Megalomaniak the code may be messed up, but i'm willing to learn and understand. Thank you.

extends KinematicBody2D

const GRAVITY = 15
const SPEED = 40
const CHASE_SPEED = 60

var left = true
var motion = Vector2.ZERO
var is_attacking := false
var can_move := true
var is_chasing := false
var attack_name = 'combo0'
onready var player = get_node('/root/World/Player')

func _ready():
	$AnimatedSprite.play('walk')

func _process(delta):
	if is_attacking: return
	chase_player()
	detect_floor()
	if can_move and !is_chasing: 
		move_character()
		if motion.x == 0:$AnimatedSprite.play('idle')
		else:$AnimatedSprite.play('walk')
	if is_chasing:
		if motion.x == 0:$AnimatedSprite.play('idle')
		else:$AnimatedSprite.play('walk')
		

func move_character():
	motion.x = -SPEED if left else SPEED
	motion.y += GRAVITY
	
	motion = move_and_slide(motion,Vector2.UP)
func detect_floor():
	if (not $HoleChecker.is_colliding() and is_on_floor() and !is_chasing):
		left = !left
		scale.x = -scale.x
		$HoleChecker.enabled = true
	if is_chasing and motion.x !=0:
		if motion.x > 0:
				$AnimatedSprite.flip_h = true
				$Vision.rotation_degrees = 90
				$PlayerChecker.rotation_degrees = 0
		else:
			$AnimatedSprite.flip_h = false
			$Vision.rotation_degrees = -90
			$PlayerChecker.rotation_degrees = 180
func chase_player():
	var direction = (player.position - position).normalized()
	if $Vision.is_colliding() and is_on_floor():
		is_chasing = true
	if is_chasing:
		motion.x = direction.x * CHASE_SPEED
		motion.y += GRAVITY
		motion = move_and_slide(motion,Vector2.UP)
	if   abs(direction.x) > 0.9998:
		is_chasing = false
		
func attack(attack_name,delay):
	can_move = false
	$AttackTimer.set_wait_time(delay)
	$AttackTimer.start()
	$AnimatedSprite.play(attack_name)
	is_attacking = true


func _on_PlayerChecker_body_entered(body):
	attack(attack_name,1.1)

func _on_PlayerChecker_body_exited(body):
	is_attacking = false
	attack_name = 'combo0'


func _on_AttackTimer_timeout():
	if attack_name == 'combo0' and is_attacking:
		 attack_name = 'combo1'
		 attack(attack_name,1.6) 
	elif is_attacking:
		attack_name = 'combo0'
		attack(attack_name,1.1) 


func _on_AnimatedSprite_animation_finished():
	can_move = true

    MAyno16 it glitches everytime

    Also could you give a description of exactly what and how 'glitches'?

        Megalomaniak the problem is the chasing phase and the direction the ennemy is facing. it does seem to work only when it detects me from the left but when it detects me from the right he flips to the other side, and i don't know exactly what part of my code did the problem

          Have you tried using breakpoints to debug it during runtime?

          ps. the video doesn't work for me, but I also have js/script blocking add-on installed on my browser so it could be that I didn't give the necessary privileges to the right thing.

          There is a godot behavior tree plugin on github called beehav, which will make your life a lot easier if you could intergrate,it into your exist AI codes.

            MagickPanda
            it was hard to understand how to integrate it into my own project because the developper didn't explain how it actually works. He did demonstrate its usage on his personal project tho. Can you suggest any documentation or tutorial please ?

                MAyno16
                Just take a look at his tutorial example demo's video here:

                In this video's comment area there are also more videos targetting wider audience and newbie godot devs.

                    MagickPanda
                    Thank you very much but i actually got the code fixed on my own. Nevertheless, i will definitely try Beehave
                    Here is the Reworked chase code part:

                    func chase_player():
	var direction = (player.position - position).normalized()
	if $Vision.is_colliding() and is_on_floor() and !is_chasing:
		last_dir = direction.x
		is_chasing = true
	if is_chasing:
		if abs(last_dir-direction.x)>abs(last_dir) and not(flipped):
			flipped = true
			flipSK()
		elif abs(last_dir-direction.x)<abs(last_dir) and flipped:
			flipped = false
			flipSK()
		motion.x = direction.x * CHASE_SPEED
		motion.y += GRAVITY
		motion = move_and_slide(motion,Vector2.UP)
		if abs(direction.x) > 0.9998:
			is_chasing = false
func flipSK():
	$AnimatedSprite.flip_h = not($AnimatedSprite.flip_h)
	$HoleChecker.position.x = -$HoleChecker.position.x
	$PlayerChecker.scale.x = -$PlayerChecker.scale.x
	$AttackChecker.scale.x = -$AttackChecker.scale.x
	$Vision.rotation_degrees = -$Vision.rotation_degrees

                        MAyno16 That's good to know,you finally got it working.
                        Ultimately beehave will make ai behaviors more manageable and maintain–able, though plugging it into exist codes can be rather frustrating, I am also trying to use beehave as my game's individual unit AI, and It's taking alot more efforts compare to a primitive state machine stuff, but imo it will pay off in a long run.

                          18 days later

                          MAyno16 I will write up some better explanations on how to use the addon. I agree, while I show how to use it, I am not explaining the reasoning/logic for people to come up with their own behaviour trees.