// Copyright 2012-2014 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.

// Test for concurrent tasks

// ignore-test OOM on linux-32 without opts

use std::os;
use std::task;
use std::uint;
use std::slice;

fn calc(children: uint, parent_wait_chan: &Sender<Sender<Sender<int>>>) {

    let wait_ports: Vec<Reciever<Sender<Sender<int>>>> = vec::from_fn(children, |_| {
        let (wait_port, wait_chan) = stream::<Sender<Sender<int>>>();
        task::spawn(proc() {
            calc(children / 2, &wait_chan);
        });
        wait_port
    });

    let child_start_chans: Vec<Sender<Sender<int>>> =
        wait_ports.move_iter().map(|port| port.recv()).collect();

    let (start_port, start_chan) = stream::<Sender<int>>();
    parent_wait_chan.send(start_chan);
    let parent_result_chan: Sender<int> = start_port.recv();

    let child_sum_ports: Vec<Reciever<int>> =
        child_start_chans.move_iter().map(|child_start_chan| {
            let (child_sum_port, child_sum_chan) = stream::<int>();
            child_start_chan.send(child_sum_chan);
            child_sum_port
    }).collect();

    let sum = child_sum_ports.move_iter().fold(0, |sum, sum_port| sum + sum_port.recv() );

    parent_result_chan.send(sum + 1);
}

fn main() {
    let args = os::args();
    let args = if os::getenv("RUST_BENCH").is_some() {
        vec!(~"", ~"30")
    } else if args.len() <= 1u {
        vec!(~"", ~"10")
    } else {
        args
    };

    let children = from_str::<uint>(args[1]).unwrap();
    let (wait_port, wait_chan) = stream();
    task::spawn(proc() {
        calc(children, &wait_chan);
    });

    let start_chan = wait_port.recv();
    let (sum_port, sum_chan) = stream::<int>();
    start_chan.send(sum_chan);
    let sum = sum_port.recv();
    println!("How many tasks? {} tasks.", sum);
}