// client/src/output/audio.rs

use gstreamer as gst;
use gstreamer_app as gst_app;
use lesavka_common::lesavka::AudioPacket;
use gst::prelude::*;

pub struct AudioOut {
    src: gst_app::AppSrc,
}

impl AudioOut {
    pub fn new() -> anyhow::Result<Self> {
        gst::init()?;

        // Auto‑audiosink picks PipeWire / Pulse etc.
        const PIPE: &str =
            "appsrc name=src is-live=true format=time do-timestamp=true block=false ! \
             queue leaky=downstream ! aacparse ! avdec_aac ! audioresample ! autoaudiosink";

        // `parse_launch()` returns `gst::Element`; down‑cast manually and
        // map the error into anyhow ourselves (no `?` on the downcast).
        let pipeline: gst::Pipeline = gst::parse::launch(PIPE)?
            .downcast::<gst::Pipeline>()
            .expect("not a pipeline");

        let src: gst_app::AppSrc = pipeline
            .by_name("src")
            .expect("no src element")
            .downcast::<gst_app::AppSrc>()
            .expect("src not an AppSrc");

        src.set_format(gst::Format::Time);
        pipeline.set_state(gst::State::Playing)?;

        Ok(Self { src })
    }

    pub fn push(&self, pkt: AudioPacket) {
        let mut buf = gst::Buffer::from_slice(pkt.data);
        buf.get_mut()
            .unwrap()
            .set_pts(Some(gst::ClockTime::from_useconds(pkt.pts)));
        let _ = self.src.push_buffer(buf);
    }
}