```
import UIKit
import Foundation
import Firebase
import FirebaseDatabase
import FirebaseAuth
import GoogleSignIn
import FBSDKLoginKit
import SCLAlertView
import UserNotifications
import FirebaseStorage


class SignupViewController: UIViewController{
    
    @IBOutlet weak var usernameTextfield: UITextField!
    
    @IBOutlet weak var emailTextField: UITextField!
    
    @IBOutlet weak var passwordTextField: UITextField!
    
    @IBOutlet weak var reenterPasswordTextField: UITextField!
    
    @IBOutlet weak var signupButton: UIButton!
    
    @IBOutlet weak var errorlabel: UILabel!
    
    @IBOutlet weak var passwordEye: UIImageView!
    
    @IBOutlet weak var cameraButton: UIImageView!
    
    @IBOutlet weak var googleBtn: UIButton!
    
    @IBOutlet weak var fbBtn: UIButton!
    
    var database: DatabaseReference!
    
    private let storage = Storage.storage().reference()
    
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        setupGoogleButton()
        
        passwordTextField.isSecureTextEntry = true
        reenterPasswordTextField.isSecureTextEntry = true
        
        passwordEye.isUserInteractionEnabled = true
        passwordEye.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(eyeSelected)))
        
        setUpElements()
        cameraButton.isUserInteractionEnabled = true
        cameraButton.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(cameraButtonPressed)))
        let spacerView = UIView(frame:CGRect(x:0, y:0, width:30, height:10))
        passwordTextField.leftViewMode = UITextField.ViewMode.always
        passwordTextField.leftView = spacerView
        let spacerView2 = UIView(frame:CGRect(x:0, y:0, width:30, height:10))
        emailTextField.leftViewMode = UITextField.ViewMode.always
        emailTextField.leftView = spacerView2
        let spacerView3 = UIView(frame:CGRect(x:0, y:0, width:30, height:10))
        reenterPasswordTextField.leftViewMode = UITextField.ViewMode.always
        reenterPasswordTextField.leftView = spacerView3
        let spacerView4 = UIView(frame:CGRect(x:0, y:0, width:30, height:10))
        usernameTextfield.leftViewMode = UITextField.ViewMode.always
        usernameTextfield.leftView = spacerView4
        cameraButton.layer.masksToBounds = true
        cameraButton.layer.cornerRadius = 80
        cameraButton.contentMode = .scaleToFill
        fbBtn.layer.cornerRadius =
            fbBtn.frame.width / 2
        fbBtn.layer.masksToBounds = true
        
        database = Database.database().reference()
        
        guard  let urlString = UserDefaults.standard.value(forKey: "url") as? String,
               let url = URL(string: urlString) else {
            return
        }
        
        let task = URLSession.shared.dataTask(with: url, completionHandler: { data, _, error in
            guard let data = data, error == nil else{
                return
            }
            
            DispatchQueue.main.async {
                
                let image = UIImage(data: data)
                self.cameraButton.image = image
            }
            
        })
        
        task.resume()
    
        
    }
    
    func setupGoogleButton(){
        googleBtn.layer.cornerRadius = googleBtn.frame.width/2
        googleBtn.layer.masksToBounds = true
        GIDSignIn.sharedInstance()?.presentingViewController = self
    }
    
    func handleGoogleSignIn(){
        GIDSignIn.sharedInstance().signIn()
    }
    
    func setUpElements() {
        
        //Hides error label
        errorlabel.alpha = 0
        
    }
    
    func validateFields() -> String? {
        if usernameTextfield.text?.trimmingCharacters(in: .whitespacesAndNewlines) == ""  || emailTextField.text?.trimmingCharacters(in: .whitespacesAndNewlines) == "" {
            SCLAlertView().showError("Try Again",subTitle:"😱Please fill in all of the fields😱")
        }
        
        let cleanedPassword = passwordTextField.text!.trimmingCharacters(in: .whitespacesAndNewlines)
        
        if Utilities.isPasswordValid(cleanedPassword) == false {
            
            SCLAlertView().showError("Try Again",subTitle:"😱Please make sure your password is at least 8 characters.😱")
        }
        return nil
    }
    
    @IBAction func didChangeSegement(_ sender:UISegmentedControl){
        if sender.selectedSegmentIndex == 1{
            let vc = storyboard?.instantiateViewController(identifier: "loginVC") as! LoginViewController
            vc.modalPresentationStyle = .fullScreen
            present(vc, animated: true)
        }
    }
    
    
    func transitionToHome() {
        
        let vc = storyboard?.instantiateViewController(identifier: "tabVC") as! TabBarViewController
        vc.modalPresentationStyle = .fullScreen
        present(vc, animated: true)
        
    }
    
    @IBAction func signUpTapped(_ sender: UIButton) {
        
        let error = validateFields()
        
        if error != nil {
            
            print(error!)
