/*
 * This file is part of LEM, a Lua Event Machine.
 * Copyright 2011-2013 Emil Renner Berthing
 *
 * LEM is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * LEM is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with LEM.  If not, see <http://www.gnu.org/licenses/>.
 */

struct stream {
	struct ev_io r;
	struct ev_io w;
	unsigned int open;
	int idx;
	const char *out;
	size_t out_len;
	struct lem_parser *p;
	struct lem_inputbuf buf;
};

#define STREAM_FROM_WATCH(w, member)\
	(struct stream *)(((char *)w) - offsetof(struct stream, member))

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wstrict-aliasing"
static inline void
stream_watch_init(struct stream *s, int fd)
{
	ev_io_init(&s->r, NULL, fd, EV_READ);
	ev_io_init(&s->w, NULL, fd, EV_WRITE);
}
#pragma GCC diagnostic pop

static struct stream *
stream_new(lua_State *T, int fd, int mt)
{
	/* create userdata and set the metatable */
	struct stream *s = lua_newuserdata(T, sizeof(struct stream));
	lua_pushvalue(T, mt);
	lua_setmetatable(T, -2);

	/* initialize userdata */
	stream_watch_init(s, fd);
	s->open = 1;
	s->r.data = NULL;
	s->w.data = NULL;
	lem_inputbuf_init(&s->buf);

	return s;
}

static int
stream_gc(lua_State *T)
{
	struct stream *s = lua_touserdata(T, 1);

	if (s->open & 1)
		close(s->r.fd);
	if (s->open & 2)
		fcntl(s->w.fd, F_SETFL, 0);

	return 0;
}

static int
stream_closed(lua_State *T)
{
	struct stream *s;

	luaL_checktype(T, 1, LUA_TUSERDATA);
	s = lua_touserdata(T, 1);
	lua_pushboolean(T, !s->open);
	return 1;
}

static int
stream_close(lua_State *T)
{
	struct stream *s;

	luaL_checktype(T, 1, LUA_TUSERDATA);
	s = lua_touserdata(T, 1);
	if (!s->open)
		return io_closed(T);
	if (s->r.data != NULL) {
		ev_io_stop(LEM_ &s->r);
		lem_queue(s->r.data, io_closed(s->r.data));
		s->r.data = NULL;
	}
	if (s->w.data != NULL) {
		ev_io_stop(LEM_ &s->w);
		lem_queue(s->w.data, io_closed(s->w.data));
		s->w.data = NULL;
	}

	s->open = 0;
	if (close(s->r.fd))
		return io_strerror(T, errno);

	lua_pushboolean(T, 1);
	return 1;
}

/*
 * stream:readp() method
 */
static int
stream__readp(lua_State *T, struct stream *s)
{
	ssize_t bytes;
	int ret;
	int err;
	enum lem_preason res;

	while ((bytes = read(s->r.fd, s->buf.buf + s->buf.end,
					LEM_INPUTBUF_SIZE - s->buf.end)) > 0) {
		lem_debug("read %ld bytes from %d", bytes, s->r.fd);

		s->buf.end += bytes;

		ret = s->p->process(T, &s->buf);
		if (ret > 0)
			return ret;
	}
	err = errno;
	lem_debug("read %ld bytes from %d", bytes, s->r.fd);

	if (bytes < 0 && (err == EAGAIN || err == EINTR))
		return 0;

	if (bytes == 0 || err == ECONNRESET || err == EPIPE)
		res = LEM_PCLOSED;
	else
		res = LEM_PERROR;

	s->open = 0;
	close(s->r.fd);

	if (s->p->destroy && (ret = s->p->destroy(T, &s->buf, res)) > 0)
		return ret;

	lua_settop(T, 0);
	if (res == LEM_PCLOSED)
		return io_closed(T);

	return io_strerror(T, err);
}

static void
stream_readp_cb(EV_P_ struct ev_io *w, int revents)
{
	struct stream *s = STREAM_FROM_WATCH(w, r);
	lua_State *T = s->r.data;
	int ret;

	(void)revents;

	if (!s->open) {
		ret = 0;
		if (s->p->destroy)
			ret = s->p->destroy(T, &s->buf, LEM_PCLOSED);
		if (ret <= 0)
			ret = io_closed(T);
	} else {
		ret = stream__readp(T, s);
		if (ret == 0)
			return;
	}

	ev_io_stop(EV_A_ &s->r);
	s->r.data = NULL;
	lem_queue(T, ret);
}

static int
stream_readp(lua_State *T)
{
	struct stream *s;
	struct lem_parser *p;
	int ret;

	luaL_checktype(T, 1, LUA_TUSERDATA);
	ret = lua_type(T, 2);
	if (ret != LUA_TUSERDATA && ret != LUA_TLIGHTUSERDATA)
		return luaL_argerror(T, 2, "expected userdata");

	s = lua_touserdata(T, 1);
	if (!s->open)
		return io_closed(T);
	if (s->r.data != NULL)
		return io_busy(T);

	p = lua_touserdata(T, 2);
	if (p->init)
		p->init(T, &s->buf);

	ret = p->process(T, &s->buf);
	if (ret > 0)
		return ret;

	s->p = p;
	ret = stream__readp(T, s);
	if (ret > 0)
		return ret;

	s->r.data = T;
	s->r.cb = stream_readp_cb;
	ev_io_start(LEM_ &s->r);
	return lua_yield(T, lua_gettop(T));
}

