@tool
class_name PlayerWaterTrigger
extends Area3D

signal recovery_requested(player: Player, surface_height: float)

enum SurfaceHeightMode {
	EXPLICIT,
	PARENT_GLOBAL_Y,
}

enum EntryHeightReference {
	BODY_CENTER,
	PLAYER_ORIGIN,
}

@export_group("Surface")
@export var surface_height_mode: SurfaceHeightMode = SurfaceHeightMode.EXPLICIT:
	set(value):
		surface_height_mode = value
		if Engine.is_editor_hint():
			notify_property_list_changed()
## Legacy explicit height used when Surface Height Mode is Explicit.
@export var surface_height: float = 0.2
@export_group("Recovery Trigger")
## Point on the player used to measure entry depth below the water surface.
@export var entry_height_reference: EntryHeightReference = (
	EntryHeightReference.BODY_CENTER
)
## Recovery begins when the selected reference reaches this depth.
@export_range(0.0, 2.0, 0.05) var entry_depth_threshold: float = 0.35
## The player must remain below the threshold for this long before recovery.
## A short freshwater confirmation keeps jumps across stepping stones from
## being mistaken for a completed fall into the water.
@export_range(0.0, 1.0, 0.05) var entry_confirmation_seconds: float = 0.0

var _tracked_players: Array[Player] = []
var _triggered_players: Dictionary[StringName, bool] = {}
var _submerged_seconds: Dictionary[StringName, float] = {}


func _ready() -> void:
	if Engine.is_editor_hint():
		set_physics_process(false)
		return
	body_entered.connect(_on_body_entered)
	body_exited.connect(_on_body_exited)
	# Generated worlds can contain many independent water volumes. Keep an
	# empty trigger completely asleep instead of polling an empty array on every
	# physics tick.
	set_physics_process(false)


func _physics_process(delta: float) -> void:
	var active_surface_height: float = get_surface_height()
	for player: Player in _tracked_players.duplicate():
		if not is_instance_valid(player):
			_tracked_players.erase(player)
			continue
		var player_key: StringName = StringName(str(player.get_instance_id()))
		if _triggered_players.has(player_key):
			continue
		var entry_height := player.get_body_center_position().y
		if entry_height_reference == EntryHeightReference.PLAYER_ORIGIN:
			entry_height = player.global_position.y
		if entry_height > active_surface_height - entry_depth_threshold:
			_submerged_seconds[player_key] = 0.0
			continue
		var submerged_seconds: float = (
			_submerged_seconds.get(player_key, 0.0) + maxf(delta, 0.0)
		)
		_submerged_seconds[player_key] = submerged_seconds
		if submerged_seconds < entry_confirmation_seconds:
			continue
		_triggered_players[player_key] = true
		recovery_requested.emit(player, active_surface_height)
	if _tracked_players.is_empty():
		set_physics_process(false)


func get_surface_height() -> float:
	if surface_height_mode == SurfaceHeightMode.PARENT_GLOBAL_Y:
		var surface_owner := get_parent() as Node3D
		if surface_owner != null:
			return surface_owner.global_position.y
	return surface_height


func _validate_property(property: Dictionary) -> void:
	if (
		property.name == "surface_height"
		and surface_height_mode == SurfaceHeightMode.PARENT_GLOBAL_Y
	):
		property.usage = int(property.usage) & ~PROPERTY_USAGE_EDITOR


func _on_body_entered(body: Node3D) -> void:
	var player: Player = body as Player
	if player == null or player in _tracked_players:
		return
	_tracked_players.append(player)
	_submerged_seconds[StringName(str(player.get_instance_id()))] = 0.0
	set_physics_process(true)


func _on_body_exited(body: Node3D) -> void:
	var player: Player = body as Player
	if player == null:
		return
	_tracked_players.erase(player)
	var player_key := StringName(str(player.get_instance_id()))
	_triggered_players.erase(player_key)
	_submerged_seconds.erase(player_key)
	if _tracked_players.is_empty():
		set_physics_process(false)