SNAKE 3 START

extends Node2D

var point_pos:Vector2
var snake_body = [Vector2(5,10),Vector2(4,10),Vector2(3,10)]
var snake_direction = Vector2(1,0)
var changed_direction = false  
var remover = 1

func _ready():
	point_pos = place_point()
	draw_point()
	draw_snake()
 
func draw_snake():
	for block_index in snake_body.size():
		var block = snake_body[block_index]
		if block_index == 0:
			var head_dir = relation(snake_body[1],snake_body[0])
			match(head_dir):
				"left":
					$Board.set_cell(0,Vector2(block.x,block.y),0,Vector2(7,0))
				"right":
					$Board.set_cell(0,Vector2(block.x,block.y),0,Vector2(7,0))
				"top":
					$Board.set_cell(0,Vector2(block.x,block.y),0,Vector2(7,0))
				"down":		
					$Board.set_cell(0,Vector2(block.x,block.y),0,Vector2(7,0))
		elif block_index == snake_body.size()-1:
			var tail_dir = relation(snake_body[block_index],snake_body[block_index-1])
			match(tail_dir):
				"left":
					$Board.set_cell(0,Vector2(block.x,block.y),0,Vector2(7,0))
				"right":
					$Board.set_cell(0,Vector2(block.x,block.y),0,Vector2(7,0))
				"top":
					$Board.set_cell(0,Vector2(block.x,block.y),0,Vector2(7,0))
				"down":
					$Board.set_cell(0,Vector2(block.x,block.y),0,Vector2(7,0))
		else:
			var previous_block = relation(snake_body[block_index],snake_body[block_index-1])
			var next_block = relation(snake_body[block_index],snake_body[block_index+1])	
			match(previous_block+"_"+next_block):
				"left_top","top_left":
					$Board.set_cell(0,Vector2(block.x,block.y),0,Vector2(7,0))
				"right_top","top_right":
					$Board.set_cell(0,Vector2(block.x,block.y),0,Vector2(7,0))
				"down_top","top_down":
					$Board.set_cell(0,Vector2(block.x,block.y),0,Vector2(7,0))
				"right_left","left_right":
					$Board.set_cell(0,Vector2(block.x,block.y),0,Vector2(7,0))
				"left_down","down_left":
					$Board.set_cell(0,Vector2(block.x,block.y),0,Vector2(7,0))
				"right_down","down_right":
					$Board.set_cell(0,Vector2(block.x,block.y),0,Vector2(7,0))
 
func draw_point():
	$Board.set_cell(0,Vector2(point_pos.x,point_pos.y),1,Vector2(0,0))
 
func place_point():
	randomize()
	var x = randi() % 20
	var y = randi() % 20
	while(Vector2(x,y) in snake_body):
		x = randi() % 20
		y = randi() % 20
	return Vector2(x,y)
 
func delete_tiles(id):
	var cells = $Board.get_used_cells_by_id(0,id)
	for cell in cells:
		$Board.set_cell(0,Vector2(cell.x,cell.y),-1)	
 
func move_snake():
	delete_tiles(0)
	var body_copy = snake_body.slice(0,snake_body.size()-remover)
	remover = 1
	var new_head = body_copy[0] + snake_direction
	body_copy.insert(0,new_head)
	snake_body = body_copy
 
func _on_timer_timeout():
	changed_direction = false
	check_point_eaten()
	check_game_over()
	move_snake()
	draw_point()
	draw_snake()
	
func check_point_eaten():
	if $Board.get_cell_source_id(0,snake_body[0]+snake_direction) == 2:
		point_pos = place_point()
		remover = 0
		
func check_game_over():
	var head = snake_body[0] + snake_direction
	if head.x<2 or head.x>16 or head.y<2 or head.y>16:
		reset()
	if head in snake_body.slice(0,snake_body.size() - 1):
		reset()

func reset():
	snake_body = [Vector2(5,10),Vector2(4,10),Vector2(3,10)]
	snake_direction = Vector2(1,0)
	delete_tiles(1)
	point_pos = place_point()
 
func _process(delta):
	if not changed_direction:
		if Input.is_key_pressed(KEY_W) && snake_direction!=Vector2.DOWN:
			snake_direction = Vector2.UP
			changed_direction = true
		elif Input.is_key_pressed(KEY_A) && snake_direction!=Vector2.RIGHT:
			snake_direction = Vector2.LEFT
			changed_direction = true
		elif Input.is_key_pressed(KEY_S) && snake_direction!=Vector2.UP:
			snake_direction = Vector2.DOWN
			changed_direction = true
		elif Input.is_key_pressed(KEY_D) && snake_direction!=Vector2.LEFT:
			snake_direction = Vector2.RIGHT
			changed_direction = true	

func relation(first_block:Vector2,second_block:Vector2):
	var block_relation = second_block - first_block
	if block_relation == Vector2(-1,0):
		return "left"
	if block_relation == Vector2(1,0):
		return "right"
	if block_relation == Vector2(0,1):
		return "down"
	if block_relation == Vector2(0,-1):
		return "top"