gst-meet/lib-gst-meet-c/src/lib.rs

use std::{
  ffi::{CStr, CString, c_void},
  os::raw::c_char,
  ptr,
  sync::{Arc, atomic::{AtomicPtr, Ordering}},
};

use anyhow::Result;
use glib::{ffi::GMainContext, translate::{from_glib, from_glib_full, ToGlibPtr}};
pub use lib_gst_meet::{init_tracing, JitsiConference, JitsiConnection, MediaType};
use lib_gst_meet::JitsiConferenceConfig;
use tokio::runtime::Runtime;

pub struct Context {
  runtime: Runtime,
}

#[repr(C)]
pub struct ConferenceConfig {
  pub muc: *const c_char,
  pub focus: *const c_char,
  pub nick: *const c_char,
  pub region: *const c_char,
  pub video_codec: *const c_char,
}

#[repr(C)]
pub struct Participant {
  pub jid: *const c_char,
  pub muc_jid: *const c_char,
  pub nick: *const c_char,
}

trait ResultExt<T> {
  fn ok_raw_or_log(self) -> *mut T;
}

impl<T> ResultExt<T> for Result<T> {
  fn ok_raw_or_log(self) -> *mut T {
    match self {
      Ok(o) => Box::into_raw(Box::new(o)),
      Err(e) => {
        eprintln!("lib-gst-meet: {:?}", e);
        ptr::null_mut()
      }
    }
  }
}

#[no_mangle]
pub extern "C" fn gstmeet_init() -> *mut Context {
  Runtime::new()
    .map(|runtime| Context { runtime })
    .map_err(|e| e.into())
    .ok_raw_or_log()
}

#[no_mangle]
pub unsafe extern "C" fn gstmeet_init_tracing(level: *const c_char) {
  let level = CStr::from_ptr(level)
    .to_string_lossy()
    .parse()
    .expect("invalid tracing level");
  init_tracing(level);
}

#[no_mangle]
pub unsafe extern "C" fn gstmeet_deinit(context: *mut Context) {
  Box::from_raw(context);
}

#[no_mangle]
pub unsafe extern "C" fn gstmeet_connection_new(
  context: *mut Context,
  websocket_url: *const c_char,
  xmpp_domain: *const c_char,
) -> *mut JitsiConnection {
  let websocket_url = CStr::from_ptr(websocket_url);
  let xmpp_domain = CStr::from_ptr(xmpp_domain);
  (*context)
    .runtime
    .block_on(JitsiConnection::new(&websocket_url.to_string_lossy(), &xmpp_domain.to_string_lossy()))
    .map(|(connection, background)| {
      (*context).runtime.spawn(background);
      connection
    })
    .ok_raw_or_log()
}

#[no_mangle]
pub unsafe extern "C" fn gstmeet_connection_free(connection: *mut JitsiConnection) {
  Box::from_raw(connection);
}

#[no_mangle]
pub unsafe extern "C" fn gstmeet_connection_connect(context: *mut Context, connection: *mut JitsiConnection) -> bool {
  (*context)
    .runtime
    .block_on((*connection).connect())
    .map_err(|e| eprintln!("lib-gst-meet: {:?}", e))
    .is_ok()
}

#[no_mangle]
pub unsafe extern "C" fn gstmeet_connection_join_conference(
  context: *mut Context,
  connection: *mut JitsiConnection,
  glib_main_context: *mut GMainContext,
  config: *const ConferenceConfig,
) -> *mut JitsiConference {
  let muc = match CStr::from_ptr((*config).muc).to_string_lossy().parse() {
    Ok(jid) => jid,
    Err(e) => {
      eprintln!("lib-gst-meet: invalid MUC JID: {:?}", e);
      return ptr::null_mut();
    },
  };
  let focus = match CStr::from_ptr((*config).focus).to_string_lossy().parse() {
    Ok(jid) => jid,
    Err(e) => {
      eprintln!("lib-gst-meet: invalid focus JID: {:?}", e);
      return ptr::null_mut();
    },
  };
  let config = JitsiConferenceConfig {
    muc,
    focus,
    nick: CStr::from_ptr((*config).nick).to_string_lossy().to_string(),
    region: CStr::from_ptr((*config).region).to_string_lossy().to_string(),
    video_codec: CStr::from_ptr((*config).video_codec).to_string_lossy().to_string(),
  };
  (*context)
    .runtime
    .block_on((*connection).join_conference(from_glib_full(glib_main_context), config))
    .ok_raw_or_log()
}

