/*----------------------------------------------------------------------
  SerialReax - Reax Force Field Simulator

  Copyright (2010) Purdue University
  Hasan Metin Aktulga, haktulga@cs.purdue.edu
  Joseph Fogarty, jcfogart@mail.usf.edu
  Sagar Pandit, pandit@usf.edu
  Ananth Y Grama, ayg@cs.purdue.edu

  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; either version 2 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 General Public License for more details:
  <http://www.gnu.org/licenses/>.
  ----------------------------------------------------------------------*/

#include "mytypes.h"
#include "analyze.h"
#include "control.h"
#include "ffield.h"
#include "forces.h"
#include "init_md.h"
#include "neighbors.h"
#include "geo_tools.h"
#include "print_utils.h"
#include "reset_utils.h"
#include "restart.h"
#include "system_props.h"
#include "vector.h"


static void Post_Evolve( reax_system * const system,
        control_params * const control,
        simulation_data * const data,
        static_storage * const workspace,
        list ** const lists,
        output_controls * const out_control )
{
    int i;
    rvec diff, cross;

    /* if velocity dependent force then
       {
       Generate_Neighbor_Lists( &system, &control, &lists );
       Compute_Charges(system, control, workspace, lists[FAR_NBRS]);
       Introduce compute_force here if we are using velocity dependent forces
       Compute_Forces(system,control,data,workspace,lists);
       } */

    /* compute kinetic energy of the system */
    Compute_Kinetic_Energy( system, data );

    /* remove rotational and translational velocity of the center of mass */
    if ( control->ensemble != NVE &&
            control->remove_CoM_vel &&
            data->step && data->step % control->remove_CoM_vel == 0 )
    {

        /* compute velocity of the center of mass */
        Compute_Center_of_Mass( system, data, out_control->prs );

        for ( i = 0; i < system->N; i++ )
        {
            // remove translational
            rvec_ScaledAdd( system->atoms[i].v, -1., data->vcm );

            // remove rotational
            rvec_ScaledSum( diff, 1., system->atoms[i].x, -1., data->xcm );
            rvec_Cross( cross, data->avcm, diff );
            rvec_ScaledAdd( system->atoms[i].v, -1., cross );
        }
    }
}


void static Read_System( char * const geo_file,
        char * const ffield_file,
        char * const control_file,
        reax_system * const system,
        control_params * const control,
        simulation_data * const data,
        static_storage * const workspace,
        output_controls * const out_control )
{
    FILE *ffield, *ctrl;

    if ( (ffield = fopen( ffield_file, "r" )) == NULL )
    {
        fprintf( stderr, "Error opening the ffield file!\n" );
        exit( FILE_NOT_FOUND );
    }
    if ( (ctrl = fopen( control_file, "r" )) == NULL )
    {
        fprintf( stderr, "Error opening the ffield file!\n" );
        exit( FILE_NOT_FOUND );
    }

    /* ffield file */
    Read_Force_Field( ffield, &(system->reaxprm) );

    /* control file */
    Read_Control_File( ctrl, system, control, out_control );

    /* geo file */
    if ( control->geo_format == CUSTOM )
    {
        Read_Geo( geo_file, system, control, data, workspace );
    }
    else if ( control->geo_format == PDB )
    {
        Read_PDB( geo_file, system, control, data, workspace );
    }
    else if ( control->geo_format == BGF )
    {
        Read_BGF( geo_file, system, control, data, workspace );
    }
    else if ( control->geo_format == ASCII_RESTART )
    {
        Read_ASCII_Restart( geo_file, system, control, data, workspace );
        control->restart = 1;
    }
    else if ( control->geo_format == BINARY_RESTART )
    {
        Read_Binary_Restart( geo_file, system, control, data, workspace );
        control->restart = 1;
    }
    else
    {
        fprintf( stderr, "unknown geo file format. terminating!\n" );
        exit( INVALID_GEO );
    }

#if defined(DEBUG_FOCUS)
    fprintf( stderr, "input files have been read...\n" );
    Print_Box( &(system->box), stderr );
#endif
}


static void usage(char* argv[])
{
    fprintf(stderr, "usage: ./%s geometry ffield control\n", argv[0]);
}


int main(int argc, char* argv[])
{
    reax_system system;
    control_params control;
    simulation_data data;
    static_storage workspace;
    list *lists;
    output_controls out_control;
    evolve_function Evolve;
    int steps;

    if ( argc != 4 )
    {
        usage(argv);
        exit( INVALID_INPUT );
    }

    lists = (list*) malloc( sizeof(list) * LIST_N );

    Read_System( argv[1], argv[2], argv[3], &system, &control,
                 &data, &workspace, &out_control );

    Initialize( &system, &control, &data, &workspace, &lists,
                &out_control, &Evolve );

    /* compute f_0 */
    //if( control.restart == 0 ) {
    Reset( &system, &control, &data, &workspace, &lists );
    Generate_Neighbor_Lists( &system, &control, &data, &workspace,
                             &lists, &out_control );

    //fprintf( stderr, "total: %.2f secs\n", data.timing.nbrs);
    Compute_Forces(&system, &control, &data, &workspace, &lists, &out_control);
    Compute_Kinetic_Energy( &system, &data );
    Output_Results(&system, &control, &data, &workspace, &lists, &out_control);
    ++data.step;
    //}
    //


    for ( ; data.step <= control.nsteps; data.step++ )
    {
        if ( control.T_mode )
        {
            Temperature_Control( &control, &data, &out_control );
        }
        Evolve( &system, &control, &data, &workspace, &lists, &out_control );
        Post_Evolve( &system, &control, &data, &workspace, &lists, &out_control );
        Output_Results(&system, &control, &data, &workspace, &lists, &out_control);
        Analysis( &system, &control, &data, &workspace, &lists, &out_control );

        steps = data.step - data.prev_steps;
        if ( steps && out_control.restart_freq &&
                steps % out_control.restart_freq == 0 )
            Write_Restart( &system, &control, &data, &workspace, &out_control );
    }

    if ( out_control.write_steps > 0 )
    {
        fclose( out_control.trj );
        Write_PDB( &system, &(lists[BONDS]), &data, &control, &workspace, &out_control );
    }

    data.timing.end = Get_Time( );
    data.timing.elapsed = Get_Timing_Info( data.timing.start );
    fprintf( out_control.log, "total: %.2f secs\n", data.timing.elapsed );

    return SUCCESS;
}