mod core;
mod nodes;
mod objects;
#[cfg(feature = "wayland")]
mod wayland;

use crate::core::destroy_queue;
use crate::nodes::{drawable, hmd, input};
use crate::objects::input::mouse_pointer::MousePointer;
use crate::objects::input::sk_controller::SkController;
use crate::objects::input::sk_hand::SkHand;

use self::core::eventloop::EventLoop;
use clap::Parser;
use color_eyre::eyre::Result;
use directories::ProjectDirs;
use stardust_xr::server;
use std::path::PathBuf;
use std::process::Command;
use std::sync::Arc;
use std::time::Duration;
use stereokit::input::Handed;
use stereokit::lifecycle::DisplayMode;
use stereokit::lifecycle::{DepthMode, LogFilter};
use stereokit::render::SphericalHarmonics;
use stereokit::render::StereoKitRender;
use stereokit::texture::Texture;
use stereokit::time::StereoKitTime;
use tokio::{runtime::Handle, sync::oneshot};
use tracing::{debug_span, info};
use tracing_subscriber::{fmt, prelude::*, EnvFilter};

#[derive(Parser)]
#[clap(author, version, about, long_about = None)]
struct CliArgs {
	/// Force flatscreen mode and use the mouse pointer as a 3D pointer
	#[clap(short, long, action)]
	flatscreen: bool,

	/// Run Stardust XR as an overlay with given priority
	#[clap(id = "PRIORITY", short = 'o', long = "overlay", action)]
	overlay_priority: Option<u32>,

	/// Don't create a tip input for controller because SOME RUNTIMES will lie
	#[clap(long, action)]
	disable_controller: bool,
}

struct EventLoopInfo {
	tokio_handle: Handle,
	socket_path: PathBuf,
}

fn main() -> Result<()> {
	let registry = tracing_subscriber::registry();
	#[cfg(feature = "profile_app")]
	let (chrome_layer, _guard) = tracing_chrome::ChromeLayerBuilder::new()
		.include_args(true)
		.build();
	#[cfg(feature = "profile_app")]
	let registry = registry.with(chrome_layer);

	#[cfg(feature = "profile_tokio")]
	let (console_layer, _) = console_subscriber::ConsoleLayer::builder().build();
	#[cfg(feature = "profile_tokio")]
	let registry = registry.with(console_layer);

	let log_layer = fmt::Layer::new()
		.with_thread_names(true)
		.with_ansi(true)
		.with_filter(EnvFilter::from_default_env());
	registry.with(log_layer).init();

	let project_dirs = ProjectDirs::from("", "", "stardust").unwrap();
	let cli_args = Arc::new(CliArgs::parse());

	let stereokit = stereokit::Settings::default()
		.app_name("Stardust XR")
		.log_filter(LogFilter::None)
		.overlay_app(cli_args.overlay_priority.is_some())
		.overlay_priority(cli_args.overlay_priority.unwrap_or(u32::MAX))
		.disable_desktop_input_window(true)
		.display_preference(if cli_args.flatscreen {
			DisplayMode::Flatscreen
		} else {
			DisplayMode::MixedReality
		})
		.depth_mode(DepthMode::D32)
		.init()
		.expect("StereoKit failed to initialize");
	info!("Init StereoKit");

	// Skytex/light stuff
	{
		let skytex_path = project_dirs.config_dir().join("skytex.hdr");
		if let Some((tex, light)) = skytex_path
			.exists()
			.then(|| Texture::from_cubemap_equirectangular(&stereokit, &skytex_path, true, 100))
			.flatten()
		{
			stereokit.set_skytex(&tex);
			stereokit.set_skylight(&light);
		} else if let Some(tex) = Texture::cubemap_from_spherical_harmonics(
			&stereokit,
			&SphericalHarmonics::default(),
			16,
			0.0,
			0.0,
		) {
			stereokit.set_skytex(&tex);
		}
	}

	let mouse_pointer = cli_args.flatscreen.then(MousePointer::new);
	let mut hands =
		(!cli_args.flatscreen).then(|| (SkHand::new(Handed::Left), SkHand::new(Handed::Right)));
	let mut controllers = (!cli_args.flatscreen && !cli_args.disable_controller).then(|| {
		(
			SkController::new(Handed::Left),
			SkController::new(Handed::Right),
		)
	});

