//
//  Created by Michał Gorzałczany on 04.01.2018.
//  Copyright © 2018 Michał Gorzałczany. All rights reserved.
//

import UIKit

enum MGAlertActionType {
    case Default
    case Destructive

    func textColor() -> UIColor {
        switch self {
        case .Default:     return UIColor.darkBlue()
        case .Destructive: return UIColor.red
        }
    }
}

struct MGAlertAction {
    let title : String
    let type : MGAlertActionType
    let handler: (() -> Void)?
    let exit : Bool

    init(title: String? = "",
         type: MGAlertActionType = .Default,
         shouldExit : Bool = true,
         handler: (() -> Void)? = nil) {

        self.title = title!
        self.type = type
        self.handler = handler
        self.exit = shouldExit
    }
}

final class MGAlertViewController: UIViewController {

    private var alertView: UIView!
    private var blurView: UIView!
    private var titleLabel: UILabel!
    private var messageLabel: UILabel!
    private var bodyStackView: UIStackView!
    private var buttonsStackView: UIStackView!
    private var actions = [MGAlertAction]()
    private(set) var insideView : UIView?
    private(set) var alertTitle : String?
    private(set) var alertMessage : String?

    convenience init(title : String?, message : String?) {
        self.init()
        alertTitle = title
        alertMessage = message
    }


    func showAlert(fromViewController: UIViewController? = UIApplication.shared.keyWindow?.rootViewController) {
        modalPresentationStyle = .overCurrentContext
        modalTransitionStyle = .crossDissolve
        fromViewController?.present(self, animated: true, completion: nil)
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        configureView()
        configureActions()
        configureInsideView()

        let selector = #selector(dismiss as () -> Void)
        let tap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: selector)
        tap.cancelsTouchesInView = false
        blurView.addGestureRecognizer(tap)
    }

    func addInsideView(_ insideView: UIView) {
        self.insideView = insideView
    }

    func dismiss(){
        self.dismiss(animated: true, completion: nil)
    }

    func dismiss(_ action: MGAlertAction) {
        self.dismiss(animated: true) {
            action.handler?()
        }
    }

    func configureInsideView() {
        guard let insideView = self.insideView else {return}
        bodyStackView.addArrangedSubview(insideView)
    }

    func addAction(_ action: MGAlertAction) {
        actions.append(action)
    }

    func configureActions() {
        for action in actions {
            let button = ClosureButton(type: .system)
            button.setTitle(action.title)
            button.backgroundColor = UIColor.white
            button.setTitleColor(action.type.textColor(), for: .normal)
            button.heightAnchor.constraint(equalToConstant: 45).isActive = true

            button.didTouchUpInside = { [weak self] _ in
                if action.exit {
                    self?.dismiss(action)
                } else {
                    action.handler?()
                }
            }

            buttonsStackView.addArrangedSubview(button)
            if buttonsStackView.arrangedSubviews.count > 3 {
                buttonsStackView.axis = .vertical
            }
        }
    }

    func configureView() {
        view.backgroundColor = UIColor.clear

        alertView = UIView()
        blurView = UIView()
        buttonsStackView = UIStackView()

        alertView.translatesAutoresizingMaskIntoConstraints = false
        blurView.translatesAutoresizingMaskIntoConstraints = false
        buttonsStackView.translatesAutoresizingMaskIntoConstraints = false

        //blur View
        view.addSubview(blurView)
        view.addConstraints([
            NSLayoutConstraint(item: blurView, attribute: .width, relatedBy: .equal, toItem: view, attribute: .width, multiplier: 1, constant: 0),
            NSLayoutConstraint(item: blurView, attribute: .height, relatedBy: .equal, toItem: view, attribute: .height, multiplier: 1, constant: 0),
            NSLayoutConstraint(item: blurView, attribute: .centerX, relatedBy: .equal, toItem: view, attribute: .centerX, multiplier: 1, constant: 0),
            NSLayoutConstraint(item: blurView, attribute: .centerY, relatedBy: .equal, toItem: view, attribute: .centerY, multiplier: 1, constant: 0)
            ])

        //Alert View
        alertView.backgroundColor = UIColor.white
        alertView.clipsToBounds = true
        view.addSubview(alertView)
        view.addConstraints([
            NSLayoutConstraint(item: alertView, attribute: .width, relatedBy: .equal, toItem: view, attribute: .width, multiplier: 0.8, constant: 0),
            NSLayoutConstraint(item: alertView, attribute: .height, relatedBy: .lessThanOrEqual, toItem: view, attribute: .height, multiplier: 0.8, constant: 0),
            NSLayoutConstraint(item: alertView, attribute: .centerX, relatedBy: .equal, toItem: view, attribute: .centerX, multiplier: 1, constant: 0),
            NSLayoutConstraint(item: alertView, attribute: .centerY, relatedBy: .equal, toItem: view, attribute: .centerY, multiplier: 1, constant: 0)
            ])


