ColorSelectionControl.swift

import UIKit

final class ColorSelectionControl: UIControl {

    private var buttons = [UIButton]()
    private let colors: [UIColor]

    lazy var currentSelectedColor: UIColor = colors[0]

    init(colors: [UIColor]) {
        self.colors = colors
        super.init(frame: .zero)
        updateView()
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    private func customize(_ button: UIButton, index: Int, isSelected: Bool = false) {
        button.backgroundColor = colors[index]
        button.layer.borderWidth = isSelected ? 2 : 0
        button.layer.borderColor = isSelected ? UIColor.deepBlue.cgColor : UIColor.clear.cgColor
    }

    private func updateView() {

        for color in colors {
            let button = UIButton.init(type: .system)
            button.backgroundColor = color
            button.layer.cornerRadius = 14
            button.addTarget(self, action: #selector(buttonTapped(button:)), for: .touchUpInside)
            button.constrain(size: .init(width: 28, height: 28))
            buttons.append(button)
        }

        customize(buttons[0], index: 0, isSelected: true)

        // Create a StackView
        let stackView = UIStackView.init(arrangedSubviews: buttons).layoutable()
        stackView.axis = .horizontal
        stackView.distribution = .fillEqually
        stackView.spacing = 16
        addSubview(stackView)

        stackView.constraintCenter(to: self, axis: [.horizontal, .vertical])
    }

    @objc private func buttonTapped(button: UIButton) {
        for (buttonIndex, btn) in buttons.enumerated() {
            customize(btn, index: buttonIndex)
            if btn == button {
                currentSelectedColor = colors[buttonIndex]
                customize(btn, index: buttonIndex, isSelected: true)
            }
        }
        sendActions(for: .valueChanged)
    }

    func updateSelectorControl(index: Int) {
        for btn in buttons {
            customize(btn, index: index)
        }
        currentSelectedColor = colors[index]
        customize(buttons[index], index: index, isSelected: true)
    }
}