//
// Copyright 2017 Garrett D'Amore <garrett@damore.org>
//
// This software is supplied under the terms of the MIT License, a
// copy of which should be located in the distribution where this
// file was obtained (LICENSE.txt).  A copy of the license may also be
// found online at https://opensource.org/licenses/MIT.
//

#include "nng.h"
#include "nng_compat.h"

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

// This file supplies the legacy compatibility API.  Applications should
// avoid using these if at all possible, and instead use the new style APIs.

static struct {
	int	perr;
	int	nerr;
}
nn_errnos[] = {
	{ NNG_EINTR,	    EINTR	  },
	{ NNG_ENOMEM,	    ENOMEM	  },
	{ NNG_EINVAL,	    EINVAL	  },
	{ NNG_EBUSY,	    EBUSY	  },
	{ NNG_ETIMEDOUT,    ETIMEDOUT	  },
	{ NNG_ECONNREFUSED, ECONNREFUSED  },
	{ NNG_ECLOSED,	    EBADF	  },
	{ NNG_EAGAIN,	    EAGAIN	  },
	{ NNG_ENOTSUP,	    ENOTSUP	  },
	{ NNG_EADDRINUSE,   EADDRINUSE	  },
	{ NNG_ESTATE,	    EFSM	  },
	{ NNG_ENOENT,	    ENOENT	  },
	{ NNG_EPROTO,	    EPROTO	  },
	{ NNG_EUNREACHABLE, EHOSTUNREACH  },
	{ NNG_EADDRINVAL,   EADDRNOTAVAIL },
	{ NNG_EPERM,	    EACCES	  },
	{ NNG_EMSGSIZE,	    EMSGSIZE	  },
	{ NNG_ECONNABORTED, ECONNABORTED  },
	{ NNG_ECONNRESET,   ECONNRESET	  },
	{		 0,		0 },
};

const char *
nn_strerror(int err)
{
	int i;
	static char msgbuf[32];

	for (i = 0; nn_errnos[i].perr != 0; i++) {
		if (nn_errnos[i].perr == err) {
			return (nng_strerror(nn_errnos[i].nerr));
		}
	}
	if (err == EIO) {
		return ("Unknown I/O error");
	}

	// Arguablye we could use strerror() here, but we should only
	// be getting errnos we understand at this point.
	(void) snprintf(msgbuf, sizeof (msgbuf), "Unknown error %d", err);
	return (msgbuf);
}


static void
nn_seterror(int err)
{
	int i;

	for (i = 0; nn_errnos[i].nerr != 0; i++) {
		if (nn_errnos[i].nerr == err) {
			errno = nn_errnos[i].perr;
			return;
		}
	}
	// No idea...
	errno = EIO;
}


int
nn_socket(int domain, int protocol)
{
	nng_socket sock;
	int rv;

	if ((domain != AF_SP) && (domain != AF_SP_RAW)) {
		errno = EAFNOSUPPORT;
		return (-1);
	}
	if ((rv = nng_open(&sock, protocol)) != 0) {
		nn_seterror(rv);
		return (-1);
	}
	if (domain == AF_SP_RAW) {
		int raw = 1;
		rv = nng_setopt(sock, NNG_OPT_RAW, &raw, sizeof (raw));
		if (rv != 0) {
			nn_seterror(rv);
			nng_close(sock);
			return (-1);
		}
	}
	return ((int) sock);
}


int
nn_close(int s)
{
	int rv;

	if ((rv = nng_close((nng_socket) s)) != 0) {
		nn_seterror(rv);
		return (-1);
	}
	return (0);
}


int
nn_bind(int s, const char *addr)
{
	int rv;
	nng_endpoint ep;

	if ((rv = nng_listen((nng_socket) s, addr, &ep, NNG_FLAG_SYNCH)) != 0) {
		nn_seterror(rv);
		return (-1);
	}
	return ((int) ep);
}


int
nn_connect(int s, const char *addr)
{
	int rv;
	nng_endpoint ep;

	if ((rv = nng_dial((nng_socket) s, addr, &ep, 0)) != 0) {
		nn_seterror(rv);
		return (-1);
	}
	return ((int) ep);
}


int
nn_shutdown(int s, int ep)
{
	int rv;

	// Socket is wired into the endpoint... so passing a bad endpoint
	// ID can result in affecting the wrong socket.  But this requires
	// a buggy application, and because we don't recycle endpoints
	// until wrap, its unlikely to actually come up in practice.

