/*
 * libwebsockets - small server side websockets and web server implementation
 *
 * Copyright (C) 2010-2018 Andy Green <andy@warmcat.com>
 *
 *  This library 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:
 *  version 2.1 of the License.
 *
 *  This library 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 this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 *  MA  02110-1301  USA
 */

#include "core/private.h"

/*
 * notice this returns number of bytes consumed, or -1
 */
int lws_issue_raw(struct lws *wsi, unsigned char *buf, size_t len)
{
	struct lws_context *context = lws_get_context(wsi);
	struct lws_context_per_thread *pt = &wsi->context->pt[(int)wsi->tsi];
	size_t real_len = len;
	unsigned int n, m;

	// lwsl_notice("%s: len %d\n", __func__, (int)len);
	// lwsl_hexdump_level(LLL_NOTICE, buf, len);

	/*
	 * Detect if we got called twice without going through the
	 * event loop to handle pending.  Since that guarantees extending any
	 * existing buflist_out it's inefficient.
	 */
	if (0 && buf && wsi->could_have_pending) {
		lwsl_hexdump_level(LLL_INFO, buf, len);
		lwsl_info("** %p: vh: %s, prot: %s, role %s: "
			 "Inefficient back-to-back write of %lu detected...\n",
			 wsi, wsi->vhost->name, wsi->protocol->name,
			 wsi->role_ops->name,
			 (unsigned long)len);
	}

	lws_stats_atomic_bump(wsi->context, pt, LWSSTATS_C_API_WRITE, 1);

	/* just ignore sends after we cleared the truncation buffer */
	if (lwsi_state(wsi) == LRS_FLUSHING_BEFORE_CLOSE &&
	    !lws_has_buffered_out(wsi)
#if defined(LWS_WITH_HTTP_STREAM_COMPRESSION)
	    && !wsi->http.comp_ctx.may_have_more
#endif
	    )
		return (int)len;

	if (buf && lws_has_buffered_out(wsi)) {
		lwsl_info("** %p: vh: %s, prot: %s, incr buflist_out by %lu\n",
			 wsi, wsi->vhost->name, wsi->protocol->name,
			 (unsigned long)len);

		/*
		 * already buflist ahead of this, add it on the tail of the
		 * buflist, then ignore it for now and act like we're flushing
		 * the buflist...
		 */

		lws_buflist_append_segment(&wsi->buflist_out, buf, len);

		buf = NULL;
		len = 0;
	}

	if (wsi->buflist_out) {
		/* we have to drain the earliest buflist_out stuff first */

		len = lws_buflist_next_segment_len(&wsi->buflist_out, &buf);
		real_len = len;

		lwsl_debug("%s: draining %d\n", __func__, (int)len);
	}

	if (!len || !buf)
		return 0;

	if (!wsi->http2_substream && !lws_socket_is_valid(wsi->desc.sockfd))
		lwsl_warn("** error invalid sock but expected to send\n");

	/* limit sending */
	if (wsi->protocol->tx_packet_size)
		n = (int)wsi->protocol->tx_packet_size;
	else {
		n = (int)wsi->protocol->rx_buffer_size;
		if (!n)
			n = context->pt_serv_buf_size;
	}
	n += LWS_PRE + 4;
	if (n > len)
		n = (int)len;

	/* nope, send it on the socket directly */
	lws_latency_pre(context, wsi);
	m = lws_ssl_capable_write(wsi, buf, n);
	lws_latency(context, wsi, "send lws_issue_raw", n, n == m);

	lwsl_info("%s: ssl_capable_write (%d) says %d\n", __func__, n, m);

	/* something got written, it can have been truncated now */
	wsi->could_have_pending = 1;

	switch (m) {
	case LWS_SSL_CAPABLE_ERROR:
		/* we're going to close, let close know sends aren't possible */
		wsi->socket_is_permanently_unusable = 1;
		return -1;
	case LWS_SSL_CAPABLE_MORE_SERVICE:
		/*
		 * nothing got sent, not fatal.  Retry the whole thing later,
		 * ie, implying treat it was a truncated send so it gets
		 * retried
		 */
		m = 0;
		break;
	}

	/*
	 * we were sending this from buflist_out?  Then not sending everything
	 * is a small matter of advancing ourselves only by the amount we did
	 * send in the buflist.
	 */
	if (lws_has_buffered_out(wsi)) {
		if (m) {
			lwsl_info("%p partial adv %d (vs %ld)\n", wsi, m,
					(long)real_len);
			lws_buflist_use_segment(&wsi->buflist_out, m);
		}

		if (!lws_has_buffered_out(wsi)) {
			lwsl_info("%s: wsi %p: buflist_out flushed\n",
				  __func__, wsi);

			m = (int)real_len;
			if (lwsi_state(wsi) == LRS_FLUSHING_BEFORE_CLOSE) {
				lwsl_info("*%p signalling to close now\n", wsi);
				return -1; /* retry closing now */
			}

#if defined(LWS_ROLE_H1) || defined(LWS_ROLE_H2)
#if !defined(LWS_WITHOUT_SERVER)
			if (wsi->http.deferred_transaction_completed) {
				lwsl_notice("%s: partial completed, doing "
					    "deferred transaction completed\n",
					    __func__);
				wsi->http.deferred_transaction_completed = 0;
				return lws_http_transaction_completed(wsi) ?
							-1 : (int)real_len;
			}
#endif
#endif
		}
		/* always callback on writeable */
		lws_callback_on_writable(wsi);

		return m;
	}

#if defined(LWS_WITH_HTTP_STREAM_COMPRESSION)
	if (wsi->http.comp_ctx.may_have_more)
		lws_callback_on_writable(wsi);
#endif

	if (m == real_len)
		/* what we just sent went out cleanly */
		return m;

