#include <mariadb/mysql.h>
#include <stdlib.h>
#include <stdio.h>
#include <poll.h>

static int wait_for_mysql(MYSQL *mysql, int status) {
  struct pollfd pfd;
  int timeout, res;

  pfd.fd = mysql_get_socket(mysql);
  pfd.events =
    (status & MYSQL_WAIT_READ ? POLLIN : 0) |
    (status & MYSQL_WAIT_WRITE ? POLLOUT : 0) |
    (status & MYSQL_WAIT_EXCEPT ? POLLPRI : 0);
  if (status & MYSQL_WAIT_TIMEOUT)
    timeout = 1000*mysql_get_timeout_value(mysql);
  else
    timeout = -1;
  res = poll(&pfd, 1, timeout);
  if (res == 0)
    return MYSQL_WAIT_TIMEOUT;
  else if (res < 0)
    return MYSQL_WAIT_TIMEOUT;
  else {
    int status = 0;
    if (pfd.revents & POLLIN) status |= MYSQL_WAIT_READ;
    if (pfd.revents & POLLOUT) status |= MYSQL_WAIT_WRITE;
    if (pfd.revents & POLLPRI) status |= MYSQL_WAIT_EXCEPT;
    return status;
  }
}

void die(char const *msg)
{
    fprintf(stderr, "error in %s\n", msg);
    exit(2);
}

int main()
{
    char const *host = getenv("OCAML_MARIADB_HOST");
    char const *user = getenv("OCAML_MARIADB_USER");
    char const *pass = getenv("OCAML_MARIADB_PASS");
    char const *db = getenv("OCAML_MARIADB_DB");
    MYSQL *ret;
    int status;
    for (int i = 0; i < 500000; ++i) {
	MYSQL *mysql = mysql_init(NULL);
	mysql_options(mysql, MYSQL_OPT_NONBLOCK, 0);

	status = mysql_real_connect_start(&ret, mysql, host, user, pass, db, 3306, NULL, 0);
	while (status) {
	    status = wait_for_mysql(mysql, status);
	    status = mysql_real_connect_cont(&ret, mysql, status);
	}
	if (!ret) die("mysql_real_connect_*");

	status = mysql_close_start(mysql);
	while (status) {
	    status = wait_for_mysql(mysql, status);
	    status = mysql_close_cont(mysql, status);
	}
    }
}