elpha-ios/elpha-ios/AuthenticateViewController.swift

//
//  AuthenticateViewController.swift
//  elpha-ios
//
//  Created by Dwayne Harris on 8/26/18.
//  Copyright © 2018 Elpha. All rights reserved.
//

import Alamofire
import CoreData
import UIKit
import SafariServices

class AuthenticateViewController: UIViewController {
    @IBOutlet var signInButton: UIButton!
    @IBOutlet var instanceTextField: UITextField!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        signInButton.layer.cornerRadius = 10
        signInButton.clipsToBounds = true
        
        instanceTextField.attributedPlaceholder = NSAttributedString(string: "mastodon.social", attributes: [NSAttributedString.Key.foregroundColor: UIColor.init(red: 0.9, green: 0.9, blue: 0.9, alpha: 1)])
    }
    
    override open var shouldAutorotate: Bool {
        return false
    }
    
    func authorize(client: ClientMO) {
        AuthenticationManager.authenticationState = NSUUID().uuidString
        AuthenticationManager.authenticationClient = client
        AuthenticationManager.authenticationDelegate = self
        
        let parameters = [
            "client_id": client.clientID!,
            "response_type": "code",
            "redirect_uri": Config.clientRedirectURI,
            "scope": "read write follow".addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!,
        ]
        
        let parameterString = parameters.map { "\($0.key)=\($0.value)" }.joined(separator: "&")
        let authorizeURL = URL(string: "https://\(client.host!)/oauth/authorize?\(parameterString)")
        
        let controller = SFSafariViewController(url: authorizeURL!)
        controller.delegate = self
        controller.dismissButtonStyle = .cancel
        controller.preferredControlTintColor = UIColor(named: "Primary")
        
        present(controller, animated: true)
    }
    
    @IBAction func signIn(_ sender: Any) {
        guard var host = instanceTextField.text, !host.isEmpty else {
            return
        }
        
        if host.contains("@") {
            if let urlPart = host.split(separator: "@").last {
                host = String(urlPart)
            } else {
                return
            }
        }
        
        if host.starts(with: "https://") {
            host = String(host.dropFirst(8))
        }
        
        if host.starts(with: "http://") {
            host = String(host.dropFirst(7))
        }
        
        signInButton.isEnabled = false
        defer {
            signInButton.isEnabled = true
        }
        
        let request = NSFetchRequest<ClientMO>(entityName: "Client")
        request.predicate = NSPredicate(format: "host == %@", host)
        
        do {
            let response = try CoreDataManager.shared.context.fetch(request)
            if let client = response.first {
                self.authorize(client: client)
            } else {
                MastodonAPI.registerApp(serverURL: URL(string: "https://\(host)")!) { data, error in
                    guard let data = data, error == nil else {
                        print("\(String(describing: error))")
                        return
                    }
                    
                    let client = MastodonDataManager.saveClient(
                        id: data["id"] as! String,
                        clientID: data["client_id"] as! String,
                        clientSecret: data["client_secret"] as! String,
                        host: host
                    )
                    
                    self.authorize(client: client)
                }
            }
        } catch {
            AlertManager.shared.show(message: error.localizedDescription, category: .error)
        }
    }
}

extension AuthenticateViewController: SFSafariViewControllerDelegate {
    func safariViewControllerDidFinish(_ controller: SFSafariViewController) {
        controller.dismiss(animated: true)
    }
}

extension AuthenticateViewController: AuthenticationDelegate {
    func authenticationSuccess(_ sender: Any) {
        NotificationCenter.default.post(name: .didAuthenticate, object: nil)
        
        DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
            self.dismiss(animated: true)
        }
    }
    
    func authenticationFailure(_ sender: Any, error: Error?) {
        AlertManager.shared.show(message: error?.localizedDescription ?? "Authentication error", category: .error)
    }
}