complete forwarder bot exmple

ForwarderBot/src/main/kotlin/com/insanusmokrassar/examples/ForwarderBot.kt

@@ -0,0 +1,50 @@
+package com.insanusmokrassar.examples
+
+import com.github.insanusmokrassar.TelegramBotAPI.bot.Ktor.KtorRequestsExecutor
+import com.github.insanusmokrassar.TelegramBotAPI.extensions.api.send.sendTextMessage
+import com.github.insanusmokrassar.TelegramBotAPI.types.ParseMode.MarkdownV2
+import com.github.insanusmokrassar.TelegramBotAPI.types.message.*
+import com.github.insanusmokrassar.TelegramBotAPI.types.message.abstracts.PossiblyForwardedMessage
+import com.github.insanusmokrassar.TelegramBotAPI.types.update.abstracts.BaseMessageUpdate
+import com.github.insanusmokrassar.TelegramBotAPI.utils.TelegramAPIUrlsKeeper
+import com.github.insanusmokrassar.TelegramBotAPI.utils.extensions.UpdateReceiver
+import com.github.insanusmokrassar.TelegramBotAPI.utils.extensions.startGettingOfUpdates
+import kotlinx.coroutines.*
+
+/**
+ * This bot will always return message about forwarder. In cases when sent message was not a forward message it will
+ * send suitable message
+ */
+suspend fun main(args: Array<String>) {
+    val botToken = args.first()
+
+    val bot = KtorRequestsExecutor(TelegramAPIUrlsKeeper(botToken))
+
+    val scope = CoroutineScope(Dispatchers.Default)
+
+    val callback: UpdateReceiver<BaseMessageUpdate> = { messageUpdate ->
+        val message = messageUpdate.data
+        val infoToSend = if (message is PossiblyForwardedMessage) {
+            val forwardInfo = message.forwardInfo
+            when (forwardInfo) {
+                null -> "There is no forward info"
+                is AnonymousForwardInfo -> "Anonymous user which signed as \"${forwardInfo.senderName}\""
+                is UserForwardInfo -> forwardInfo.from.let { user ->
+                    "User `${user.id.chatId}` (`${user.firstName} ${user.lastName}`: ${user.username ?.username ?: "Without username"})"
+                }
+                is ForwardFromChannelInfo -> "Channel (${forwardInfo.channelChat})"
+            }
+        } else {
+            "There is no forward info"
+        }
+        bot.sendTextMessage(message.chat, infoToSend, MarkdownV2)
+    }
+
+    bot.startGettingOfUpdates(
+        messageCallback = callback,
+        channelPostCallback = callback,
+        scope = scope
+    )
+
+    scope.coroutineContext[Job]!!.join()
+}