	/*
	 * We were not able to send everything... and we were not sending from
	 * an existing buflist_out.  So we are starting a fresh buflist_out, by
	 * buffering the unsent remainder on it.
	 * (it will get first priority next time the socket is writable).
	 */
	lwsl_debug("%p new partial sent %d from %lu total\n", wsi, m,
		    (unsigned long)real_len);

	lws_buflist_append_segment(&wsi->buflist_out, buf + m, real_len - m);

	lws_stats_atomic_bump(wsi->context, pt, LWSSTATS_C_WRITE_PARTIALS, 1);
	lws_stats_atomic_bump(wsi->context, pt,
			      LWSSTATS_B_PARTIALS_ACCEPTED_PARTS, m);

#if !defined(LWS_WITH_ESP32)
	if (lws_wsi_is_udp(wsi)) {
		/* stash original destination for fulfilling UDP partials */
		wsi->udp->sa_pending = wsi->udp->sa;
		wsi->udp->salen_pending = wsi->udp->salen;
	}
#endif

	/* since something buffered, force it to get another chance to send */
	lws_callback_on_writable(wsi);

	return (int)real_len;
}

LWS_VISIBLE int lws_write(struct lws *wsi, unsigned char *buf, size_t len,
			  enum lws_write_protocol wp)
{
	struct lws_context_per_thread *pt = &wsi->context->pt[(int)wsi->tsi];

	lws_stats_atomic_bump(wsi->context, pt, LWSSTATS_C_API_LWS_WRITE, 1);

	if ((int)len < 0) {
		lwsl_err("%s: suspicious len int %d, ulong %lu\n", __func__,
				(int)len, (unsigned long)len);
		return -1;
	}

	lws_stats_atomic_bump(wsi->context, pt, LWSSTATS_B_WRITE, len);

#ifdef LWS_WITH_ACCESS_LOG
	wsi->http.access_log.sent += len;
#endif
	if (wsi->vhost)
		wsi->vhost->conn_stats.tx += len;

	assert(wsi->role_ops);
	if (!wsi->role_ops->write_role_protocol)
		return lws_issue_raw(wsi, buf, len);

	return wsi->role_ops->write_role_protocol(wsi, buf, len, &wp);
}

LWS_VISIBLE int
lws_ssl_capable_read_no_ssl(struct lws *wsi, unsigned char *buf, int len)
{
	struct lws_context *context = wsi->context;
	struct lws_context_per_thread *pt = &context->pt[(int)wsi->tsi];
	int n = 0;

	lws_stats_atomic_bump(context, pt, LWSSTATS_C_API_READ, 1);

	if (lws_wsi_is_udp(wsi)) {
#if !defined(LWS_WITH_ESP32)
		wsi->udp->salen = sizeof(wsi->udp->sa);
		n = recvfrom(wsi->desc.sockfd, (char *)buf, len, 0,
			     &wsi->udp->sa, &wsi->udp->salen);
#endif
	} else
		n = recv(wsi->desc.sockfd, (char *)buf, len, 0);

	if (n >= 0) {

		if (!n && wsi->unix_skt)
			return LWS_SSL_CAPABLE_ERROR;

		if (wsi->vhost)
			wsi->vhost->conn_stats.rx += n;
		lws_stats_atomic_bump(context, pt, LWSSTATS_B_READ, n);

		return n;
	}

	if (LWS_ERRNO == LWS_EAGAIN ||
	    LWS_ERRNO == LWS_EWOULDBLOCK ||
	    LWS_ERRNO == LWS_EINTR)
		return LWS_SSL_CAPABLE_MORE_SERVICE;

	lwsl_info("error on reading from skt : %d\n", LWS_ERRNO);
	return LWS_SSL_CAPABLE_ERROR;
}

LWS_VISIBLE int
lws_ssl_capable_write_no_ssl(struct lws *wsi, unsigned char *buf, int len)
{
	int n = 0;

	if (lws_wsi_is_udp(wsi)) {
#if !defined(LWS_WITH_ESP32)
		if (lws_has_buffered_out(wsi))
			n = sendto(wsi->desc.sockfd, (const char *)buf,
				   len, 0, &wsi->udp->sa_pending,
				   wsi->udp->salen_pending);
		else
			n = sendto(wsi->desc.sockfd, (const char *)buf,
				   len, 0, &wsi->udp->sa, wsi->udp->salen);
#endif
	} else
		n = send(wsi->desc.sockfd, (char *)buf, len, MSG_NOSIGNAL);
//	lwsl_info("%s: sent len %d result %d", __func__, len, n);
	if (n >= 0)
		return n;

	if (LWS_ERRNO == LWS_EAGAIN ||
	    LWS_ERRNO == LWS_EWOULDBLOCK ||
	    LWS_ERRNO == LWS_EINTR) {
		if (LWS_ERRNO == LWS_EWOULDBLOCK) {
			lws_set_blocking_send(wsi);
		}

		return LWS_SSL_CAPABLE_MORE_SERVICE;
	}

	lwsl_debug("ERROR writing len %d to skt fd %d err %d / errno %d\n",
		   len, wsi->desc.sockfd, n, LWS_ERRNO);

	return LWS_SSL_CAPABLE_ERROR;
}

LWS_VISIBLE int
lws_ssl_pending_no_ssl(struct lws *wsi)
{
	(void)wsi;
#if defined(LWS_WITH_ESP32)
	return 100;
#else
	return 0;
#endif
}