/**
 * iota.c
 *   An extension to GIMP that provides something like Scheme's iota
 *   function.   CURRENTLY BROKEN.
 *
 *   Copyright (c) 2013 Samuel A. Rebelsky.  All rights reserved.
 *
 *   This file is part of The Glimmer Guide to GIMP Plugins (aka GGGP).
 *
 *   GGGP 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.
 *
 *   GGGP 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 GGGP.  If not, see <http://www.gnu.org/licenses/>.
 */


// +---------+---------------------------------------------------------
// | Headers |
// +---------+

#include <libgimp/gimp.h>

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


// +--------+----------------------------------------------------------
// | Macros |
// +--------+

/**
 * Print a string (somewhere).  Right now, this prints to stderr, which
 * means it only works when the program is run from the terminal.
 */
#define REPORT(str) fprintf (stderr, "*** %s ***\n", str)

/**
 * Print an integer.
 */
#define REPORT_INT(i) fprintf (stderr, "*** %s: %d ***\n", #i, i)


// +--------------------------+----------------------------------------
// | Function Predeclarations |
// +--------------------------+

static void query (void);
static void run (const gchar *name,
                       gint nparams,
                       const GimpParam *params,
                       gint *nreturn_vals,
                       GimpParam **return_vals);


// +-------------+-----------------------------------------------------
// | Boilerplate |
// +-------------+

/**
 * The four key functions.  This structure *must* be called PLUG_IN_INFO.
 */
GimpPlugInInfo PLUG_IN_INFO =
  {
    NULL,
    NULL,
    query,
    run
  };

/**
 * Indicate that we're ready to begin the main part of the code.
 */
MAIN ()


// +-------------------------+-----------------------------------------
// | Standard GIMP Functions |
// +-------------------------+

static void
init (void)
{
} // init

static void
quit (void)
{
} // quit

static void 
query (void)
{
  // Build the description of the parameters that the function expects.  
  // Each parameter has a type, a name, and a description
  // All plug-ins must take a run-mode.   Plug-ins associated with an
  // image
  static GimpParamDef args[] =
    {
      { GIMP_PDB_INT32, "n", "number of elements in array" }
    }; // args

  static GimpParamDef returns[]=
    {
      { GIMP_PDB_INT32, "nvalues", "number of values in the array" },
      { GIMP_PDB_INT32ARRAY, "values", "numbers from 0 to n-1" }
    }; // returns

  // Tell the GIMP about our plugin.
  gimp_install_procedure (
    "gggp/iota",                                        // Name
    "Make an array of numbers from 0 to n-1, inclusive",// Blurb
    "Make an array of numbers from 0 to n-1, inclusive",// Help
    "Samuel A. Rebelsky",                               // Author
    "Copyright (c) Samuel A. Rebelsky.  All rights reserved.",
                                                        // Copyright
    "2013",                                             // Year
    "",                                                 // Path
    "",                                                 // Image types
    GIMP_PLUGIN,                                        // Type
    1,                                                  // Number of params
    2,                                                  // Number of return vals
    args,                                               // Param descriptions
    returns                                             // Return descriptions
    );

} // query

static void
run (const gchar      *name,
           gint              nparams,
           const GimpParam  *params,
           gint             *nreturn_vals,
           GimpParam       **return_vals)
{

  // Prepare status
  static GimpParam results[3];
  results[0].type = GIMP_PDB_STATUS;
  results[0].data.d_status = GIMP_PDB_SUCCESS;
  *nreturn_vals = 3;
  *return_vals = results;

  // Grab the parameter
  int n = params[0].data.d_int32;

  // Build the array
  int *numbers = malloc (n * sizeof (int));
  int i;
  for (i = 0; i < n; i++)
    numbers[i] = i;

  // Fill in the return values
  results[1].type = GIMP_PDB_INT32;
  results[1].data.d_int32 = n;
  results[2].type = GIMP_PDB_INT32ARRAY;
  results[2].data.d_int32array = numbers;
} // run