	if ((rv = nng_endpoint_close((nng_endpoint) ep)) != 0) {
		nn_seterror(rv);
		return (-1);
	}
	return (0);
}


void *
nn_allocmsg(size_t size, int type)
{
	uintptr_t *ch;
	nng_msg *msg;
	int rv;

	// Validate type and non-zero size.  This also checks for overflow.
	if ((type != 0) || (size < 1) || ((size + sizeof (msg) < size))) {
		nn_seterror(NNG_EINVAL);
		return (NULL);
	}

	// So our "messages" from nn are really going to be nng messages
	// but to make this work, we use a bit of headroom in the message
	// to stash the message header.
	if ((rv = nng_msg_alloc(&msg, size + (sizeof (msg)))) != 0) {
		nn_seterror(rv);
		return (NULL);
	}

	memcpy(nng_msg_body(msg), &msg, sizeof (msg));

	// We are counting on the implementation of nn_msg_trim to not
	// reallocate the message but just to leave the prefix inplace.
	(void) nng_msg_trim(msg, sizeof (msg));

	return (nng_msg_body(msg));
}


int
nn_freemsg(void *ptr)
{
	nng_msg *msg;

	memcpy(&msg, ((char *) ptr) - sizeof (msg), sizeof (msg));
	nng_msg_free(msg);
	return (0);
}


void *
nn_reallocmsg(void *ptr, size_t len)
{
	nng_msg *msg;
	int rv;

	if ((len + sizeof (msg)) < len) {
		// overflowed!
		nn_seterror(NNG_EINVAL);
		return (NULL);
	}

	memcpy(&msg, ((char *) ptr) - sizeof (msg), sizeof (msg));

	// We need to realloc the requested len, plus size for our header.
	if ((rv = nng_msg_realloc(msg, len + sizeof (msg))) != 0) {
		// We don't free the old message.  Code is free to cope
		// as it sees fit.
		nn_seterror(rv);
		return (NULL);
	}
	// Stash the msg header pointer
	memcpy(nng_msg_body(msg), &msg, sizeof (msg));
	nng_msg_trim(msg, sizeof (msg));
	return (nng_msg_body(msg));
}


static int
nn_flags(int flags)
{
	switch (flags) {
	case 0:
		return (0);

	case NN_DONTWAIT:
		return (NNG_FLAG_NONBLOCK);

	default:
		nn_seterror(NNG_EINVAL);
		return (-1);
	}
}


int
nn_send(int s, const void *buf, size_t len, int flags)
{
	int rv;

	if ((flags = nn_flags(flags)) == -1) {
		return (-1);
	}
	if (len == NN_MSG) {
		nng_msg *msg;
		memcpy(&msg, ((char *) buf) - sizeof (msg), sizeof (msg));
		len = nng_msg_len(msg);
		rv = nng_sendmsg((nng_socket) s, msg, flags);
	} else {
		rv = nng_send((nng_socket) s, (void *) buf, len, flags);
	}
	if (rv != 0) {
		nn_seterror(rv);
		return (-1);
	}
	return ((int) len);
}


int
nn_recv(int s, void *buf, size_t len, int flags)
{
	int rv;

	if ((flags = nn_flags(flags)) == -1) {
		return (-1);
	}

	if (len == NN_MSG) {
		nng_msg *msg;
		void *body;
		if ((rv = nng_recvmsg((nng_socket) s, &msg, flags)) != 0) {
			nn_seterror(rv);
			return (-1);
		}

		// prepend our header to the body...
		// Note that this *can* alter the message,
		// although for performance reasons it ought not.
		// (There should be sufficient headroom.)
		if ((rv = nng_msg_prepend(msg, &msg, sizeof (msg))) != 0) {
			nng_msg_free(msg);
			nn_seterror(rv);
			return (-1);
		}

		// now "trim" it off... the value is still there, but the
		// contents are unreferenced.  We rely on legacy nanomsg's
		// ignorance of nng msgs to preserve this.
		nng_msg_trim(msg, sizeof (msg));