#[no_mangle]
pub unsafe extern "C" fn gstmeet_conference_leave(context: *mut Context, conference: *mut JitsiConference) -> bool {
  (*context)
    .runtime
    .block_on(Box::from_raw(conference).leave())
    .map_err(|e| eprintln!("lib-gst-meet: {:?}", e))
    .is_ok()
}

#[no_mangle]
pub unsafe extern "C" fn gstmeet_conference_set_muted(context: *mut Context, conference: *mut JitsiConference, media_type: MediaType, muted: bool) -> bool {
  (*context)
    .runtime
    .block_on((*conference).set_muted(media_type, muted))
    .map_err(|e| eprintln!("lib-gst-meet: {:?}", e))
    .is_ok()
}

#[no_mangle]
pub unsafe extern "C" fn gstmeet_conference_pipeline(context: *mut Context, conference: *mut JitsiConference) -> *mut gstreamer::ffi::GstPipeline {
  (*context)
    .runtime
    .block_on((*conference).pipeline())
    .map(|pipeline| pipeline.to_glib_full())
    .map_err(|e| eprintln!("lib-gst-meet: {:?}", e))
    .unwrap_or(ptr::null_mut())
}

#[no_mangle]
pub unsafe extern "C" fn gstmeet_conference_audio_sink_element(context: *mut Context, conference: *mut JitsiConference) -> *mut gstreamer::ffi::GstElement {
  (*context)
    .runtime
    .block_on((*conference).audio_sink_element())
    .map(|pipeline| pipeline.to_glib_full())
    .map_err(|e| eprintln!("lib-gst-meet: {:?}", e))
    .unwrap_or(ptr::null_mut())
}

#[no_mangle]
pub unsafe extern "C" fn gstmeet_conference_video_sink_element(context: *mut Context, conference: *mut JitsiConference) -> *mut gstreamer::ffi::GstElement {
  (*context)
    .runtime
    .block_on((*conference).video_sink_element())
    .map(|pipeline| pipeline.to_glib_full())
    .map_err(|e| eprintln!("lib-gst-meet: {:?}", e))
    .unwrap_or(ptr::null_mut())
}

#[no_mangle]
pub unsafe extern "C" fn gstmeet_conference_on_participant(
  context: *mut Context,
  conference: *mut JitsiConference,
  f: unsafe extern "C" fn(*mut JitsiConference, Participant, *mut c_void) -> *mut gstreamer::ffi::GstBin,
  ctx: *mut c_void,
) {
  let ctx = Arc::new(AtomicPtr::new(ctx));
  (*context)
    .runtime
    .block_on((*conference).on_participant(move |conference, participant| {
      let ctx = ctx.clone();
      Box::pin(async move {
        let participant = Participant {
          jid: CString::new(participant.jid.to_string())?.into_raw() as *const _,
          muc_jid: CString::new(participant.muc_jid.to_string())?.into_raw() as *const _,
          nick: participant
            .nick
            .map(|nick| Ok::<_, anyhow::Error>(CString::new(nick)?.into_raw() as *const _))
            .transpose()?
            .unwrap_or_else(ptr::null),
        };
        f(Box::into_raw(Box::new(conference)), participant, ctx.load(Ordering::Relaxed));
        Ok(())
      })
    }));
}

#[no_mangle]
pub unsafe extern "C" fn gstmeet_conference_set_pipeline_state(
  context: *mut Context,
  conference: *mut JitsiConference,
  state: gstreamer::ffi::GstState,
) -> bool {
  (*context)
    .runtime
    .block_on((*conference).set_pipeline_state(from_glib(state)))
    .map_err(|e| eprintln!("lib-gst-meet: {:?}", e))
    .is_ok()
}