ecency-mobile/ios/eshare/ShareViewController.swift

//
//  ShareViewController.swift
//  eshare
//
//  Created by Feruz Muradov on 2020-07-30.
//  Copyright © 2020 Facebook. All rights reserved.
//

import UIKit
import Social
import MobileCoreServices
import Photos

class ShareViewController: SLComposeServiceViewController {
    let hostAppBundleIdentifier = "app.esteem.mobile.ios"
    let sharedKey = "ShareKey"
    var sharedMedia: [SharedMediaFile] = []
    var sharedText: [String] = []
    let imageContentType = kUTTypeImage as String
    let textContentType = kUTTypeText as String
    let urlContentType = kUTTypeURL as String
  
    override func isContentValid() -> Bool {
        // Do validation of contentText and/or NSExtensionContext attachments here
        return true
    }

    override func didSelectPost() {
        // This is called after the user selects Post. Do the upload of contentText and/or NSExtensionContext attachments.
        if let content = extensionContext!.inputItems[0] as? NSExtensionItem {
            if let contents = content.attachments {
                for (index, attachment) in (contents).enumerated() {
                    if attachment.hasItemConformingToTypeIdentifier(imageContentType) {
                        handleImages(content: content, attachment: attachment, index: index)
                    } else if attachment.hasItemConformingToTypeIdentifier(textContentType) {
                        handleText(content: content, attachment: attachment, index: index)
                    } else if attachment.hasItemConformingToTypeIdentifier(urlContentType) {
                        handleUrl(content: content, attachment: attachment, index: index)
                    }
                }
            }
        }
        // Inform the host that we're done, so it un-blocks its UI. Note: Alternatively you could call super's -didSelectPost, which will similarly complete the extension context.
        // self.extensionContext!.completeRequest(returningItems: [], completionHandler: nil)
    }

    override func configurationItems() -> [Any]! {
        // To add configuration options via table cells at the bottom of the sheet, return an array of SLComposeSheetConfigurationItem here.
        return []
    }
    private func handleText (content: NSExtensionItem, attachment: NSItemProvider, index: Int) {
        attachment.loadItem(forTypeIdentifier: textContentType, options: nil) { [weak self] data, error in
            
            if error == nil, let item = data as? String, let this = self {
                this.sharedText.append(item)
                // If this is the last item, save imagesData in userDefaults and redirect to host app
                if index == (content.attachments?.count)! - 1 {
                    let userDefaults = UserDefaults(suiteName: "group.com.ecency.eshare")
                    userDefaults?.set(this.sharedText, forKey: this.sharedKey)
                    userDefaults?.synchronize()
                    this.redirectToHostApp(type: .text)
                }
            } else {
                self?.dismissWithError()
            }
        }
    }

    private func handleUrl (content: NSExtensionItem, attachment: NSItemProvider, index: Int) {
        attachment.loadItem(forTypeIdentifier: urlContentType, options: nil) { [weak self] data, error in
            if error == nil, let item = data as? URL, let this = self {
                this.sharedText.append(item.absoluteString)
                // If this is the last item, save imagesData in userDefaults and redirect to host app
                if index == (content.attachments?.count)! - 1 {
                    let userDefaults = UserDefaults(suiteName: "group.com.ecency.eshare")
                    userDefaults?.set(this.sharedText, forKey: this.sharedKey)
                    userDefaults?.synchronize()
                    this.redirectToHostApp(type: .text)
                }
            } else {
                self?.dismissWithError()
            }
        }
    }

    private func handleImages (content: NSExtensionItem, attachment: NSItemProvider, index: Int) {
        attachment.loadItem(forTypeIdentifier: imageContentType, options: nil) { [weak self] data, error in
            if error == nil, let url = data as? URL, let this = self {
                //  this.redirectToHostApp(type: .media)
                // Always copy
                let fileExtension = this.getExtension(from: url, type: .image)
                let newName = UUID().uuidString
                let newPath = FileManager.default
                    .containerURL(forSecurityApplicationGroupIdentifier: "group.com.ecency.eshare")!
                    .appendingPathComponent("\(newName).\(fileExtension)")
                let copied = this.copyFile(at: url, to: newPath)
                if(copied) {
                    this.sharedMedia.append(SharedMediaFile(path: newPath.absoluteString, thumbnail: nil, duration: nil, type: .image))
                }
                // If this is the last item, save imagesData in userDefaults and redirect to host app
                if index == (content.attachments?.count)! - 1 {
                    let userDefaults = UserDefaults(suiteName: "group.com.ecency.eshare")
                    userDefaults?.set(this.toData(data: this.sharedMedia), forKey: this.sharedKey)
                    userDefaults?.synchronize()
                    this.redirectToHostApp(type: .media)
                }
            } else {
                self?.dismissWithError()
            }
        }
    }

