update readmes

HelloBot/README.md

@@ -1,9 +1,43 @@
 # HelloBot
 
-The main purpose of this bot is just to answer "Oh, hi, " and add user mention here
+HelloBot is a small long-polling example that greets the chat or sender when a
+message addresses the bot by username.
 
-## Launch
+## Trigger and replies
+
+There are no slash commands. The bot handles a content message only when its
+text contains the bot's full username. This is a case-sensitive substring
+check; messages without text or without the username are ignored.
+
+- In a private chat, it replies with a MarkdownV2 text mention of the user.
+- In a group or supergroup, it greets the group and links its title to a public
+  username or invite link when one is available.
+- For a message sent to a group on behalf of a channel, it greets the sender
+  channel instead.
+- In a channel, it greets the channel and includes the sender chat when Telegram
+  supplies one.
+- In a business chat, it mentions the underlying private-chat user.
+
+Every received update is also printed to standard output for demonstration and
+debugging.
+
+## Setup
+
+1. Create a bot with BotFather and keep its token private.
+2. Add the bot to each chat where it should respond. Explicit username mentions
+   work with Telegram's normal group privacy mode.
+3. For channel posts, make the bot a channel administrator and allow it to post
+   messages. Admin access may also make a private group invite link available;
+   otherwise the group reply falls back to an unlinked title.
+
+## Run
+
+From the repository root, pass the token as the first positional argument:
 
 ```bash
-../gradlew run --args="BOT_TOKEN"
+./gradlew :HelloBot:run --args="BOT_TOKEN"
 ```
+
+The token is required. Additional command-line arguments are ignored. The bot
+runs until the process is stopped and uses long polling, so no webhook setup is
+needed.

HelloBot/src/main/kotlin/HelloBot.kt

@@ -18,7 +18,13 @@ import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 
 /**
- * The main purpose of this bot is just to answer "Oh, hi, " and add user mention here
+ * Starts HelloBot with long polling and logs every received update.
+ *
+ * Content messages are handled when their text contains the bot's full
+ * username. The reply varies for private, group, channel, and business chats.
+ *
+ * @param args the bot token at index `0`; any remaining arguments are ignored
+ * @throws NoSuchElementException when no bot token is supplied
  */
 @OptIn(PreviewFeature::class)
 suspend fun main(vararg args: String) {