/*
 * StarPU
 * Copyright (C) Université Bordeaux 1, CNRS 2008-2010 (see AUTHORS file)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at
 * your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * See the GNU Lesser General Public License in COPYING.LGPL for more details.
 */

#include "fxt_tool.h"

/* Returns 0 if a barrier is found, -1 otherwise. In case of success, offset is
 * filled with the timestamp of the barrier */
int find_sync_point(char *filename_in, uint64_t *offset, int *key, int *rank)
{
	STARPU_ASSERT(offset);

	/* Open the trace file */
	int fd_in;
	fd_in = open(filename_in, O_RDONLY);
	if (fd_in < 0) {
	        perror("open failed :");
	        exit(-1);
	}

	static fxt_t fut;
	fut = fxt_fdopen(fd_in);
	if (!fut) {
	        perror("fxt_fdopen :");
	        exit(-1);
	}
	
	fxt_blockev_t block;
	block = fxt_blockev_enter(fut);

	struct fxt_ev_64 ev;

	int func_ret = -1;
	unsigned found = 0;
	while(!found) {
		int ret = fxt_next_ev(block, FXT_EV_TYPE_64, (struct fxt_ev *)&ev);
		if (ret != FXT_EV_OK) {
			fprintf(stderr, "no more block ...\n");
			break;
		}

		if (ev.code == FUT_MPI_BARRIER)
		{
			/* We found the sync point */
			*offset = ev.time;
			*rank = ev.param[0];
			*key = ev.param[2];
			found = 1;
			func_ret = 0;
		}
	}

	/* Close the trace file */
	if (close(fd_in))
	{
	        perror("close failed :");
	        exit(-1);
	}

	return func_ret;
}

/*
 *	Deal with the actual MPI transfers performed with the MPI lib
 */

/* the list of MPI transfers found in the different traces */
static struct mpi_transfer *mpi_sends[64] = {NULL};
static struct mpi_transfer *mpi_recvs[64] = {NULL};

/* number of available slots in the lists  */
unsigned mpi_sends_list_size[64] = {0};
unsigned mpi_recvs_list_size[64] = {0};

/* number of slots actually used in the list  */
unsigned mpi_sends_used[64] = {0};
unsigned mpi_recvs_used[64] = {0};

/* number of slots already matched at the beginning of the list. This permits
 * going through the lists from the beginning to match each and every
 * transfer, thus avoiding a quadratic complexity. */
unsigned mpi_recvs_matched[64] = {0};

void add_mpi_send_transfer(int src, int dst, int mpi_tag, size_t size, float date)
{
	unsigned slot = mpi_sends_used[src]++;

	if (mpi_sends_used[src] > mpi_sends_list_size[src])
	{
		if (mpi_sends_list_size[src] > 0)
		{
			mpi_sends_list_size[src] *= 2;
		}
		else {
			mpi_sends_list_size[src] = 1;
		}

		mpi_sends[src] = realloc(mpi_sends[src], mpi_sends_list_size[src]*sizeof(struct mpi_transfer));
	}

	mpi_sends[src][slot].matched = 0;
	mpi_sends[src][slot].other_rank = dst;
	mpi_sends[src][slot].mpi_tag = mpi_tag;
	mpi_sends[src][slot].size = size;
	mpi_sends[src][slot].date = date;
}

void add_mpi_recv_transfer(int src, int dst, int mpi_tag, float date)
{
	unsigned slot = mpi_recvs_used[dst]++;

	if (mpi_recvs_used[dst] > mpi_recvs_list_size[dst])
	{
		if (mpi_recvs_list_size[dst] > 0)
		{
			mpi_recvs_list_size[dst] *= 2;
		}
		else {
			mpi_recvs_list_size[dst] = 1;
		}

		mpi_recvs[dst] = realloc(mpi_recvs[dst], mpi_recvs_list_size[dst]*sizeof(struct mpi_transfer));
	}

	mpi_recvs[dst][slot].matched = 0;
	mpi_recvs[dst][slot].other_rank = dst;
	mpi_recvs[dst][slot].mpi_tag = mpi_tag;
	mpi_recvs[dst][slot].date = date;
}

struct mpi_transfer *try_to_match_send_transfer(int src, int dst, int mpi_tag)
{
	unsigned slot;
	unsigned firstslot = mpi_recvs_matched[dst];

	unsigned all_previous_were_matched = 1;

	for (slot = firstslot; slot < mpi_recvs_used[dst]; slot++)
	{
		if (!mpi_recvs[dst][slot].matched)
		{
			if (mpi_recvs[dst][slot].mpi_tag == mpi_tag)
			{
				/* we found a match ! */
				mpi_recvs[dst][slot].matched = 1;
				return &mpi_recvs[dst][slot];
			}

			all_previous_were_matched = 0;
		}
		else {
			if (all_previous_were_matched)
			{
				/* All previous transfers are already matched,
				 * we need not consider them anymore */
				mpi_recvs_matched[dst] = slot;
			}
		}
	}

	/* If we reached that point, we could not find a match */
	return NULL;
}

static unsigned long mpi_com_id = 0;

void display_all_transfers_from_trace(FILE *out_paje_file, int src)
{
	unsigned slot;
	for (slot = 0; slot < mpi_sends_used[src]; slot++)
	{
		int dst = mpi_sends[src][slot].other_rank;
		int mpi_tag = mpi_sends[src][slot].mpi_tag;
		float start_date = mpi_sends[src][slot].date;
		size_t size = mpi_sends[src][slot].size;

		struct mpi_transfer *match;
		match = try_to_match_send_transfer(src, dst, mpi_tag);

		if (match)
		{
			float end_date = match->date;

			unsigned long id = mpi_com_id++;
			/* TODO replace 0 by a MPI program ? */
			fprintf(out_paje_file, "18	%f	MPIL	MPIroot   %d	mpi_%d_p	mpicom_%ld\n", start_date, size, /* XXX */src, id);
			fprintf(out_paje_file, "19	%f	MPIL	MPIroot	  %d	mpi_%d_p	mpicom_%ld\n", end_date, size, /* XXX */dst, id);
		}
		else
		{
			fprintf(stderr, "Warning, could not match MPI transfer from %d to %d (tag %x) starting at %f\n",
												src, dst, mpi_tag, start_date);
		}

	}
}