CurencyTextField.swift

//
//  CurencyTextField.swift
//  TestEnv
//
//  Created by Yigit Serin on 4.08.2016.
//  Copyright © 2016 Yigit Serin. All rights reserved.
//

import UIKit

class CurencyTextField: UIViewController {

    @IBOutlet weak var textField: UITextField!
    
    let digitsAfterComma = 2
    
    override func viewDidLoad() {
        super.viewDidLoad()
        textField.addTarget(self, action: #selector(ViewController.textFieldDidChange(_:)), forControlEvents: .EditingChanged)
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    
    func textFieldDidChange(sender: UITextField){
        sender.text = removeSpecialCharsFromString(sender.text!)
        sender.text = addCharacters(sender.text!)
        
    }
    
    func removeSpecialCharsFromString(text: String) -> String {
        let okayChars : Set<Character> =
            Set("0123456789".characters)
        return String(text.characters.filter {okayChars.contains($0) })
    }
    
    func addCharacters(text: String) -> String{
        //print(text.characters.count)
        if text.characters.count <= digitsAfterComma{
            return text
        }else if text.characters.count <= digitsAfterComma + 3{
            var finalText = text
            finalText.insert(",", atIndex: finalText.endIndex.advancedBy(-digitsAfterComma))
            return finalText
        }else{
            var finalText = text
            var dots = 0
            finalText.insert(",", atIndex: finalText.endIndex.advancedBy(-digitsAfterComma))
 
            for i in (digitsAfterComma+3)...text.characters.count{
                if i%3 == 0{

                    finalText.insert(".", atIndex: finalText.endIndex.advancedBy(-i - dots))
                    dots += 1
                }
            }
            

            return finalText
        }
        
    }


}