extends KinematicBody


var acceleration := Vector3(0.0, -9.81, 0.0)
var velocity := Vector3(0.0, 0.0, 0.0)

var move_speed = 5.0
var jump_accel = 300.0

export(NodePath) var solar_system


# Called when the node enters the scene tree for the first time.
func _ready():
	pass # Replace with function body.


# Called every frame. 'delta' is the elapsed time since the previous frame.
func _physics_process(delta):
	var move_velocity := Vector3.ZERO
	var move_acceleration := Vector3.ZERO
	
	# Movement and rotation
	if Input.is_action_pressed("ui_up"):
		move_velocity.z -= move_speed
	if Input.is_action_pressed("ui_down"):
		move_velocity.z += move_speed
	if Input.is_action_pressed("ui_left"):
		rotate(transform.basis.y, delta)
	if Input.is_action_pressed("ui_right"):
		rotate(transform.basis.y, -delta)
	
	# Make movement local
	move_velocity = transform.basis * move_velocity
	
	# Jumping
	if Input.is_action_just_pressed("ui_select"):
		move_acceleration.y += jump_accel
	
	# Gravity
	var gravity_acceleration = get_node(solar_system).get_gravitation_acceleration(transform.origin)
	velocity += (gravity_acceleration * 9.81 - gravity_acceleration * move_acceleration.y) * delta
	var movement = (move_velocity + velocity) * delta
	
	# Apply movement to position
	var collision = move_and_collide(movement)
	
	# Reset the velocity if the body is colliding
	if collision:
		velocity = Vector3.ZERO
	
	# Rotate down vector to face center of gravity
	var down = gravity_acceleration
	var local_down = transform.basis * Vector3.DOWN
	var angle = local_down.angle_to(down)
	var axis = local_down.cross(down).normalized()
	
	if axis != Vector3.ZERO: # Happens if we're perfectly aligned already (local_down and down are equal)
		rotate(axis, angle)