//: Playground - noun: a place where people can play

import UIKit
import PlaygroundSupport

protocol TextChangedEvent {
    func onTextChanged(_ closure: @escaping (String?) -> ()) -> Self
}

@objc class TextFieldChangeHandler: NSObject {
    private var closure: (String?) -> ()

    init(closure: @escaping (String?) -> ()) {
        self.closure = closure
    }

    @objc func change(_ textField: UITextField) {
        closure(textField.text)
    }
}

private var TextFieldChangeHandlerAssociatedObjectHandle: UInt8 = 0

extension UITextField {
    func onTextChanged(_ closure: @escaping (String?) -> ()) -> Self {
        let context = TextFieldChangeHandler(closure: closure)
        objc_setAssociatedObject(self, &TextFieldChangeHandlerAssociatedObjectHandle, context, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
        addTarget(context, action: #selector(TextFieldChangeHandler.change), for: .editingChanged)
        return self
    }
}

protocol TapEvent {
    func onTap(_ closure: @escaping () -> ()) -> Self
}

@objc class TapContext: NSObject {
    private var closure: () -> ()

    init(closure: @escaping () -> ()) {
        self.closure = closure
    }

    @objc func press() {
        closure()
    }
}

private var TapContextAssociatedObjectHandle: UInt8 = 0

extension UIButton: TapEvent {
    func onTap(_ closure: @escaping () -> ()) -> Self {
        let context = TapContext(closure: closure)
        objc_setAssociatedObject(self, &TapContextAssociatedObjectHandle, context, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
        addTarget(context, action: #selector(TapContext.press), for: .touchUpInside)
        return self
    }
}

protocol Initializable {
    init()
}

func createInstance<T>(_ type: T.Type) -> T where T: Initializable {
    return type.init()
}

extension UIView: Initializable { }

extension UIControl: Initializable { }

func component<T: Initializable>(_ type: T.Type, configuration: (T) -> ()) -> T {
    let instance: T = createInstance(type)
    configuration(instance)
    return instance
}

protocol Handler {
    func login()
    func changePassword(_ text: String?)
    func changeEmail(_ text: String?)
}

class MockHandler: Handler {
    func login() {
        print("Login pressed")
    }

    func changeEmail(_ text: String?) {
        print("Changed email to \(text)")
    }

    func changePassword(_ text: String?) {
        print("Changed password to \(text)")
    }
}

let handler: Handler = MockHandler()

let email = component(UITextField.self) {
    $0.translatesAutoresizingMaskIntoConstraints = false
    $0.placeholder = "Email"
    $0.keyboardType = .emailAddress
    $0.returnKeyType = .next
    $0.autocapitalizationType = .none
    $0.autocorrectionType = .no
    $0.onTextChanged(handler.changeEmail(_:))
}

let password = component(UITextField.self) {
    $0.translatesAutoresizingMaskIntoConstraints = false
    $0.placeholder = "Password"
    $0.keyboardType = .default
    $0.returnKeyType = .send
    $0.isSecureTextEntry = true
    $0.autocapitalizationType = .none
    $0.autocorrectionType = .no
    $0.onTextChanged(handler.changePassword(_:))
}

let button = component(UIButton.self) {
    $0.translatesAutoresizingMaskIntoConstraints = false
    $0.setTitle("Login", for: .normal)
    $0.backgroundColor = .gray
    $0.layer.borderWidth = 1 / UIScreen.main.scale
    $0.layer.borderColor = UIColor.black.cgColor
    $0.onTap(handler.login)
}

let view = component(UIView.self) {
    $0.frame = CGRect(x: 0, y: 0, width: 300, height: 230)
    $0.backgroundColor = .white
    $0.addSubview(email)
    $0.addSubview(password)
    $0.addSubview(button)

    NSLayoutConstraint.activate([
        email.leadingAnchor.constraint(equalTo: $0.leadingAnchor, constant: 20), email.trailingAnchor.constraint(equalTo: $0.trailingAnchor, constant: -20), email.topAnchor.constraint(equalTo: $0.topAnchor, constant: 20), email.heightAnchor.constraint(equalToConstant: 44),
         password.leadingAnchor.constraint(equalTo: $0.leadingAnchor, constant: 20), password.trailingAnchor.constraint(equalTo: $0.trailingAnchor, constant: -20), password.topAnchor.constraint(equalTo: email.bottomAnchor, constant: 20), password.heightAnchor.constraint(equalToConstant: 44),
          button.leadingAnchor.constraint(equalTo: $0.leadingAnchor, constant: 20), button.trailingAnchor.constraint(equalTo: $0.trailingAnchor, constant: -20), button.topAnchor.constraint(equalTo: password.bottomAnchor, constant: 20), button.heightAnchor.constraint(equalToConstant: 60)
    ])
}

PlaygroundPage.current.liveView = view

email.text = "test@email.com"
password.text = "password123"
button.sendActions(for: .touchUpInside)