// client/src/output/video.rs

use gstreamer as gst;
use gstreamer_app as gst_app;
use gst::prelude::*;
use gst_app::prelude::*;
use lesavka_common::lesavka::VideoPacket;
use winit::window::{Window, WindowAttributes};
use winit::event_loop::EventLoop;

pub struct MonitorWindow {
    id: u32,
    _window: Window,
    src: gst_app::AppSrc,
}

impl MonitorWindow {
    pub fn new(id: u32, el: &EventLoop<()>) -> anyhow::Result<Self> {
        gst::init()?;

        let window = el.create_window(
            WindowAttributes::default()
                .with_title(format!("Lesavka‑monitor‑{id}"))
                .with_decorations(false)
        )?;

        let caps = gst::Caps::builder("video/x-h264")
            .field("stream-format", &"byte-stream")
            .field("alignment", &"au")
            .build();

        let desc = if std::env::var_os("LESAVKA_HW_DEC").is_some() {
            "appsrc name=src is-live=true format=time do-timestamp=true block=false ! \
            capsfilter caps=video/x-h264,stream-format=byte-stream,alignment=au ! \
            queue max-size-buffers=0 max-size-bytes=0 max-size-time=0 leaky=downstream ! \
            h264parse ! vaapih264dec low-latency=true ! videoconvert ! \
            autovideosink sync=false max-lateness=-1"
        } else {
            "appsrc name=src is-live=true format=time do-timestamp=true block=false ! \
            capsfilter caps=video/x-h264,stream-format=byte-stream,alignment=au ! \
            queue max-size-buffers=0 max-size-bytes=0 max-size-time=0 leaky=downstream ! \
            h264parse ! decodebin ! videoconvert ! autovideosink sync=false max-lateness=-1"
        };

        let pipeline = gst::parse::launch(desc)?
            .downcast::<gst::Pipeline>()
            .unwrap();

        let src = pipeline.by_name("src").unwrap()
            .downcast::<gst_app::AppSrc>().unwrap();

        src.set_caps(Some(&caps));

        // use the dedicated helpers from `AppSrcExt` instead of the generic
        // `set_property`, which returns `()` (hence the earlier E0277).
        src.set_format(gst::Format::Time);           // timestamps are in running-time

        // “blocksize=0” → deliver whole access-units (no chunking).  The generic
        // `set_property()` API returns a `Result<(), glib::BoolError>` so we just
        // unwrap: this property always exists on AppSrc.
        src.set_property("blocksize", &0u32);
        src.set_latency(gst::ClockTime::NONE, gst::ClockTime::NONE);

        pipeline.set_state(gst::State::Playing)?;

        Ok(Self { id, _window: window, src })
    }

    pub fn push_packet(&self, pkt: VideoPacket) {
        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);
    }
}