//
//  ServersController.swift
//  Privado
//
//  Created by Jura on 10/10/19.
//  Copyright © 2019 Omicronmedia. All rights reserved.
//


import Foundation
import UIKit

protocol ServersControllerOutput: AnyObject {
    func viewDidAppear()
}

protocol ServersControllerInput: AnyObject {
    func upgradeWarning(show: Bool)
    func changeMessageVisibility(isHidden: Bool)
    func updateBackground(isHighlighted: Bool)
    func changeMenuState()
    func changeNotificationsState()
    func changeTutorialState(show: Bool)
    func scrollServers(direction: ServersScrollDirection)
}

enum ServersControllerComponent {
    case location
    case serverList
    case connection
    case menu
    case notifications
    case message
    case upgradeWarning
    case traffic
}

enum ServersControllerModalComponent {
    case upgrade
    case tutorial
}

final class ServersController: UIViewController, ServersControllerInput {
    
    private enum Constants {
        static let serverCellIndex = 3
        enum ImageName {
            static let notificationsButton = "notifications_button"
            static let mapBackground = "map.background"
            static let title = "mainTitle"
        }
        enum Font {
            static let title = UIFont(name: "SFProText-Bold", size: 20) ?? .boldSystemFont(ofSize: 20)
        }
        enum Geometry {
            static let titleImageSize = CGSize(width: 147, height: 20)
            static let menuLeading: CGFloat = 15
            static let menuHeight: CGFloat = 50
            static let statusBarHeight: CGFloat = UIApplication.shared.statusBarFrame.height
            static let trafficCounterIndent: CGFloat = 26
            static let trafficCounterHeight: CGFloat = 70
            
            static let messageViewIndent: CGFloat = 26
        }
        enum Color {
            static let background = UIColor(red: 21, green: 25, blue: 53)
            static let navBar = UIColor(red: 3, green: 15, blue: 72)
            static let statusBar = UIColor(red: 18, green: 23, blue: 45)
            
            static let bgGradientStart = UIColor(red: 47, green: 42, blue: 96)
            static let bgGradientEnd = UIColor(red: 80, green: 88, blue: 200)
        }
        static let bgGradientAlpha: CGFloat = 0.45
        
        static let connectionTop: CGFloat = 43
        static let bottom: CGFloat = -60
        static let between: CGFloat = 20
        static let locationTop: CGFloat = 4
        static let listBetweenLocation: CGFloat = 60
        static let buttonBetweenList: CGFloat = 40
        static let notificationsButtonRight: CGFloat = 8
        static let navBarHeight: CGFloat = 51
        
    }
    
    private let output: ServersControllerOutput

    private var background: UIImageView?
    private var upgradeView: UIView?
    private var upgradeWarningView: UIView?
    private var messageView: UIView?
    private var serverList: UIView?
    private var tutorialViewController: UIViewController?
    
    private var componentCreationClosure: ComponentCreationClosure

    private let modalCreationClosure: ModalCreationClosure
    
    typealias ComponentCreationClosure = (ServersControllerComponent) -> UIView
    typealias ModalCreationClosure = (ServersControllerModalComponent) -> UIViewController

    // MARK: - Init
    
    init(output: ServersControllerOutput,
         componentCreation: @escaping ComponentCreationClosure,
         modalCreation: @escaping ModalCreationClosure) {
        self.output = output
        self.componentCreationClosure = componentCreation
        self.modalCreationClosure = modalCreation
        super.init(nibName: nil, bundle: nil)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    // MARK: - Lyfecycle
    override var preferredStatusBarStyle: UIStatusBarStyle {
        return .lightContent // .default
    }

    override func loadView() {
        let view = UIView(frame: .zero)
        view.translatesAutoresizingMaskIntoConstraints = false
        view.backgroundColor = Constants.Color.background
        self.view = view
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.configureUI()
    }
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        
        guard let superview = self.view.superview else { return }
        
        NSLayoutConstraint.activate([
            self.view.topAnchor.constraint(equalTo: superview.topAnchor),
            self.view.bottomAnchor.constraint(equalTo: superview.bottomAnchor),
            self.view.leadingAnchor.constraint(equalTo: superview.leadingAnchor),
            self.view.trailingAnchor.constraint(equalTo: superview.trailingAnchor)
        ])
        
        self.output.viewDidAppear()
    }
    
    // MARK: - ServersControllerInput
    
    func upgradeWarning(show: Bool) {
        self.upgradeWarningView?.isHidden = !show
    }

    func changeMessageVisibility(isHidden: Bool) {
        guard let messageView = self.messageView else { return }
        if isHidden {
            messageView.removeFromSuperview()
        } else {
            self.layoutMessageView()
            if let serverList = self.serverList {
                self.view.insertSubview(messageView, belowSubview: serverList)
            } else {
                self.view.addSubview(messageView)
            }
        }
    }
    
    func updateBackground(isHighlighted: Bool) { }
    
    func changeMenuState() { }
    
    func changeNotificationsState() { }
    
    func changeTutorialState(show: Bool) {
        self.tutorialViewController?.view.fade(fadeIn: show)
    }
    
    func scrollServers(direction: ServersScrollDirection) {
        guard let serverList = self.serverList as? ServerListViewController else { return }

        switch direction {
        case .up:
            serverList.pullUpList()
            serverList.expandOrCollapse(index: Constants.serverCellIndex)
        case .down:
            serverList.pullDownList()
            serverList.expandOrCollapse(index: Constants.serverCellIndex)
        }
    }

