# gizlang:webrtc

WebRTC media and data channels through libdatachannel's stable C API. No inference or application policy lives here.

```gizlang
import * as Webrtc from "gizlang:webrtc";
```

## Types

### `Peer`

```gizlang
type Peer
```

One WebRTC peer connection: its audio and video tracks and data channels (-1: absent) over libdatachannel.

- `id`: `i64`
- `audio`: `i64`
- `video`: `i64`
- `data`: `i64`
- `remoteData`: `i64`

## Functions

### `iceUrl`

```gizlang
function iceUrl(url: string, username: string, password: string): string throws string
```

libdatachannel carries TURN credentials in the URL, with user-info percent encoding.

Effects: fail.

### `h264Payload`

```gizlang
function h264Payload(offer: string): i64 throws string
```

A baseline H.264 payload with non-interleaved packets, matching the stream the encoder emits.

Effects: fail.

### `answer`

```gizlang
function answer(sys: System, offer: string, iceServers: Vec<string>, audioOnly: bool): Peer throws string
```

Answers a receive-only browser offer. iceServers use STUN/TURN URLs understood by libdatachannel.

Effects: fail, io.

## Methods

### `Peer.description`

```gizlang
function Peer.description(self: Peer, timeoutMs: i64 = 3000): string throws string
```

Current gathered SDP. Wait until candidates have appeared, bounded by timeoutMs.

Effects: fail, io.

### `Peer.candidate`

```gizlang
function Peer.candidate(self: Peer, candidate: string, mid: string): void throws string
```

Adds the remote ICE candidate `candidate` of media section `mid`.

Effects: fail, io.

### `Peer.receive`

```gizlang
function Peer.receive(self: mut Peer): Vec<string> throws string
```

The data-channel messages that arrived since the last call; it also takes in the connection's state changes.

Effects: fail, io.

### `Peer.connected`

```gizlang
function Peer.connected(self: Peer): bool
```

Whether the connection is up.

### `Peer.ended`

```gizlang
function Peer.ended(self: Peer): bool
```

Whether the connection failed or closed.

### `Peer.event`

```gizlang
function Peer.event(self: Peer, message: string): void throws string
```

Sends `message` on the first open data channel (the own, else the remote one); without one it is dropped.

Effects: fail, io.

### `Peer.send`

```gizlang
function Peer.send(self: Peer, video: bool, data: bytes, timestamp: u64): void throws string
```

A packetized H264 length-prefixed access unit or an Opus packet at the track's timestamp.

Effects: fail, io.

### `Peer.close`

```gizlang
function Peer.close(self: mut Peer): void
```

Closes the connection and releases its callbacks; a second close does nothing.

Effects: fail, io.