extends Node
## Survival stats: health, stamina, hunger (satiety) and warmth, each 0..100.
##
## - Hunger drains over about a day and a quarter, faster when you're cold.
## - Warmth moves toward a target: air temperature (day/night, altitude),
##   plus heat from fires and a held torch, minus being wet.
## - Health drains while starving or freezing, and regenerates when fed and warm.
## - Stamina pays for sprinting, jumping and swinging, and regenerates after a
##   short pause.
##
## step(dt) holds all the rules, so tests can fast-forward time. In M2 this runs
## on the server.

signal changed
signal died

const MAX := 100.0
const HUNGER_DRAIN := 100.0 / 1500.0   ## full to empty in ~1.25 in-game days
const STAMINA_REGEN := 24.0
const STAMINA_DELAY := 1.0
const WET_SECONDS := 90.0
const REST_AFTER := 20.0       ## seconds sheltered by a fire before you're Rested
const REST_SECONDS := 300.0    ## Rested: stamina regenerates 50% faster

var health := MAX
var stamina := MAX
var hunger := MAX            ## satiety: 100 = full, 0 = starving
var warmth := 70.0
var wet := 0.0               ## seconds of "Wet" left
var heat := 0.0              ## 0..1 from nearby fires etc (last step)
var statuses: Array[String] = []
var dead := false
var roofed := false          ## a roof overhead (rain can't reach you)
var sheltered := false       ## roof and walls (the weather barely reaches you)
var rested := 0.0            ## seconds of Rested left
var _shelter_left := 0.0
var _rest_build := 0.0

var player: CharacterBody3D
var world: Node3D
var _stamina_wait := 0.0

func _process(delta: float) -> void:
	if world != null and not world.menu_mode:
		step(delta)

func step(dt: float) -> void:
	if dead:
		return
	var p := player.global_position
	heat = world.heat_at(p)
	_shelter_left -= dt
	if _shelter_left <= 0.0:
		_shelter_left = 0.25
		roofed = world.build.roofed_at(p)
		sheltered = roofed and world.build.enclosure_at(p) >= 0.74
	# Rain soaks you unless there's a roof over your head.
	if not roofed and world.weather.rain_at(p) > 0.25:
		wet = WET_SECONDS
	# Resting: a while by a fire with a roof and walls around you.
	if sheltered and heat > 0.25:
		_rest_build += dt
		if _rest_build >= REST_AFTER:
			rested = maxf(rested, REST_SECONDS)
	else:
		_rest_build = 0.0
	rested = maxf(rested - dt, 0.0)
	var target: float = world.air_warmth(p, sheltered) + heat * 70.0
	if wet > 0.0:
		target -= 22.0
		wet = maxf(wet - dt * (3.0 if heat > 0.3 else 1.0), 0.0)   # fires dry you off
	target = clampf(target, 0.0, MAX)
	# Warm up faster than you cool down: getting to a fire should feel good.
	warmth = move_toward(warmth, target, (7.0 if target > warmth else 1.6) * dt)

	hunger = maxf(hunger - HUNGER_DRAIN * dt * (1.5 if warmth < 30.0 else 1.0), 0.0)

	if _stamina_wait > 0.0:
		_stamina_wait -= dt
	else:
		stamina = minf(stamina + STAMINA_REGEN * (1.5 if rested > 0.0 else 1.0) * dt, MAX)

	var dmg := 0.0
	if hunger <= 0.0:
		dmg += 0.6
	if warmth < 12.0:
		dmg += 0.5
	if dmg > 0.0:
		health = maxf(health - dmg * dt, 0.0)
	elif hunger > 40.0 and warmth > 35.0:
		health = minf(health + 0.5 * dt, MAX)

	_update_statuses()
	changed.emit()
	if health <= 0.0:
		dead = true
		died.emit()

func _update_statuses() -> void:
	statuses.clear()
	if heat > 0.25:
		statuses.append("Warm")
	if warmth < 12.0:
		statuses.append("Freezing")
	elif warmth < 30.0:
		statuses.append("Cold")
	if hunger <= 0.0:
		statuses.append("Starving")
	elif hunger < 25.0:
		statuses.append("Hungry")
	if wet > 0.0:
		statuses.append("Wet")
	if sheltered:
		statuses.append("Sheltered")
	if rested > 0.0:
		statuses.append("Rested")

## Spends stamina for an action. Returns false (and spends nothing) if you're
## too tired. Continuous costs (sprinting) pass `partial = true`.
func use_stamina(amount: float, partial: bool = false) -> bool:
	if stamina <= 0.0 or (not partial and stamina < amount * 0.5):
		return false
	stamina = maxf(stamina - amount, 0.0)
	_stamina_wait = STAMINA_DELAY
	return true

func eat(food: Dictionary) -> void:
	hunger = minf(hunger + float(food.get("hunger", 0)), MAX)
	health = minf(health + float(food.get("health", 0)), MAX)
	changed.emit()

func soak() -> void:
	wet = WET_SECONDS

## After a night's sleep: a little hungrier, dry, warm and rested.
func after_sleep(seconds: float) -> void:
	hunger = maxf(hunger - HUNGER_DRAIN * seconds * 0.3, 0.0)
	wet = 0.0
	warmth = maxf(warmth, 60.0)
	stamina = MAX
	rested = REST_SECONDS * 2.0
	_update_statuses()
	changed.emit()

func reset_after_death() -> void:
	dead = false
	health = 50.0
	stamina = MAX
	hunger = 50.0
	warmth = 60.0
	wet = 0.0
	changed.emit()

func to_data() -> Dictionary:
	return {"health": health, "stamina": stamina, "hunger": hunger, "warmth": warmth, "wet": wet, "rested": rested}

func load_data(d: Dictionary) -> void:
	health = float(d.get("health", health))
	stamina = float(d.get("stamina", stamina))
	hunger = float(d.get("hunger", hunger))
	warmth = float(d.get("warmth", warmth))
	wet = float(d.get("wet", 0.0))
	rested = float(d.get("rested", 0.0))
	dead = false
	changed.emit()