/*
  * RTSP demuxer
  * Copyright (c) 2002 Fabrice Bellard
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg 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 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg 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 FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include "libavutil/avstring.h"
 #include "libavutil/intreadwrite.h"

 #include "libavutil/mathematics.h"

 #include "avformat.h"
 
 #include "internal.h"
 #include "network.h"
 #include "os_support.h"
 #include "rtsp.h"
 #include "rdt.h"

 #include "url.h"

 
 static int rtsp_read_play(AVFormatContext *s)
 {
     RTSPState *rt = s->priv_data;
     RTSPMessageHeader reply1, *reply = &reply1;
     int i;
     char cmd[1024];
 
     av_log(s, AV_LOG_DEBUG, "hello state=%d\n", rt->state);
     rt->nb_byes = 0;
 
     if (!(rt->server_type == RTSP_SERVER_REAL && rt->need_subscription)) {

         if (rt->transport == RTSP_TRANSPORT_RTP) {
             for (i = 0; i < rt->nb_rtsp_streams; i++) {
                 RTSPStream *rtsp_st = rt->rtsp_streams[i];
                 RTPDemuxContext *rtpctx = rtsp_st->transport_priv;
                 if (!rtpctx)
                     continue;
                 ff_rtp_reset_packet_queue(rtpctx);
                 rtpctx->last_rtcp_ntp_time  = AV_NOPTS_VALUE;
                 rtpctx->first_rtcp_ntp_time = AV_NOPTS_VALUE;
                 rtpctx->base_timestamp      = 0;

                 rtpctx->timestamp           = 0;
                 rtpctx->unwrapped_timestamp = 0;

                 rtpctx->rtcp_ts_offset      = 0;
             }
         }

         if (rt->state == RTSP_STATE_PAUSED) {
             cmd[0] = 0;
         } else {
             snprintf(cmd, sizeof(cmd),

                      "Range: npt=%"PRId64".%03"PRId64"-\r\n",
                      rt->seek_timestamp / AV_TIME_BASE,
                      rt->seek_timestamp / (AV_TIME_BASE / 1000) % 1000);

         }
         ff_rtsp_send_cmd(s, "PLAY", rt->control_uri, cmd, reply, NULL);
         if (reply->status_code != RTSP_STATUS_OK) {
             return -1;
         }

         if (rt->transport == RTSP_TRANSPORT_RTP &&
             reply->range_start != AV_NOPTS_VALUE) {

             for (i = 0; i < rt->nb_rtsp_streams; i++) {
                 RTSPStream *rtsp_st = rt->rtsp_streams[i];
                 RTPDemuxContext *rtpctx = rtsp_st->transport_priv;
                 AVStream *st = NULL;

                 if (!rtpctx || rtsp_st->stream_index < 0)

                     continue;

                 st = s->streams[rtsp_st->stream_index];

                 rtpctx->range_start_offset =
                     av_rescale_q(reply->range_start, AV_TIME_BASE_Q,
                                  st->time_base);

             }
         }
     }
     rt->state = RTSP_STATE_STREAMING;
     return 0;
 }
 

 /* pause the stream */
 static int rtsp_read_pause(AVFormatContext *s)
 {
     RTSPState *rt = s->priv_data;
     RTSPMessageHeader reply1, *reply = &reply1;
 
     if (rt->state != RTSP_STATE_STREAMING)
         return 0;
     else if (!(rt->server_type == RTSP_SERVER_REAL && rt->need_subscription)) {
         ff_rtsp_send_cmd(s, "PAUSE", rt->control_uri, NULL, reply, NULL);
         if (reply->status_code != RTSP_STATUS_OK) {
             return -1;
         }
     }
     rt->state = RTSP_STATE_PAUSED;
     return 0;
 }
 

 int ff_rtsp_setup_input_streams(AVFormatContext *s, RTSPMessageHeader *reply)
 {
     RTSPState *rt = s->priv_data;
     char cmd[1024];
     unsigned char *content = NULL;
     int ret;
 
     /* describe the stream */
     snprintf(cmd, sizeof(cmd),
              "Accept: application/sdp\r\n");
     if (rt->server_type == RTSP_SERVER_REAL) {
         /**
          * The Require: attribute is needed for proper streaming from
          * Realmedia servers.
          */
         av_strlcat(cmd,
                    "Require: com.real.retain-entity-for-setup\r\n",
                    sizeof(cmd));
     }
     ff_rtsp_send_cmd(s, "DESCRIBE", rt->control_uri, cmd, reply, &content);
     if (!content)
         return AVERROR_INVALIDDATA;
     if (reply->status_code != RTSP_STATUS_OK) {
         av_freep(&content);
         return AVERROR_INVALIDDATA;
     }
 
     av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", content);
     /* now we got the SDP description, we parse it */
     ret = ff_sdp_parse(s, (const char *)content);
     av_freep(&content);
     if (ret < 0)

         return ret;

 
     return 0;
 }
 
 static int rtsp_probe(AVProbeData *p)
 {
     if (av_strstart(p->filename, "rtsp:", NULL))
         return AVPROBE_SCORE_MAX;
     return 0;
 }
 
 static int rtsp_read_header(AVFormatContext *s,
                             AVFormatParameters *ap)
 {
     RTSPState *rt = s->priv_data;
     int ret;
 
