IBANTextField (Swift 3.1)

IBANTextField.swift

//
//  IBANTextField.swift
//  IBAN
//
//  Created by Dylan Gyesbreghs on 27/08/2017.
//  Copyright © 2017 Dylan Gyesbreghs. All rights reserved.
//

import UIKit

// MARK: - Properties
class IBANTextField: UITextField {
    fileprivate let separator = " "
}

// MARK: - Override methods
extension IBANTextField {
    override func awakeFromNib() {
        super.awakeFromNib()
        overrideProperties()
        setupView()
        setupAction()
    }
    
    override func textRect(forBounds bounds: CGRect) -> CGRect {
        return bounds.insetBy(dx: 10, dy: 10)
    }
    
    override func editingRect(forBounds bounds: CGRect) -> CGRect {
        return bounds.insetBy(dx: 10, dy: 10)
    }
}


// MARK: - Setup Methods
fileprivate extension IBANTextField {
    func overrideProperties() {
        spellCheckingType = .no
        autocorrectionType = .no
        autocapitalizationType = .allCharacters
    }
    
    func setupView() {
        self.layer.borderColor = UIColor.green.cgColor
        self.layer.borderWidth = 2
    }
    
    func setupAction() {
        addTarget(self, action: #selector(textFieldDidBegin(_:)), for: .editingDidBegin)
        addTarget(self, action: #selector(textFieldDidEnd(_:)), for: .editingDidEnd)
    }
}

// MARK: - Actions
extension IBANTextField {
    func textFieldDidBegin(_ textField: UITextField) {
        guard var text = textField.text else { return }
        text.remove(separator: separator)
        textField.text = text
    }
    
    func textFieldDidEnd(_ textField: UITextField) {
        guard var text = textField.text else { return }
        text.insert(separator: separator, every: 4)
        textField.text = text
    }
}

fileprivate extension String {
    
    // MARK: - Insert a separator
    mutating func insert(separator: String, every n: Int) {
        self = inserting(separator: separator, every: n)
    }
    
    func inserting(separator: String, every n: Int) -> String {
        var result: String = ""
        let characters = Array(self.characters)
        stride(from: 0, to: characters.count, by: n).forEach {
            result += String(characters[$0..<min($0+n, characters.count)])
            if $0+n < characters.count {
                result += separator
            }
        }
        return result
    }
    
    // MARK: - Remove a separator
    mutating func remove(separator: String) {
        self = removing(separator: separator)
    }
    
    func removing(separator: String) -> String {
        var result: String = ""
        let characters = Array(self.characters)
        for character in characters {
            if String(character) != separator {
                result += String(character)
            }
        }
        return result
    }
}