.ACTION_EAT)
		else:
			set_task(SimulationIds.ACTION_GATHER_FOOD)
		return

	if energy < 25.0:
		set_task(SimulationIds.ACTION_REST)
		return

	set_task(choose_best_work_task(village))
			
func should_eat_immediately_after_task() -> bool:
	return (
		current_task == SimulationIds.ACTION_GATHER_FOOD
		and is_starving
		and not is_dead
	)

func choose_best_work_task(village: SimVillage) -> StringName:
	var food_score := calculate_task_score(
		SimulationIds.ACTION_GATHER_FOOD,
		village.food_priority,
		village.food,
		15.0,
		30.0,
		3.0,
		1.5
	)

	var wood_score := calculate_task_score(
		SimulationIds.ACTION_GATHER_WOOD,
		village.wood_priority,
		village.wood,
		10.0,
		20.0,
		2.5,
		1.0
	)

	var safety_score := calculate_task_score(
		SimulationIds.ACTION_PATROL,
		village.safety_priority,
		village.safety,
		30.0,
		50.0,
		3.0,
		1.5
	)

	var knowledge_score := calculate_task_score(
		SimulationIds.ACTION_STUDY,
		village.knowledge_priority,
		village.knowledge,
		10.0,
		25.0,
		1.5,
		0.75
	)

	var best_task := SimulationIds.ACTION_GATHER_FOOD
	var best_score := food_score

	if wood_score > best_score:
		best_task = SimulationIds.ACTION_GATHER_WOOD
		best_score = wood_score

	if safety_score > best_score:
		best_task = SimulationIds.ACTION_PATROL
		best_score = safety_score

	if knowledge_score > best_score:
		best_task = SimulationIds.ACTION_STUDY
		best_score = knowledge_score

	return best_task
	
func calculate_task_score(
	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 profession == definition.preferred_profession_id
	):
		score += 2.0

	if action_id == last_task:
		score -= 1.5

	score += random_source.randf_range(0.0, 0.5)

	if debug_logs:
		print(
			"[SimNPC] ",
			npc_name,
			" score ",
			action_id,
			" = ",
			score
		)

	return score

func set_task(action_id: StringName, duration: float = -1.0) -> void:
	var definition := SimulationDefinitions.get_action(action_id)
	if definition == null:
		push_error("SimNPC: unknown action_id '%s'" % action_id)
		return
	current_task = action_id
	task_duration = (
		duration if duration >= 0.0 else definition.default_duration
	)
	task_progress = 0.0
	task_complete = false
	task_state = TASK_STATE_TRAVELING

func start_working() -> void:
	if task_state != TASK_STATE_TRAVELING:
		return

	task_state = TASK_STATE_WORKING
	task_progress = 0.0
	task_complete = false