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

# include "polyomino_lp_write.h"

/******************************************************************************/

void polyomino_lp_write ( char *filename, char *label, int m, int n, int a[], 
  int b[] )

/******************************************************************************/
/*
  Purpose:

    POLYOMINO_LP_WRITE writes an LP file for the polyomino problem.

  Licensing:

    This code is distributed under the GNU LGPL license.

  Modified:

    17 May 2018

  Author:

    John Burkardt

  Parameters:

    Input, char *FILENAME, the output filename.

    Input, char *LABEL, the problem title.

    Input, int M, the number of equations

    Input, int N, the number of variables.

    Input, int A[M*N], the coefficients.

    Input, int B[M], the right hand sides.
*/
{
  bool first;
  int i;
  int j;
  FILE *output;
/*
  Open the file.
*/
  output = fopen ( filename, "w" );

  if ( ! output ) 
  {
    fprintf ( stderr, "\n" );
    fprintf ( stderr, "POLYOMINO_LP_WRITE - Error!\n" );
    fprintf ( stderr, "  Could not open the output file.\n" );
    exit ( 1 );
  }

  fprintf ( output, "%s\n", label );
  fprintf ( output, "\n" );

  fprintf ( output, "Maximize\n" );
  fprintf ( output, "  Obj: 0\n" );

  fprintf ( output, "Subject to\n" );

  for ( i = 0; i < m; i++ )
  {
    first = true;
    for ( j = 0; j< n; j++ )
    {
      if ( a[i+j*m] != 0 )
      {
        if ( a[i+j*m] < 0 )
        {
          fprintf ( output, " -" );
        }
        else if ( ! first )
        {
          fprintf ( output, " +" );
        }

        if ( abs ( a[i+j*m] ) == 1 )
        {
          fprintf ( output, " x%d", j + 1 );
        }
        else
        {
          fprintf ( output, " %d x%d", abs ( a[i+j*m] ), j + 1 );
        }
        first = false;
      }
    }
    fprintf ( output, " = %d\n", b[i] );
  }

  fprintf ( output, "Binary\n" );
  fprintf ( output, " " );
  for ( j = 0; j < n; j++ )
  {
    fprintf ( output, " x%d", j + 1 );
  }
  fprintf ( output, "\n" );

  fprintf ( output, "End\n" );
/*
  Close the file.
*/
  fclose ( output );

  return;
}
/******************************************************************************/

void timestamp ( )

/******************************************************************************/
/*
  Purpose:

    TIMESTAMP prints the current YMDHMS date as a time stamp.

  Example:

    17 June 2014 09:45:54 AM

  Licensing:

    This code is distributed under the GNU LGPL license. 

  Modified:

    17 June 2014

  Author:

    John Burkardt

  Parameters:

    None
*/
{
# define TIME_SIZE 40

  static char time_buffer[TIME_SIZE];
  const struct tm *tm;
  time_t now;

  now = time ( NULL );
  tm = localtime ( &now );

  strftime ( time_buffer, TIME_SIZE, "%d %B %Y %I:%M:%S %p", tm );

  printf ( "%s\n", time_buffer );

  return;
# undef TIME_SIZE
}