    
    // MARK: - UI
    
    // swiftlint:disable function_body_length
    private func configureUI() {
        
        // Background gradient
        let gradientView = self.initializeBackgroundGradient()
        NSLayoutConstraint.activate([
            gradientView.topAnchor.constraint(equalTo: self.view.topAnchor),
            gradientView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
            gradientView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
            gradientView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor)
        ])
        
        // Background image
        let bgImageView = self.initializeBackgroundImageView()
        NSLayoutConstraint.activate([
            bgImageView.topAnchor.constraint(equalTo: self.view.topAnchor),
            bgImageView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor),
            bgImageView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
            bgImageView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor)
        ])
        
        // Status bar
        let statusBarView = UIView()
        statusBarView.backgroundColor = Constants.Color.statusBar
        statusBarView.translatesAutoresizingMaskIntoConstraints = false
        self.view.addSubview(statusBarView)
        NSLayoutConstraint.activate([
            statusBarView.heightAnchor.constraint(equalToConstant: Constants.Geometry.statusBarHeight),
            statusBarView.topAnchor.constraint(equalTo: self.view.topAnchor),
            statusBarView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
            statusBarView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor)
        ])
        
        // Nav bar
        let navBarBackground = UIView()
        navBarBackground.backgroundColor = Constants.Color.navBar
        navBarBackground.translatesAutoresizingMaskIntoConstraints = false
        self.view.addSubview(navBarBackground)
        NSLayoutConstraint.activate([
            navBarBackground.topAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.topAnchor),
            navBarBackground.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
            navBarBackground.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
            navBarBackground.heightAnchor.constraint(equalToConstant: Constants.navBarHeight)
        ])
        
        // left menu
        let menuButton = self.componentCreationClosure(.menu)
        menuButton.translatesAutoresizingMaskIntoConstraints = false
        navBarBackground.addSubview(menuButton)
        NSLayoutConstraint.activate([
            menuButton.leadingAnchor.constraint(equalTo: self.view.leadingAnchor, constant: Constants.Geometry.menuLeading),
            menuButton.centerYAnchor.constraint(equalTo: navBarBackground.centerYAnchor),
            menuButton.heightAnchor.constraint(equalToConstant: Constants.Geometry.menuHeight),
            menuButton.widthAnchor.constraint(equalTo: menuButton.heightAnchor)
        ])
        
        // title
        let titleImage = UIImage(imageLiteralResourceName: Constants.ImageName.title)
        let titleView = UIImageView(image: titleImage)
        titleView.translatesAutoresizingMaskIntoConstraints = false
        navBarBackground.addSubview(titleView)
        NSLayoutConstraint.activate([
            titleView.centerXAnchor.constraint(equalTo: navBarBackground.centerXAnchor),
            titleView.centerYAnchor.constraint(equalTo: navBarBackground.centerYAnchor),
            titleView.heightAnchor.constraint(equalToConstant: Constants.Geometry.titleImageSize.height),
            titleView.widthAnchor.constraint(equalToConstant: Constants.Geometry.titleImageSize.width)
        ])
        
        // notifications button
        let notificationsButton = self.componentCreationClosure(.notifications)
        notificationsButton.translatesAutoresizingMaskIntoConstraints = false
        navBarBackground.addSubview(notificationsButton)
        NSLayoutConstraint.activate([
            notificationsButton.rightAnchor.constraint(equalTo: self.view.rightAnchor, constant: -Constants.notificationsButtonRight),
            notificationsButton.centerYAnchor.constraint(equalTo: navBarBackground.centerYAnchor),
            notificationsButton.heightAnchor.constraint(equalToConstant: 50),
            notificationsButton.widthAnchor.constraint(equalTo: menuButton.heightAnchor)
        ])
        
        // message
        let messageView = self.componentCreationClosure(.message)
        self.messageView = messageView
        
        // Connection status
        let connection = self.componentCreationClosure(.connection)
        self.view.addSubview(connection)
        NSLayoutConstraint.activate([
            connection.topAnchor.constraint(equalTo: navBarBackground.bottomAnchor, constant: Constants.connectionTop),
            connection.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
            connection.trailingAnchor.constraint(equalTo: self.view.trailingAnchor)
        ])

