// Client pipeline data flow — Phase 2
// Sender machine (Wayland, VAAPI GPU)
digraph client_pipeline {
    graph [fontname="monospace" bgcolor="#1e1e2e" rankdir=TB pad="0.6" splines=polyline]
    node  [fontname="monospace" fontcolor="#cdd6f4" style=filled shape=box
           fillcolor="#313244" color="#585b70" margin="0.25,0.12"]
    edge  [color="#585b70" fontname="monospace" fontcolor="#a6adc8" labelfontname="monospace"]

    // Hardware
    drm   [label="/dev/dri/card0\n(KMS scanout)" shape=cylinder fillcolor="#1e3a2f" color="#a6e3a1"]
    vaapi [label="/dev/dri/renderD128\n(VAAPI)" shape=cylinder fillcolor="#1e3a2f" color="#a6e3a1"]
    net   [label="TCP :4444\nmcrndeb" shape=parallelogram fillcolor="#1e2a3e" color="#89b4fa"]

    // Thread boundary
    subgraph cluster_main {
        label="main thread  (tokio async)" fontcolor="#a6adc8" color="#45475a" fontname="monospace"

        session_start [label="session_start\ncontrol message" fillcolor="#2d2038" color="#cba6f7"]
        mux           [label="select!\npkt_rx  |  keepalive  |  ctrl-c" fillcolor="#2d2038" color="#cba6f7"]
        keepalive     [label="keepalive / 5s" fillcolor="#2d2038" color="#cba6f7"]
        write         [label="BufWriter\nwrite_packet()" fillcolor="#1e2d3e" color="#89b4fa"]
    }

    subgraph cluster_pipeline {
        label="capture-pipeline thread  (blocking)" fontcolor="#a6adc8" color="#45475a" fontname="monospace"

        capture [label="KmsCapture\n─────────────────\nffmpeg kmsgrab device\ndecoder: passthrough\noutput: DRM_PRIME frames\n+ hw_frames_ctx (DRM device)"
                 fillcolor="#1e2d3e" color="#89b4fa"]

        encoder [label="VaapiEncoder\n─────────────────\n[lazy init on frame 1]\nbuffersrc ← hw_frames_ctx\nhwmap derive_device=vaapi\nscale_vaapi NV12 1920×1080\nh264_vaapi QP=20 GOP=30"
                 fillcolor="#1e2d3e" color="#89b4fa"]

        chan    [label="mpsc::channel(64)\nEncodedPacket" shape=parallelogram fillcolor="#2d2038" color="#cba6f7"]
    }

    // Flow
    drm   -> capture  [label="DMA-BUF\n(zero copy)"]
    vaapi -> encoder  [label="hw device\n(derived)" style=dashed color="#a6e3a1"]
    capture -> encoder [label="AVFrame\nDRM_PRIME"]
    encoder -> chan    [label="EncodedPacket\n{ data, pts, keyframe, … }"]
    chan    -> mux
    session_start -> write
    mux    -> write   [label="WirePacket"]
    mux    -> keepalive [style=dashed]
    keepalive -> write
    write  -> net

    // Types note
    types [label="EncodedPacket\n─────────────\ndata: Vec\<u8\>  (H.264 NALUs)\npts / dts: i64\nkeyframe: bool\ntime_base: num/den"
           shape=note fillcolor="#2a2a3e" color="#585b70"]
}