//
//  PasswordManager.swift
//  AeroBuddy
//
//  Created by Luke Collister on 12/11/2019.
//  Copyright © 2019 Luke Collister. All rights reserved.
//

import Foundation

class ServHandler {
    static let shared = ServHandler() // singleton instance
    static let connectProtocol = "http"
    static let baseURL = "fe01.kilosierracharlie.me"
    static let emailValidator = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}"
    private var loggedInUser: String
    private lazy var protectionSpace: URLProtectionSpace = {
        return URLProtectionSpace(host: ServHandler.baseURL,
        port: 0,
        protocol: ServHandler.connectProtocol,
        realm: nil,
        authenticationMethod: nil)
    }()
    private init() { }

    func password(for userID: String) -> String? {
        guard let credentials = URLCredentialStorage.shared.credentials(for: protectionSpace) else { return nil }
        return credentials[userID]?.password
    }

    func set(password: String, for userID: String) {
        let credential = URLCredential(user: userID, password: password, persistence: .permanent)
        URLCredentialStorage.shared.set(credential, for: protectionSpace)
        loggedInUser = userID
    }

    func checkCredentials( password: String, for userID: String, completion: @escaping (Bool) -> Bool ) {
        let emailTest = NSPredicate(format:"SELF MATCHES[c] %@", ServHandler.emailValidator)
        if( password.count > 3 && emailTest.evaluate(with: userID) ){
            set(password: password, for: userID)
            let url = URL(string: "\(ServHandler.connectProtocol)://\(ServHandler.baseURL)/user")!

            let config = URLSessionConfiguration.default
            let session = URLSession(configuration: config)
            let task = session.dataTask(with: url) { (data, response, error) in
                guard error == nil else {
                    completion(false)
                    return
                }
                if let httpStatus = response as? HTTPURLResponse {
                    if httpStatus.statusCode == 200 {
                        completion(true)
                    }
                    completion(false)
                }
            }
            task.resume()
        }
    }

    func clear(for userID: String) {
        guard let creds = URLCredentialStorage.shared.credentials(for: protectionSpace) else { return }
        guard let cred = creds[userID] else { return }
        URLCredentialStorage.shared.remove(cred, for: protectionSpace)
    }

    func logout() {
        if(loggedInUser == nil){ return }
        clear(for: loggedInUser)
    }
}