//
//  KilSwitchPanelView.swift
//  PrivadoVPN
//
//  Created by Juraldinio on 1/31/21.
//  Copyright © 2021 Privado LLC. All rights reserved.
//

import Foundation
import AppKit

protocol KilSwitchPanelViewInput: AnyObject {
    func show(enabled: Bool)
    func killSwitch(enabled: Bool)
}

protocol KilSwitchPanelViewOutput: AnyObject {
    func viewIsReady(view: KilSwitchPanelViewInput)
    func viewWillDisappear()
    //
    func killSwitch(in view: KilSwitchPanelViewInput, enabled: Bool)
    func requirePopoverMessage() -> (String, String)
}

final class KilSwitchPanelView: NSView {
    
    private enum Constants {
        
        enum LocalizedString {
            static let killSwitchText = "connection.killswitch.text"
        }
        
        enum Image {
            static let info = "info"
        }
        
        enum Color {
            static let title = NSColor.white
            static let fill = NSColor(red: 122, green: 134, blue: 190)
            static let background = NSColor(red: 21, green: 25, blue: 53)
        }
        
        enum Font {
            
            // swiftlint:disable nesting
            enum Name {
                static let medium = PrivadoConstants.Font.semiBold
            }
            
            enum Size {
                static let title: CGFloat = 14.0
            }
            // swiftlint:enable nesting
        }
        
        enum Geometry {
            
            static let height: CGFloat = 45
            
            static let titleLeading: CGFloat = 30
            static let titleHeight: CGFloat = 19
            static let titleWidth: CGFloat = 90
            
            static let titleTrailingInfo: CGFloat = 3
            
            static let infoImageWidth: CGFloat = 18
            static let infoImageHeight: CGFloat = 18
            
            static let switchWidth: CGFloat = 56
            static let switchHeight: CGFloat = 26
            static let switchTrailing: CGFloat = 32
        }
    }
    
    private let output: KilSwitchPanelViewOutput
    
    private var titleField: NSTextField?
    private var infoView: ImageView?
    private var tooltip: NSPopover?
    private var switchToggle: Switch?
    
    // MARK: - Init
    
    init(output: KilSwitchPanelViewOutput) {
        
        self.output = output
        
        super.init(frame: .zero)
        
        self.translatesAutoresizingMaskIntoConstraints = false
        self.isHidden = true
        
        self.createUI()
        self.activateLayout()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    // MARK: - Lyfecycle
    
    override func viewDidMoveToSuperview() {
        super.viewDidMoveToSuperview()
        
        if self.superview.isExist {
            self.output.viewIsReady(view: self)
        }
    }
    
    override func removeFromSuperview() {
        self.output.viewWillDisappear()
        super.removeFromSuperview()
    }
    
    // MARK: - Private
    
    private func createUI() {
        
        let titleFont = NSFont(name: PrivadoConstants.Font.bold, size: Constants.Font.Size.title)
        let titleField = self.initializeTextField(color: Constants.Color.title, font: titleFont)
        titleField.stringValue = NSLocalizedString(Constants.LocalizedString.killSwitchText, comment: "")
        //
        self.titleField = titleField
        self.addSubview(titleField)
        
        let infoView = self.initializeImageView(resource: Constants.Image.info)
        self.infoView = infoView
        if #available(OSX 10.14, *) {
            infoView.mouseOverTracker = { [weak self] _, entered in
                
                guard let self = self
                      , let infoView = self.infoView else {
                    return
                }
                
                if entered {
                    guard !self.tooltip.isExist else { return }
                    
                    let messages = self.output.requirePopoverMessage()
                    let tooltip = self.createPopover(on: infoView, title: messages.0, description: messages.1)
                    self.tooltip = tooltip
                } else {
                    
                    guard let tooltip = self.tooltip else { return }
                    tooltip.performClose(nil)
                    self.tooltip = nil
                }
            }
        }
        self.addSubview(infoView)
        
        let switchToggle = self.initializeSwitchToggle(height: Constants.Geometry.switchHeight,
                                                       fillColor: Constants.Color.fill,
                                                       backColor: Constants.Color.background)
        switchToggle.target = self
        switchToggle.action = #selector(self.switchAction)
//        switchToggle.callback = { [weak self] isOn in
//            guard let self = self else { return }
//            self.output.killSwitch(in: self, enabled: isOn)
//        }
        self.switchToggle = switchToggle
        self.addSubview(switchToggle)
    }
    
    @objc
    private func switchAction() {
        guard let switchToggle = self.switchToggle else {
            return
        }
        self.output.killSwitch(in: self, enabled: switchToggle.isOn)
    }
    
    private func activateLayout() {
        
        guard let titleField = self.titleField
              , let infoView = self.infoView
              , let switchToggle = self.switchToggle else {
            return
        }
        
        NSLayoutConstraint.activate([
            
            self.heightAnchor.constraint(equalToConstant: Constants.Geometry.height),
            //
            titleField.centerYAnchor.constraint(equalTo: self.centerYAnchor),
            titleField.leadingAnchor.constraint(equalTo: self.leadingAnchor, constant: Constants.Geometry.titleLeading),
            titleField.widthAnchor.constraint(equalToConstant: Constants.Geometry.titleWidth),
            titleField.heightAnchor.constraint(equalToConstant: Constants.Geometry.titleHeight),
            //
            infoView.centerYAnchor.constraint(equalTo: self.centerYAnchor),
            infoView.leadingAnchor.constraint(equalTo: titleField.trailingAnchor, constant: Constants.Geometry.titleTrailingInfo),
            infoView.widthAnchor.constraint(equalToConstant: Constants.Geometry.infoImageWidth),
            infoView.heightAnchor.constraint(equalToConstant: Constants.Geometry.infoImageHeight),
            //
            switchToggle.centerYAnchor.constraint(equalTo: self.centerYAnchor),
            switchToggle.trailingAnchor.constraint(equalTo: self.trailingAnchor, constant: -Constants.Geometry.switchTrailing),
            switchToggle.widthAnchor.constraint(equalToConstant: Constants.Geometry.switchWidth),
            switchToggle.heightAnchor.constraint(equalToConstant: Constants.Geometry.switchHeight)
        ])
    }
    
    private func createPopover(on view: NSView, title: String, description: String) -> NSPopover {
        let popover = NSPopover()
        popover.behavior = .semitransient
        popover.appearance = NSAppearance(named: NSAppearance.Name.vibrantDark)
        popover.contentViewController = KillSwitchHelpViewController(title: title, description: description)
        popover.show(relativeTo: .zero, of: view, preferredEdge: .minY)
        
        // popover.delegate = self
        return popover
    }
}

// MARK: - KilSwitchPanelViewInput

extension KilSwitchPanelView: KilSwitchPanelViewInput {
    
    func show(enabled: Bool) {
        self.isHidden = !enabled
    }

    func killSwitch(enabled: Bool) {
        self.switchToggle?.isOn = enabled
    }
}