//! Phase 13.2.b.3 — Client de test visuel pour wl_subcompositor.
//!
//! Crée un toplevel parent 300×200 bleu uni avec bordure noire, et lui
//! attache une subsurface 60×60 rouge à l'offset (50, 50). Si le rendering
//! côté compositor (phase 13.2.b.2) est correct, on doit voir à l'écran :
//!
//!   - Fenêtre bleue en haut-gauche (selon cascading compositor)
//!   - Un carré rouge dedans, en haut-gauche de la fenêtre bleue, à 50px
//!     du coin haut-gauche du parent
//!
//! Le client tourne ~60s puis exit. ESC ferme proprement avant timeout
//! (path keyboard via wl_keyboard.enter envoyé au focus = parent toplevel).
//!
//! NB : sans cascade sync ni propagation parent-move (limitations 13.2.b.2),
//! la subsurface est figée à la position de création. Acceptable pour
//! validation visuelle de base.

use std::ffi::CString;
use std::fs::OpenOptions;
use std::io::Write;
use std::os::fd::{AsFd, FromRawFd, OwnedFd};
use std::os::unix::net::UnixStream;
use std::process::ExitCode;
use std::ptr;
use std::sync::{Mutex, OnceLock};
use std::thread;
use std::time::Duration;

use wayland_client::{
    backend::Backend,
    protocol::{
        wl_buffer::WlBuffer, wl_compositor::WlCompositor, wl_keyboard, wl_registry,
        wl_seat::WlSeat, wl_shm::WlShm, wl_shm_pool::WlShmPool,
        wl_subcompositor::WlSubcompositor, wl_subsurface::WlSubsurface, wl_surface::WlSurface,
    },
    Connection, Dispatch, EventQueue, Proxy, QueueHandle,
};
use wayland_protocols::xdg::shell::client::{
    xdg_surface::{self, XdgSurface},
    xdg_toplevel::{self, XdgToplevel},
    xdg_wm_base::{self, XdgWmBase},
};

const SOCKET_PATH: &str = "/tmp/redox-wl-comp.sock";

// Parent : 300×200 bleu nuit
const PW: i32 = 300;
const PH: i32 = 200;
const PSTRIDE: i32 = PW * 4;
const PSIZE: i32 = PSTRIDE * PH;
const PCOLOR: u32 = 0xFF_22_44_AA;

// Subsurface : 60×60 rouge, offset (50, 50)
const SW: i32 = 60;
const SH: i32 = 60;
const SSTRIDE: i32 = SW * 4;
const SSIZE: i32 = SSTRIDE * SH;
const SCOLOR: u32 = 0xFF_CC_30_30;
const SOFF_X: i32 = 50;
const SOFF_Y: i32 = 50;

struct DebugSink(Mutex<Option<std::fs::File>>);
impl DebugSink {
    fn new() -> Self {
        Self(Mutex::new(
            OpenOptions::new().write(true).open("/scheme/debug").ok(),
        ))
    }
    fn writeln(&self, s: &str) {
        println!("{s}");
        if let Ok(mut g) = self.0.lock() {
            if let Some(f) = g.as_mut() {
                let _ = writeln!(f, "{s}");
            }
        }
    }
}
fn dlog(s: &str) {
    static SINK: OnceLock<DebugSink> = OnceLock::new();
    SINK.get_or_init(DebugSink::new).writeln(s);
}

#[derive(Default)]
struct State {
    compositor: Option<WlCompositor>,
    shm: Option<WlShm>,
    wm_base: Option<XdgWmBase>,
    seat: Option<WlSeat>,
    subcompositor: Option<WlSubcompositor>,
    pending_serial: Option<u32>,
    configured: bool,
    running: bool,
}

impl Dispatch<wl_registry::WlRegistry, ()> for State {
    fn event(
        state: &mut Self,
        registry: &wl_registry::WlRegistry,
        event: wl_registry::Event,
        _: &(),
        _conn: &Connection,
        qh: &QueueHandle<Self>,
    ) {
        if let wl_registry::Event::Global {
            name,
            interface,
            version,
        } = event
        {
            match interface.as_str() {
                "wl_compositor" => {
                    state.compositor = Some(registry.bind(name, version.min(5), qh, ()));
                }
                "wl_shm" => {
                    state.shm = Some(registry.bind(name, 1, qh, ()));
                }
                "xdg_wm_base" => {
                    state.wm_base = Some(registry.bind(name, version.min(5), qh, ()));
                }
                "wl_seat" => {
                    state.seat = Some(registry.bind(name, version.min(7), qh, ()));
                }
                "wl_subcompositor" => {
                    state.subcompositor = Some(registry.bind(name, 1, qh, ()));
                }
                _ => {}
            }
        }
    }
}

