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 OAuthSwift
import UIKit

class AuthenticateViewController: UIViewController {
    @IBOutlet var signInButton: UIButton!
    @IBOutlet var instanceTextField: UITextField!
    
    var oauthswift: OAuthSwift?
    let defaultInstanceName = "mastodon.social"
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        signInButton.layer.cornerRadius = 10
        signInButton.clipsToBounds = true
        
        randomInstanceName { instance in
            self.instanceTextField.attributedPlaceholder = NSAttributedString(string: instance, 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 randomInstanceName(completion: @escaping (String) -> Void) {
        let requestURL = "\(Config.instancesServiceURL)\(Config.instancesServiceRandomEndpoint)?count=1"
        let headers: HTTPHeaders = ["Authorization": "Bearer \(Config.instancesServiceSecret)"]
        
        Alamofire.request(requestURL, headers: headers).validate().responseJSON { response in
            switch response.result {
            case .success(let value):
                guard let result = value as? [String: Any],
                    let instances = result["instances"] as? [Any],
                    let instance = instances.first as? [String: Any],
                    let name = instance["name"] as? String else {
                    completion(self.defaultInstanceName)
                    return
                }
                
                completion(name)
            case .failure(let error):
                print("\(error)")
                completion(self.defaultInstanceName)
            }
        }
    }
    
    func authorize(client: ClientMO) {
        let oauthswift = OAuth2Swift(
            consumerKey: client.clientID!,
            consumerSecret: client.clientSecret!,
            authorizeUrl: "https://\(client.host!)/oauth/authorize",
            accessTokenUrl: "https://\(client.host!)/oauth/token",
            responseType: "code"
        )
        
        oauthswift.authorizeURLHandler = OAuthSwiftOpenURLExternally.sharedInstance
        self.oauthswift = oauthswift
        
        let _ = oauthswift.authorize(
            withCallbackURL: URL(string: "elpha://oauth")!,
            scope: "read write follow",
            state: NSUUID().uuidString,
            success: { credential, _, _ in
                let token = credential.oauthToken
                let serverURL = URL(string: "https://\(client.host!)")
                
                MastodonAPI.currentUser(token: token, serverURL: serverURL!) { data, error in
                    guard let data = data, error == nil else {
                        print("\(String(describing: error))")
                        return
                    }
                    
                    let account = MastodonDataManager.upsertAccount(data)
                    _ = AuthenticationManager.saveSession(client: client, account: account!, token: credential.oauthToken)
                    
                    self.dismiss(animated: true)
                }
            },
            failure: { error in
                print("\(error)")
            }
        )
    }
    
    @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 {
            print("\(error)")
        }
    }
}