extends Area3D
class_name CombatArea

## The play volume. Leaving it starts a five second countdown with an on-screen
## warning and a reddening overlay; reaching zero kills the player.
##
## ── Every map needs one ──────────────────────────────────────────────────────
##
## This existed for a long while and only dust2 installed it, which meant that
## on every other map a player who got over a boundary wall — and this game has
## a grapple and a dash — simply fell out of the world and kept falling, with no
## warning, no death and no way back. `add_to()` exists so wiring it up is one
## line at the bottom of a level builder rather than fifteen, because the reason
## it was missing everywhere was that it was fiddly to add.
##
## Size it GENEROUSLY: the volume is the point at which a player is told they
## have left, not the edge of the level geometry. A box tight to the boundary
## walls fires the warning while someone is still standing on a legitimate
## rooftop.
static func add_to(level: Node, size: Vector3, centre: Vector3 = Vector3.ZERO,
		node_name: String = "CombatArea") -> CombatArea:
	if level.has_node(NodePath(node_name)):
		return level.get_node(NodePath(node_name)) as CombatArea
	var area := CombatArea.new()
	area.name = node_name
	var shape := CollisionShape3D.new()
	var box := BoxShape3D.new()
	box.size = size
	shape.shape = box
	area.add_child(shape)
	area.position = centre
	level.add_child(area)
	return area

var out_of_bounds_players: Dictionary = {} # body -> { time_left: 5.0 }
var recovery_players: Dictionary = {} # body -> { time_safe: 0.0, time_left: float }

var _ui_layer: CanvasLayer = null
var _ui_label: Label = null
var _ui_overlay: ColorRect = null
var _is_local_player_out: bool = false
var _local_player_body: Node3D = null

func _ready() -> void:
	collision_layer = 0
	collision_mask = 4294967295 # All layers
	body_exited.connect(_on_body_exited)
	body_entered.connect(_on_body_entered)
	# Own the warning UI for the same lifetime as the combat volume. Creating it
	# from body_exited races level teardown: removing the player from physics can
	# emit that signal while the scene is already being freed, leaving the
	# deferred overlay orphaned.
	_create_ui()
	_ui_layer.visible = false
	set_process(false)
	
func _process(delta: float) -> void:
	# Process players who are actively out of bounds
	var to_kill: Array = []
	for body in out_of_bounds_players.keys():
		if "is_dead" in body and body.is_dead:
			out_of_bounds_players.erase(body)
			if body == _local_player_body:
				_remove_ui()
			continue
			
		var data = out_of_bounds_players[body]
		data.time_left -= delta
		if data.time_left <= 0.0:
			data.time_left = 0.0
			to_kill.append(body)
			
		if body == _local_player_body and _is_local_player_out and _ui_label and _ui_overlay:
			_ui_label.text = "WARNING: RETURN TO COMBAT AREA\n%.1f" % data.time_left
			_ui_overlay.color = Color(1.0, 0.0, 0.0, 0.8 * (1.0 - (data.time_left / 5.0)))
			
	for body in to_kill:
		_kill_player(body)
		
	# Process players who returned but are recovering
	var recovered: Array = []
	for body in recovery_players.keys():
		if "is_dead" in body and body.is_dead:
			recovered.append(body)
			continue
			
		var data = recovery_players[body]
		data.time_safe += delta
		if data.time_safe >= 10.0:
			recovered.append(body)
			
	for body in recovered:
		recovery_players.erase(body)
		
	if out_of_bounds_players.is_empty() and recovery_players.is_empty():
		set_process(false)

func _on_body_exited(body: Node3D) -> void:
	if body is CharacterBody3D and body.has_method("take_damage") and str(body.name).is_valid_int():
		if "is_dead" in body and body.is_dead:
			return
		if body.is_queued_for_deletion() or not is_inside_tree():
			return
			
		var start_time = 5.0
		if recovery_players.has(body):
			start_time = recovery_players[body].time_left
			recovery_players.erase(body)
			
		out_of_bounds_players[body] = { "time_left": start_time }
		
		# Singleplayer goes through OfflineMultiplayerPeer, so it takes the
		# branch below and works. This default covers the case with NO peer at
		# all — a level opened directly, without NetworkManager having started a
		# match, which is how the debug and capture tools run it. There is one
		# player then and they are the local one; without this they would get
		# the silent countdown and no warning.
		var is_local := true
		if multiplayer.has_multiplayer_peer():
			is_local = body.get_multiplayer_authority() == multiplayer.get_unique_id()


		if is_local:
			_is_local_player_out = true
			_local_player_body = body
			_create_ui()
			
		set_process(true)

func _on_body_entered(body: Node3D) -> void:
	if out_of_bounds_players.has(body):
		var time_left_val = out_of_bounds_players[body].time_left
		out_of_bounds_players.erase(body)
		
		if time_left_val < 5.0:
			recovery_players[body] = { "time_left": time_left_val, "time_safe": 0.0 }
			set_process(true)
			
		if body == _local_player_body and _is_local_player_out:
			_remove_ui()
			_is_local_player_out = false
			_local_player_body = null

func _create_ui() -> void:
	if _ui_layer:
		_ui_layer.visible = true
		return
	
	_ui_layer = CanvasLayer.new()
	_ui_layer.layer = 100 # Put it on top of everything
	
	_ui_overlay = ColorRect.new()
	_ui_overlay.set_anchors_preset(Control.PRESET_FULL_RECT)
	_ui_overlay.color = Color(1.0, 0.0, 0.0, 0.0)
	_ui_overlay.mouse_filter = Control.MOUSE_FILTER_IGNORE
	_ui_layer.add_child(_ui_overlay)
	
	_ui_label = Label.new()
	_ui_label.set_anchors_preset(Control.PRESET_CENTER)
	_ui_label.grow_horizontal = Control.GROW_DIRECTION_BOTH
	_ui_label.grow_vertical = Control.GROW_DIRECTION_BOTH
	_ui_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
	_ui_label.add_theme_font_size_override("font_size", 48)
	_ui_label.add_theme_color_override("font_color", Color(1, 0.2, 0.2))
	_ui_label.add_theme_color_override("font_outline_color", Color(0, 0, 0))
	_ui_label.add_theme_constant_override("outline_size", 8)
	var display_time = 5.0
	if out_of_bounds_players.has(_local_player_body):
		display_time = out_of_bounds_players[_local_player_body].time_left
	_ui_label.text = "WARNING: RETURN TO COMBAT AREA\n%.1f" % display_time
	
	_ui_layer.add_child(_ui_label)
	
	add_child(_ui_layer)

func _remove_ui() -> void:
	if _ui_layer:
		_ui_layer.visible = false

func _kill_player(body: Node3D) -> void:
	if body:
		# Damage is the server's call. With no peer there is no server to defer
		# to and `is_server()` answers false, so without this a level opened
		# outside a match would count down to zero and then quietly drop the
		# player from its own list without ever killing them.
		var authoritative := not multiplayer.has_multiplayer_peer() \
			or multiplayer.is_server()
		if authoritative and body.has_method("take_damage"):
			body.take_damage(9999, Vector3.ZERO, null, Vector3.ZERO)
		
		out_of_bounds_players.erase(body)
		if body == _local_player_body and _is_local_player_out:
			_remove_ui()
			_is_local_player_out = false
			_local_player_body = null