#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include <math.h>
#include "common.h"

//
//  saving parameters
//
#define SAVEFREQ 10

inline int min( int a, int b ) { return a < b ? a : b; }
inline int max( int a, int b ) { return a > b ? a : b; }

void apply_all_forces(particle_t*, int, char); //defined in nbody_kernel.cu

int main( int argc, char **argv ) {    

    if( find_option( argc, argv, "-h" ) >= 0 )
    {
        printf( "Options:\n" );
        printf( "-h to see this help\n" );
        printf( "-t to enable step-by-step timing\n" );
        printf( "-n <int> to set the number of particles\n" );
        printf( "-s <int> to set the number of timesteps\n" );
        printf( "-o <filename> to specify the output file name\n" );
        return 0;
    }
 
    int step,i,j;
    char timing = 'n';
    
    int n = read_int( argc, argv, "-n", 1000 );
    int NSTEPS = read_int( argc, argv, "-s", 100);

    if( find_option(argc, argv, "-t" ) >= 0 )
        timing = 'y';

    char *savename = read_string( argc, argv, "-o", NULL );
    
    FILE *fsave = savename ? fopen( savename, "w" ) : NULL;
    particle_t *particles = (particle_t*) malloc( n * sizeof(particle_t) );
    set_size( n );
    init_particles( n, particles );
    
    for( step = 0; step < NSTEPS; step++ ) {
        //
        //  compute forces
        //  
        apply_all_forces(particles, n, timing); // This function is in kernel.cu
        //
        //  move particles
        //
        for(i = 0; i < n; i++ ) 
            move( &(particles[i]) );
        
        //
        //  save if necessary
        //
        if( fsave && (step%SAVEFREQ) == 0 )
            save( fsave, n, particles );
	}			

    printf( "n = %d\n", n);
    
    free( particles );
    if( fsave )
        fclose( fsave );
    
    return 0;
}