#include <liburing.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/resource.h>
#include <unistd.h>

static const int RSIZE = 2;
static const int OPEN_FLAGS = O_RDWR | O_CREAT;
static const mode_t OPEN_MODE = S_IRUSR | S_IWUSR;

#define DIE(...) do {\
		fprintf(stderr, __VA_ARGS__);\
		abort();\
	} while(0);

void do_write(struct io_uring *ring, int sync, int fd, off_t offset)
{
	fprintf(stderr, "%s write at offset %lld\n", sync ? "sync": "io_uring", offset);
	char buf[] = "some test write buf";
	int res;
	if (sync) {
		res = pwrite(fd, buf, sizeof(buf), offset);
		if (res < 0) {
			res = -errno;
		}
	}
	else {
		struct io_uring_sqe *sqe;
		sqe = io_uring_get_sqe(ring);
		if (!sqe) {
			fprintf(stderr, "failed to get sqe\n");
			return;
		}
		io_uring_prep_write(sqe, fd, buf, sizeof(buf), offset);
		int ret = io_uring_submit(ring);
		if (ret < 0) {
			fprintf(stderr, "failed to submit write: %s\n", strerror(-ret));
			return;
		}

		struct io_uring_cqe *cqe;
		ret = io_uring_wait_cqe(ring, &cqe);
		res = cqe->res;
		io_uring_cqe_seen(ring, cqe);
		if (ret < 0) {
			fprintf(stderr, "wait_cqe failed: %s\n", strerror(-ret));
			return;
		}
	}
	if (res < 0) {
		fprintf(stderr, "write failed: %s\n", strerror(-res));
	}
	else {
		fprintf(stderr, "write succeeded\n");
	}
}

void test_open_write(struct io_uring *ring, int sync_open, int sync_write, int dfd, const char* fn)
{
	fprintf(stderr, "\n*** %s openat\n", sync_open ? "sync" : "io_uring");
	struct io_uring_sqe *sqe;
	int fd = -1;
	if (sync_open) {
		fd = openat(dfd, fn, OPEN_FLAGS, OPEN_MODE);
		if (fd < 0) {
			fd = -errno;
		}
	}
	else {
		sqe = io_uring_get_sqe(ring);
		if (!sqe) {
			fprintf(stderr, "failed to get sqe\n");
			return;
		}
		io_uring_prep_openat(sqe, dfd, fn, OPEN_FLAGS, OPEN_MODE);
		int ret = io_uring_submit(ring);
		if (ret < 0) {
			fprintf(stderr, "failed to submit openat: %s\n", strerror(-ret));
			return;
		}

		struct io_uring_cqe *cqe;
		ret = io_uring_wait_cqe(ring, &cqe);
		fd = cqe->res;
		io_uring_cqe_seen(ring, cqe);
		if (ret < 0) {
			fprintf(stderr, "wait_cqe failed: %s\n", strerror(-ret));
			return;
		}
	}
	if (fd < 0) {
		fprintf(stderr, "openat failed: %s\n", strerror(-fd));
	}
	else {
		fprintf(stderr, "openat succeeded\n");
		do_write(ring, sync_write, fd, 0);
		do_write(ring, sync_write, fd, 1ull << 32);
		close(fd);
	}
}

int main()
{
	int dfd = open("/tmp", O_RDONLY | O_DIRECTORY);
	if (dfd < 0) {
		DIE("open /tmp: %s\n", strerror(errno));
	}
	struct io_uring ring;
	int ret = io_uring_queue_init(RSIZE, &ring, 0);
	if (ret < 0) {
		DIE("failed to init io_uring: %s\n", strerror(-ret));
	}

	test_open_write(&ring, 1, 1, dfd, "io_uring_openat_write_test1");
	test_open_write(&ring, 1, 0, dfd, "io_uring_openat_write_test2");
	test_open_write(&ring, 0, 1, dfd, "io_uring_openat_write_test3");
	test_open_write(&ring, 0, 0, dfd, "io_uring_openat_write_test4");

	io_uring_queue_exit(&ring);
	close(dfd);
	return 0;
}