extends CharacterBody2D

# editor variables
@export var max_speed = 800
@export var steer_force = 20
@export var acceleration = 8
@export var mass = 1.0
@export var look_ahead = 75
@export var num_rays = 32
@export var driving = false

# context array
var ray_directions = []
var interest = []
var danger = []

var chosen_dir = Vector2.ZERO
var current_speed = 0


# Called when the node enters the scene tree for the first time.
func _ready():
	interest.resize(num_rays)
	danger.resize(num_rays)
	ray_directions.resize(num_rays)
	for i in num_rays:
		var angle = i * 2 * PI / num_rays
		ray_directions[i] = Vector2.RIGHT.rotated(angle)

func _physics_process(delta):
	if not driving:
		return
	
	# Code for getting the next desired direction based on the environment
	set_interest()
	set_danger()
	choose_direction()
	
#	example_movement(delta)
#	own_movement(delta)
	own_movement_improved(delta)


func set_interest():
	# Set interest in each slot based on world direction
#	if owner and owner.has_method("get_path_direction"):
	if owner and owner.has_method("get_path_next_position"):
#		var path_direction = owner.get_path_direction(position)
		var next_pos = owner.get_path_next_position(position)
		var path_direction = (next_pos - position).normalized()

		for i in num_rays:
			var d = ray_directions[i].rotated(rotation).dot(path_direction)
			interest[i] = max(0, d)
	# If no world path, use default interest
	else:
		set_default_interest()

func set_default_interest():
	# Default to moving forward
	for i in num_rays:
		var d = ray_directions[i].rotated(rotation).dot(transform.x)
		interest[i] = max(0, d)

func set_danger():
	# Cast rays to find danger directions
	var space_state = get_world_2d().direct_space_state
	
	var params = PhysicsRayQueryParameters2D.new()
	params.from = position
	params.exclude = [self]
	
	for i in num_rays:
		params.to = position + ray_directions[i].rotated(rotation) * look_ahead
		var result = space_state.intersect_ray(params)
		danger[i] = 1.0 if result else 0.0

func choose_direction():
	# Eliminate interest in slots with danger
	for i in num_rays:
		if danger[i] > 0.0:
			interest[i] = 0.0
	# Choose direction based on remaining interest
	chosen_dir = Vector2.ZERO
	for i in num_rays:
		chosen_dir += ray_directions[i] * interest[i]
	chosen_dir = chosen_dir.normalized()


func example_movement(delta):
	var desired_velocity = chosen_dir.rotated(rotation) * max_speed
	velocity = velocity.lerp(desired_velocity, steer_force)
	rotation = velocity.angle()
	move_and_collide(velocity * delta)


func own_movement(delta):
	var desired_velocity = chosen_dir.rotated(rotation) * max_speed

	var new_speed = lerpf(velocity.length(), max_speed, acceleration)
	var new_angle = lerp_angle(velocity.angle(), desired_velocity.angle(), steer_force)
	
	velocity = Vector2.from_angle(new_angle) * new_speed
	rotation = new_angle
	move_and_collide(velocity * delta)
	

func own_movement_improved(delta):
	var desired_velocity = chosen_dir.rotated(rotation) * max_speed
	print('==========')
	print('current speed: ', velocity.length(), ' | current angle: ', velocity.angle())
	print('desired speed: ', desired_velocity.length(), ' | desired angle: ', desired_velocity.angle())
	
#	var possible_radius = mass * velocity.length_squared() / steer_force
#	var possible_steer_angle = velocity.length() / possible_radius
	var possible_steer_angle = steer_force / (mass * velocity.length())
	var angle_change = clampf(wrapf(desired_velocity.angle() - velocity.angle(), -PI, PI), -possible_steer_angle, possible_steer_angle)
	var new_angle = wrapf(velocity.angle() + angle_change, -PI, PI)
	print('possible_steer_angle: ', possible_steer_angle, ' | angle_change: ', angle_change, ' | new_angle: ', new_angle )
	
	var wanted_speed = steer_force / (mass * absf(desired_velocity.angle() - velocity.angle()))
	var new_max_speed = min(velocity.length() + (acceleration), max_speed)
	var new_min_speed = max(velocity.length() - (acceleration), 0)
	var new_speed = clampf(wanted_speed, new_min_speed, new_max_speed)
	print('wanted: ', wanted_speed, ' | min: ', new_min_speed, ' | max: ', new_max_speed, ' | new: ', new_speed)
	
	velocity = Vector2.from_angle(new_angle) * new_speed
	rotation = new_angle
	move_and_collide(velocity * delta)