#[cfg(any(
	feature = "sync time rt-threaded",
  ))]

extern crate tokio;

use std::io::{self, Write};
use std::sync::Arc;
use std::sync::atomic::{AtomicU64, AtomicBool,Ordering};
use std::time::{Instant,Duration};

use tokio::runtime::Builder;
use tokio::sync;
use tokio::time;

use isatty::stdout_isatty;

use num_format::{Locale, ToFormattedString};

use clap::{Arg, App};

use std::cell::UnsafeCell;
use std::mem::MaybeUninit;
use std::ops;

pub struct InitializeCell<T> {
    inner: UnsafeCell<MaybeUninit<T>>,
}

unsafe impl<T> Sync for InitializeCell<T> {}

impl<T> InitializeCell<T> {
    pub const unsafe fn new_uninitialized() -> InitializeCell<T> {
	  InitializeCell {
		inner: UnsafeCell::new(MaybeUninit::uninit()),
	  }
    }
    pub const fn new(init: T) -> InitializeCell<T> {
	  InitializeCell {
		inner: UnsafeCell::new(MaybeUninit::new(init)),
	  }
    }
    pub unsafe fn init(&self, init: T) {
	  (*self.inner.get()) = MaybeUninit::new(init);
    }
}

impl<T> ops::Deref for InitializeCell<T> {
    type Target = T;
    fn deref(&self) -> &T {
	  unsafe {
		&*(*self.inner.get()).as_ptr()
	  }
    }
}

static CLOCK_MODE: InitializeCell<bool> = unsafe { InitializeCell::new_uninitialized() };
static STOP_COUNT: InitializeCell<u64>  = unsafe { InitializeCell::new_uninitialized() };
static DURATION: InitializeCell<f64>    = unsafe { InitializeCell::new_uninitialized() };
static STOP         : AtomicBool = AtomicBool::new(false);
static THREADS_LEFT : AtomicU64  = AtomicU64 ::new(10);

struct Partner {
	sem: sync::Semaphore,
	next: usize,
}

async fn partner_main(result: sync::oneshot::Sender<u64>, idx: usize, others: Arc<Vec<Arc<Partner>>> ) {
	let this = &others[idx];
	let mut count:u64 = 0;
	loop {
		this.sem.acquire().await.forget();
		others[this.next].sem.add_permits(1);
		count += 1;

		if  *CLOCK_MODE && STOP.load(Ordering::Relaxed) { break; }
		if !*CLOCK_MODE && count >= *STOP_COUNT { break; }
	}

	THREADS_LEFT.fetch_sub(1, Ordering::SeqCst);
	result.send( count ).unwrap();
}

fn prep(nthreads: usize, tthreads: usize) -> Vec<Arc<Partner>> {
	let mut thddata = Vec::with_capacity(tthreads);
	for i in 0..tthreads {
		let pi = (i + nthreads) % tthreads;
		thddata.push(Arc::new(Partner{
			sem: sync::Semaphore::new(0),
			next: pi,
		}));
	}
	return thddata;
}

async fn wait(start: &Instant, is_tty: bool) {
	loop {
		time::sleep(Duration::from_micros(100000)).await;
		let delta = start.elapsed();
		if is_tty {
			print!(" {:.1}\r", delta.as_secs_f32());
			io::stdout().flush().unwrap();
		}
		if *CLOCK_MODE && delta >= Duration::from_secs_f64(*DURATION)  {
			break;
		}
		else if !*CLOCK_MODE && THREADS_LEFT.load(Ordering::Relaxed) == 0 {
			break;
		}
	}
}

fn main() {
	let options = App::new("Cycle Tokio")
		.arg(Arg::with_name("duration")  .short("d").long("duration")  .takes_value(true).default_value("5").help("Duration of the experiments in seconds"))
		.arg(Arg::with_name("iterations").short("i").long("iterations").takes_value(true).conflicts_with("duration").help("Number of iterations of the experiments"))
		.arg(Arg::with_name("nthreads")  .short("t").long("nthreads")  .takes_value(true).default_value("1").help("Number of threads to use"))
		.arg(Arg::with_name("nprocs")    .short("p").long("nprocs")    .takes_value(true).default_value("1").help("Number of processors to use"))
		.arg(Arg::with_name("ringsize")  .short("r").long("ringsize")  .takes_value(true).default_value("1").help("Number of threads in a cycle"))
		.get_matches();

