#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <err.h>
#include "liburing.h"

#define CHECK_NEGERR(_expr) \
	({ typeof(_expr) _ret = (_expr); if (_ret < 0) { errno = -_ret; err(1, #_expr); } _ret; })
#define CHECK_NULL(_expr) \
	({ typeof(_expr) _ret = (_expr); if (_ret == NULL) { errx(1, #_expr " returned NULL"); } _ret; })


int main(int argc, char *argv[])
{
	struct io_uring ring;
	int ret, o, i, j, x, num, slot;
	struct io_uring_sqe *sqe;
	struct io_uring_cqe *cqe;
	char *s, **bufs;
	int *fds;
	const size_t bufsize = 131072;
	const int ops_per_file = 2;

	if (argc < 2)
		errx(1, "usage: %s file [...]", argv[0]);

	num = argc - 1;
	bufs = CHECK_NULL(calloc(num, sizeof(bufs[0])));
	fds = CHECK_NULL(calloc(num, sizeof(fds[0])));
	for (i = 0; i < num; i++) {
		bufs[i] = CHECK_NULL(malloc(bufsize));
		fds[i] = -1;
	}

	ret = CHECK_NEGERR(io_uring_queue_init(num * ops_per_file, &ring, 0));
	ret = CHECK_NEGERR(io_uring_register_files(&ring, fds, num));

	for (i = 0; i < num; i++) {
		slot = i;

		sqe = CHECK_NULL(io_uring_get_sqe(&ring));
		sqe->user_data = i * ops_per_file;
		io_uring_prep_openat_direct(sqe, AT_FDCWD, argv[i + 1],
					    O_RDONLY, 0, slot);
//		sqe->flags |= IOSQE_IO_DRAIN;
//		sqe->flags |= IOSQE_IO_LINK;

		sqe = CHECK_NULL(io_uring_get_sqe(&ring));
		sqe->user_data = i * ops_per_file + 1;
		io_uring_prep_read(sqe, slot, bufs[i], bufsize, 0);
		sqe->flags |= IOSQE_FIXED_FILE;
//		sqe->flags |= IOSQE_IO_DRAIN;
//		sqe->flags |= IOSQE_IO_LINK;
	}

	ret = CHECK_NEGERR(io_uring_submit(&ring));
	if (ret != num * ops_per_file)
		warnx("io_uring_submit submitted less: %d\n", ret);

	for (j = ret; j; j--) {
		CHECK_NEGERR(io_uring_wait_cqe(&ring, &cqe));

		x = cqe->user_data % ops_per_file;
		i = cqe->user_data / ops_per_file;
		printf("%i/%i [%s] = ", i, x, argv[i + 1]);

		ret = cqe->res;
		if (ret < 0) {
			printf("ERROR: %s (%i)\n", strerror(-ret), ret);
		} else if (x == 1) {
			s = bufs[i];

			for (o = 0; o < ret; o += strlen(s + o) + 1)
				printf("\"%.*s\" ", ret - o, s + o);

			printf("(len=%i)\n", ret);
		} else if (x == 0) {
			printf("SUCCESS open\n");
		} else {
			printf("SUCCESS ???\n");
		}
		io_uring_cqe_seen(&ring, cqe);
	}

	io_uring_queue_exit(&ring);
	return 0;
}