class_name DamageCalculator
extends RefCounted

const CRIT_CHANCE : float = 1.0 / 24.0
const CRIT_MULTIPLIER : float = 1.5
const STAB_MULTIPLIER : float = 1.5
const SPREAD_MULTIPLIER : float = 0.75 #capacite touchant plusieurs cibles

static func calculate(attacker : BattleMon, defender : BattleMon, move : MoveData, rng : RandomNumberGenerator = null, spread : bool = false, deterministic : bool = false) -> Dictionary:
	#renvoie {"damage": int, "effectiveness": float, "critical": bool}
	var result : Dictionary = {"damage": 0, "effectiveness": 1.0, "critical": false}
	if move.power <= 0 or move.category == "status": return result
	
	var effectiveness : float = TypeChart.get_multiplier(move.type, defender.get_types())
	result["effectiveness"] = effectiveness
	if effectiveness == 0.0: return result
	
	var physical : bool = move.category == "physical"
	var attack : float = attacker.get_stat(PokemonNature.Stat.ATTACK if physical else PokemonNature.Stat.SP_ATTACK)
	var defense : float = defender.get_stat(PokemonNature.Stat.DEFENSE if physical else PokemonNature.Stat.SP_DEFENSE)
	var level : int = attacker.pokemon.level
	
	#formule officielle
	var damage : float = floorf(floorf(floorf(2.0 * level / 5.0 + 2.0) * move.power * attack / maxf(defense, 1.0)) / 50.0) + 2.0
	
	var critical : bool = !deterministic and rng != null and rng.randf() < CRIT_CHANCE
	var roll : float = 0.925 if (deterministic or rng == null) else rng.randi_range(85, 100) / 100.0
	var stab : float = STAB_MULTIPLIER if attacker.get_types().has(move.type.to_lower()) else 1.0
	
	damage *= roll * stab * effectiveness
	if critical: damage *= CRIT_MULTIPLIER
	if spread: damage *= SPREAD_MULTIPLIER
	
	result["critical"] = critical
	result["damage"] = maxi(1, floori(damage))
	return result

static func estimate(attacker : BattleMon, defender : BattleMon, move : MoveData, spread : bool = false) -> int:
	#degats attendus, sans hasard (utilise par l'IA)
	return int(calculate(attacker, defender, move, null, spread, true)["damage"])