add files loader bot

FilesLoaderBot/src/main/kotlin/FilesLoaderBot.kt

@@ -0,0 +1,42 @@
+import com.github.insanusmokrassar.TelegramBotAPI.extensions.api.downloadFile
+import com.github.insanusmokrassar.TelegramBotAPI.extensions.api.get.getFileAdditionalInfo
+import com.github.insanusmokrassar.TelegramBotAPI.extensions.api.telegramBot
+import com.github.insanusmokrassar.TelegramBotAPI.extensions.utils.flatMap
+import com.github.insanusmokrassar.TelegramBotAPI.extensions.utils.safely
+import com.github.insanusmokrassar.TelegramBotAPI.extensions.utils.shortcuts.*
+import com.github.insanusmokrassar.TelegramBotAPI.extensions.utils.updates.retrieving.startGettingFlowsUpdatesByLongPolling
+import com.github.insanusmokrassar.TelegramBotAPI.types.message.content.abstracts.MediaContent
+import com.github.insanusmokrassar.TelegramBotAPI.utils.filenameFromUrl
+import kotlinx.coroutines.*
+import kotlinx.coroutines.flow.*
+import java.io.File
+
+/**
+ * This bot will download incoming files
+ */
+suspend fun main(args: Array<String>) {
+    val botToken = args.first()
+    val directoryOrFile = args.getOrNull(1) ?.let { File(it) } ?: File("")
+    directoryOrFile.mkdirs()
+
+    val bot = telegramBot(botToken)
+    val scope = CoroutineScope(Dispatchers.Default)
+
+    bot.startGettingFlowsUpdatesByLongPolling(scope = scope) {
+        val flow = merge (
+            filterContentMessages<MediaContent>(),
+            mediaGroupMessages().flatMap()
+        )
+        flow.onEach {
+            safely({ it.printStackTrace() }) {
+                val pathedFile = bot.getFileAdditionalInfo(it.content.media)
+                File(directoryOrFile, pathedFile.filePath.filenameFromUrl).apply {
+                    createNewFile()
+                    writeBytes(bot.downloadFile(pathedFile))
+                }
+            }
+        }.launchIn(scope)
+    }
+
+    scope.coroutineContext[Job]!!.join()
+}