space-ios/iOSClient/Viewer/NCViewerQuickLook/NCViewerQuickLook.swift

//
//  NCViewerQuickLook.swift
//  Nextcloud
//
//  Created by Marino Faggiana on 03/05/2020.
//  Copyright © 2020 Marino Faggiana. All rights reserved.
//
//  Author Marino Faggiana <marino.faggiana@nextcloud.com>
//
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this program.  If not, see <http://www.gnu.org/licenses/>.
//

import UIKit
import QuickLook

@objc class NCViewerQuickLook: QLPreviewController {
    
    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let previewController = QLPreviewController()
    var previewItems: [PreviewItem] = []
    var editingMode: Bool
    enum saveModeType{
        case overwrite
        case copy
        case discard
    }
    var saveMode: saveModeType = .discard
        
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    init(with url: URL, editingMode: Bool) {
        self.editingMode = editingMode
        super.init(nibName: nil, bundle: nil)
        
        self.dataSource = self
        self.delegate = self
        self.navigationItem.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: .done, target: self, action: #selector(dismissPreviewController))

        URLSession.shared.dataTask(with: url) { data, response, error in
            
            guard let _ = data, error == nil else {
                self.presentAlertController(with: error?.localizedDescription ?? "Failed to look the file")
                return
            }
            
            var previewURL = url
            previewURL.hasHiddenExtension = true
            let previewItem = PreviewItem()
            previewItem.previewItemURL = previewURL
            self.previewItems.append(previewItem)
            self.currentPreviewItemIndex = 0
          
        }.resume()
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
    }
    
    func presentAlertController(with message: String) {
         // present your alert controller from the main thread
        DispatchQueue.main.async {
            UIApplication.shared.isNetworkActivityIndicatorVisible = false
            let alert = UIAlertController(title: "Alert", message: message, preferredStyle: .alert)
            alert.addAction(.init(title: "OK", style: .default))
            self.appDelegate.window?.rootViewController?.present(alert, animated: true)
        }
    }
    
    @objc func dismissPreviewController() {
        
        if editingMode {
            let alertController = UIAlertController(title: NSLocalizedString("_save_", comment: ""), message: "", preferredStyle: .alert)
            
            alertController.addAction(UIAlertAction(title: NSLocalizedString("_overwrite_original_", comment: ""), style: .default) { (action:UIAlertAction) in
                self.saveMode = .overwrite
                self.dismiss(animated: true)
            })
            alertController.addAction(UIAlertAction(title: NSLocalizedString("_save_as_copy_", comment: ""), style: .default) { (action:UIAlertAction) in
                self.saveMode = .copy
                self.dismiss(animated: true)
            })
            alertController.addAction(UIAlertAction(title: NSLocalizedString("_discard_changes_", comment: ""), style: .destructive) { (action:UIAlertAction) in
                self.saveMode = .discard
                self.dismiss(animated: true)
            })
            
            self.present(alertController, animated: true)
        } else {
            self.dismiss(animated: true)
        }
    }
}

extension NCViewerQuickLook: QLPreviewControllerDataSource, QLPreviewControllerDelegate {
    
    func numberOfPreviewItems(in controller: QLPreviewController) -> Int {
        previewItems.count
    }
    
    func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> QLPreviewItem {
        previewItems[index]
    }
    
    func previewController(_ controller: QLPreviewController, didUpdateContentsOf previewItem: QLPreviewItem) {
    }
    
    @available(iOS 13.0, *)
    func previewController(_ controller: QLPreviewController, editingModeFor previewItem: QLPreviewItem) -> QLPreviewItemEditingMode {
        if editingMode {
            return .createCopy
        } else {
            return .disabled
        }
    }
    
    func previewController(_ controller: QLPreviewController, didSaveEditedCopyOf previewItem: QLPreviewItem, at modifiedContentsURL: URL) {
        
    }
}

extension URL {
    var hasHiddenExtension: Bool {
        get { (try? resourceValues(forKeys: [.hasHiddenExtensionKey]))?.hasHiddenExtension == true }
        set {
            var resourceValues = URLResourceValues()
            resourceValues.hasHiddenExtension = newValue
            try? setResourceValues(resourceValues)
        }
    }
}

import QuickLook
class PreviewItem: NSObject, QLPreviewItem {
    var previewItemURL: URL?
}