#version 100

import std.reo;

composite main(in ai, out ao, in bi, out bo, in ci, out co, in di, out do) {
    // Three parts:
    channel xo -> xi;
    {
        channel afo -> aii;
        channel bfo -> bii;
        channel cfo -> cii;
        channel dfo -> dii;
        // Part 1. Collect all in msgs.
        new fifo(ai, afo, null);
        new fifo(bi, bfo, null);
        new fifo(ci, cfo, null);
        new fifo(di, dfo, null);
        // Part 2. Compute maximum.
        new computeMax(aii, bii, cii, dii, xo);
    }
    // Part 3. Send maximum to all out msgs, and repeat.
    {
        channel xxo -> xxi;
        channel xxxo -> xxxi;
        new replicator(xi, xxo, ao);
        new replicator(xxi, xxxo, bo);
        new replicator(xxxi, co, do);
    }
}

primitive computeMax(in a, in b, in c, in d, out x) {
	while (true) {
		sync {
            if (fires(a) && fires(b) && fires(c) && fires(d) && fires(x)) {
            	msg aa = get(a);
            	msg bb = get(b);
            	msg cc = get(c);
            	msg dd = get(d);
            	uint16_t aaa = aa[0] & aa[1] << 8;
                uint16_t bbb = bb[0] & bb[1] << 8;
                uint16_t ccc = cc[0] & cc[1] << 8;
                uint16_t ddd = dd[0] & dd[1] << 8;
                // broadcast message with highest header
                uint16_t max = aaa;
                if (bbb > max) max = bbb;
                if (ccc > max) max = ccc;
                if (ddd > max) max = ddd;
                if (max == aaa) put(x, aa);
                else if (max == bbb) put(x, bb);
                else if (max == ccc) put(x, cc);
                else if (max == ddd) put(x, dd);
            } else {
	            assert !fires(a) && !fires(b) && !fires(c) && !fires(d) && !fires(x);
            }
        }
    }
}