search for new media files in the folders, from which we already have files

app/src/main/kotlin/com/simplemobiletools/gallery/asynctasks/GetDirectoriesAsynctask.kt

@@ -22,8 +22,9 @@ class GetDirectoriesAsynctask(val context: Context, val isPickVideo: Boolean, va
     val mediaFetcher = MediaFetcher(context)
 
     override fun doInBackground(vararg params: Void): ArrayList<Directory> {
-        if (!context.hasPermission(PERMISSION_WRITE_STORAGE))
+        if (!context.hasPermission(PERMISSION_WRITE_STORAGE)) {
             return ArrayList()
+        }
 
         val config = context.config
         val groupedMedia = mediaFetcher.getMediaByDirectories(isPickVideo, isPickImage)

app/src/main/kotlin/com/simplemobiletools/gallery/helpers/MediaFetcher.kt

@@ -40,9 +40,42 @@ class MediaFetcher(val context: Context) {
             directories.remove(it)
         }
 
+        searchNewFiles(directories, showHidden)
         return directories
     }
 
+    // search for undiscovered media files in the folders, from which we already have some media files
+    private fun searchNewFiles(directories: Map<String, ArrayList<Medium>>, showHidden: Boolean) {
+        Thread {
+            // try not to delay the main media file loading
+            Thread.sleep(3000)
+            for ((path, dirMedia) in directories) {
+                if (path.contains("/.thumbnails/", true)) {
+                    continue
+                }
+
+                // get the file parent this way, "path" is lowercased
+                val folder = File(dirMedia.first().path).parentFile
+                val files = folder.listFiles() ?: continue
+                val fileCnt = files.filter { it.isFile }.size
+                val newPaths = ArrayList<String>()
+
+                if (dirMedia.size != fileCnt) {
+                    val dirPaths = dirMedia.map { it.path }
+                    files.forEach {
+                        val filePath = it.absolutePath
+                        if ((showHidden || !it.name.startsWith(".")) && !dirPaths.contains(filePath)) {
+                            if (it.exists() && it.length() > 0 && it.isImageVideoGif()) {
+                                newPaths.add(it.absolutePath)
+                            }
+                        }
+                    }
+                }
+                context.scanPaths(newPaths)
+            }
+        }.start()
+    }
+
     fun getFilesFrom(curPath: String, isPickImage: Boolean, isPickVideo: Boolean): ArrayList<Medium> {
         val projection = arrayOf(MediaStore.Images.Media._ID,
                 MediaStore.Images.Media.DISPLAY_NAME,