tauri-plugins-workspace/plugins/dialog/ios/Sources/DialogPlugin.swift

// Copyright 2019-2023 Tauri Programme within The Commons Conservancy
// SPDX-License-Identifier: Apache-2.0
// SPDX-License-Identifier: MIT

import MobileCoreServices
import Photos
import PhotosUI
import SwiftRs
import Tauri
import UIKit
import WebKit

enum FilePickerEvent {
  case selected([URL])
  case cancelled
  case error(String)
}

struct MessageDialogOptions: Decodable {
  var title: String?
  let message: String
  var okButtonLabel: String?
  var cancelButtonLabel: String?
}

struct Filter: Decodable {
  var extensions: [String]?
}

struct FilePickerOptions: Decodable {
  var multiple: Bool?
  var filters: [Filter]?
  var defaultPath: String?
}

struct SaveFileDialogOptions: Decodable {
  var fileName: String?
  var defaultPath: String?
}

class DialogPlugin: Plugin {
  var filePickerController: FilePickerController!
  var onFilePickerResult: ((FilePickerEvent) -> Void)? = nil

  override init() {
    super.init()
    filePickerController = FilePickerController(self)
  }

  @objc public func showFilePicker(_ invoke: Invoke) throws {
    let args = try invoke.parseArgs(FilePickerOptions.self)

    let parsedTypes = parseFiltersOption(args.filters ?? [])
    Logger.error("Parsed Types: %@", parsedTypes)

    var hasImage = false
    var hasVideo = false
    var hasFile = false

    for type in parsedTypes {
      let kind = kindOfMedia(type)
      if kind == "file" {
        hasFile = true
        break
      } else if kind == "image" {
        hasImage = true
      } else if kind == "video" {
        hasVideo = true
      }
    }

    onFilePickerResult = { (event: FilePickerEvent) in
      switch event {
      case let .selected(urls):
        invoke.resolve(["files": urls])
      case .cancelled:
        invoke.resolve(["files": nil])
      case let .error(error):
        invoke.reject(error)
      }
    }

    if !hasFile {
      DispatchQueue.main.async {
        if #available(iOS 14, *) {
          var configuration = PHPickerConfiguration(photoLibrary: PHPhotoLibrary.shared())
          configuration.selectionLimit = (args.multiple ?? false) ? 0 : 1
          if hasImage && !hasVideo {
            configuration.filter = .images
          } else if hasVideo && !hasImage {
            configuration.filter = .videos
          }
          let picker = PHPickerViewController(configuration: configuration)
          picker.delegate = self.filePickerController
          picker.modalPresentationStyle = .fullScreen
          self.presentViewController(picker)
        } else {
          let picker = UIImagePickerController()
          picker.delegate = self.filePickerController

          if hasImage && hasVideo {
            picker.mediaTypes = [kUTTypeImage as String, kUTTypeMovie as String]
          } else if hasImage {
            picker.mediaTypes = [kUTTypeImage as String]
          } else if hasVideo {
            picker.mediaTypes = [kUTTypeMovie as String]
          }

          picker.sourceType = .photoLibrary
          picker.modalPresentationStyle = .fullScreen
          self.presentViewController(picker)
        }
      }
    } else {
      let documentTypes = parsedTypes.isEmpty ? ["public.data"] : parsedTypes
      DispatchQueue.main.async {
        let picker = UIDocumentPickerViewController(documentTypes: documentTypes, in: .import)
        if let defaultPath = args.defaultPath {
          picker.directoryURL = URL(string: defaultPath)
        }
        picker.delegate = self.filePickerController
        picker.allowsMultipleSelection = args.multiple ?? false
        picker.modalPresentationStyle = .fullScreen
        self.presentViewController(picker)
      }
    }
  }

  @objc public func saveFileDialog(_ invoke: Invoke) throws {
    let args = try invoke.parseArgs(SaveFileDialogOptions.self)