	if hands.is_none() {
		unsafe {
			stereokit::sys::input_hand_visible(stereokit::sys::handed__handed_left, false as i32);
			stereokit::sys::input_hand_visible(stereokit::sys::handed__handed_right, false as i32);
		}
	}

	let (event_stop_tx, event_stop_rx) = oneshot::channel::<()>();
	let (info_sender, info_receiver) = oneshot::channel::<EventLoopInfo>();
	let event_thread = std::thread::Builder::new()
		.name("event_loop".to_owned())
		.spawn(move || event_loop(info_sender, event_stop_rx))?;
	let event_loop_info = info_receiver.blocking_recv()?;
	let _tokio_handle = event_loop_info.tokio_handle.enter();

	#[cfg(feature = "wayland")]
	let mut wayland = wayland::Wayland::new()?;
	info!("Stardust ready!");

	let _startup = Command::new(project_dirs.config_dir().join("startup"))
		.env("WAYLAND_DISPLAY", &wayland.socket_name)
		.env(
			"STARDUST_INSTANCE",
			event_loop_info.socket_path.file_name().unwrap(),
		)
		.spawn();

	let mut last_frame_delta = Duration::ZERO;
	let mut sleep_duration = Duration::ZERO;
	debug_span!("StereoKit").in_scope(|| {
		stereokit.run(
			|sk| {
				let _span = debug_span!("StereoKit step");
				let _span = _span.enter();

				hmd::frame(sk);
				#[cfg(feature = "wayland")]
				wayland.frame(sk);
				destroy_queue::clear();

				if let Some(mouse_pointer) = &mouse_pointer {
					mouse_pointer.update(sk);
				}
				if let Some((left_hand, right_hand)) = &mut hands {
					left_hand.update(sk);
					right_hand.update(sk);
				}
				if let Some((left_controller, right_controller)) = &mut controllers {
					left_controller.update(sk);
					right_controller.update(sk);
				}
				input::process_input();
				nodes::root::Root::logic_step(sk.time_elapsed());
				{
					let frame_delta = Duration::from_secs_f64(sk.time_elapsed_unscaled());
					if last_frame_delta < frame_delta {
						if let Some(frame_delta_delta) = frame_delta.checked_sub(last_frame_delta) {
							if let Some(new_sleep_duration) =
								sleep_duration.checked_sub(frame_delta_delta)
							{
								sleep_duration = new_sleep_duration;
							}
						}
					} else {
						sleep_duration += Duration::from_micros(250);
					}

					debug_span!("Sleep", ?sleep_duration, ?frame_delta, ?last_frame_delta)
						.in_scope(|| {
							last_frame_delta = frame_delta;
							std::thread::sleep(sleep_duration); // to give clients a chance to even update anything before drawing
						});
				}
				drawable::draw(sk);

				#[cfg(feature = "wayland")]
				wayland.make_context_current();
			},
			|_| {
				info!("Cleanly shut down StereoKit");
			},
		)
	});

	#[cfg(feature = "wayland")]
	drop(wayland);

	let _ = event_stop_tx.send(());
	event_thread
		.join()
		.expect("Failed to cleanly shut down event loop")?;
	info!("Cleanly shut down Stardust");
	Ok(())
}

// #[tokio::main]
#[tokio::main]
async fn event_loop(
	info_sender: oneshot::Sender<EventLoopInfo>,
	stop_rx: oneshot::Receiver<()>,
) -> color_eyre::eyre::Result<()> {
	let socket_path = server::get_free_socket_path().unwrap();
	let _event_loop = EventLoop::new(socket_path.clone()).expect("Couldn't create server socket");
	info!("Init event loop");
	info!(
		socket_path = ?socket_path.display(),
		"Stardust socket created"
	);
	let _ = info_sender.send(EventLoopInfo {
		tokio_handle: Handle::current(),
		socket_path,
	});

	let result = tokio::select! {
		biased;
		_ = tokio::signal::ctrl_c() => Ok(()),
		_ = stop_rx => Ok(()),
	};

	info!("Cleanly shut down event loop");

	unsafe {
		stereokit::sys::sk_quit();
	}

	result
}