		*(void **) buf = nng_msg_body(msg);
		return ((int) nng_msg_len(msg));
	}

	if ((rv = nng_recv((nng_socket) s, buf, &len, flags)) != 0) {
		nn_seterror(rv);
		return (-1);
	}
	return ((int) len);
}


int
nn_recvmsg(int s, struct nn_msghdr *mh, int flags)
{
	int rv;
	nng_msg *msg;
	size_t len;
	int keep = 0;

	if ((flags = nn_flags(flags)) == -1) {
		return (-1);
	}
	if (mh == NULL) {
		nn_seterror(NNG_EINVAL);
		return (-1);
	}

	if ((rv = nng_recvmsg((nng_socket) s, &msg, flags)) != 0) {
		nn_seterror(rv);
		return (-1);
	}
	if ((mh->msg_iovlen == 1) && (mh->msg_iov[0].iov_len == NN_MSG)) {
		// Receiver wants to have a dynamically allocated message.
		// There can only be one of these.
		if ((rv = nng_msg_prepend(msg, &msg, sizeof (msg))) != 0) {
			nng_msg_free(msg);
			nn_seterror(rv);
			return (-1);
		}
		nng_msg_trim(msg, sizeof (msg));
		*(void **) (mh->msg_iov[0].iov_base) = nng_msg_body(msg);
		len = nng_msg_len(msg);
		keep = 1; // Do not discard message!
	} else {
		// copyout to multiple iovecs.
		char *ptr = nng_msg_body(msg);
		int i;
		size_t n;
		len = nng_msg_len(msg);

		for (i = 0; i < mh->msg_iovlen; i++) {
			if ((n = mh->msg_iov[i].iov_len) == NN_MSG) {
				// This is forbidden!
				nn_seterror(NNG_EINVAL);
				nng_msg_free(msg);
				return (-1);
			}
			if (n > len) {
				n = len;
			}
			memcpy(mh->msg_iov[i].iov_base, ptr, n);
			len -= n;
			ptr += n;
		}

		// If we copied everything, len will be zero, otherwise,
		// it represents the amount of data that we were unable to
		// copyout.  The caller is responsible for noticing this,
		// as there is no API to pass this information out.
		len = nng_msg_len(msg);
	}

	// If the caller has requested control information (header details),
	// we grab it.
	if (mh->msg_control != NULL) {
		char *cdata;
		size_t clen;
		size_t tlen;
		struct nn_cmsghdr *hdr;

		clen = NN_CMSG_SPACE(nng_msg_header_len(msg));

		if ((tlen = mh->msg_controllen) == NN_MSG) {
			// Ideally we'd use the same msg, but we would need
			// to set up reference counts on the message, so
			// instead we just make a new message.
			nng_msg *nmsg;

			rv = nng_msg_alloc(&nmsg, clen + sizeof (nmsg));
			if (rv != 0) {
				nng_msg_free(msg);
				nn_seterror(rv);
				return (-1);
			}
			memcpy(nng_msg_body(nmsg), &nmsg, sizeof (nmsg));
			nng_msg_trim(nmsg, sizeof (nmsg));
			cdata = nng_msg_body(nmsg);
			*(void **) mh->msg_control = cdata;
			tlen = clen;
		} else {
			cdata = mh->msg_control;
			memset(cdata, 0,
			    tlen > sizeof (*hdr) ? sizeof (*hdr) : tlen);
		}

		if (clen <= tlen) {
			hdr = (void *) cdata;
			hdr->cmsg_len = nng_msg_header_len(msg);
			hdr->cmsg_level = PROTO_SP;
			hdr->cmsg_type = SP_HDR;

			memcpy(NN_CMSG_DATA(cdata), nng_msg_header(msg),
			    nng_msg_header_len(msg));
		}
	}

	if (!keep) {
		nng_msg_free(msg);
	}
	return (len);
}


#if 0
int
nn_sendmsg(int s, const struct nn_msghdr *mh, int flags)
{
	void *chunk;

	switch (flags) {
	case NN_DONTWAIT:
		flags = NN_FLAG_NONBLOCK;
		break;
	case 0:
		break;
	default:
		nn_seterror(NNG_EINVAL);
		return (-1);
	}

	// Iterate over the iovecs.  The first iov may be NN_MSG,
	// in which case it must be the only iovec.

	if ((mh->msg_iovlen == 1) && (mh->msg_iov[0].iov_len == NN_MSG)) {
		// Chunk is stored at the offset...
		chunk = *(void **) mh->msg_iov[0].iov_base;
		// Chunk must be aligned
		if ((chuink & (sizeof (void *) - 1)) != 0) {
			nn_seterror(NNG_EINVAL);
			return (-1);
		}
		size = (size_t) (*(uintptr_t *) (((void **) chunk) - 1));
	}
}


#endif