class_name Piece
extends MeshInstance3D

const WALL = preload("res://model/wall.tres")
const GOAL = preload("res://model/goal.tres")
const BALL = preload("res://model/ball.tres")
const PLAYER = preload("res://model/player.tres")
const FLOOR_ICE = preload("res://model/floor_ice.tres")

enum Type {
	Wall,
	Goal,
	Ball,
	Player,
	FloorIce,
}

# idea: SLOW MO KEY!!!!!!!!!!!!!!!
## squares per second
@export_range(0.1, 50) var anim_speed := 10.0
@export_range(0.1, 50) var anim_speed_slow := 2.0

## logical position
@export var lpos: Vector2i:
	get:
		return lpos
	set(val):
		lpos = val
		position = target_pos
		start_pos = position
		target_pos = Vector3(lpos.x, position.y, lpos.y)
		anim_progress = 0

## logical velocity
@export var lvel := Vector2i.ZERO

@export var type: Piece.Type

@onready var start_pos := position
@onready var target_pos := position
@onready var anim_progress := 1.0
var speedometer: Label3D

# TODO: this is *complex*, transfer momentum and stuff
func do_step(board: Board):
	if lvel == Vector2i.ZERO:
		return
	if board.solid_at(lpos + lvel.clampi(-1, 1)):
		lpos = lpos
		lvel -= lvel.clampi(-1, 1)
		return
	lpos += lvel.clampi(-1, 1)
	var on_ice := !!board.type_at(lpos, Piece.Type.FloorIce)
	if not on_ice:
		lvel -= lvel.clampi(-1, 1)

func undo_step() -> Callable:
	var old_pos := lpos
	var old_vel := lvel
	return func():
		lpos = old_pos
		lvel = old_vel

func do_move(move: Vector2i) -> Callable:
	return func():
		lpos += move

func undo_move() -> Callable:
	var old_pos := lpos
	return func():
		lpos = old_pos

func do_push(move: Vector2i) -> Callable:
	return func():
		lvel += move
		anim_progress = 1

func undo_push() -> Callable:
	var old_vel := lvel
	return func():
		lvel = old_vel
		anim_progress = 1

static func make(lpos: Vector2i, type: Piece.Type, mesh: Mesh) -> Piece:
	var piece := Piece.new()
	piece.lpos = lpos
	piece.mesh = mesh
	piece.type = type
	return piece

static func wall(lpos: Vector2i) -> Piece:
	return make(lpos, Piece.Type.Wall, WALL)

static func goal(lpos: Vector2i) -> Piece:
	return make(lpos, Piece.Type.Goal, GOAL)

static func ball(lpos: Vector2i) -> Piece:
	return make(lpos, Piece.Type.Ball, BALL)

static func player(lpos: Vector2i) -> Piece:
	return make(lpos, Piece.Type.Player, PLAYER)

static func floor_ice(lpos: Vector2i) -> Piece:
	return make(lpos, Piece.Type.FloorIce, FLOOR_ICE)

func _ready() -> void:
	lpos = lpos
	anim_progress = 1
	speedometer = Label3D.new()
	speedometer.billboard = BaseMaterial3D.BILLBOARD_ENABLED
	speedometer.no_depth_test = true
	speedometer.font_size = 64
	add_child(speedometer)

#TODO: arrow!
func format_vel(vel: Vector2) -> String:
	if vel.is_zero_approx():
		return ""
	else:
		return "%d,%d" % [vel.x,vel.y]

func _process(delta: float) -> void:
	var speed := anim_speed_slow if Input.is_action_pressed("slowmo") else anim_speed
	anim_progress = min(1, anim_progress + speed*delta)
	position = start_pos.lerp(target_pos, anim_progress)
	speedometer.text = format_vel(lvel)