#define _DEBUG
#include <assert.h>
#include <sys/signalfd.h>
#include <signal.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <poll.h>
#include <sys/timerfd.h>
#include <fcntl.h>              /* Obtain O_* constant definitions */
#include <vector>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int
main(int argc, char *argv[])
{
	int wr_fds[2] = { -1, -1 };
	int rd_fds[2] = { -1, -1 };
	int status;

	int
	res = pipe(rd_fds);
	assert(res != -1);

	res = pipe(wr_fds);
	assert(res != -1);

	fcntl(wr_fds[0], F_SETPIPE_SZ, sizeof(int));
	fcntl(wr_fds[1], F_SETPIPE_SZ, sizeof(int));
	fcntl(rd_fds[0], F_SETPIPE_SZ, sizeof(int));
	fcntl(rd_fds[1], F_SETPIPE_SZ, sizeof(int));

	int count = atoi(argv[1]);
	int delay = atoi(argv[2]);

	pid_t ppid = fork();
	if (ppid) {

		sigset_t mask;

		sigfillset(&mask);
		sigprocmask(SIG_BLOCK, &mask, NULL);

		close(wr_fds[0]);
		close(rd_fds[1]);

		fprintf(stderr, "%s: STARTED\n", __FUNCTION__);

		while (--count) {

			if (waitpid(ppid, &status, WNOHANG)) break;

			int cmd = count % 2;

			if (write(wr_fds[1], &cmd, sizeof(cmd)) < 0) break;
			printf("%s: sent %d\n", __FUNCTION__, cmd);

			if (read(rd_fds[0], &cmd, sizeof(cmd)) < 0) break;
			printf("%s: ack %d\n", __FUNCTION__, cmd);

			usleep(delay * 1000);
		}

		fprintf(stderr, "%s: FINISHED\n", __FUNCTION__);

		wait(&status);

		return 0;

	} else {

		//
		// test 10 1000 perf stat -cmd-fd 1 --cmd-ack-fd 2 -vvv ....

		// wr_fds[0] == cmd-fd
		close(wr_fds[1]);
		// rd_fds[1] == cmd-ack-fd
		close(rd_fds[0]);

		std::vector<char*> new_argv;
		new_argv.push_back(argv[3]); // perfstat
		new_argv.push_back(argv[4]); // stat

		std::vector<char> buff(64, '\0');
		new_argv.push_back("--cmd-fd");
		snprintf(&buff[0], 64, "%d", wr_fds[0]);
		new_argv.push_back(&buff[0]);

		std::vector<char> buff2(64, '\0');
		new_argv.push_back("--cmd-ack-fd");
		snprintf(&buff2[0], 64, "%d", rd_fds[1]);
		new_argv.push_back(&buff2[0]);

		int i = 5;
		for (; argv[i]; i++)
			new_argv.push_back(argv[i]);

		new_argv.push_back(NULL);

		execv(argv[3], &new_argv[0]);
	}
}