    // The Tauri save dialog API prompts the user to select a path where a file must be saved
    // This behavior maps to the operating system interfaces on all platforms except iOS,
    // which only exposes a mechanism to "move file `srcPath` to a location defined by the user"
    //
    // so we have to work around it by creating an empty file matching the requested `args.fileName`,
    // and using it as `srcPath` for the operation - returning the path the user selected
    // so the app dev can write to it later - matching cross platform behavior as mentioned above
    let fileManager = FileManager.default
    let srcFolder = fileManager.urls(for: .documentDirectory, in: .userDomainMask).first!
    let srcPath = srcFolder.appendingPathComponent(args.fileName ?? "file")
    if !fileManager.fileExists(atPath: srcPath.path) {
      // the file contents must be actually provided by the tauri dev after the path is resolved by the save API
      try "".write(to: srcPath, atomically: true, encoding: .utf8)
    }

    onFilePickerResult = { (event: FilePickerEvent) in
      switch event {
      case let .selected(urls):
        invoke.resolve(["file": urls.first!])
      case .cancelled:
        invoke.resolve(["file": nil])
      case let .error(error):
        invoke.reject(error)
      }
    }

    DispatchQueue.main.async {
      let picker = UIDocumentPickerViewController(url: srcPath, in: .exportToService)
      if let defaultPath = args.defaultPath {
        picker.directoryURL = URL(string: defaultPath)
      }
      picker.delegate = self.filePickerController
      picker.modalPresentationStyle = .fullScreen
      self.presentViewController(picker)
    }
  }

  private func presentViewController(_ viewControllerToPresent: UIViewController) {
    manager.viewController?.present(viewControllerToPresent, animated: true, completion: nil)
  }

  private func parseFiltersOption(_ filters: [Filter]) -> [String] {
    var parsedTypes: [String] = []
    for filter in filters {
      for ext in filter.extensions ?? [] {
        if #available(iOS 14.0, *) {
          if let utType = UTType(filenameExtension: ext) {
            parsedTypes.append(utType.identifier)
          }
        } else {
          if let unmanagedUTI = UTTypeCreatePreferredIdentifierForTag(
            kUTTagClassFilenameExtension,
            ext as CFString,
            nil
          ) {
            let uti = unmanagedUTI.takeRetainedValue() as String
            parsedTypes.append(uti)
          }
        }
      }
    }
    return parsedTypes
  }

  private func kindOfMedia(_ uti: String) -> String {
    if #available(iOS 14.0, *) {
      let utType = UTType(uti)
      if utType?.conforms(to: .image) == true {
        return "image"
      } else if utType?.conforms(to: .movie) == true {
        return "video"
      } else if utType?.conforms(to: .video) == true {
        return "video"
      }
    } else {
      if UTTypeConformsTo(uti as CFString, kUTTypeImage) {
        return "image"
      } else if UTTypeConformsTo(uti as CFString, kUTTypeMovie) {
        return "video"
      } else if UTTypeConformsTo(uti as CFString, kUTTypeVideo) {
        return "video"
      }
    }
    return "file"
  }

  public func onFilePickerEvent(_ event: FilePickerEvent) {
    onFilePickerResult?(event)
  }

  @objc public func showMessageDialog(_ invoke: Invoke) throws {
    let manager = self.manager
    let args = try invoke.parseArgs(MessageDialogOptions.self)

    DispatchQueue.main.async { [] in
      let alert = UIAlertController(
        title: args.title, message: args.message, preferredStyle: UIAlertController.Style.alert
      )

      let cancelButtonLabel = args.cancelButtonLabel ?? ""
      if !cancelButtonLabel.isEmpty {
        alert.addAction(
          UIAlertAction(
            title: cancelButtonLabel, style: UIAlertAction.Style.default,
            handler: { _ in
              Logger.error("cancel")

              invoke.resolve([
                "value": false,
                "cancelled": false,
              ])
            }
          ))
      }

      let okButtonLabel = args.okButtonLabel ?? (cancelButtonLabel.isEmpty ? "OK" : "")
      if !okButtonLabel.isEmpty {
        alert.addAction(
          UIAlertAction(
            title: okButtonLabel, style: UIAlertAction.Style.default,
            handler: { _ in
              Logger.error("ok")

              invoke.resolve([
                "value": true,
                "cancelled": false,
              ])
            }
          ))
      }

      manager.viewController?.present(alert, animated: true, completion: nil)
    }
  }
}

@_cdecl("init_plugin_dialog")
func initPlugin() -> Plugin {
  return DialogPlugin()
}