#include <string.h>
#include <stdio.h>
#include "fitsio.h"

int main(int argc, char *argv[])
{
    fitsfile *infptr, *outfptr;  /* FITS file pointers */
    int status = 0;   /* CFITSIO status value MUST be initialized to zero! */
    int icol, incols, outcols, intype, outtype, hdunum, check = 1;
    long inrep, outrep, width, inrows, outrows, ii, jj;
    unsigned char *buffer = 0;

    if (argc != 3) { 
      printf("Usage:  tabmerge infile1[ext][filter] outfile[ext]\n");
      printf("\n");
      printf("Merge 2 tables by copying all the rows from the 1st table\n");
      printf("into the 2nd table.  The  2 tables must have identical\n");
      printf("structure, with the same number of columns with the same\n");
      printf("datatypes.  This program modifies the output file in place,\n");
      printf("rather than creating a whole new output file.\n");
      printf("\n");
      printf("Examples: \n");
      printf("\n");
      printf("1. tabmerge intab.fit+1 outtab.fit+2\n");
      printf("\n");
      printf("    merge the table in the 1st extension of intab.fit with\n");
      printf("    the table in the 2nd extension of outtab.fit.\n");
      printf("\n");
      printf("2. tabmerge 'intab.fit+1[PI > 45]' outab.fits+2\n");
      printf("\n");
      printf("    Same as the 1st example, except only rows that have a PI\n");
      printf("    column value > 45 will be merged into the output table.\n");
      printf("\n");
      return(0);
    }

    /* open both input and output files and perform validity checks */
    if ( fits_open_file(&infptr,  argv[1], READONLY,  &status) ||
         fits_open_file(&outfptr, argv[2], READWRITE, &status) )
        printf(" Couldn't open both files\n");
        
    else if ( fits_get_hdu_type(infptr,  &intype,  &status) ||
              fits_get_hdu_type(outfptr, &outtype, &status) )
        printf("couldn't get the type of HDU for the files\n");

    else if (intype == IMAGE_HDU)
        printf("The input HDU is an image, not a table\n");

    else if (outtype == IMAGE_HDU)
        printf("The output HDU is an image, not a table\n");

    else if (outtype != intype)
        printf("Input and output HDUs are not the same type of table.\n");

    else if ( fits_get_num_cols(infptr,  &incols,  &status) ||
              fits_get_num_cols(outfptr, &outcols, &status) )
        printf("Couldn't get number of columns in the tables\n");

    else if ( incols != outcols )
        printf("Input and output HDUs don't have same # of columns.\n");        

    else if ( fits_read_key(infptr, TLONG, "NAXIS1", &width, NULL, &status) )
        printf("Couldn't get width of input table\n");

    else if (!(buffer = (unsigned char *) malloc(width)) )
        printf("memory allocation error\n");

    else if ( fits_get_num_rows(infptr,  &inrows,  &status) ||
              fits_get_num_rows(outfptr, &outrows, &status) )
        printf("Couldn't get the number of rows in the tables\n");

    else  {
        /* check that the corresponding columns have the same datatypes */
        for (icol = 1; icol <= incols; icol++) {
            fits_get_coltype(infptr,  icol, &intype,  &inrep,  NULL, &status);
            fits_get_coltype(outfptr, icol, &outtype, &outrep, NULL, &status);
            if (intype != outtype || inrep != outrep) {
                printf("Column %d is not the same in both tables\n", icol);
                check = 0;
            }
        }

        if (check && !status) 
        {
            /* insert 'inrows' empty rows at the end of the output table */
            fits_insert_rows(outfptr, outrows, inrows, &status);

            for (ii = 1, jj = outrows +1; ii <= inrows; ii++, jj++)
            {
                /* read row from input and write it to the output table */
                fits_read_tblbytes( infptr,  ii, 1, width, buffer, &status);
                fits_write_tblbytes(outfptr, jj, 1, width, buffer, &status);
                if (status)break;  /* jump out of loop if error occurred */
            }

            /* all done; now free memory and close files */
            fits_close_file(outfptr, &status);
            fits_close_file(infptr,  &status); 
        }
    }

    if (buffer)
        free(buffer);

    if (status) fits_report_error(stderr, status); /* print any error message */
    return(status);
}