/* 
 * counters_intersect.c - test intersection of two counters
 *
 * CS50, Spring 2022
 */

#include <stdio.h>
#include <stdlib.h>
#include "libcs50/counters.h"
#include "libcs50/memory.h"

/******** local data types *******/
struct twocts {
	counters_t *result;
	counters_t *another;
};

/******** local function prototypes *******/
void counters_intersect(counters_t* ct1, counters_t* ct2); 
void intersect_helper(void *arg, const int key, const int count);

static inline int min(const int a, const int b) {
  return (a < b ? a : b);
}

/******** main *******/
int main()
{
	// create two counters for demo
	counters_t *c1 = assertp(counters_new(), "counters_new() failed");
	counters_t *c2 = assertp(counters_new(), "counters_new() failed");

	// init counters 1
	counters_set(c1, 3, 6);
	counters_set(c1, 4, 7);
	counters_set(c1, 5, 1);
	counters_set(c1, 7, 4);

	// init counters 2
	counters_set(c2, 1, 3);
	counters_set(c2, 3, 2);
	counters_set(c2, 5, 4);
	counters_set(c2, 6, 6);
	counters_set(c2, 7, 3);

	// take the intersection, store the results in c1
	counters_intersect(c1, c2);
	counters_print(c1, stdout);
	printf("\n");

	// clean up
	counters_delete(c1);
	counters_delete(c2);

	return 0;
}

// TODO: fill in this function
void counters_intersect(counters_t* ct1, counters_t* ct2)
{
	assertp(ct1, "counters 1 invalid");
	assertp(ct2, "counters 2 invalid");

	struct twocts args = {ct1, ct2}; 
	counters_iterate(ct1, &args, intersect_helper);
}

void intersect_helper(void *arg, const int key, const int count)
{
	struct twocts *two = arg; 

	counters_set(two->result, key, min(count, counters_get(two->another, key)));
}