/* SolarSim.c */
#include "SolarSim.h"

int sock = 0;

long SIM_STEPS, DT, SAVE;

void
do_work(AState state) {
	int i, j;
	long sim_step;
	real norm_square, norm;
	int n = state->particles;
	vector *r = state->positions;
	vector *v = state->velocities;
	vector *a = state->accelerations;
	real *m = state->masses;

	sim_step = 0;
	while( sim_step < SIM_STEPS ) {
		if( (SAVE != 0) && (sim_step % SAVE == 0) ) {
			write_state(sock, state);
		}

		// compute accelerations
		memset( a, 0, n * sizeof(vector) );
		for( i = 0; i < n-1; i++ ) {
			for( j = i+1; j < n; j++ ) {
				compute_acc(r+i, r+j, v+i, v+j, a+i, a+j, m[i], m[j]);
			}
		}

		// update positions and speeds
		for( i = 0; i < n; i++ ) {
			update_pos_vel(r+i, v+i, a+i, DT);
		}

		sim_step ++;
	}

	if( SAVE != 0 )
		write_state(sock, state);
}

int
main( int argc, char **argv ) {
	TState state;
	double before, after;
	int i;

	SIM_STEPS = atol(argv[3]);
	DT = atol(argv[4]);
	SAVE = atol(argv[5]);

	if( SAVE != 0 ) {
		sock = open( argv[2], O_WRONLY | O_CREAT | O_TRUNC, 644 );
	}

	read_initial( &state, argv[1] );

	before = omp_get_wtime();
	do_work(&state);
	after = omp_get_wtime();

	if( SAVE != 0 ) {
		i = 0;
		write( sock, &i, sizeof(int) );
		close(sock);
	}

	printf("%li s %lf\n", SIM_STEPS, after-before);

	return EXIT_SUCCESS;
}