// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

// This test creates a bunch of tasks that simultaneously send to each
// other in a ring. The messages should all be basically
// independent.
// This is like msgsend-ring-pipes but adapted to use Arcs.

// This also serves as a pipes test, because Arcs are implemented with pipes.

extern mod extra;

use extra::arc;
use extra::future::Future;
use extra::time;
use std::os;
use std::uint;

// A poor man's pipe.
type pipe = arc::RWArc<~[uint]>;

fn send(p: &pipe, msg: uint) {
    p.write_cond(|state, cond| {
        state.push(msg);
        cond.signal();
    })
}
fn recv(p: &pipe) -> uint {
    p.write_cond(|state, cond| {
        while state.is_empty() {
            cond.wait();
        }
        state.pop().unwrap()
    })
}

fn init() -> (pipe,pipe) {
    let x = arc::RWArc::new(~[]);
    ((&x).clone(), x)
}


fn thread_ring(i: uint, count: uint, num_chan: pipe, num_port: pipe) {
    let mut num_chan = Some(num_chan);
    let mut num_port = Some(num_port);
    // Send/Receive lots of messages.
    for j in range(0u, count) {
        //error!("task %?, iter %?", i, j);
        let num_chan2 = num_chan.take_unwrap();
        let num_port2 = num_port.take_unwrap();
        send(&num_chan2, i * j);
        num_chan = Some(num_chan2);
        let _n = recv(&num_port2);
        //log(error, _n);
        num_port = Some(num_port2);
    };
}

fn main() {
    let args = os::args();
    let args = if os::getenv("RUST_BENCH").is_some() {
        ~[~"", ~"100", ~"10000"]
    } else if args.len() <= 1u {
        ~[~"", ~"10", ~"100"]
    } else {
        args.clone()
    };

    let num_tasks = from_str::<uint>(args[1]).unwrap();
    let msg_per_task = from_str::<uint>(args[2]).unwrap();

    let (mut num_chan, num_port) = init();

    let start = time::precise_time_s();

    // create the ring
    let mut futures = ~[];

    for i in range(1u, num_tasks) {
        //error!("spawning %?", i);
        let (new_chan, num_port) = init();
        let num_chan_2 = num_chan.clone();
        let new_future = Future::spawn(proc() {
            thread_ring(i, msg_per_task, num_chan_2, num_port)
        });
        futures.push(new_future);
        num_chan = new_chan;
    };

    // do our iteration
    thread_ring(0, msg_per_task, num_chan, num_port);

    // synchronize
    for f in futures.mut_iter() {
        let _ = f.get();
    }

    let stop = time::precise_time_s();

    // all done, report stats.
    let num_msgs = num_tasks * msg_per_task;
    let elapsed = (stop - start);
    let rate = (num_msgs as f64) / elapsed;

    println!("Sent {} messages in {} seconds", num_msgs, elapsed);
    println!("  {} messages / second", rate);
    println!("  {} μs / message", 1000000. / rate);
}