extends Node
class_name StateWallRun

const FLAG: int = 0  # unused

var machine: MovementStateMachine
var params: MovementParams:
	get: return machine.params

var elapsed: float = 0.0


func enter(_data: Dictionary = {}) -> void:
	elapsed = 0.0
	machine.register_chain_mechanic("wall_run")
	machine.player.velocity.y = params.wall_run_vertical_speed


func exit() -> void:
	pass


func update(delta: float) -> void:
	elapsed += delta
	if elapsed > params.wall_run_duration:
		machine.wall_normal = Vector3.ZERO
		machine.switch_to("air")
		return

	var vel: Vector3 = machine.player.velocity

	# Stick to wall
	vel.y = min(vel.y, params.wall_run_vertical_speed)

	# Move along wall: project velocity onto wall tangent
	var wall_tangent := (machine.wall_normal.cross(Vector3.UP)).normalized()
	if machine.input_dir.y < 0.0:
		wall_tangent = -wall_tangent
	var move_dir: Vector3 = wall_tangent * params.wall_run_speed
	vel.x = move_dir.x
	vel.z = move_dir.z

	if machine.input_jump_just_pressed:
		var jump_vel: Vector3 = vel + (machine.wall_normal * params.wall_run_jump_off_normal)
		jump_vel.y = params.wall_run_auto_jump_speed
		machine.player.velocity = jump_vel
		machine.wall_normal = Vector3.ZERO
		machine.register_chain_mechanic("wall_jump")
		machine.switch_to("air")
		return

	# Wall cling fall-through
	if machine.input_dir.length() < 0.1:
		machine.switch_to("wall_cling")
		return

	# Lose wall contact
	var still_on_wall: bool = machine.wall_normal != Vector3.ZERO and detect_wall(machine.wall_normal).length_squared() > 0.0
	if not still_on_wall:
		machine.wall_normal = Vector3.ZERO
		machine.register_chain_mechanic("wall_run_off")
		machine.switch_to("air")

	machine.player.velocity = vel
	machine.player.move_and_slide()

	if machine.player.is_on_floor():
		machine.on_ground = true
		machine.wall_normal = Vector3.ZERO
		machine.current_jump_count = 0
		machine.register_chain_mechanic("wall_run_land")
		machine.switch_to("ground")


func detect_wall(expected_normal: Vector3) -> Vector3:
	var origin := machine.player.global_position
	var offset := expected_normal.cross(Vector3.UP).normalized()
	var space_state := machine.player.get_world_3d().direct_space_state
	for side in [1.0, -1.0]:
		var ray_origin := origin + offset * side * params.wall_detect_distance + Vector3.UP * params.wall_ray_up_height
		var ray_end := origin + offset * side * params.wall_detect_distance - Vector3.DOWN * params.wall_ray_down_height
		var ray := PhysicsRayQueryParameters3D.create(ray_origin, ray_end)
		ray.exclude = [machine.player.get_rid()]
		var hit := space_state.intersect_ray(ray)
		if not hit.is_empty():
			return hit.get("normal", Vector3.ZERO).normalized()
	return Vector3.ZERO