macro_rules! noop {
    ($ty:ty) => {
        impl Dispatch<$ty, ()> for State {
            fn event(
                _: &mut Self,
                _: &$ty,
                _: <$ty as Proxy>::Event,
                _: &(),
                _: &Connection,
                _: &QueueHandle<Self>,
            ) {
            }
        }
    };
}
noop!(WlCompositor);
noop!(WlShm);
noop!(WlShmPool);
noop!(WlBuffer);
noop!(WlSurface);
noop!(WlSeat);
noop!(WlSubcompositor);
noop!(WlSubsurface);

impl Dispatch<XdgWmBase, ()> for State {
    fn event(
        _: &mut Self,
        wm_base: &XdgWmBase,
        event: xdg_wm_base::Event,
        _: &(),
        _: &Connection,
        _: &QueueHandle<Self>,
    ) {
        if let xdg_wm_base::Event::Ping { serial } = event {
            wm_base.pong(serial);
        }
    }
}

impl Dispatch<XdgSurface, ()> for State {
    fn event(
        state: &mut Self,
        _: &XdgSurface,
        event: xdg_surface::Event,
        _: &(),
        _: &Connection,
        _: &QueueHandle<Self>,
    ) {
        if let xdg_surface::Event::Configure { serial } = event {
            state.pending_serial = Some(serial);
            state.configured = true;
        }
    }
}

impl Dispatch<XdgToplevel, ()> for State {
    fn event(
        state: &mut Self,
        _: &XdgToplevel,
        event: xdg_toplevel::Event,
        _: &(),
        _: &Connection,
        _: &QueueHandle<Self>,
    ) {
        if matches!(event, xdg_toplevel::Event::Close) {
            state.running = false;
        }
    }
}

// ESC → exit. Même logique qu'en 13.1.b sur le client simple_window.
impl Dispatch<wl_keyboard::WlKeyboard, ()> for State {
    fn event(
        state: &mut Self,
        _: &wl_keyboard::WlKeyboard,
        event: wl_keyboard::Event,
        _: &(),
        _: &Connection,
        _: &QueueHandle<Self>,
    ) {
        if let wl_keyboard::Event::Key { key, .. } = event {
            if key == 1 {
                dlog("[sub-client] ESC → exit");
                state.running = false;
            }
        }
    }
}

unsafe fn create_shm(name: &str, size: i32, w: i32, h: i32, color: u32) -> Result<OwnedFd, String> {
    let cname = CString::new(name).unwrap();
    let _ = libc::shm_unlink(cname.as_ptr());
    let fd = libc::shm_open(cname.as_ptr(), libc::O_RDWR | libc::O_CREAT, 0o600);
    if fd < 0 {
        return Err("shm_open failed".into());
    }
    if libc::ftruncate(fd, size as _) != 0 {
        libc::close(fd);
        return Err("ftruncate failed".into());
    }
    let p = libc::mmap(
        ptr::null_mut(),
        size as usize,
        libc::PROT_READ | libc::PROT_WRITE,
        libc::MAP_SHARED,
        fd,
        0,
    );
    if p == libc::MAP_FAILED {
        libc::close(fd);
        return Err("mmap failed".into());
    }
    let pixels = std::slice::from_raw_parts_mut(p as *mut u32, (w * h) as usize);
    // Remplissage uni avec bordure noire 2px
    for y in 0..h {
        for x in 0..w {
            let on_border = x < 2 || x >= w - 2 || y < 2 || y >= h - 2;
            pixels[(y * w + x) as usize] = if on_border { 0xFF_10_10_10 } else { color };
        }
    }
    libc::munmap(p, size as usize);
    Ok(OwnedFd::from_raw_fd(fd))
}

fn run() -> Result<(), Box<dyn std::error::Error>> {
    dlog("[sub-client] start (Phase 13.2.b.3 — visual subsurface)");

    for i in 0..50 {
        if std::path::Path::new(SOCKET_PATH).exists() {
            break;
        }
        if i == 49 {
            return Err("compositor socket missing after 5s".into());
        }
        thread::sleep(Duration::from_millis(100));
    }

    let stream = UnixStream::connect(SOCKET_PATH)?;
    let backend = Backend::connect(stream)?;
    let conn = Connection::from_backend(backend);
    let mut event_queue: EventQueue<State> = conn.new_event_queue();
    let qh = event_queue.handle();
    let _registry = conn.display().get_registry(&qh, ());

    let mut state = State {
        running: true,
        ..State::default()
    };
    event_queue.roundtrip(&mut state)?;
    let compositor = state.compositor.clone().ok_or("no wl_compositor")?;
    let shm = state.shm.clone().ok_or("no wl_shm")?;
    let wm_base = state.wm_base.clone().ok_or("no xdg_wm_base")?;
    let subcomp = state
        .subcompositor
        .clone()
        .ok_or("no wl_subcompositor (compositor patché 13.2.b.1 ?)")?;
    let seat = state.seat.clone();