	let ring_size = options.value_of("ringsize").unwrap().parse::<usize>().unwrap();
	let nthreads  = options.value_of("nthreads").unwrap().parse::<usize>().unwrap();
	let nprocs    = options.value_of("nprocs").unwrap().parse::<usize>().unwrap();

	if options.is_present("iterations") {
		unsafe{
			CLOCK_MODE.init( false );
			STOP_COUNT.init( options.value_of("iterations").unwrap().parse::<u64>().unwrap() );
		}
	}
	else {
		unsafe{
			CLOCK_MODE.init(true);
			DURATION  .init(options.value_of("duration").unwrap().parse::<f64>().unwrap());
		}
	}

	let s = (1000000 as u64).to_formatted_string(&Locale::en);
	assert_eq!(&s, "1,000,000");


	let tthreads = nthreads * ring_size;
	THREADS_LEFT.store(tthreads as u64, Ordering::SeqCst);
	let thddata = Arc::new(prep(nthreads, tthreads));

	let mut global_counter :u64 = 0;
	let mut duration : std::time::Duration = std::time::Duration::from_secs(0);
	let runtime = Builder::new_multi_thread()
		.worker_threads(nprocs)
		.enable_all()
		.build()
		.unwrap();

	runtime.block_on(async {
		let mut result  : Vec<sync::oneshot::Receiver::<u64>> = Vec::with_capacity(tthreads);
		{
			let mut threads = Vec::with_capacity(tthreads);
			for i in 0..tthreads {
				let (s, r) = sync::oneshot::channel::<u64>();
				result.push(r);
				threads.push(tokio::spawn(partner_main(s, i, thddata.clone())));
			}
			println!("Starting");

			let is_tty = stdout_isatty();
			let start = Instant::now();

			for i in 0..nthreads {
				thddata[i].sem.add_permits(1);
			}

			wait(&start, is_tty).await;

			STOP.store(true, Ordering::SeqCst);
			duration = start.elapsed();

			println!("\nDone");

			for i in 0..tthreads {
				thddata[i].sem.add_permits(1);
			}

			for _ in 0..tthreads {
				global_counter += result.pop().unwrap().await.unwrap();
			}
		}
	});

	println!("Duration (ms)        : {}", (duration.as_millis()).to_formatted_string(&Locale::en));
	println!("Number of processors : {}", (nprocs).to_formatted_string(&Locale::en));
	println!("Number of threads    : {}", (tthreads).to_formatted_string(&Locale::en));
	println!("Cycle size (# thrds) : {}", (ring_size).to_formatted_string(&Locale::en));
	println!("Total Operations(ops): {:>15}", (global_counter).to_formatted_string(&Locale::en));
	println!("Ops per second       : {:>15}", (((global_counter as f64) / duration.as_secs() as f64) as u64).to_formatted_string(&Locale::en));
	println!("ns per ops           : {:>15}", ((duration.as_nanos() as f64 / global_counter as f64) as u64).to_formatted_string(&Locale::en));
	println!("Ops per threads      : {:>15}", (global_counter / tthreads as u64).to_formatted_string(&Locale::en));
	println!("Ops per procs        : {:>15}", (global_counter / nprocs as u64).to_formatted_string(&Locale::en));
	println!("Ops/sec/procs        : {:>15}", ((((global_counter as f64) / nprocs as f64) / duration.as_secs() as f64) as u64).to_formatted_string(&Locale::en));
	println!("ns per ops/procs     : {:>15}", ((duration.as_nanos() as f64 / (global_counter as f64 / nprocs as f64)) as u64).to_formatted_string(&Locale::en));
}