        // Location IP address
        let currentLocation = self.componentCreationClosure(.location)
        self.view.addSubview(currentLocation)
        NSLayoutConstraint.activate([
            currentLocation.topAnchor.constraint(equalTo: connection.bottomAnchor, constant: Constants.locationTop),
            currentLocation.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
            currentLocation.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
            currentLocation.heightAnchor.constraint(greaterThanOrEqualToConstant: 30)
        ])

        // Serverlist
        guard let serverlist = self.componentCreationClosure(.serverList) as? (UIView & ServerListPullable) else {
            return
        }
        self.serverList = serverlist
        serverlist.translatesAutoresizingMaskIntoConstraints = false
        self.view.addSubview(serverlist)
        let heightConstraint = serverlist.heightAnchor.constraint(equalToConstant: serverlist.minHeight)
        NSLayoutConstraint.activate([
            serverlist.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
            serverlist.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
            heightConstraint,
            serverlist.bottomAnchor.constraint(equalTo: self.view.bottomAnchor),
            serverlist.topAnchor.constraint(greaterThanOrEqualTo: self.view.safeAreaLayoutGuide.topAnchor)
        ])
        serverlist.heightConstraint = heightConstraint
        serverlist.isHidden = true
        
        // Upgrade
        let upgradeController = self.modalCreationClosure(.upgrade)
        self.addChild(upgradeController)
        upgradeController.didMove(toParent: self)
        self.view.addSubview(upgradeController.view)
        NSLayoutConstraint.activate([
            upgradeController.view.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
            upgradeController.view.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
            upgradeController.view.bottomAnchor.constraint(equalTo: self.view.bottomAnchor),
            upgradeController.view.topAnchor.constraint(equalTo: navBarBackground.bottomAnchor)
        ])
        
        // Traffic Counter
        let trafficCounterView = self.componentCreationClosure(.traffic)
        self.view.addSubview(trafficCounterView)
        NSLayoutConstraint.activate([
            trafficCounterView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor),
            trafficCounterView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor,
                                                        constant: Constants.Geometry.trafficCounterIndent),
            trafficCounterView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor,
                                                         constant: -Constants.Geometry.trafficCounterIndent),
            trafficCounterView.heightAnchor.constraint(equalToConstant: Constants.Geometry.trafficCounterHeight)
        ])
        
        // Upgrade warning to show when selected premium server from list
        let upgradeWarningView = self.componentCreationClosure(.upgradeWarning)
        upgradeWarningView.isHidden = true
        self.upgradeWarningView = upgradeWarningView
        self.view.addSubview(upgradeWarningView)
        NSLayoutConstraint.activate([
            upgradeWarningView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor),
            upgradeWarningView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
            upgradeWarningView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
            upgradeWarningView.topAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.topAnchor)
        ])
        
        // App tutorial view
        let appTutorialViewController = self.modalCreationClosure(.tutorial)
        appTutorialViewController.view.isHidden = true
        self.tutorialViewController = appTutorialViewController
        self.addChild(appTutorialViewController)
        self.view.addSubview(appTutorialViewController.view)
        NSLayoutConstraint.activate([
            appTutorialViewController.view.topAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.topAnchor),
            appTutorialViewController.view.bottomAnchor.constraint(equalTo: self.view.bottomAnchor),
            appTutorialViewController.view.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
            appTutorialViewController.view.leadingAnchor.constraint(equalTo: self.view.leadingAnchor)
        ])
    }
    // swiftlint:enable function_body_length
    
    private func layoutMessageView() {
        guard let messageView = self.messageView else { return }
        self.view.addSubview(messageView)
        NSLayoutConstraint.activate([
            messageView.topAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.topAnchor, constant: Constants.navBarHeight),
            messageView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor, constant: Constants.Geometry.messageViewIndent),
            messageView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor, constant: -Constants.Geometry.messageViewIndent)
        ])
    }
    
    private func initializeBackgroundImageView() -> UIImageView {
        let image = UIImage(imageLiteralResourceName: Constants.ImageName.mapBackground)
        let imageView = ImageView(image: image)
        self.view.addSubview(imageView)
        self.background = imageView
        return imageView
    }
    
    private func initializeBackgroundGradient() -> UIView {
        let gradientView = GradientView()
        gradientView.translatesAutoresizingMaskIntoConstraints = false
        gradientView.horizontalMode = true
        gradientView.alpha = Constants.bgGradientAlpha
        gradientView.stops = [
            .init(color: Constants.Color.bgGradientStart, location: 0),
            .init(color: Constants.Color.bgGradientEnd, location: 1)
        ]
        self.view.addSubview(gradientView)
        return gradientView
    }
}

extension ServersController: ViewModuleControllerType { }