/*
 * stream:write() method
 */
static int
stream__write(lua_State *T, struct stream *s)
{
	ssize_t bytes;
	int err;

	while ((bytes = write(s->w.fd, s->out, s->out_len)) > 0) {
		lem_debug("wrote %ld bytes to fd %d", bytes, s->w.fd);
		s->out += bytes;
		s->out_len -= bytes;
		while (s->out_len == 0) {
			if (s->idx == lua_gettop(T)) {
				lua_pushboolean(T, 1);
				return 1;
			}
			s->out = lua_tolstring(T, ++s->idx, &s->out_len);
		}
	}
	err = errno;
	lem_debug("wrote %ld bytes to fd %d", bytes, s->w.fd);

	if (bytes < 0 && (err == EAGAIN || err == EINTR))
		return 0;

	s->open = 0;
	close(s->w.fd);

	if (bytes == 0 || err == ECONNRESET || err == EPIPE)
		return io_closed(T);

	return io_strerror(T, err);
}

static void
stream_write_cb(EV_P_ struct ev_io *w, int revents)
{
	struct stream *s = STREAM_FROM_WATCH(w, w);
	lua_State *T = s->w.data;
	int ret;

	(void)revents;

	if (!s->open)
		ret = io_closed(T);
	else {
		ret = stream__write(T, s);
		if (ret == 0)
			return;
	}

	ev_io_stop(EV_A_ &s->w);
	s->w.data = NULL;
	lem_queue(T, ret);
}

static int
stream_write(lua_State *T)
{
	struct stream *s;
	const char *out;
	size_t out_len;
	int idx;
	int i;
	int top;
	int ret;

	luaL_checktype(T, 1, LUA_TUSERDATA);
	top = lua_gettop(T);
	idx = 1;
	do {
		out = luaL_checklstring(T, ++idx, &out_len);
	} while (out_len == 0 && idx < top);
	for (i = idx+1; i <= top; i++)
		(void)luaL_checkstring(T, i);

	s = lua_touserdata(T, 1);
	if (!s->open)
		return io_closed(T);
	if (s->w.data != NULL)
		return io_busy(T);
	if (out_len == 0) {
		lua_pushboolean(T, 1);
		return 1;
	}

	s->out = out;
	s->out_len = out_len;
	s->idx = idx;
	ret = stream__write(T, s);
	if (ret > 0)
		return ret;

	s->w.data = T;
	s->w.cb = stream_write_cb;
	ev_io_start(LEM_ &s->w);
	return lua_yield(T, top);
}

#ifdef TCP_CORK
static int
stream_setcork(lua_State *T, int state)
{
	struct stream *s;

	luaL_checktype(T, 1, LUA_TUSERDATA);
	s = lua_touserdata(T, 1);
	if (!s->open)
		return io_closed(T);
	if (s->w.data != NULL)
		return io_busy(T);

	if (setsockopt(s->w.fd, IPPROTO_TCP, TCP_CORK, &state, sizeof(int)))
		return io_strerror(T, errno);

	lua_pushboolean(T, 1);
	return 1;
}

static int
stream_cork(lua_State *T)
{
	return stream_setcork(T, 1);
}

static int
stream_uncork(lua_State *T)
{
	return stream_setcork(T, 0);
}
#endif

static int
stream_getpeer(lua_State *T)
{
	struct stream *s;
	union {
		struct sockaddr all;
		struct sockaddr_in in;
		struct sockaddr_in6 in6;
	} addr;
	socklen_t len;

	luaL_checktype(T, 1, LUA_TUSERDATA);
	s = lua_touserdata(T, 1);
	if (!s->open)
		return io_closed(T);

	len = sizeof(addr);
	if (getpeername(s->r.fd, &addr.all, &len))
		return io_strerror(T, errno);

	switch (addr.all.sa_family) {
	case AF_UNIX: {
#if defined(__FreeBSD__) || defined(__APPLE__)
			struct xucred cred;

			len = sizeof(struct xucred);
			if (getsockopt(s->r.fd, 0, LOCAL_PEERCRED, &cred, &len))
				return io_strerror(T, errno);

