import UIKit
import FirebaseStorage

class UploadDataViewController: UIViewController {
    let imageName = "/profile.jpg"
    var imageFileURL: URL?
    var storageRef: StorageReference! = nil
    typealias CompletionHandler = (_ success: Bool,_ metadata: StorageMetadata?,_ downloadUrl: URL?) -> Void

    override func viewDidLoad() {
        super.viewDidLoad()
        self.storageRef = Storage.storage().reference()
        self.saveUserProfile()
    }

    func saveUserProfile() {
       let image = UIImage(named: "profile")
       if createImgUrl(image: image!) {
          self.uploadImageWithUrl(fileUrl: self.imageFileURL!, fileName: "userID1") { (success, metadata, downloadUrl) in
               if success {
                   // Can save this download url into your database for further use/download
                   print("Image uploaded successfully and downloading url is \(downloadUrl)")
               } else {
                   print("Error while uploading image")
               }
          }
       } else {
          print("Error while creating document url for this image")
       }
    }

    // save your image to document directory
    func createImgUrl(image:UIImage) -> Bool {
        let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
        self.imageFileURL = documentsDirectory.appendingPathComponent(self.imageName)
        if let data = UIImageJPEGRepresentation(image, 0.5) {
            do {
                try data.write(to: self.imageFileURL!)
                return true
            } catch {
                print("error saving file:", error)
            }
        }
        return false
    }

    // Upload an image file to Firebase - (Google cloud storage bucket)
    func uploadImageWithUrl(fileUrl:URL, fileName:String, completionHandler: @escaping CompletionHandler) {
        let imagesRef = storageRef.child("user_profile")
        let fileRef = imagesRef.child(fileName).child(self.imageName)
        let imgMetadata = StorageMetadata()
        imgMetadata.contentType = "image/jpeg"
        let uploadTask = fileRef.putFile(from: fileUrl, metadata: imgMetadata) { metadata, error in
            guard let metadata = metadata else {
                return completionHandler(false, nil, nil)
            }
            fileRef.downloadURL { (url, error) in
                guard let downloadURL = url else {
                    return completionHandler(false, nil, nil)
                }
                print("Downloaded Url for uploaded image is: \(downloadURL)")
                completionHandler(true, metadata, downloadURL)
            }
        }
    }
}