//
//  PurchaseVerifyController.swift
//  OpenVPN
//
//  Created by Zhandos Bolatbekov on 23.08.2021.
//  Copyright © 2021 Privado LLC. All rights reserved.
//

import UIKit

protocol PurchaseVerifyControllerInput: AnyObject {
    func showLoader(_ show: Bool)
}

protocol PurchaseVerifyControllerOutput: AnyObject {
    func viewIsReady()
}

final class PurchaseVerifyController: UIViewController, PurchaseVerifyControllerInput {
    
    private enum Constants {
        enum Color {
            static let background = UIColor(rgb: 0x03072a).withAlphaComponent(0.9)
            static let titleText = UIColor.white
        }
        enum Font {
            static let title = UIFont(name: "SFProText-Regular", size: 21.3)
        }
        enum Geometry {
            static let titleTop: CGFloat = 16
            static let titleHorizontalOffset: CGFloat = 24
        }
        enum LocalizedString {
            static let title = "purchaseVerify.title.processing"
        }
    }
    
    private let output: PurchaseVerifyControllerOutput
    
    private var activity: UIActivityIndicatorView?
    
    // MARK: - Init
    
    init(output: PurchaseVerifyControllerOutput) {
        self.output = output
        super.init(nibName: nil, bundle: nil)
    }
    
    required init?(coder: NSCoder) { nil }
    
    // MARK: - Life-cycle
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.configureUI()
        self.output.viewIsReady()
    }
    
    // MARK: - PurchaseVerifyControllerInput
    
    func showLoader(_ show: Bool) {
        DispatchQueue.main.async { [weak self] in
            show ? self?.activity?.startAnimating() : self?.activity?.stopAnimating()
        }
    }
    
    // MARK: - Private
    
    private func configureUI() {
        self.view.backgroundColor = Constants.Color.background
        
        var constraints = [NSLayoutConstraint]()
        
        let activity = self.initActivityIndicator()
        constraints.append(contentsOf: [
            activity.centerXAnchor.constraint(equalTo: self.view.centerXAnchor),
            activity.centerYAnchor.constraint(equalTo: self.view.centerYAnchor)
        ])
        
        let label = self.initTitleLabel()
        constraints.append(contentsOf: [
            label.topAnchor.constraint(equalTo: activity.bottomAnchor,
                                       constant: Constants.Geometry.titleTop),
            label.centerXAnchor.constraint(equalTo: self.view.centerXAnchor),
            label.leadingAnchor.constraint(equalTo: self.view.leadingAnchor,
                                           constant: Constants.Geometry.titleHorizontalOffset),
            label.trailingAnchor.constraint(equalTo: self.view.trailingAnchor,
                                            constant: -Constants.Geometry.titleHorizontalOffset)
            
        ])
        
        NSLayoutConstraint.activate(constraints)
    }
    
    private func initActivityIndicator() -> UIActivityIndicatorView {
        let activity = UIActivityIndicatorView(style: .whiteLarge)
        activity.hidesWhenStopped = true
        activity.translatesAutoresizingMaskIntoConstraints = false
        self.activity = activity
        self.view.addSubview(activity)
        return activity
    }
    
    private func initTitleLabel() -> UILabel {
        let label = UILabel()
        label.translatesAutoresizingMaskIntoConstraints = false
        label.numberOfLines = 0
        label.textColor = Constants.Color.titleText
        label.font = Constants.Font.title
        label.textAlignment = .center
        label.text = NSLocalizedString(Constants.LocalizedString.title,
                                       comment: "Processing subscription...")
        self.view.addSubview(label)
        return label
    }
}