pub mod compositor;
mod data_device;
pub mod decoration;
pub mod panel_item;
pub mod seat;
pub mod shaders;
pub mod state;
pub mod surface;
pub mod xdg_activation;
pub mod xdg_shell;

use self::{panel_item::PanelItem, state::WaylandState, surface::CORE_SURFACES};
use crate::wayland::state::ClientState;
use anyhow::{ensure, Result};
use once_cell::sync::OnceCell;
use parking_lot::Mutex;
use slog::Drain;
use smithay::{
	backend::{egl::EGLContext, renderer::gles2::Gles2Renderer},
	reexports::wayland_server::{backend::GlobalId, Display, ListeningSocket, Resource},
};
use std::{
	ffi::c_void,
	os::unix::{net::UnixListener, prelude::FromRawFd},
	sync::Arc,
};
use std::{os::unix::prelude::AsRawFd, time::Duration};
use stereokit as sk;
use stereokit::StereoKit;
use tokio::{
	io::unix::AsyncFd, net::UnixListener as AsyncUnixListener, sync::mpsc, task::JoinHandle,
};

struct EGLRawHandles {
	display: *const c_void,
	config: *const c_void,
	context: *const c_void,
}
fn get_sk_egl() -> Result<EGLRawHandles> {
	ensure!(
		unsafe { sk::sys::backend_graphics_get() }
			== sk::sys::backend_graphics__backend_graphics_opengles_egl,
		"StereoKit is not running using EGL!"
	);

	Ok(unsafe {
		EGLRawHandles {
			display: sk::sys::backend_opengl_egl_get_display() as *const c_void,
			config: sk::sys::backend_opengl_egl_get_config() as *const c_void,
			context: sk::sys::backend_opengl_egl_get_context() as *const c_void,
		}
	})
}

static GLOBAL_DESTROY_QUEUE: OnceCell<mpsc::Sender<GlobalId>> = OnceCell::new();

pub struct Wayland {
	log: slog::Logger,

	display: Arc<Mutex<Display<WaylandState>>>,
	join_handle: JoinHandle<Result<()>>,
	renderer: Gles2Renderer,
	state: Arc<Mutex<WaylandState>>,
}
impl Wayland {
	pub fn new() -> Result<Self> {
		let log = ::slog::Logger::root(::slog_stdlog::StdLog.fuse(), slog::o!());
		slog_stdlog::init()?;

		let egl_raw_handles = get_sk_egl()?;
		let renderer = unsafe {
			Gles2Renderer::new(
				EGLContext::from_raw(
					egl_raw_handles.display,
					egl_raw_handles.config,
					egl_raw_handles.context,
					log.clone(),
				)?,
				log.clone(),
			)?
		};

		let display: Display<WaylandState> = Display::new()?;
		let display_handle = display.handle();

		let display = Arc::new(Mutex::new(display));
		let state = WaylandState::new(log.clone(), display.clone(), display_handle);

		let (global_destroy_queue_in, global_destroy_queue) = mpsc::channel(8);
		GLOBAL_DESTROY_QUEUE.set(global_destroy_queue_in).unwrap();

		let join_handle =
			Wayland::start_loop(display.clone(), state.clone(), global_destroy_queue)?;

		Ok(Wayland {
			log,
			display,
			join_handle,
			renderer,
			state,
		})
	}

	fn start_loop(
		display: Arc<Mutex<Display<WaylandState>>>,
		state: Arc<Mutex<WaylandState>>,
		mut global_destroy_queue: mpsc::Receiver<GlobalId>,
	) -> Result<JoinHandle<Result<()>>> {
		let socket = ListeningSocket::bind_auto("wayland", 0..33)?;
		if let Some(socket_name) = socket.socket_name() {
			println!("Wayland compositor {:?} active", socket_name);
		}

		let listen_async =
			AsyncUnixListener::from_std(unsafe { UnixListener::from_raw_fd(socket.as_raw_fd()) })?;

		let dispatch_poll_fd = display.lock().backend().poll_fd().try_clone_to_owned()?;
		let dispatch_poll_listener = AsyncFd::new(dispatch_poll_fd)?;

		let dh1 = display.lock().handle();
		let mut dh2 = dh1.clone();

		Ok(tokio::task::spawn(async move {
			let _socket = socket; // Keep the socket alive
			loop {
				tokio::select! {
					e = global_destroy_queue.recv() => { // New global to destroy
						dh1.remove_global::<WaylandState>(e.unwrap());
					}
					acc = listen_async.accept() => { // New client connected
						let (stream, _) = acc?;
						let client = dh2.insert_client(stream.into_std()?, Arc::new(ClientState))?;

						state.lock().new_client(client.id(), &dh2);
					}
					e = dispatch_poll_listener.readable() => { // Dispatch
						let mut guard = e?;
						let mut display = display.lock();
						display.dispatch_clients(&mut *state.lock())?;
						display.flush_clients()?;
						guard.clear_ready();
					}
				}
			}
		}))
	}

	pub fn frame(&mut self, sk: &StereoKit) {
		let time_ms = (sk.time_getf() * 1000.) as u64;

		for core_surface in CORE_SURFACES.get_valid_contents() {
			let Some(client_id) = 
				core_surface
					.wl_surface()
					.and_then(|surf| surf.client())
					.map(|c| c.id()) else { continue };
			let state = self.state.lock();
			let Some(seat_data) = state.seats.get(&client_id).cloned() else { continue };
			let output = state.output.clone();
			core_surface.process(
				sk,
				&mut self.renderer,
				output,
				Duration::from_millis(time_ms),
				&self.log,
				|data| {
					PanelItem::on_mapped(&core_surface, data, seat_data);
				},
				|data| {
					PanelItem::if_mapped(&core_surface, data);
				},
			);
		}

		self.display.lock().flush_clients().unwrap();
	}

	pub fn make_context_current(&self) {
		unsafe {
			self.renderer.egl_context().make_current().unwrap();
		}
	}
}
impl Drop for Wayland {
	fn drop(&mut self) {
		self.join_handle.abort();
	}
}