        //Body Stack View
        bodyStackView = UIStackView()
        bodyStackView.translatesAutoresizingMaskIntoConstraints = false
        bodyStackView.axis = .vertical
        alertView.addSubview(bodyStackView)

        view.addConstraints([
            NSLayoutConstraint(item: bodyStackView, attribute: .top, relatedBy: .equal, toItem: alertView, attribute: .top, multiplier: 1, constant: 16),
            NSLayoutConstraint(item: bodyStackView, attribute: .trailing, relatedBy: .equal, toItem: alertView, attribute: .trailing, multiplier: 1, constant: -16),
            NSLayoutConstraint(item: bodyStackView, attribute: .leading, relatedBy: .equal, toItem: alertView, attribute: .leading, multiplier: 1, constant: 16),
            ])


        //Title Label
        if let title = alertTitle {
            titleLabel = UILabel()
            titleLabel.numberOfLines = 0
            titleLabel.textAlignment = .center
            titleLabel.text = title
            bodyStackView.addArrangedSubview(titleLabel)
        }

        //Message Label
        if let message = alertMessage {
            messageLabel = UILabel()
            messageLabel.numberOfLines = 0
            messageLabel.textAlignment = .center
            messageLabel.text = message
            bodyStackView.addArrangedSubview(messageLabel)
        }

        //Buttons Stack View
        alertView.addSubview(buttonsStackView)

        view.addConstraints([
            NSLayoutConstraint(item: buttonsStackView, attribute: .top, relatedBy: .equal, toItem: bodyStackView, attribute: .bottom, multiplier: 1, constant: 16),
            NSLayoutConstraint(item: buttonsStackView, attribute: .bottom, relatedBy: .equal, toItem: alertView, attribute: .bottom, multiplier: 1, constant: 0),
            NSLayoutConstraint(item: buttonsStackView, attribute: .trailing, relatedBy: .equal, toItem: alertView, attribute: .trailing, multiplier: 1, constant: 0),
            NSLayoutConstraint(item: buttonsStackView, attribute: .leading, relatedBy: .equal, toItem: alertView, attribute: .leading, multiplier: 1, constant: 0),
            ])

        //stack view spacer
        let spacerView = UIView()
        spacerView.backgroundColor = UIColor.lightGray
        spacerView.translatesAutoresizingMaskIntoConstraints = false
        alertView.insertSubview(spacerView, belowSubview: buttonsStackView)

        view.addConstraints([
            NSLayoutConstraint(item: spacerView, attribute: .width, relatedBy: .equal, toItem: buttonsStackView, attribute: .width, multiplier: 1, constant: 0),
            NSLayoutConstraint(item: spacerView, attribute: .height, relatedBy: .equal, toItem: buttonsStackView, attribute: .height, multiplier: 1, constant: 0.5),
            NSLayoutConstraint(item: spacerView, attribute: .centerX, relatedBy: .equal, toItem: buttonsStackView, attribute: .centerX, multiplier: 1, constant: 0),
            NSLayoutConstraint(item: spacerView, attribute: .centerY, relatedBy: .equal, toItem: buttonsStackView, attribute: .centerY, multiplier: 1, constant: -0.5)
            ])


        //Settings
        alertView.layer.cornerRadius = 0
        blurView.backgroundColor = UIColor.darkGray
        blurView.alpha = 0.5
        buttonsStackView.spacing = 0.5
        spacerView.alpha = 0.2
        buttonsStackView.layoutMargins = UIEdgeInsetsMake(0, 8, 0, 8)
        buttonsStackView.axis = .horizontal
        buttonsStackView.distribution = .fillEqually
    }
}

class ClosureButton: UIButton {

    typealias DidTapButton = (ClosureButton) -> ()

    var didTouchUpInside: DidTapButton? {
        didSet {
            if didTouchUpInside != nil {
                addTarget(self, action: #selector(ClosureButton.didTouchUpInside(sender:)), for: .touchUpInside)
            } else {
                removeTarget(self, action: #selector(ClosureButton.didTouchUpInside(sender:)), for: .touchUpInside)
            }
        }
    }

    func didTouchUpInside(sender: UIButton) {
        if let handler = didTouchUpInside {
            handler(self)
        }
    }
}