# Telegram Channel

The Telegram integration consists of two classes: `TelegramChannel` (the `IChannel` implementation) and `TelegramAdapter` (the hosted service that manages channel lifecycles). Both live in the `Luna.Channels.Telegram` namespace.

## TelegramChannel

Handles interaction with the Telegram Bot API, implementing the `IChannel` interface defined in [[Channels]].

### Message Splitting
Telegram enforces a 4096-character limit per message. `TelegramChannel` automatically splits long responses into sequential chunks that respect this limit.

### Streaming
Rather than forwarding every `ChatStreamUpdate` individually (which would hit Telegram's rate limits), the channel accumulates streaming updates and sends them in periodic batches.

### Typing Indicators
Uses `KeepTypingAsync` to maintain a "typing..." indicator in the Telegram chat while the AI generates a response. This runs as a background loop until the response completes.

### User Filtering
`RaiseMessageReceived` filters incoming updates by `AllowedUserIds` (configured via `TelegramOptions` in [[Configuration]]). Messages from unauthorized users or with empty content are silently dropped.

## TelegramAdapter

An `IHostedService` and `IUpdateHandler` that polls Telegram for updates using long polling.

### Lifecycle
1. On startup, begins polling the Telegram Bot API.
2. For each incoming update, identifies the chat ID.
3. Creates a new `TelegramChannel` instance for each unique chat (if one doesn't already exist).
4. Registers the channel with `IChannelManager` from [[Channels]].
5. Routes the update to the appropriate `TelegramChannel`.

### Configuration
Configured via `TelegramOptions` (see [[Configuration]]), which includes:
- `BotToken` — Telegram Bot API token.
- `AllowedUserIds` — Whitelist of Telegram user IDs permitted to interact with Luna.

## Namespace

`Luna.Channels.Telegram`