medea-jason 0.7.1

//! [`RtcRtpTransceiver`] wrapper.

use std::{future::Future, rc::Rc};

use derive_more::From;
use js_sys::Reflect;
use medea_client_api_proto::EncodingParameters;
use wasm_bindgen::JsValue;
use wasm_bindgen_futures::JsFuture;
use web_sys::{
    RtcRtpEncodingParameters, RtcRtpTransceiver, RtcRtpTransceiverInit,
};

use crate::{
    media::track::local,
    platform::{
        send_encoding_parameters::SendEncodingParameters,
        wasm::codec_capability::CodecCapability, Error, TransceiverDirection,
    },
};

/// Wrapper around an [`RtcRtpTransceiverInit`].
#[derive(Debug)]
pub struct TransceiverInit(RtcRtpTransceiverInit);

impl TransceiverInit {
    /// Creates a new [`TransceiverInit`].
    #[must_use]
    pub fn new(direction: TransceiverDirection) -> Self {
        let init = RtcRtpTransceiverInit::new();
        init.set_direction(direction.into());
        Self(init)
    }

    /// Returns underlying [`RtcRtpTransceiverInit`].
    #[must_use]
    pub const fn handle(&self) -> &RtcRtpTransceiverInit {
        &self.0
    }

    /// Adds the provided [`SendEncodingParameters`] to this
    /// [`TransceiverInit`].
    pub fn set_send_encodings(&self, encodings: Vec<SendEncodingParameters>) {
        let send_encoding = ::js_sys::Array::new();
        for enc in encodings {
            _ = send_encoding.push(enc.handle());
        }
        self.0.set_send_encodings(&send_encoding);
    }
}

/// Wrapper around [`RtcRtpTransceiver`] which provides handy methods for
/// direction changes.
#[derive(Clone, Debug, From)]
pub struct Transceiver(RtcRtpTransceiver);

impl Transceiver {
    /// Returns current [`TransceiverDirection`] of this [`Transceiver`].
    fn direction(&self) -> TransceiverDirection {
        TransceiverDirection::from(self.0.direction())
    }

    /// Changes the receive direction of this [`Transceiver`].
    pub fn set_recv(&self, active: bool) -> impl Future<Output = ()> + 'static {
        let transceiver = self.0.clone();
        async move {
            let current_direction =
                TransceiverDirection::from(transceiver.direction());
            let new_direction = if active {
                current_direction | TransceiverDirection::RECV
            } else {
                current_direction - TransceiverDirection::RECV
            };
            transceiver.set_direction(new_direction.into());
        }
    }

    /// Changes the send direction of this [`Transceiver`].
    pub fn set_send(&self, active: bool) -> impl Future<Output = ()> + 'static {
        let transceiver = self.0.clone();
        async move {
            let current_direction =
                TransceiverDirection::from(transceiver.direction());
            let new_direction = if active {
                current_direction | TransceiverDirection::SEND
            } else {
                current_direction - TransceiverDirection::SEND
            };
            transceiver.set_direction(new_direction.into());
        }
    }

    /// Indicates whether the provided [`TransceiverDirection`] is enabled for
    /// this [`Transceiver`].
    #[expect(clippy::unused_async, reason = "`cfg` code uniformity")]
    pub async fn has_direction(&self, direction: TransceiverDirection) -> bool {
        self.direction().contains(direction)
    }

    /// Replaces [`TransceiverDirection::SEND`] [`local::Track`] of this
    /// [`Transceiver`].
    ///
    /// # Errors
    ///
    /// Errors with JS error if the underlying [`replaceTrack`][1] call fails.
    ///
    /// [1]: https://w3.org/TR/webrtc#dom-rtcrtpsender-replacetrack
    pub async fn set_send_track(
        &self,
        new_track: Option<&Rc<local::Track>>,
    ) -> Result<(), Error> {
        drop(
            JsFuture::from(self.0.sender().replace_track(
                new_track.map(|track| (**track).as_ref().as_ref()),
            ))
            .await?,
        );
        Ok(())
    }

    /// Returns [`mid`] of this [`Transceiver`].
    ///
    /// [`mid`]: https://w3.org/TR/webrtc#dom-rtptransceiver-mid
    #[must_use]
    pub fn mid(&self) -> Option<String> {
        self.0.mid()
    }

