//! `lumen-host` — the Linux streaming host (plan §2, §6, §7).
//!
//! Creates a client-sized virtual display, captures it via PipeWire, encodes with
//! VAAPI/NVENC, and hands encoded access units to `lumen_core` for FEC + packetization +
//! pacing + send. Input flows back via libei/uinput. The platform backends are
//! `#[cfg(target_os = "linux")]`; the crate compiles everywhere so the workspace builds
//! on non-Linux dev machines — it just can't run the pipeline there.
//!
//! Status: M0. The `m0` subcommand runs the capture→encode→file pipeline spike and feeds
//! the encoded AUs through a `lumen_core` loopback. M2 wires the full P1 host that a stock
//! Moonlight client connects to.

// Scaffold: trait methods and config paths are defined ahead of their backends.
#![allow(dead_code)]

mod audio;
mod capture;
mod encode;
mod gamestream;
mod inject;
mod m0;
mod pipeline;
mod pwinit;
mod vdisplay;
mod web;
#[cfg(target_os = "linux")]
mod zerocopy;

use anyhow::{bail, Result};
use encode::Codec;
use m0::{Options, Source};
use std::path::PathBuf;

fn main() {
    tracing_subscriber::fmt()
        .with_env_filter(
            tracing_subscriber::EnvFilter::try_from_default_env().unwrap_or_else(|_| "info".into()),
        )
        .init();

    if let Err(e) = real_main() {
        tracing::error!("{e:#}");
        std::process::exit(1);
    }
}

fn real_main() -> Result<()> {
    tracing::info!("lumen-host (lumen_core ABI v{})", lumen_core::ABI_VERSION);

    let args: Vec<String> = std::env::args().skip(1).collect();
    match args.first().map(String::as_str) {
        // M2 GameStream host control plane (P1.1: mDNS + serverinfo).
        Some("serve") => gamestream::serve(),
        // Standalone input-injection smoke test (no client needed): open the session's input
        // backend and inject a scripted mouse/keyboard pattern. Watch a focused app / `wev`.
        Some("input-test") => input_test(),
        // Zero-copy FFI/GPU probe: init the EGL importer + CUDA context (no capture needed).
        #[cfg(target_os = "linux")]
        Some("zerocopy-probe") => zerocopy::probe(),
        // M0 pipeline spike.
        Some("m0") => m0::run(parse_m0(&args[1..])?),
        Some("-h") | Some("--help") | Some("help") | None => {
            print_usage();
            Ok(())
        }
        // Bare flags (no subcommand) default to the m0 spike for back-compat.
        Some(_) => m0::run(parse_m0(&args)?),
    }
}

/// Inject a scripted mouse + keyboard pattern through the session's input backend (libei on
/// KWin/GNOME, wlr on Sway). Lets us validate input injection without a Moonlight client.
#[cfg(target_os = "linux")]
fn input_test() -> Result<()> {
    use lumen_core::input::{InputEvent, InputKind};
    use std::time::Duration;

    let backend = inject::default_backend();
    tracing::info!(?backend, "input-test: opening injector");
    let mut inj = inject::open(backend)?;
    // An async backend (libei) needs a moment to establish its portal/EIS session + device
    // resume; events injected before then are dropped.
    std::thread::sleep(Duration::from_secs(4));

    let ev = |kind, code, x, y| InputEvent {
        kind,
        _pad: [0; 3],
        code,
        x,
        y,
        flags: 0,
    };
    tracing::info!(
        "input-test: injecting a mouse square + 'A'/click taps for ~8s (watch wev / focused app)"
    );
    for i in 0..160u32 {
        let (dx, dy) = match (i / 10) % 4 {
            0 => (12, 0),
            1 => (0, 12),
            2 => (-12, 0),
            _ => (0, -12),
        };
        if let Err(e) = inj.inject(&ev(InputKind::MouseMove, 0, dx, dy)) {
            tracing::warn!(error = %format!("{e:#}"), "input-test: inject failed");
        }
        if i % 20 == 0 {
            let _ = inj.inject(&ev(InputKind::KeyDown, 0x41, 0, 0)); // 'A'
            let _ = inj.inject(&ev(InputKind::KeyUp, 0x41, 0, 0));
            let _ = inj.inject(&ev(InputKind::MouseButtonDown, 1, 0, 0)); // left click
            let _ = inj.inject(&ev(InputKind::MouseButtonUp, 1, 0, 0));
        }
        std::thread::sleep(Duration::from_millis(50));
    }
    tracing::info!("input-test: done");
    Ok(())
}