            sender.shake()
            SCLAlertView().showError("Uh Oh",subTitle:"Something went wrong")
        }else if reenterPasswordTextField.text! != passwordTextField.text!{
            sender.shake()
            SCLAlertView().showError("Try Again",subTitle:"😱Your passwords do not match.😱")
        }else {
            usernameTextfield.resignFirstResponder()
            emailTextField.resignFirstResponder()
            passwordTextField.resignFirstResponder()
            
            let username = usernameTextfield.text!.trimmingCharacters(in: .whitespacesAndNewlines)
            let email = emailTextField.text!.trimmingCharacters(in: .whitespacesAndNewlines)
            let password = passwordTextField.text!.trimmingCharacters(in: .whitespacesAndNewlines)
            DatabaseManager.shared.userExists(with: email, completion: { [weak self] exists in
                
                guard !exists else{
                    sender.shake()
                    SCLAlertView().showError("Uh Oh",subTitle:"😱This account alreeady exists.😱")
                    return
                }
                
                let email2 = email.replacingOccurrences(of: ".", with: "-")
                let safeEmail = email2.replacingOccurrences(of: "@", with: "-")
                
                Auth.auth().createUser(withEmail: email, password: password, completion: { authResult, error in
                    guard authResult != nil, error == nil else {
                        sender.shake()
                        SCLAlertView().showError("Uh Oh",subTitle: "Something went wrong")
                        print(safeEmail)
                        print(error!)
                        return
                    }
                    
                    UserDefaults.standard.setValue(email, forKey: "email")
                    UserDefaults.standard.setValue(username, forKey: "username")
                    
                    
                    let newUser = UserModel(username: username,
                                            email: email,
                                            password: password)
                    DatabaseManager.shared.insertUser(with: newUser, completion: { success in
                        if success {
                            guard let image = self?.cameraButton.image,
                                  let data = image.pngData() else {
                                return
                            }
                            let filename = newUser.profilePictureURL
                            StorageManager.shared.uploadProfilePicture(with: data, fileName: filename, completion: { result in
                                
                                switch result {
                                    case .success(let downloadUrl):
                                        UserDefaults.standard.set(downloadUrl, forKey: "profile_picture_url")
                                        UserDefaults.standard.set(true, forKey:  "isLoggedIn")
                                        UserDefaults.standard.synchronize()
                                        self?.transitionToHome()
                                    case .failure( _):
                                        SCLAlertView().showError("Failed to upload Image", subTitle:"😱Choose another image.😱")
                                }
                            })
                        }
                    })
                })
            })
        }
        
    }
    
    @objc private func eyeSelected(){
        passwordTextField.isSecureTextEntry.toggle()
        if passwordTextField.isSecureTextEntry ==  true{
            passwordEye.image = UIImage(systemName: "eye")
        }else{
            passwordEye.image = UIImage(systemName: "eye.fill")
        }
    }
    
    
    
    @IBAction func googleBtnPressed(_ sender: Any) {
        if GIDSignIn.sharedInstance()?.currentUser != nil{
            return
        }else{
            GIDSignIn.sharedInstance()?.signIn()
            if let user = GIDSignIn.sharedInstance()?.currentUser{
                DatabaseManager.shared.userExists(with: user.profile.email, completion: { [weak self] exists in
                    guard !exists else{
                        SCLAlertView().showError("Uh Oh",subTitle:"😱This account alreeady exists.😱")
                        return
                    }
                    
                    let email2 = user.profile.email.replacingOccurrences(of: ".", with: "-")
                    let safeEmail = email2.replacingOccurrences(of: "@", with: "-")
                    
                    Auth.auth().createUser(withEmail: safeEmail, password: "null (Google User)", completion: { [weak self] authResult, error in
                        guard authResult != nil, error == nil else {
                            SCLAlertView().showError("Uh Oh",subTitle: "Something went wrong")
                            return
                        }
                        
                        UserDefaults.standard.setValue(user.profile.email, forKey: "email")
                        UserDefaults.standard.setValue(user.profile.name, forKey: "username")
                        
                        
                        let newUser = UserModel(username: user.profile.name,
                                                email: user.profile.email,
                                                password: "null (Google User)")
                        DatabaseManager.shared.insertUser(with: newUser, completion: { [weak self] success in
                            if success {
                                if user.profile.hasImage {
                                    guard let url = user.profile.imageURL(withDimension: 200) else{
                                        return
                                    }
                                    
                                    
                                    URLSession.shared.dataTask(with: url, completionHandler: { data, _, _ in
                                        guard let data = data else{
                                            return
                                        }
                                        
                                        let fileName = newUser.profilePictureURL
                                        StorageManager.shared.uploadProfilePicture(with: data, fileName: fileName, completion: { [weak self] result in
                                            switch result {
                                                case .success(let downloadUrl):
                                                    UserDefaults.standard.set(downloadUrl, forKey: "profile_picture_url")
                                                    let vc = self?.storyboard?.instantiateViewController(identifier: "tabBarVC") as! TabBarViewController
                                                    vc.modalPresentationStyle = .fullScreen
                                                    self?.present(vc, animated: true)
                                                case .failure( _):
                                                    SCLAlertView().showError("Failed to upload Image", subTitle:"😱Choose another image.😱")
                                            }
                                        })
                                    }).resume()
                                }
                            }
                        })
                    })
                })
            }
        }
    }
    
    
    @IBAction func fbBtnPressed(_ sender: Any) {
        
        let fbLoginManager = LoginManager()
        fbLoginManager.logIn(permissions: ["public_profile", "email", "picture.type(large)"], from: self) { [weak self] (result, error) in
            if error != nil {
                SCLAlertView().showError("Oof",subTitle:"😱Error signing you in.😱")
                return
            }
            
            guard let accessToken = AccessToken.current else {
                SCLAlertView().showError("Oof",subTitle:"😱Try again without Facebook😱")
                return
            }
            
            let credential = FacebookAuthProvider.credential(withAccessToken: accessToken.tokenString)
            
            Auth.auth().signIn(with: credential, completion: { (user, error) in
                if error != nil {
                    SCLAlertView().showError("Oof",subTitle:"😱Error signing you in.😱")
                    return
                }
                else {
                    
                    
                    let user = Auth.auth().currentUser!