			if (len != sizeof(struct xucred) ||
					cred.cr_version != XUCRED_VERSION) {
				lua_pushnil(T);
				lua_pushliteral(T, "version mismatch");
				return 2;
			}

			lua_pushliteral(T, "*unix");
			lua_pushnumber(T, cred.cr_uid);
			lua_pushnumber(T, cred.cr_gid);
#else
			struct ucred cred;

			len = sizeof(struct ucred);
			if (getsockopt(s->r.fd, SOL_SOCKET, SO_PEERCRED, &cred, &len))
				return io_strerror(T, errno);

			lua_pushliteral(T, "*unix");
			lua_pushnumber(T, cred.uid);
			lua_pushnumber(T, cred.gid);
#endif
			return 3;
		}

	case AF_INET: {
			char buf[INET_ADDRSTRLEN];

			if (inet_ntop(addr.in.sin_family, &addr.in.sin_addr,
						buf, sizeof(buf)) == NULL)
				return io_strerror(T, errno);

			lua_pushstring(T, buf);
			lua_pushnumber(T, ntohs(addr.in.sin_port));
			return 2;
		}

	case AF_INET6: {
			char buf[INET6_ADDRSTRLEN];

			if (inet_ntop(addr.in6.sin6_family, &addr.in6.sin6_addr,
						buf, sizeof(buf)) == NULL)
				return io_strerror(T, errno);

			lua_pushstring(T, buf);
			lua_pushnumber(T, ntohs(addr.in6.sin6_port));
			return 2;
		}
	}

	return io_strerror(T, EINVAL);
}

struct sfhandle {
	struct lem_async a;
	lua_State *T;
	struct stream *s;
	off_t size;
	off_t offset;
	int fd;
	int ret;
};

static void
stream_sendfile_work(struct lem_async *a)
{
	struct sfhandle *sf = (struct sfhandle *)a;
	struct stream *s = sf->s;

	/* make socket blocking */
	if (fcntl(s->w.fd, F_SETFL, 0) == -1) {
		sf->ret = errno;
		return;
	}

#ifdef __FreeBSD__
	off_t written;
	int ret = sendfile(sf->fd, s->w.fd,
			sf->offset, sf->size,
			NULL, &written, SF_SYNC);
	if (ret == 0) {
		sf->ret = 0;
		sf->size = written;
	} else
		sf->ret = errno;
	lem_debug("wrote = %ld bytes", written);
#else
#ifdef __APPLE__
	int ret = sendfile(sf->fd, s->w.fd,
			sf->offset, &sf->size,
			NULL, 0);
	if (ret == 0)
		sf->ret = 0;
	else
		sf->ret = errno;
	lem_debug("wrote = %lld bytes", sf->size);
#else
	ssize_t ret = sendfile(s->w.fd, sf->fd,
			&sf->offset, sf->size);
	if (ret >= 0) {
		sf->ret = 0;
		sf->size = ret;
	} else
		sf->ret = errno;
	lem_debug("wrote = %ld bytes", ret);
#endif
#endif

	/* make socket non-blocking again */
	if (fcntl(s->w.fd, F_SETFL, O_NONBLOCK) == -1) {
		sf->ret = errno;
		return;
	}
}

static void
stream_sendfile_reap(struct lem_async *a)
{
	struct sfhandle *sf = (struct sfhandle *)a;
	lua_State *T = sf->T;
	struct stream *s = sf->s;
	int ret;

	if (sf->ret == 0) {
		lua_pushnumber(T, sf->size);
		ret = 1;
	} else {
		if (s->open)
			close(s->w.fd);
		s->open = 0;
		ret = io_strerror(T, sf->ret);
	}

	free(sf);

	s->w.data = NULL;
	lem_queue(T, ret);
}

static int
stream_sendfile(lua_State *T)
{
	struct stream *s;
	struct file *f;
	off_t size;
	off_t offset;
	struct sfhandle *sf;

	luaL_checktype(T, 1, LUA_TUSERDATA);
	luaL_checktype(T, 2, LUA_TUSERDATA);
	size = (off_t)luaL_checknumber(T, 3);
	offset = (off_t)luaL_optnumber(T, 4, 0);

	s = lua_touserdata(T, 1);
	if (!s->open)
		return io_closed(T);
	if (s->w.data != NULL)
		return io_busy(T);

	f = lua_touserdata(T, 2);
	if (f->fd < 0) {
		lua_pushnil(T);
		lua_pushliteral(T, "file closed");
		return 2;
	}

	s->w.data = T;

	sf = lem_xmalloc(sizeof(struct sfhandle));
	sf->T = T;
	sf->s = s;
	sf->size = size;
	sf->offset = offset;
	sf->fd = f->fd;
	lem_async_do(&sf->a, stream_sendfile_work, stream_sendfile_reap);

	lua_settop(T, 2);
	return lua_yield(T, 2);
}