class_name EulerCalculator extends Control



func _on_test_button_down() -> void:
	var answer:int = calc_biggest_palindromic_number(2)
	show_result(answer)

func _on_calculate_button_down() -> void:
	var answer:int = calc_biggest_palindromic_number(3)
	show_result(answer)

func show_result(answer:int) -> void:
	$VBoxContainer/Label.text = str(answer) 

func calc_biggest_palindromic_number(digits:int) -> int:
	var highest_palindrome:int = -1
	var min:int=pow(10,digits-1)
	var max:int=pow(10,digits)
	for a in range(min, max):
		for b in range(min, max):
			var p:int = a*b
			var arr:Array = [0]
			for k in range(1, digits*2+1):
				var unit:int = p % (pow(10,k) as int)
				unit /= (pow(10,k-1) as int)
				arr.append(unit)
			arr.remove_at(0)
			if arr.size() != digits*2:
				continue
			var is_palindrome:bool = true
			for k in range(0,digits):
				is_palindrome = is_palindrome and arr[k] == arr[digits*2-k-1]
			if is_palindrome and highest_palindrome<p:
				highest_palindrome = p
	return highest_palindrome