#include <stdio.h>

/* #define DEBUG 1   */

/* count3.c - example showing use of the Fril embedded foreign language
 * interface to play a "countdown" style game. Select 6 numbers (typically
 * four numbers which are less than 10 and two from {25, 50, 75, 100} and 
 * a target number in the range 100-999, then use the six numbers at most once each to 
 * create an expression involving +, -, * and / which evaluates to the target value.
 * e.g. target = 643, numbers = {1, 2, 5, 7, 25, 75}
 * expression = (((((5 - 1) * 75) + 25) * 2) - 7)
 * Mostly uses the high level interface functions. Little error checking is performed - return values from the
 * Fril interface functions are ignored, and
 * it is assumed that options arrive in the correct order. 
 *
 * Author T. P. Martin	March 2002 - beta release at best
 */


#define LOWERTARGET 100
#define UPPERTARGET 999
#define N_VALUES  (sizeof(allowed_values)/sizeof(int))
#define N_NUMBERS  6
typedef  int Boolean;
#define false 0
#define TRUE 1

static int allowed_values[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 25, 50, 75, 100};

/* dummy function needed for embedded Fril output */
output_fn(mesg)
    char           *mesg;
{
    printf("%s", mesg);

    return (1);
}
/* main  - loads the file "count3" and repeatedly runs
 * the countdown solver in Fril, reporting answers back to the
 * user.
 * Any target value outside the range 100-999 terminates the program.
 * This version uses the high level exec_fril call, and allows
 * Fril to print the result.
 */
main(int argc, char **argv)
{

    char            tmp[256];
    char            buffer[2048];
    int           err = 0;
	int values[N_NUMBERS];
	Boolean status;
	int value;


    int             output_fn();
    int             fril_ans = 1;
    int             target=0;
    int             i;

    if (initialise_fril() != 1)
		printf("couldn't initialise fril");
    else
    {
		status = exec_fril("load count3", &output_fn);
		
		while(status)
		{
			printf("Fril Countdown demo - input a target integer in the range 100-999\n");
			printf("\t and six numbers from {1, 2, 3, ..., 9, 10, 25, 50, 75, 100}\n");
			printf("\t Fril will attempt to find an arithmetic expression involving those numbers\n");
			printf("\t which evaluates to the target.\n\n");
			printf("what is the target number? (0 to finish) ");
			
			scanf("%d", &target);
			
			if ((target < 100) || (target > 999))		/* check the value - anything outside the range stops execution */
				status = false;
			else
			{
				printf("now enter %d numbers from the set: ",  N_NUMBERS);
				for(i=0; i < N_VALUES; i++ )
					printf("%d ", allowed_values[i]);
				printf("\n");
	
				for(i=0; i < N_NUMBERS; )
				{
					scanf("%d", &value);
					if (check_value(value, allowed_values, N_VALUES))
						values[i++] = value;
					printf("accepted %d numbers, %d more required\n", i, N_NUMBERS-i);
				}
				sprintf(buffer, "?((build %d (%d %d %d %d %d %d) EXPR) (pp EXPR))", target, values[0], values[1], 
									values[2], values[3], values[4], values[5]);
									
				printf("\nCalling fril with the query %s\n", buffer);
				fril_ans = exec_fril(buffer, &output_fn);
				
				while(fril_ans)
				{
					printf("\nfind another expression for %d? y/n", target);
				
					scanf("%s", tmp);
				
					fril_ans = (tmp[0] == 'y');
					if(fril_ans)
						fril_ans = resume_fril("", &output_fn);
				}
			}
		}
	}
	printf("Demo finished - thank you for playing\n");

}

/* check that an input value is in the set allowed 
 * NB in the real version, there are restrictions on how many large/small values
 * are permitted, and no there are repeats of large numbers.
 */
 Boolean check_value(int val, int *allowed, int array_size)
 {
 	Boolean found = false;
 	int i;
 	
 	for (i=0; (i<array_size) && !found; i++)
 		if(allowed[i] == val) found = TRUE;
 		
 	if(!found)
 		fprintf(stderr, "value %d ignored - not in the allowed set\n", val);
 		
 	return found;
 }