/* vim: set sw=8: -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
 * eg-beginner:        examples #1 for beginners
 *
 * Authors:
 *   Lloyd ALLISON     Lloyd.Allison@infotech.monash.edu.au  10/2003
 *     from bits in gnumeric_1.2.0 and particularly plugins/fn_d@te,
 *     and writing-functions.sgml (which is maybe not uptodate?)
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include <gnumeric-config.h>
#include <gnumeric-i18n.h>
#include <gnumeric.h>
#include <func.h>

#include <parse-util.h>
#include <str.h>
#include <cell.h>
#include <value.h>
#include <mathfunc.h>
#include <format.h>
#include <workbook.h>
#include <sheet.h>

#include <math.h>
#include <string.h>
#include <stdlib.h>

#include "plugin.h"
#include "plugin-util.h"
#include "module-plugin-defs.h"

GNUMERIC_MODULE_PLUGIN_INFO_DECL;

/***************************************************************************/
/* For each function, blah, define a help_blah and blah code               */
/* then add them to the data-structure at the end of the file.             */
/* Also see the README.html in this directory.                             */

static char const * help_add2numbers = {
	N_("@FUNCTION=add2numbers\n"
	   "@SYNTAX=add2numbers(number,number)\n"
	   "@DESCRIPTION="
	   "toy demonstration function (it adds two numbers)\n"
           "to illustrate how to extend gnumeric.\n"
	   "\n"
	   "@EXAMPLES=\n"
	   "add2numbers(1,1) returns 2, in principle.\n "
	   "\n" )
};     /* the above is shown in gnumeric's `Insert' / `Function Selector' */


/* following based on gnumeric-1.2.0/doc/developer/writing-functions.sgml */

static GnmValue *
add2numbers (FunctionEvalInfo *ei, GnmValue **argv)
{
	float number_a, number_b;

	switch (argv [0] -> type){
	case VALUE_INTEGER:
		number_a = value_get_as_int (argv [0]);
		break;

	case VALUE_FLOAT:
		number_a = value_get_as_float (argv [0]);
		break;

	default:
	        return value_new_error (&ei->pos, "Invalid argument type");
	}

	switch (argv [1] -> type){
	case VALUE_INTEGER:
		number_b = value_get_as_int (argv [1]);
		break;

	case VALUE_FLOAT:
		number_b = value_get_as_float (argv [1]);
		break;

	default:
	        return value_new_error (&ei->pos, "Invalid argument type");
	}

	return value_new_float (number_a + number_b);
}

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

static char const * help_eg_rangefn = {
        N_("@FUNCTION=eg_rangefn\n"
           "@SYNTAX=eg_rangefn(dataset)\n"
           "@DESCRIPTION="
           "toy demonstration function on a range\n"
           "\n"
           "@EXAMPLES=\n"
           "eg_rangefn(A1:B5).\n "
           "\n" )
};

/* worth looking in e.g.  plugins/fn-stat/functions.c */

static GnmValue *
eg_rangefn (FunctionEvalInfo *ei, GnmValue **argv)
{
	int		height = 0, width = 0;

	if (argv[0] == NULL
	|| (argv[0]->type != VALUE_ARRAY && argv[0]->type != VALUE_CELLRANGE))
		return value_new_error (&ei->pos, "Invalid argument type");

	if (argv[0]->type == VALUE_CELLRANGE) {
		width  = argv[0]->v_range.cell.b.col
		       - argv[0]->v_range.cell.a.col + 1;
		height = argv[0]->v_range.cell.b.row
		       - argv[0]->v_range.cell.a.row + 1;

		return value_new_int (height * width); /* something to do */

	} /* VALUE_CELLRANGE */

	else /* VALUE_ARRAY */
		return value_new_error (&ei->pos, "array not yet implemented");

} /* eg_rangefn */

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


/*  ??? what about the GNM_... flags below */

GnmFuncDescriptor const beginner_functions[] = {         /* see src/func.h */

	{ "add2numbers",                 /* name */
	  "ff",                          /* args, takes 2 floats (or ints) */
	  N_("number,number"),           /* arg names */
	  &help_add2numbers,             /* Help stuff,  see above */
	  add2numbers,                   /* Code proper, see above */
	  NULL,                          /* fn_args  ??? */
          NULL,                          /* linker   ??? */
          NULL,                          /* unlinker ??? */
          NULL,                          /* ref_notify ??? */
	  GNM_FUNC_SIMPLE,               /* flags ??? */
	  GNM_FUNC_IMPL_STATUS_COMPLETE, /* impl_status ??? */
          GNM_FUNC_TEST_STATUS_BASIC     /* test_status ??? */
        },

        { "eg_rangefn",
          "A",                           /* NB. A == range or array */
          N_("dataset"),
          &help_eg_rangefn,
          eg_rangefn,
          NULL, NULL, NULL, NULL,
          GNM_FUNC_SIMPLE,
          GNM_FUNC_IMPL_STATUS_COMPLETE,
          GNM_FUNC_TEST_STATUS_BASIC
	},
 
        {NULL}                           /* end of sequence */
};

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