#ifdef TNG_BUILD_OPENMP_EXAMPLES

/* This code is part of the tng binary trajectory format.
 *
 * Written by Magnus Lundborg
 * Copyright (c) 2012-2013, The GROMACS development team.
 * Check out http://www.gromacs.org for more information.
 *
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the Revised BSD License.
 */

#include "tng/tng_io.h"

#include <stdlib.h>
#include <stdio.h>


/* N.B. this code is for testing parallel reading of trajectory frame sets. The
 * performance is not improved very much and is to a large extent limited by
 * disk i/o. It can however be used as inspiration for writing parallel code
 * using the TNG library. The code is NOT fully tested and may behave strangely. */

int main(int argc, char **argv)
{
    tng_trajectory_t traj, local_traj = 0;
    union data_values ***local_positions = 0; // A 3-dimensional array to be populated
    union data_values **particle_pos = 0;
    int64_t n_particles, n_values_per_frame, n_frame_sets, n_frames;
    int64_t n_frames_per_frame_set, tot_n_frames = 0;
    char data_type;
    int i, j, fail;
    int64_t particle = 0, local_first_frame, local_last_frame;
    char atom_name[64], res_name[64];
    tng_trajectory_frame_set_t frame_set = 0;

    if(argc <= 1)
    {
        printf("No file specified\n");
        printf("Usage:\n");
        printf("tng_parallel_read <tng_file> [particle number = %"PRId64"]\n",
               particle);
        exit(1);
    }

    // A reference must be passed to allocate memory
    if(tng_trajectory_init(&traj) != TNG_SUCCESS)
    {
        tng_trajectory_destroy(&traj);
        exit(1);
    }
    tng_input_file_set(traj, argv[1]);

    tng_current_frame_set_get(traj, &frame_set);

    // Read the file headers
    tng_file_headers_read(traj, TNG_USE_HASH);

    if(argc >= 3)
    {
        particle = strtoll(argv[2], 0, 10);
    }

    tng_num_frame_sets_get(traj, &n_frame_sets);
    tng_num_frames_per_frame_set_get(traj, &n_frames_per_frame_set);

    particle_pos = malloc(sizeof(union data_values *) * n_frame_sets *
    n_frames_per_frame_set);
    for(i = n_frame_sets * n_frames_per_frame_set; i--;)
    {
        /* Assume 3 values per frame even if it's not determined yet */
        particle_pos[i] = malloc(sizeof(union data_values) * 3);
    }

    printf("%"PRId64" frame sets\n", n_frame_sets);

    if(tng_atom_name_of_particle_nr_get(traj, particle, atom_name,
                                        sizeof(atom_name)) ==
       TNG_SUCCESS &&
       tng_residue_name_of_particle_nr_get(traj, particle, res_name,
                                           sizeof(res_name)) ==
       TNG_SUCCESS)
    {
        printf("Particle: %s (%s)\n", atom_name, res_name);
    }
    else
    {
        printf("Particle name not found\n");
    }

    fail = 0;

#pragma omp parallel \
private (n_frames, n_particles, n_values_per_frame, \
         local_first_frame, local_last_frame, j, fail) \
firstprivate (local_traj, local_positions, frame_set)\
shared(data_type, traj, n_frame_sets, particle_pos, particle, i, tot_n_frames)\
default(none)
{
    /* Each tng_trajectory_t keeps its own file pointers and i/o positions.
     * Therefore there must be a copy for each thread. */
    tng_trajectory_init_from_src(traj, &local_traj);
#pragma omp for
    for(i = 0; i < n_frame_sets; i++)
    {
        if(tng_frame_set_nr_find(local_traj, i) != TNG_SUCCESS)
        {
            printf("FAILED finding frame set %d!\n", i);
            tot_n_frames = 0;
            fail = 1;
        }
        if(tng_particle_data_get(local_traj, TNG_TRAJ_POSITIONS, &local_positions,
                                 &n_frames, &n_particles, &n_values_per_frame,
                                 &data_type) != TNG_SUCCESS)
        {
            printf("FAILED getting particle data\n");
            tot_n_frames = 0;
            fail = 1;
        }
        if(!fail)
        {
            tng_current_frame_set_get(local_traj, &frame_set);
            tng_frame_set_frame_range_get(local_traj, frame_set, &local_first_frame, &local_last_frame);
    //         printf("Frame %"PRId64"-%"PRId64":\n", local_first_frame, local_last_frame);
    //         printf("%"PRId64" %"PRId64" %"PRId64"\n", n_frames, n_particles, n_values_per_frame);
            tot_n_frames += n_frames;
            for(j = 0; j < n_frames; j++)
            {
                particle_pos[local_first_frame + j][0] = local_positions[j][particle][0];
                particle_pos[local_first_frame + j][1] = local_positions[j][particle][1];
                particle_pos[local_first_frame + j][2] = local_positions[j][particle][2];
            }
        }
    }

    // Free memory
    if(local_positions)
    {
        tng_particle_data_values_free(local_traj, local_positions, n_frames, n_particles,
                                      n_values_per_frame, data_type);
    }
    tng_trajectory_destroy(&local_traj);
}
    switch(data_type)
    {
    case TNG_INT_DATA:
        for(j = 0; j < tot_n_frames; j++)
        {
            printf("\t%"PRId64"\t%"PRId64"\t%"PRId64"\n", particle_pos[j][0].i,
                   particle_pos[j][1].i, particle_pos[j][2].i);
        }
        break;
    case TNG_FLOAT_DATA:
        for(j = 0; j < tot_n_frames; j++)
        {
            printf("\t%f\t%f\t%f\n", particle_pos[j][0].f,
                   particle_pos[j][1].f, particle_pos[j][2].f);
        }
        break;
    case TNG_DOUBLE_DATA:
        for(j = 0; j < tot_n_frames; j++)
        {
            printf("\t%f\t%f\t%f\n", particle_pos[j][0].d,
                   particle_pos[j][1].d, particle_pos[j][2].d);
        }
        break;
    default:
        break;
    }

    /* Free more memory */
    for(i = n_frame_sets * n_frames_per_frame_set; i--;)
    {
        free(particle_pos[i]);
    }
    free(particle_pos);

    tng_trajectory_destroy(&traj);

    return(0);
}

#endif