# Teams Bot Service

AI-powered Microsoft Teams meeting bot. Joins meetings, captures live transcripts, monitors chat, and responds via voice and/or chat messages.

## Architecture

```
  ┌───────────────┐                                    ┌───────────────────────┐
  │               │         WebSocket                  │                       │
  │    Gateway    │◄──────────────────────────────────►│      Bot Service      │
  │               │  transcripts, status, chat,        │                       │
  │  ● AI engine  │  audioChunks, voiceGreeting        │  Joins Teams meetings │
  │  ● TTS        │                                    │  as a participant     │
  │  ● Sessions   │  playAudio, sendChatMessage,       │                       │
  │  ● Billing    │  stopAudio                         │  Capabilities:        │
  │               │                                    │  ├ Live transcripts   │
  │               │         HTTP                       │  ├ Chat messages      │
  │               │────────────────────────────────────►  ├ Voice playback     │
  └───────────────┘  join, leave, status               │  └ Audio capture      │
                                                       └───────────────────────┘
```

| Path | Protocol | Purpose |
|------|----------|---------|
| Gateway ↔ Bot | WebSocket | Real-time transcript, chat, audio, status exchange |
| Gateway → Bot | HTTP | Session control (join, leave, status) |

## Integration Guide

### How It Works

1. Gateway sends a **POST** to the Bot with a meeting URL and optional credentials
2. Bot joins the meeting and appears as a regular participant
3. A **WebSocket** connection is established for real-time data exchange
4. Bot streams transcript segments and chat messages to the Gateway
5. Gateway can send TTS audio or chat responses back into the meeting

### Step 1: Start a Session

```http
POST /api/bot
Content-Type: application/json

{
  "sessionId": "550e8400-e29b-41d4-a716-446655440000",
  "meetingUrl": "https://teams.microsoft.com/meet/123456789?p=abc123",
  "botName": "AI Assistant",
  "instanceId": "feature-instance-uuid",
  "gatewayWsUrl": "wss://gateway.example.com/api/teamsbot/ws",
  "language": "de-DE",
  "botAccountEmail": "bot@example.com",
  "botAccountPassword": "decrypted-password",
  "transferMode": "caption"
}
```

| Field | Required | Description |
|-------|----------|-------------|
| `sessionId` | Yes | Unique session UUID (generated by Gateway) |
| `meetingUrl` | Yes | Teams meeting URL (classic or short format) |
| `botName` | No | Display name in meeting (default: env `BOT_NAME`) |
| `instanceId` | No | Feature instance ID for Gateway WebSocket path |
| `gatewayWsUrl` | No | Gateway WebSocket base URL (default: env `GATEWAY_WS_URL`) |
| `language` | No | BCP-47 language code (default: `de-DE`) |
| `botAccountEmail` | No | Microsoft account for authenticated join |
| `botAccountPassword` | No | Decrypted password for authenticated join |
| `transferMode` | No | `caption` or `audio` |

If `botAccountEmail` + `botAccountPassword` are provided, the bot joins as an authenticated user. Otherwise, it joins as an anonymous guest.

**Response:**

```json
{
  "success": true,
  "sessionId": "550e8400-e29b-41d4-a716-446655440000",
  "message": "Bot deployment initiated"
}
```

### Step 2: Receive Data via WebSocket

After deployment, the Bot connects to the Gateway at:

```
wss://{gatewayHost}/api/teamsbot/{instanceId}/bot/ws/{sessionId}
```

#### Messages: Bot → Gateway

**Transcript segment:**

```json
{
  "type": "transcript",
  "sessionId": "...",
  "transcript": {
    "speaker": "Jane Doe",
    "text": "Hey Bot, can you summarize this?",
    "timestamp": "2026-02-18T10:30:00.000Z",
    "isFinal": true
  }
}
```

**Chat message:**

```json
{
  "type": "chatMessage",
  "sessionId": "...",
  "chat": {
    "speaker": "Jane Doe",
    "text": "Please summarize the discussion",
    "timestamp": "2026-02-18T10:31:00.000Z"
  }
}
```

**Status update:**

```json
{
  "type": "status",
  "sessionId": "...",
  "status": "joined",
  "message": "Bot joined the meeting"
}
```

Status values: `connecting` | `in_lobby` | `joined` | `left` | `error`

**Voice greeting request** (bot asks Gateway for TTS):

```json
{
  "type": "voiceGreeting",
  "sessionId": "...",
  "text": "Hello, I am ready.",
  "language": "de-DE"
}
```

**Raw audio chunk** (`transferMode: "audio"` only):

```json
{
  "type": "audioChunk",
  "sessionId": "...",
  "audio": {
    "data": "<base64-encoded PCM16>",
    "sampleRate": 16000,
    "format": "pcm16",
    "timestamp": "2026-02-18T10:30:00.500Z"
  }
}
```

**Keepalive:**

```json
{ "type": "ping" }
```

#### Messages: Gateway → Bot

**Play TTS audio:**

```json
{
  "type": "playAudio",
  "sessionId": "...",
  "audio": {
    "data": "<base64-encoded MP3>",
    "format": "mp3"
  }
}
```

**Send chat message:**

```json
{
  "type": "sendChatMessage",
  "sessionId": "...",
  "text": "Here is my summary of the discussion..."
}
```

**Stop audio playback:**

```json
{ "type": "stopAudio", "sessionId": "..." }
```

**Keepalive response:**

```json
{ "type": "pong" }
```

### Step 3: Leave the Meeting

```http
POST /api/bot/:sessionId/leave
```

```json
{
  "success": true,
  "message": "Leave initiated"
}
```

### Step 4: Check Status

```http
GET /api/bot/:sessionId/status
```

```json
{
  "sessionId": "550e8400-e29b-41d4-a716-446655440000",
  "state": "in_meeting",
  "error": null
}
```

### Health Check

```http
GET /health
```

Returns `200 OK` with `{ "status": "ok", "timestamp": "..." }`.

## Meeting URL Formats

Both formats are supported:

```
# Classic
https://teams.microsoft.com/l/meetup-join/19%3ameeting_xxx/0?context=...

# Short
https://teams.microsoft.com/meet/123456789?p=abc123
```

## Running the Service

### Local

```bash
npm install
cp .env.sample .env   # Configure Gateway URL, bot name, etc.
npm run dev            # Dev mode
```

### Docker

```bash
docker build -t teams-bot .

docker run -p 4100:4100 \
  -e GATEWAY_WS_URL=wss://gateway.example.com/api/teamsbot/ws \
  teams-bot
```

## Configuration

| Variable | Description | Default |
|----------|-------------|---------|
| `PORT` | HTTP server port | `4100` |
| `GATEWAY_WS_URL` | Gateway WebSocket base URL | — |
| `BOT_NAME` | Default bot display name | — |
| `LOG_LEVEL` | Log level (`debug`, `info`, `warn`, `error`) | `info` |