//! Test 5 — Wayland handshake server/client sur Redox.
//!
//! Valide que wayland-rs (server + client + backend) ne se contente pas de
//! compiler pour Redox mais fonctionne réellement à l'exécution :
//!
//! 1. Serveur Wayland local + globals (wl_compositor, wl_shm)
//! 2. socketpair AF_UNIX, on insère le côté serveur via insert_client
//! 3. Client Wayland connecté sur l'autre côté via WAYLAND_SOCKET fd env
//! 4. Client fait wl_display.get_registry, dispatch
//! 5. On vérifie que les globals attendus arrivent côté client
//!
//! Si ça passe, le port wayland-rs sur Redox est validé runtime, pas juste
//! compile-time.

use std::os::unix::net::UnixStream;
use std::process::ExitCode;
use std::sync::Arc;

use wayland_client::{
    Connection as ClientConnection, Dispatch as ClientDispatch, EventQueue,
    backend::Backend as ClientBackend,
    protocol::wl_registry,
};
use wayland_server::{
    Display as ServerDisplay, GlobalDispatch, New,
    backend::ClientData,
    protocol::{wl_compositor, wl_shm},
};

// ---- Server side ----

struct ServerState;

#[derive(Debug)]
struct DumbClientData;
impl ClientData for DumbClientData {}

impl GlobalDispatch<wl_compositor::WlCompositor, ()> for ServerState {
    fn bind(
        _state: &mut Self,
        _handle: &wayland_server::DisplayHandle,
        _client: &wayland_server::Client,
        _resource: New<wl_compositor::WlCompositor>,
        _data: &(),
        _data_init: &mut wayland_server::DataInit<'_, Self>,
    ) {
    }
}

impl wayland_server::Dispatch<wl_compositor::WlCompositor, ()> for ServerState {
    fn request(
        _state: &mut Self,
        _client: &wayland_server::Client,
        _resource: &wl_compositor::WlCompositor,
        _request: wl_compositor::Request,
        _data: &(),
        _dh: &wayland_server::DisplayHandle,
        _data_init: &mut wayland_server::DataInit<'_, Self>,
    ) {
    }
}

impl GlobalDispatch<wl_shm::WlShm, ()> for ServerState {
    fn bind(
        _state: &mut Self,
        _handle: &wayland_server::DisplayHandle,
        _client: &wayland_server::Client,
        _resource: New<wl_shm::WlShm>,
        _data: &(),
        _data_init: &mut wayland_server::DataInit<'_, Self>,
    ) {
    }
}

impl wayland_server::Dispatch<wl_shm::WlShm, ()> for ServerState {
    fn request(
        _state: &mut Self,
        _client: &wayland_server::Client,
        _resource: &wl_shm::WlShm,
        _request: wl_shm::Request,
        _data: &(),
        _dh: &wayland_server::DisplayHandle,
        _data_init: &mut wayland_server::DataInit<'_, Self>,
    ) {
    }
}

// ---- Client side ----

#[derive(Default, Debug)]
struct ClientState {
    globals: Vec<(u32, String, u32)>,
    done: bool,
}

impl ClientDispatch<wl_registry::WlRegistry, ()> for ClientState {
    fn event(
        state: &mut Self,
        _registry: &wl_registry::WlRegistry,
        event: wl_registry::Event,
        _data: &(),
        _conn: &ClientConnection,
        _qhandle: &wayland_client::QueueHandle<Self>,
    ) {
        if let wl_registry::Event::Global { name, interface, version } = event {
            println!("[test-05 CLIENT] global #{name}: {interface} v{version}");
            state.globals.push((name, interface, version));
        }
    }
}

fn run() -> Result<(), Box<dyn std::error::Error>> {
    println!("[test-05] wayland-rs handshake server/client on Redox");

    // -- Server setup --
    let mut server_display: ServerDisplay<ServerState> = ServerDisplay::new()?;
    let mut dh = server_display.handle();
    dh.create_global::<ServerState, wl_compositor::WlCompositor, _>(5, ());
    dh.create_global::<ServerState, wl_shm::WlShm, _>(1, ());
    println!("[test-05 SERVER] created wl_compositor v5 + wl_shm v1 globals");

    // -- Socket linking --
    let (s_server, s_client) = UnixStream::pair()?;
    s_server.set_nonblocking(true)?;
    let _client_handle = dh.insert_client(s_server, Arc::new(DumbClientData))?;
    println!("[test-05] linked server side via insert_client");

    // -- Client setup using the other end of the socketpair --
    let client_backend = ClientBackend::connect(s_client)?;
    let client_conn = ClientConnection::from_backend(client_backend);
    let mut event_queue: EventQueue<ClientState> = client_conn.new_event_queue();
    let qhandle = event_queue.handle();
    let _registry = client_conn.display().get_registry(&qhandle, ());
    println!("[test-05 CLIENT] called get_registry, dispatching...");

    let mut server_state = ServerState;
    let mut client_state = ClientState::default();

    // -- Roundtrip: dispatch alternately until client has events --
    for round in 0..10 {
        // server side
        server_display.dispatch_clients(&mut server_state)?;
        server_display.flush_clients()?;
        // client side
        let _ = event_queue.flush();
        let processed = event_queue.dispatch_pending(&mut client_state)?;
        if processed > 0 {
            println!("[test-05] round {round}: client processed {processed} event(s)");
        }
        if !client_state.globals.is_empty() {
            client_state.done = true;
            break;
        }
        // Block briefly waiting for incoming events on client side
        match event_queue.prepare_read() {
            Some(read_guard) => {
                let _ = read_guard.read();
            }
            None => {}
        }
    }

    if !client_state.done || client_state.globals.is_empty() {
        return Err(format!(
            "client did not receive globals (got {})",
            client_state.globals.len()
        )
        .into());
    }

    let names: Vec<&str> = client_state.globals.iter().map(|(_, n, _)| n.as_str()).collect();
    let has_compositor = names.contains(&"wl_compositor");
    let has_shm = names.contains(&"wl_shm");

    if !has_compositor || !has_shm {
        return Err(format!("missing expected globals: got {:?}", names).into());
    }

    println!(
        "[test-05] received {} global(s): {:?}",
        client_state.globals.len(),
        names
    );

    Ok(())
}

fn main() -> ExitCode {
    match run() {
        Ok(()) => {
            println!("[test-05] PASS: wayland-rs server/client handshake works on Redox");
            ExitCode::SUCCESS
        }
        Err(e) => {
            eprintln!("[test-05] FAIL: {e}");
            ExitCode::FAILURE
        }
    }
}