    // Bind keyboard pour gérer ESC
    if let Some(s) = &seat {
        let _kb = s.get_keyboard(&qh, ());
    }

    // --- Parent toplevel ---
    let parent_surface = compositor.create_surface(&qh, ());
    let xdg_surface = wm_base.get_xdg_surface(&parent_surface, &qh, ());
    let toplevel = xdg_surface.get_toplevel(&qh, ());
    toplevel.set_title("Phase 13.2.b.3 — subcompositor visual".into());
    toplevel.set_app_id("redox.wl.test.client.subcompositor".into());
    parent_surface.commit();
    dlog("[sub-client] parent xdg_toplevel créé");

    let start = std::time::Instant::now();
    while !state.configured && start.elapsed() < Duration::from_secs(5) {
        event_queue.roundtrip(&mut state)?;
        thread::sleep(Duration::from_millis(50));
    }
    let serial = state.pending_serial.ok_or("no initial configure")?;
    xdg_surface.ack_configure(serial);
    state.pending_serial = None;
    dlog(&format!("[sub-client] ack_configure({serial})"));

    // Parent buffer + attach + commit
    let parent_fd = unsafe { create_shm("redox-sub-client-parent", PSIZE, PW, PH, PCOLOR) }?;
    let parent_pool = shm.create_pool(parent_fd.as_fd(), PSIZE, &qh, ());
    let parent_buffer = parent_pool.create_buffer(
        0,
        PW,
        PH,
        PSTRIDE,
        wayland_client::protocol::wl_shm::Format::Argb8888,
        &qh,
        (),
    );
    parent_surface.attach(Some(&parent_buffer), 0, 0);
    parent_surface.commit();
    dlog("[sub-client] parent buffer attached + commit");

    // --- Subsurface ---
    let child_surface = compositor.create_surface(&qh, ());
    let subsurface: WlSubsurface =
        subcomp.get_subsurface(&child_surface, &parent_surface, &qh, ());
    subsurface.set_position(SOFF_X, SOFF_Y);
    subsurface.set_desync(); // mode desync → commit du child suffit pour appliquer
    dlog(&format!(
        "[sub-client] subsurface créée + set_position({SOFF_X}, {SOFF_Y}) + set_desync"
    ));

    let child_fd = unsafe { create_shm("redox-sub-client-child", SSIZE, SW, SH, SCOLOR) }?;
    let child_pool = shm.create_pool(child_fd.as_fd(), SSIZE, &qh, ());
    let child_buffer = child_pool.create_buffer(
        0,
        SW,
        SH,
        SSTRIDE,
        wayland_client::protocol::wl_shm::Format::Argb8888,
        &qh,
        (),
    );
    child_surface.attach(Some(&child_buffer), 0, 0);
    child_surface.commit();
    dlog("[sub-client] child buffer attached + commit");

    // Re-commit du parent pour rendre les changements visibles en sync.
    // (En desync ce n'est pas strictement nécessaire mais ça force un redraw.)
    parent_surface.commit();

    dlog("[sub-client] entering event loop");
    let deadline = std::time::Instant::now() + Duration::from_secs(60);
    while state.running && std::time::Instant::now() < deadline {
        match event_queue.blocking_dispatch(&mut state) {
            Ok(_) => {}
            Err(e) => {
                let s = format!("{e}");
                if s.contains("Broken pipe") || s.contains("Connection reset") {
                    dlog("[sub-client] compositor disconnected → exit cleanly");
                    break;
                }
                return Err(e.into());
            }
        }
    }

    dlog("[sub-client] loop exited cleanly");
    Ok(())
}

fn main() -> ExitCode {
    match run() {
        Ok(()) => {
            dlog("[sub-client] PASS");
            ExitCode::SUCCESS
        }
        Err(e) => {
            dlog(&format!("[sub-client] FAIL: {e}"));
            ExitCode::FAILURE
        }
    }
}