/* Filename:	color_test.c
 * Purpose:	Show usage of function pointers in a small example
 *		that shows having handlers to processing certain colors
 *		in a small little program
 * Author:	Alain Hoang
 */

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

/** Function declarations **/
int handle_orange(char *str);
int handle_red(char *str);
int handle_green(char *str);
int handle_blue(char *str);
int handle_yellow(char *str);

/** Globals **/

/* An enum to hold all the types of colors.  END is a special type that
 * signifies the end
 *
 * enums are ints by default
 *
 * Might have been useful to use a typedef on the enum type
 */
enum {
	ORANGE,		/* ORANGE = 0 */
	RED,		/* RED    = 1 */
	GREEN,		/* GREEN  = 2 */
	BLUE,		/* BLUE   = 3 */
	YELLOW,		/* YELLOW = 4 */
	END			/* END    = 5 */
};

/* The struct we're using to hold the color type and the test to run when
 * we see that color type
 */
struct colors {
	int type;					/* What color type am I */
	int (*color_handler)(char *);
};

/* Define a table of for determining which type of color it is.
 * The first field in the struct determines the color type
 * The second field is a pointer to a function which handles what to do
 * with the color
 */
struct colors color_table[] = {
	{ ORANGE,  handle_orange },
	{ RED,     handle_red },
	{ GREEN,   handle_green },
	{ BLUE,    handle_blue },
	{ YELLOW,  handle_yellow },
	{ END,     0 }
};

int
main(int ac, char *av[])
{

	int i;

	/* Argument parsing.  Make sure appropriate args and that the type
	 * doesn't exceed the number of known types
	 */
	if (ac != 3) {
		printf("Usage: fp_test <type> <name>");
		exit(1);
	}
	if (atoi(av[1]) >= END) {
		printf("Type is too large.  Try a value smaller than %d\n", END);
		exit(1);
	}

	/* Loop through the table and find the appropriate type.  If we find one
	 * then we call that handler with the 3rd argument as the name
	 */
	for (i = 0; color_table[i].type != END; i++) {
		if(color_table[i].type == atoi(av[1])) {
			color_table[i].color_handler(av[2]);
		}
	}

	return 0;
}


/*
 * Handlers for the colors.  All follow the same structure.
 * args: str - A string identifying the name of the object
 * returns: An int, 0 means success
 *
 * NOTES: It might be better to put all the handlers in their own file
 * for slightly better modularization.
 */

int handle_orange(char *str)
{
	printf("%s is orange\n", str);
	return 0;
}

int handle_green(char *str)
{
	printf("%s is green\n", str);
	return 0;
}

int handle_red(char *str)
{
	printf("%s is red\n", str);
	return 0;
}

int handle_blue(char *str)
{
	printf("%s is blue\n", str);
	return 0;
}

int handle_yellow(char *str)
{
	printf("%s is yellow\n", str);
	return 0;
}