    private func dismissWithError() {
        print("[ERROR] Error loading data!")
        let alert = UIAlertController(title: "Error", message: "Error loading data", preferredStyle: .alert)
        let action = UIAlertAction(title: "Error", style: .cancel) { _ in
            self.dismiss(animated: true, completion: nil)
        }
        alert.addAction(action)
        present(alert, animated: true, completion: nil)
        extensionContext!.completeRequest(returningItems: [], completionHandler: nil)
    }

    private func redirectToHostApp(type: RedirectType) {
        let url = URL(string: "ShareMedia://dataUrl=\(sharedKey)#\(type)")
        var responder = self as UIResponder?
        let selectorOpenURL = sel_registerName("openURL:")
        
        while (responder != nil) {
            if (responder?.responds(to: selectorOpenURL))! {
                let _ = responder?.perform(selectorOpenURL, with: url)
            }
            responder = responder!.next
        }
        extensionContext!.completeRequest(returningItems: [], completionHandler: nil)
    }

    enum RedirectType {
        case media
        case text
        case file
    }

    func getExtension(from url: URL, type: SharedMediaType) -> String {
        let parts = url.lastPathComponent.components(separatedBy: ".")
        var ex: String? = nil
        if (parts.count > 1) {
            ex = parts.last
        }
        
        if (ex == nil) {
            switch type {
                case .image:
                    ex = "PNG"
                case .file:
                    ex = "TXT"
            }
        }
        return ex ?? "Unknown"
    }

    func getFileName(from url: URL) -> String {
        var name = url.lastPathComponent
        if (name == "") {
            name = UUID().uuidString + "." + getExtension(from: url, type: .file)
        }
        return name
    }

    func copyFile(at srcURL: URL, to dstURL: URL) -> Bool {
        do {
            if FileManager.default.fileExists(atPath: dstURL.path) {
                try FileManager.default.removeItem(at: dstURL)
            }
            try FileManager.default.copyItem(at: srcURL, to: dstURL)
        } catch (let error) {
            print("Cannot copy item at \(srcURL) to \(dstURL): \(error)")
            return false
        }
        return true
    }

    private func getThumbnailPath(for url: URL) -> URL {
        let fileName = Data(url.lastPathComponent.utf8).base64EncodedString().replacingOccurrences(of: "==", with: "")
        let path = FileManager.default
        .containerURL(forSecurityApplicationGroupIdentifier: "group.com.ecency.eshare")!
        .appendingPathComponent("\(fileName).jpg")
        return path
    }

    class SharedMediaFile: Codable {
        var path: String; // can be image, video or url path. It can also be text content
        var thumbnail: String?; // video thumbnail
        var duration: Double?; // video duration in milliseconds
        var type: SharedMediaType;
        
        
        init(path: String, thumbnail: String?, duration: Double?, type: SharedMediaType) {
            self.path = path
            self.thumbnail = thumbnail
            self.duration = duration
            self.type = type
        }
        
        // Debug method to print out SharedMediaFile details in the console
        func toString() {
            print("[SharedMediaFile] \n\tpath: \(self.path)\n\tthumbnail: \(self.thumbnail)\n\tduration: \(self.duration)\n\ttype: \(self.type)")
        }
    }

    enum SharedMediaType: Int, Codable {
        case image
        case file
    }

    func toData(data: [SharedMediaFile]) -> Data {
        let encodedData = try? JSONEncoder().encode(data)
        return encodedData!
    }
}

extension Array {
    subscript (safe index: UInt) -> Element? {
        return Int(index) < count ? self[Int(index)] : nil
    }
}