// client/src/input/camera.rs
#![forbid(unsafe_code)]

use anyhow::Result;
use gstreamer as gst;
use gstreamer_app as gst_app;
use gst::prelude::*;
use lesavka_common::lesavka::VideoPacket;

pub struct CameraCapture {
    pipeline: gst::Pipeline,
    sink:     gst_app::AppSink,
}

impl CameraCapture {
    pub fn new(device_fragment: Option<&str>) -> anyhow::Result<Self> {
        gst::init().ok();

        // Pick device
        let dev = device_fragment
            .and_then(Self::find_device)
            .unwrap_or_else(|| "/dev/video0".into());

        let desc = format!(
            "v4l2src device={dev} io-mode=dmabuf-do-timestamp=true ! \
                videoconvert ! videoscale ! video/x-raw,width=1280,height=720 ! \
                v4l2h264enc key-int-max=30 \
                extra-controls=\"encode,frame_level_rate_control_enable=1,h264_profile=4\" ! \
                h264parse config-interval=-1 ! \
                appsink name=asink emit-signals=true max-buffers=60 drop=true"
        );

        // --- NEW: propagate the Result and down‑cast with `?`
        let pipeline: gst::Pipeline = gst::parse::launch(&desc)?
            .downcast::<gst::Pipeline>()
            .expect("not a pipeline");

        // --- NEW: the lookup already returns the concrete AppSink → just unwrap with `?`
        let sink: gst_app::AppSink = pipeline
            .by_name("asink")
            .expect("appsink element not found")
            .downcast::<gst_app::AppSink>()
            .expect("appsink down‑cast");

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

        Ok(Self { pipeline, sink })
    }

    pub fn pull(&self) -> Option<VideoPacket> {
        let sample = self.sink.pull_sample().ok()?;
        let buf    = sample.buffer()?;
        let map    = buf.map_readable().ok()?;
        let pts = buf.pts().unwrap_or(gst::ClockTime::ZERO).nseconds() / 1_000;
        Some(VideoPacket { id: 100, pts, data: map.as_slice().to_vec() })
    }

    /// Fuzzy‑match devices under `/dev/v4l/by-id`
    fn find_device(substr: &str) -> Option<String> {
        let dir = std::fs::read_dir("/dev/v4l/by-id").ok()?;
        for e in dir.flatten() {
            let p = e.path();
            if p.file_name()?.to_string_lossy().contains(substr) {
                if let Ok(target) = std::fs::read_link(&p) {
                    return Some(format!("/dev/{}", target.file_name()?.to_string_lossy()));
                }
            }
        }
        None
    }

    /// Cheap stub used when the web‑cam is disabled
    pub fn new_stub() -> Self {
        let pipeline = gst::Pipeline::new();

        // --- NEW: AppSink factory helper (AppSink::new() does not exist)
        let sink: gst_app::AppSink = gst::ElementFactory::make("appsink")
            .build()
            .expect("make appsink")
            .downcast::<gst_app::AppSink>()
            .expect("appsink down‑cast");

        Self { pipeline, sink }
    }
}