                    
                    DatabaseManager.shared.userExists(with: user.email!, completion: { exists in
                        guard !exists else{
                            SCLAlertView().showError("Uh Oh",subTitle:"😱This account alreeady exists.😱")
                            return
                        }
                        
                        let email2 = user.email!.replacingOccurrences(of: ".", with: "-")
                        let safeEmail = email2.replacingOccurrences(of: "@", with: "-")
                        
                        Auth.auth().createUser(withEmail: safeEmail, password: "null (Facebook User)", completion: { [weak self] authResult, error in
                            guard authResult != nil, error == nil else {
                                SCLAlertView().showError("Uh Oh",subTitle: "Something went wrong")
                                return
                            }
                            
                            UserDefaults.standard.setValue(user.email!, forKey: "email")
                            UserDefaults.standard.setValue(user.displayName!, forKey: "username")
                            
                            
                            let newUser = UserModel(username: user.displayName!,
                                                    email: user.email!,
                                                    password: "null (Facebook User)")
                            DatabaseManager.shared.insertUser(with: newUser, completion: { [weak self] success in
                                if success {
                                    guard let url = user.photoURL else{
                                        return
                                    }
                                    
                                    
                                    URLSession.shared.dataTask(with: url, completionHandler: { data, _, _ in
                                        guard let data = data else{
                                            return
                                        }
                                        
                                        let fileName = newUser.profilePictureURL
                                        StorageManager.shared.uploadProfilePicture(with: data, fileName: fileName, completion: { [weak self] result in
                                            switch result {
                                                case .success(let downloadUrl):
                                                    UserDefaults.standard.set(downloadUrl, forKey: "profile_picture_url")
                                                    self?.transitionToHome()
                                                case .failure( _):
                                                    SCLAlertView().showError("Failed to upload Image", subTitle:"😱Choose another image.😱")
                                            }
                                        })
                                    }).resume()
                                }
                            })
                        })
                    })
                }
            })
            
        }
        
    }
    
    @objc private func cameraButtonPressed(){
        
        presentPhotoActionSheet()
        
    }
    
}

extension SignupViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    
    func presentPhotoActionSheet(){
        
        let actionSheet = UIAlertController(title: "Profile Picture", message: "Which way would you like to select a profile picture", preferredStyle: .actionSheet)
        actionSheet.addAction(UIAlertAction(title: "Cancel", style: .destructive, handler:nil))
        actionSheet.addAction(UIAlertAction(title: "Take Photo", style: .default, handler: { [ weak self ] _ in
            
            self?.presentCamera()
            
        }))
        
        actionSheet.addAction(UIAlertAction(title: "Choose Photo", style: .default, handler: { [ weak self ]  _ in
            
            
            self?.presentPhotoPicker()
        }))
        
        present(actionSheet, animated: true)
        
    }
    
    func presentCamera(){
        
        let vc = UIImagePickerController()
        vc.sourceType = .camera
        vc.delegate = self
        vc.allowsEditing = true
        present(vc, animated: true)
        
    }
    
    func presentPhotoPicker(){
        
        let vc = UIImagePickerController()
        vc.sourceType = .photoLibrary
        vc.delegate = self
        vc.allowsEditing = true
        present(vc, animated: true)
        
    }
    
    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
        picker.dismiss(animated: true, completion: nil)
        print(info)
        
        guard let selectedImage = info[UIImagePickerController.InfoKey.editedImage] as? UIImage else{
            return
        }
        
        guard let imageData = selectedImage.pngData() else{
            return
        }
        
        storage.child("images/" +  "filename" +  ".png").putData(imageData, metadata: nil, completion: { _, error in
            guard error == nil else{
                SCLAlertView().showError("Image can't be uploaded",subTitle:"😱Please choose another image😱")
                return
            }
            
            self.storage.child("images/file.png").downloadURL(completion: { url, error in
                guard let url = url, error == nil else{
                    return
                }
                
                let urlString = url.absoluteString
                UserDefaults.standard.set(urlString, forKey: "url")
            })
        })
        self.cameraButton.image = selectedImage
    }
    
    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        picker.dismiss(animated: true, completion: nil)
    }
    
}
```