#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>
#include <netinet/in.h>
#include <sys/stat.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <unistd.h>

#include <time.h>
#include <errno.h>
#include <assert.h>
#include <stdarg.h>

#include "ipc.h"

/**
 * TODO:
 * describe a protocol to get this working into networkd
 *   asking networkd for a fd with an URI
 *     URI should contain: who (the service name), where (destination), how (protocol)
 *   networkd initiates a communication with the requested service
 *   networkd sends the fd
 * get a networkd working with this
 */

struct ipc_error ipc_receive_fd (int sock, int *fd)
{
	T_R ((fd == NULL), IPC_ERROR_RECEIVE_FD__NO_PARAM_FD);
	*fd = -1;

	SECURE_DECLARATION (struct msghdr, msg);
	SECURE_BUFFER_DECLARATION (char, c_buffer, 256);

	/* On Mac OS X, the struct iovec is needed, even if it points to minimal data */
	char m_buffer[1];
	struct iovec io = {.iov_base = m_buffer,.iov_len = sizeof (m_buffer) };
	msg.msg_iov = &io;
	msg.msg_iovlen = 1;

	msg.msg_control = c_buffer;
	msg.msg_controllen = sizeof (c_buffer);

	T_PERROR_RIPC ((recvmsg (sock, &msg, 0) <= 0), "recvmsg", IPC_ERROR_RECEIVE_FD__RECVMSG);

	struct cmsghdr *cmsg = CMSG_FIRSTHDR (&msg);

	memmove (fd, CMSG_DATA (cmsg), sizeof (*fd));

	IPC_RETURN_NO_ERROR;
}

struct ipc_error ipc_provide_fd (int sock, int fd)
{
	SECURE_DECLARATION (struct msghdr, msg);
	SECURE_BUFFER_DECLARATION (char, buf, CMSG_SPACE (sizeof (fd)));

	/* On Mac OS X, the struct iovec is needed, even if it points to minimal data */
	struct iovec io = {.iov_base = "",.iov_len = 1 };

	msg.msg_iov = &io;
	msg.msg_iovlen = 1;
	msg.msg_control = buf;
	msg.msg_controllen = sizeof (buf);

	struct cmsghdr *cmsg = CMSG_FIRSTHDR (&msg);
	cmsg->cmsg_level = SOL_SOCKET;
	cmsg->cmsg_type = SCM_RIGHTS;
	cmsg->cmsg_len = CMSG_LEN (sizeof (fd));

	memmove (CMSG_DATA (cmsg), &fd, sizeof (fd));

	msg.msg_controllen = cmsg->cmsg_len;

	T_PERROR_RIPC ((sendmsg (sock, &msg, 0) < 0), "sendmsg", IPC_ERROR_PROVIDE_FD__SENDMSG);

	IPC_RETURN_NO_ERROR;
}

void ipc_switching_add (struct ipc_switchings *is, int orig, int dest)
{
	is->collection = realloc (is->collection, sizeof (struct ipc_switching) * (is->size + 1));
	if (is->collection == NULL) {
		fprintf (stderr, __FILE__ " error realloc line %d", __LINE__);
		exit (EXIT_FAILURE);
	}

	is->size++;

	is->collection[is->size - 1].orig = orig;
	is->collection[is->size - 1].dest = dest;
}

int ipc_switching_del (struct ipc_switchings *is, int fd)
{
	for (size_t i = 0; i < is->size; i++) {
		if (is->collection[i].orig == fd || is->collection[i].dest == fd) {
			int ret;

			if (fd == is->collection[i].orig) {
				ret = is->collection[i].dest;
			} else {
				ret = is->collection[i].orig;
			}

			is->collection[i].orig = is->collection[is->size - 1].orig;
			is->collection[i].dest = is->collection[is->size - 1].dest;

			size_t s = (is->size - 1) > 0 ? (is->size - 1) : 1;

			is->collection = realloc (is->collection, sizeof (struct ipc_switching) * s);
			if (is->collection == NULL) {
				/** TODO: not sure we want this behavior */
				fprintf (stderr, __FILE__ " error realloc line %d", __LINE__);
				exit (EXIT_FAILURE);
			}

			is->size--;
			return ret;
		}
	}

	return -1;
}

int ipc_switching_get (struct ipc_switchings *is, int fd)
{
	for (size_t i = 0; i < is->size; i++) {
		if (is->collection[i].orig == fd) {
			return is->collection[i].dest;
		} else if (is->collection[i].dest == fd) {
			return is->collection[i].orig;
		}
	}

	return -1;
}

void ipc_switching_free (struct ipc_switchings *is)
{
	if (is == NULL)
		return;

	if (is->collection != NULL) {
		free (is->collection);
		is->collection = NULL;
	}
	is->size = 0;
}