class_name Player
extends CharacterBody3D

@export var camera: Camera

@export_group("Movement")
@export var move_accel     :=   6.0
@export var move_max_speed :=   4.0
@export var friction_floor :=  12.0
@export var friction_air   :=   2.0
@export var gravity        := -12.0

@export_group("Jumping")
@export var jump_velocity    := 5.0
@export var jump_early_time  := 0.0 # Time (in seconds) after pressing the jump button a jump may occur late.
@export var jump_coyote_time := 0.0 # Time (in seconds) after leaving a jumpable surface when a jump may still occur.

enum MovementModeEnum { DEFAULT, FLYING, NO_CLIP }
var movement_mode := MovementModeEnum.DEFAULT

var is_moving    := false
var is_sprinting := false

var time_since_jump_pressed := INF
var time_since_on_floor     := INF


func _input(event: InputEvent) -> void:
	# Inputs that are valid when the game is focused.
	# ===============================================

	if event.is_action("move_sprint"):
		is_sprinting = event.is_pressed()
		get_viewport().set_input_as_handled()

	if event.is_action_pressed("move_jump"):
		time_since_jump_pressed = 0
		get_viewport().set_input_as_handled()

	# Cycle movement mode between default, flying and noclip.
	if event.is_action_pressed("cycle_movement_mode"):
		if (+movement_mode > MovementModeEnum.NO_CLIP):
			movement_mode = MovementModeEnum.DEFAULT;
		get_viewport().set_input_as_handled()

	# Inputs that are valid only when the mouse is captured.
	# ======================================================
	if Input.mouse_mode == Input.MOUSE_MODE_CAPTURED:
		pass


func _physics_process(delta: float) -> void:
	match movement_mode:
		MovementModeEnum.DEFAULT:
			process_movement_default(delta)
		MovementModeEnum.FLYING:
			process_movement_flying(delta, false)
		MovementModeEnum.NO_CLIP:
			process_movement_flying(delta, true)


func process_movement_default(delta: float) -> void:
	var input := Input.get_vector("move_strafe_left", "move_strafe_right", "move_forward", "move_backward")

	velocity.y += gravity * delta
	var hor_vel := Vector3(velocity.x, 0, velocity.z)

	var target := basis.rotated(Vector3.UP, camera.current_yaw) * Vector3(input.x, 0, input.y) * move_max_speed
	is_moving = target.dot(hor_vel) > 0

	var accel: float
	if is_moving:       accel = move_accel
	elif is_on_floor(): accel = friction_floor
	else:               accel = friction_air

	if is_sprinting:
		target *= 5
		accel  *= 5

	hor_vel  = hor_vel.lerp(target, accel * delta)
	velocity = Vector3(hor_vel.x, velocity.y, hor_vel.z)

	# TODO: Check if this still applies.
	# Sometimes, when pushing into a wall, jumping wasn't working.
	# Possibly due to `IsOnFloor` returning `false` for some reason.
	# The `JumpEarlyTime` feature seems to avoid this issue, thankfully.

	if is_on_floor(): time_since_on_floor = 0
	else:             time_since_on_floor += delta

	if time_since_jump_pressed <= jump_early_time && time_since_on_floor <= jump_coyote_time:
		velocity.y = jump_velocity
		time_since_jump_pressed = INF
		time_since_on_floor = INF

	move_and_slide()

func process_movement_flying(delta: float, no_clip: bool) -> void:
	var input := Vector3(
		Input.get_axis("move_strafe_left", "move_strafe_right"),
		Input.get_axis("move_downward", "move_upward"),
		Input.get_axis("move_forward", "move_backward"))

	velocity *= 1 - friction_air * delta;

	var target := camera.global_transform.basis.get_rotation_quaternion() * input * move_max_speed
	is_moving = target.dot(velocity) > 0

	var accel: float
	if is_moving: accel = move_accel
	else:         accel = friction_air

	target *= 4
	accel  *= 4

	if is_sprinting:
		target *= 5
		accel  *= 5

	velocity = velocity.lerp(target, accel * delta)

	if no_clip: translate(velocity * delta)
	else:       move_and_slide()