    /// Indicates whether the underlying [`RtcRtpTransceiver`] is stopped.
    #[must_use]
    pub fn is_stopped(&self) -> bool {
        self.0.stopped()
    }

    /// Updates parameters of `encodings` for the underlying [RTCRtpSender] of
    /// this [`Transceiver`].
    ///
    /// # Errors
    ///
    /// With [`platform::Error`] if the underlying [setParameters()][1] call
    /// fails.
    ///
    /// [RTCRtpSender]: https://w3.org/TR/webrtc#dom-rtcrtpsender
    /// [1]: https://w3.org/TR/webrtc#dom-rtcrtpsender-setparameters
    pub async fn update_send_encodings(
        &self,
        encodings: Vec<EncodingParameters>,
    ) -> Result<(), Error> {
        let params = self.0.sender().get_parameters();
        let Some(encs) = params.get_encodings() else {
            return Ok(());
        };

        for enc in encs.iter().map(RtcRtpEncodingParameters::from) {
            let rid = enc.get_rid();

            let Some(encoding) =
                encodings.iter().find(|e| Some(&e.rid) == rid.as_ref())
            else {
                continue;
            };

            enc.set_active(encoding.active);
            if let Some(max_bitrate) = encoding.max_bitrate {
                enc.set_max_bitrate(max_bitrate);
            }
            if let Some(scale_resolution_down_by) =
                encoding.scale_resolution_down_by
            {
                enc.set_scale_resolution_down_by(
                    scale_resolution_down_by.into(),
                );
            }
        }

        drop(
            JsFuture::from(
                self.0.sender().set_parameters_with_parameters(&params),
            )
            .await?,
        );

        Ok(())
    }

    /// Sets the preferred [`CodecCapability`]s for this [`Transceiver`].
    pub fn set_codec_preferences(&self, codecs: Vec<CodecCapability>) {
        let is_api_available =
            Reflect::get(&self.0, &JsValue::from_str("setCodecPreferences"))
                .map_or(None, |val| (!val.is_undefined()).then_some(val))
                .is_some();

        // Unsupported on Firefox < 128.
        if is_api_available {
            let arr = ::js_sys::Array::new();
            for codec in codecs {
                _ = arr.push(codec.handle());
            }
            self.0.set_codec_preferences(&arr);
        }
    }
}

#[cfg(test)]
mod tests {
    use web_sys::RtcRtpTransceiverDirection;

    use super::TransceiverDirection;

    #[test]
    fn enable_works_correctly() {
        use TransceiverDirection as D;

        for (init, enable_dir, result) in [
            (D::INACTIVE, D::SEND, D::SEND),
            (D::INACTIVE, D::RECV, D::RECV),
            (D::SEND, D::RECV, D::RECV | D::SEND),
            (D::RECV, D::SEND, D::RECV | D::SEND),
        ] {
            assert_eq!(init | enable_dir, result);
        }
    }

    #[test]
    fn disable_works_correctly() {
        use TransceiverDirection as D;

        for (init, disable_dir, result) in [
            (D::SEND, D::SEND, D::INACTIVE),
            (D::RECV, D::RECV, D::INACTIVE),
            (D::RECV | D::SEND, D::SEND, D::RECV),
            (D::RECV | D::SEND, D::RECV, D::SEND),
        ] {
            assert_eq!(init - disable_dir, result);
        }
    }

    #[test]
    fn from_trnscvr_direction_to_sys() {
        use RtcRtpTransceiverDirection as S;
        use TransceiverDirection as D;

        for (trnscvr_dir, sys_dir) in [
            (D::SEND, S::Sendonly),
            (D::RECV, S::Recvonly),
            (D::RECV | D::SEND, S::Sendrecv),
            (D::INACTIVE, S::Inactive),
        ] {
            assert_eq!(S::from(trnscvr_dir), sys_dir);
        }
    }

    #[test]
    fn from_sys_direction_to_trnscvr() {
        use RtcRtpTransceiverDirection as S;
        use TransceiverDirection as D;

        for (sys_dir, trnscvr_dir) in [
            (S::Sendonly, D::SEND),
            (S::Recvonly, D::RECV),
            (S::Sendrecv, D::RECV | D::SEND),
            (S::Inactive, D::INACTIVE),
        ] {
            assert_eq!(D::from(sys_dir), trnscvr_dir);
        }
    }
}