#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <error.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <endian.h>

#include "net9p.h"

/* "T" messages are client->server requests, and "R" messages are
 * server->client responses.  I do not know what the Plan 9 designers
 * intended "T" and "R" to stand for.
 */
enum v9fs_msg_type {
	/* "9P2000" base protocol
	 * https://ericvh.github.io/9p-rfc/rfc9p2000.html
	 * https://github.com/ericvh/9p-rfc/blob/master/9p2000.xml
	 *
	 * But due to incompleteness, the Plan 9 manual section-5 and
	 * the Plan 9 headers (particularly fcall.h) are a better
	 * references.
	 */
	V9FS_Tversion = 100, /* "412" "4s" */
	V9FS_Rversion = 101, /* "412" "4s" */
	V9FS_Tauth    = 102, /* "412" "4ss" */
	V9FS_Rauth    = 103, /* "412" "TODO" */
	V9FS_Tattach  = 104, /* "412" "TODO" */
	V9FS_Rattach  = 105, /* "412" "TODO" */
	/*V9FS_Terror   = 106, /* There is no Terror request, only Rerror responses */
	V9FS_Rerror   = 107, /* "412" "TODO" */
	V9FS_Tflush   = 108, /* "412" "TODO" */
	V9FS_Rflush   = 109, /* "412" "TODO" */
	V9FS_Twalk    = 110, /* "412" "TODO" */
	V9FS_Rwalk    = 111, /* "412" "TODO" */
	V9FS_Topen    = 112, /* "412" "TODO" */
	V9FS_Ropen    = 113, /* "412" "TODO" */
	V9FS_Tcreate  = 114, /* "412" "TODO" */
	V9FS_Rcreate  = 115, /* "412" "TODO" */
	V9FS_Tread    = 116, /* "412" "TODO" */
	V9FS_Rread    = 117, /* "412" "TODO" */
	V9FS_Twrite   = 118, /* "412" "TODO" */
	V9FS_Rwrite   = 119, /* "412" "TODO" */
	V9FS_Tclunk   = 120, /* "412" "TODO" */
	V9FS_Rclunk   = 121, /* "412" "TODO" */
	V9FS_Tremove  = 122, /* "412" "TODO" */
	V9FS_Rremove  = 123, /* "412" "TODO" */
	V9FS_Tstat    = 124, /* "412" "TODO" */
	V9FS_Rstat    = 125, /* "412" "TODO" */
	V9FS_Twstat   = 126, /* "412" "TODO" */
	V9FS_Rwstat   = 127, /* "412" "TODO" */

	/* "9P2000.u" Unix extension
	 * https://ericvh.github.io/9p-rfc/rfc9p2000.u.html
	 * https://github.com/ericvh/9p-rfc/blob/master/9p2000.u.xml
	 */

	/* "9P2000.L" Linux extension
	 * https://github.com/ericvh/9p-rfc/blob/master/9p2000.L.xml
	 */
	V9FS_TLERROR = 6,
	V9FS_RLERROR,
	V9FS_TSTATFS = 8,
	V9FS_RSTATFS,
	V9FS_TLOPEN = 12,
	V9FS_RLOPEN,
	V9FS_TLCREATE = 14,
	V9FS_RLCREATE,
	V9FS_TSYMLINK = 16,
	V9FS_RSYMLINK,
	V9FS_TMKNOD = 18,
	V9FS_RMKNOD,
	V9FS_TRENAME = 20,
	V9FS_RRENAME,
	V9FS_TREADLINK = 22,
	V9FS_RREADLINK,
	V9FS_TGETATTR = 24,
	V9FS_RGETATTR,
	V9FS_TSETATTR = 26,
	V9FS_RSETATTR,
	V9FS_TXATTRWALK = 30,
	V9FS_RXATTRWALK,
	V9FS_TXATTRCREATE = 32,
	V9FS_RXATTRCREATE,
	V9FS_TREADDIR = 40,
	V9FS_RREADDIR,
	V9FS_TFSYNC = 50,
	V9FS_RFSYNC,
	V9FS_TLOCK = 52,
	V9FS_RLOCK,
	V9FS_TGETLOCK = 54,
	V9FS_RGETLOCK,
	V9FS_TLINK = 70,
	V9FS_RLINK,
	V9FS_TMKDIR = 72,
	V9FS_RMKDIR,
	V9FS_TRENAMEAT = 74,
	V9FS_RRENAMEAT,
	V9FS_TUNLINKAT = 76,
	V9FS_RUNLINKAT,
};

/* 1 - u8
 * 2 - u16le
 * 4 - u32le
 * 8 - u16le
 * d - data (u32le `n`, then `n` bytes of data)
 * s - string (u16le `n`, then `n` bytes of UTF-8)
 * q - qid (13 bytes, idk)
 */

static const char const *msgfmt[255] = {
	/* All messages start with a "size[4] type[1] tag[2]"
	 * prefix; that is not included in this table.  */

	[V9FS_Tversion] = "max_msg_size[4] s",
	[V9FS_Rversion] = "4s",

	[V9FS_Tauth]    = "4ss",
	[V9FS_Rauth]    = "q",

	[V9FS_Rerror]   = "s",

	[V9FS_Tflush]   = "2",
	[V9FS_Rflush]   = "",

	[V9FS_Tattach]  = "44ss",
	[V9FS_Rattach]  = "q",

	[V9FS_Twalk]    = "TODO",
	[V9FS_Rwalk]    = "TODO",

	[V9FS_Topen]    = "41",
	[V9FS_Ropen]    = "q4",

	[V9FS_Tcreate]  = "4s41",
	[V9FS_Rcreate]  = "q4",

	[V9FS_Tread]    = "484",
	[V9FS_Rread]    = "d",

	[V9FS_Twrite]   = "48d",
	[V9FS_Rwrite]   = "4",

	[V9FS_Tclunk]   = "4",
	[V9FS_Rclunk]   = "",

	[V9FS_Tremove]  = "4",
	[V9FS_Rremove]  = "",

	[V9FS_Tstat]    = "4",
	[V9FS_Rstat]    = "TODO",

	[V9FS_Twstat]   = "TODO",
	[V9FS_Rwstat]   = "",
};	



void net9p_listen_cr(void *_arg) {
	(void)_arg;
	cr_begin();

	union {
		struct sockaddr_in in;
		struct sockaddr gen;
	} addr;
	memset(&addr, 0, sizeof addr);
	addr.in.sin_family = AF_INET;
	addr.in.sin_port = htons(9001);
	
	int fd = socket(AF_INET, SOCK_STREAM|SOCK_NONBLOCK, 0);
	if (fd < 0)
		error(1, errno, "socket");
	if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &(int){1}, sizeof(int)) < 0)
		error(1, errno, "setsockopt");
	if (bind(fd, &addr.gen, sizeof addr) < 0)
		error(1, errno, "bind");
	if (listen(fd, 5) < 0)
		error(1, errno, "listen");

	for (;;) {
		int conn = accept(fd, NULL, NULL);
		if (conn < 0) {
			if (errno == EAGAIN || errno == EWOULDBLOCK) {
				cr_yield();
				continue;
			}
			error(1, errno, "accept");
		}
		if (!coroutine_add(net9p_worker_cr, &conn))
			error(1, 0, "coroutine_add(net9p_worker_cr, &%d)", conn);
	}

	cr_end();
}

void net9p_worker_cr(void *_arg) {
	int fd = *((int *)_arg);
	cr_begin();

	close(fd);

	cr_end();
}