import UIKit

final public class HideKeyboardTapGestureManager {

    // MARK: - Private
    public private (set) var targets: Set<UIView> = Set<UIView>() {
        didSet {
            targets.subtracting(oldValue).forEach {addGesture(to: $0)}
        }
    }

    private func addGesture(to target: UIView) {
        let gesture = UITapGestureRecognizer(target: self, action: #selector(dismissKeyboard))
        target.addGestureRecognizer(gesture)
    }

    @objc private func dismissKeyboard() {
        targets.first?.superview?.endEditing(true)
    }

    // MARK: - Public
    public func add(targets: [UIView]) {
        self.targets = self.targets.union(Set(targets))
    }

    public func remove(_ target: UIView) {
        target.gestureRecognizers?.forEach {target.removeGestureRecognizer($0)}
        self.targets.remove(target)
    }

    public func remove(_ targets: [UIView]) {
        targets.forEach {self.remove($0)}
    }

    public func removeAllTargets() {
        self.remove(Array(self.targets))
    }
}