CommunitiesBot

This long-polling example demonstrates Communities support introduced in Telegram Bot API 10.2: typed service events when a chat joins or leaves a community, and inspection of a chat's current community.

Behavior, commands, and triggers

At startup, the bot calls getMe and prints its bot information. It also prints every received update to standard output.

Command or trigger	Behavior
`community_chat_added` service message	`onCommunityChatAdded` logs the chat and community name/ID, sends a join notice, then calls `getChat` and logs its nullable `community`.
`community_chat_removed` service message	`onCommunityChatRemoved` logs the chat and sends a leave notice. This event is fieldless, so it has no former-community details.
`/community`	Calls `getChat` and replies with the current community name/ID, or says the chat is not in a community.
`/wait_community_added`	Waits without a timeout for the next added event in the command's chat, then replies with the community name/ID.
`/wait_community_removed`	Waits without a timeout for the next removed event in the command's chat, then replies with the chat ID. Its initial waiting reply currently says "added."

Commands use no positional arguments; other commands only appear in the generic update log. Each wait first sends a waiting reply, filters events with sameChat, and takes the first match.

API concepts

CommunityChatAdded carries a Community with a CommunityId and name; CommunityChatRemoved carries no fields.
onCommunityChatAdded and onCommunityChatRemoved provide typed handlers for the service events.
getChat(...).community exposes the nullable community on ExtendedChat without a subtype cast.
waitCommunityChatAddedEventsMessages and waitCommunityChatRemovedEventsMessages expose typed event-message flows.

Telegram setup and permissions

Create a bot with BotFather and obtain its token.
Add it to the target chat before changing that chat's community membership if you want to observe both service events.
Allow it to send messages so notifications and command replies succeed.

The bot does not create or modify communities. It calls no administrator-only method and does not inspect arbitrary user messages, so it needs neither administrator rights nor disabled Group Privacy Mode. The user changing community membership still needs the appropriate Telegram rights. API failures are left to the library's normal error handling.

Arguments

The token is required as the first argument. Optional flags are exact and case-sensitive, may follow in either order, and unknown extra arguments are ignored.

Argument	Effect
`BOT_TOKEN`	Bot token; omitting it fails before polling starts.
`debug`	Sends tgbotapi/KSLog diagnostics to standard output.
`testServer`	Uses Telegram's Bot API test environment.

Launch

From the repository root:

./gradlew :CommunitiesBot:run --args="BOT_TOKEN"

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