/* Reading and writing table columns.
 *
 * This example program reads three columns from a table. Having the
 * columns in memory, it will print them out along with their sum. The
 * rest of the program is a demonstration of writing a table.
 *
 * Copyright (C) 2024      Your Name <your@@email.address>
 * Copyright (C) 2020-2024 Mohammad Akhlaghi <mohammad@@akhlaghi.org>
 *
 * 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 3 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

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

#include <gnuastro/table.h>

int
main(void)
{
  /* File names and column names (which may also be numbers). */
  char *c1_name="NAME1", *c2_name="NAME2", *c3_name="10";
  char *inname="input.fits", *hdu="1", *outname="out.fits";

  /* Internal parameters. */
  float *array2=NULL;
  double *array3=NULL;
  int32_t *array1=NULL;
  size_t i, counter=0;
  gal_data_t *c1=NULL;
  gal_data_t *c2=NULL;
  gal_data_t tmp, *col, *columns;
  gal_list_str_t *column_ids=NULL;

  /* Define the columns to read. */
  gal_list_str_add(&column_ids, c1_name, 0);
  gal_list_str_add(&column_ids, c2_name, 0);
  gal_list_str_add(&column_ids, c3_name, 0);

  /* The columns were added in reverse, so correct it. */
  gal_list_str_reverse(&column_ids);

  /* Read the desired columns. */
  columns = gal_table_read(inname, hdu, NULL, column_ids,
                           GAL_TABLE_SEARCH_NAME, 0, 1, -1, 1, NULL);

  /* Go over the columns, we will assume that you do not know their type
   * a-priori, so we will check  */
  counter=1;
  for(col=columns; col!=NULL; col=col->next)
    switch(counter++)
      {
      case 1:              /* First column: we want it as int32_t. */
        c1=gal_data_copy_to_new_type(col, GAL_TYPE_INT32);
        array1 = c1->array;
        break;

      case 2:              /* Second column: we want it as float.  */
        c2=gal_data_copy_to_new_type(col, GAL_TYPE_FLOAT32);
        array2 = c2->array;
        break;

      case 3:              /* Third column: it MUST be double.     */
        if(col->type!=GAL_TYPE_FLOAT64)
          {
            fprintf(stderr, "Column %s must be float64 type, it is "
                    "%s", c3_name, gal_type_name(col->type, 1));
            exit(EXIT_FAILURE);
          }
        array3 = col->array;
        break;

      default:
        exit(EXIT_FAILURE);
      }

  /* As an example application we will just print them out. In the
   * meantime (just for a simple demonstration), change the first
   * array value to the counter and multiply the second by 10. */
  for(i=0;i<c1->size;++i)
    {
      printf("%zu: %d + %f + %f = %f\n", i+1, array1[i], array2[i],
             array3[i], array1[i]+array2[i]+array3[i]);
      array1[i]  = i+1;
      array2[i] *= 10;
    }

  /* Link the first two columns as a list. */
  c1->next = c2;
  c2->next = NULL;

  /* Set names for the columns and write them out. */
  c1->name = "COUNTER";
  c2->name = "VALUE";
  gal_table_write(c1, NULL, NULL, GAL_TABLE_FORMAT_BFITS, outname,
                  "MY-COLUMNS", 0, 0);

  /* The names were not allocated, so to avoid cleaning-up problems,
   * we will set them to NULL. */
  c1->name = c2->name = NULL;

  /* Clean up and return.  */
  gal_data_free(c1);
  gal_data_free(c2);
  gal_list_data_free(columns);
  gal_list_str_free(column_ids, 0); /* strings were not allocated. */
  return EXIT_SUCCESS;
}