#[cfg(not(target_os = "linux"))]
fn input_test() -> Result<()> {
    bail!("input-test requires Linux")
}

fn parse_m0(args: &[String]) -> Result<Options> {
    let mut source = Source::Portal;
    let mut width = 1920u32;
    let mut height = 1080u32;
    let mut fps = 60u32;
    let mut seconds = 5u32;
    let mut codec = Codec::H265;
    let mut bitrate_mbps = 20u64;
    let mut out: Option<PathBuf> = None;
    let mut loopback = true;

    let mut i = 0;
    while i < args.len() {
        let arg = args[i].as_str();
        let mut next = || {
            i += 1;
            args.get(i)
                .cloned()
                .ok_or_else(|| anyhow::anyhow!("missing value for {arg}"))
        };
        match arg {
            "--source" => {
                source = match next()?.as_str() {
                    "synthetic" => Source::Synthetic,
                    "portal" => Source::Portal,
                    other => bail!("unknown --source '{other}' (synthetic|portal)"),
                }
            }
            "--width" => {
                width = next()?
                    .parse()
                    .map_err(|_| anyhow::anyhow!("bad --width"))?
            }
            "--height" => {
                height = next()?
                    .parse()
                    .map_err(|_| anyhow::anyhow!("bad --height"))?
            }
            "--fps" => fps = next()?.parse().map_err(|_| anyhow::anyhow!("bad --fps"))?,
            "--seconds" => {
                seconds = next()?
                    .parse()
                    .map_err(|_| anyhow::anyhow!("bad --seconds"))?
            }
            "--codec" => {
                codec = match next()?.as_str() {
                    "h264" => Codec::H264,
                    "h265" | "hevc" => Codec::H265,
                    "av1" => Codec::Av1,
                    other => bail!("unknown --codec '{other}' (h264|h265|av1)"),
                }
            }
            "--bitrate" => {
                bitrate_mbps = next()?
                    .parse()
                    .map_err(|_| anyhow::anyhow!("bad --bitrate (Mbps)"))?
            }
            "--out" => out = Some(PathBuf::from(next()?)),
            "--no-loopback" => loopback = false,
            "-h" | "--help" => {
                print_usage();
                std::process::exit(0);
            }
            other => bail!("unknown argument '{other}' (try --help)"),
        }
        i += 1;
    }

    if fps == 0 || width == 0 || height == 0 || seconds == 0 {
        bail!("--fps/--width/--height/--seconds must be > 0");
    }

    let out = out.unwrap_or_else(|| {
        let ext = match codec {
            Codec::H264 => "h264",
            Codec::H265 => "h265",
            Codec::Av1 => "obu",
        };
        PathBuf::from(format!("/tmp/lumen-m0.{ext}"))
    });

    Ok(Options {
        source,
        width,
        height,
        fps,
        seconds,
        codec,
        bitrate_bps: bitrate_mbps.saturating_mul(1_000_000),
        out,
        loopback,
    })
}

fn print_usage() {
    eprintln!(
        "lumen-host — Linux streaming host

USAGE:
    lumen-host serve              GameStream host control plane (M2: mDNS + serverinfo …)
    lumen-host m0 [OPTIONS]       M0 capture→encode→file pipeline spike

OPTIONS:
    --source <synthetic|portal>  frame source (default: portal)
    --seconds <N>                capture duration in seconds (default: 5)
    --fps <N>                    target frame rate (default: 60)
    --codec <h264|h265|av1>      NVENC codec (default: h265)
    --bitrate <MBPS>             target bitrate in Mbps (default: 20)
    --width <W> --height <H>     synthetic source size (default: 1920x1080)
    --out <PATH>                 raw Annex-B output (default: /tmp/lumen-m0.<ext>)
    --no-loopback                skip the lumen_core round-trip verification
    -h, --help                   this help

NOTES:
    'portal' needs headless Sway + xdg-desktop-portal-wlr running in this session
    (see docs/linux-setup.md). 'synthetic' needs no capture session and always runs.
    Encoded AUs are written to a playable file AND (unless --no-loopback) fed through a
    lumen_core host→client loopback that reassembles and byte-verifies each one."
    );
}