     ret = ff_rtsp_connect(s);
     if (ret)
         return ret;
 
     rt->real_setup_cache = av_mallocz(2 * s->nb_streams * sizeof(*rt->real_setup_cache));
     if (!rt->real_setup_cache)
         return AVERROR(ENOMEM);

     rt->real_setup = rt->real_setup_cache + s->nb_streams;

     if (rt->initial_pause) {

          /* do not start immediately */
     } else {
          if (rtsp_read_play(s) < 0) {
             ff_rtsp_close_streams(s);
             ff_rtsp_close_connections(s);
             return AVERROR_INVALIDDATA;
         }
     }
 
     return 0;
 }
 
 int ff_rtsp_tcp_read_packet(AVFormatContext *s, RTSPStream **prtsp_st,
                             uint8_t *buf, int buf_size)
 {
     RTSPState *rt = s->priv_data;
     int id, len, i, ret;
     RTSPStream *rtsp_st;
 

     av_dlog(s, "tcp_read_packet:\n");

 redo:
     for (;;) {
         RTSPMessageHeader reply;
 

         ret = ff_rtsp_read_reply(s, &reply, NULL, 1, NULL);

         if (ret < 0)
             return ret;
         if (ret == 1) /* received '$' */
             break;
         /* XXX: parse message */
         if (rt->state != RTSP_STATE_STREAMING)
             return 0;
     }

     ret = ffurl_read_complete(rt->rtsp_hd, buf, 3);

     if (ret != 3)
         return -1;
     id  = buf[0];
     len = AV_RB16(buf + 1);

     av_dlog(s, "id=%d len=%d\n", id, len);

     if (len > buf_size || len < 8)

         goto redo;
     /* get the data */

     ret = ffurl_read_complete(rt->rtsp_hd, buf, len);

     if (ret != len)
         return -1;
     if (rt->transport == RTSP_TRANSPORT_RDT &&
         ff_rdt_parse_header(buf, len, &id, NULL, NULL, NULL, NULL) < 0)
         return -1;
 
     /* find the matching stream */
     for (i = 0; i < rt->nb_rtsp_streams; i++) {
         rtsp_st = rt->rtsp_streams[i];
         if (id >= rtsp_st->interleaved_min &&
             id <= rtsp_st->interleaved_max)
             goto found;
     }
     goto redo;
 found:
     *prtsp_st = rtsp_st;
     return len;
 }

 
 static int resetup_tcp(AVFormatContext *s)
 {
     RTSPState *rt = s->priv_data;
     char host[1024];
     int port;
 
     av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port, NULL, 0,
                  s->filename);
     ff_rtsp_undo_setup(s);
     return ff_rtsp_make_setup_request(s, host, port, RTSP_LOWER_TRANSPORT_TCP,
                                       rt->real_challenge);
 }
 

 static int rtsp_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     RTSPState *rt = s->priv_data;
     int ret;
     RTSPMessageHeader reply1, *reply = &reply1;
     char cmd[1024];
 

 retry:

     if (rt->server_type == RTSP_SERVER_REAL) {
         int i;
 
         for (i = 0; i < s->nb_streams; i++)
             rt->real_setup[i] = s->streams[i]->discard;
 
         if (!rt->need_subscription) {
             if (memcmp (rt->real_setup, rt->real_setup_cache,
                         sizeof(enum AVDiscard) * s->nb_streams)) {
                 snprintf(cmd, sizeof(cmd),
                          "Unsubscribe: %s\r\n",
                          rt->last_subscription);
                 ff_rtsp_send_cmd(s, "SET_PARAMETER", rt->control_uri,
                                  cmd, reply, NULL);
                 if (reply->status_code != RTSP_STATUS_OK)
                     return AVERROR_INVALIDDATA;
                 rt->need_subscription = 1;
             }
         }
 
         if (rt->need_subscription) {
             int r, rule_nr, first = 1;
 
             memcpy(rt->real_setup_cache, rt->real_setup,
                    sizeof(enum AVDiscard) * s->nb_streams);
             rt->last_subscription[0] = 0;
 
             snprintf(cmd, sizeof(cmd),
                      "Subscribe: ");
             for (i = 0; i < rt->nb_rtsp_streams; i++) {
                 rule_nr = 0;
                 for (r = 0; r < s->nb_streams; r++) {

                     if (s->streams[r]->id == i) {

                         if (s->streams[r]->discard != AVDISCARD_ALL) {
                             if (!first)
                                 av_strlcat(rt->last_subscription, ",",
                                            sizeof(rt->last_subscription));
                             ff_rdt_subscribe_rule(
                                 rt->last_subscription,
                                 sizeof(rt->last_subscription), i, rule_nr);
                             first = 0;
                         }
                         rule_nr++;
                     }
                 }
             }
             av_strlcatf(cmd, sizeof(cmd), "%s\r\n", rt->last_subscription);
             ff_rtsp_send_cmd(s, "SET_PARAMETER", rt->control_uri,
                              cmd, reply, NULL);
             if (reply->status_code != RTSP_STATUS_OK)
                 return AVERROR_INVALIDDATA;
             rt->need_subscription = 0;
 
             if (rt->state == RTSP_STATE_STREAMING)
                 rtsp_read_play (s);
         }
     }
 
     ret = ff_rtsp_fetch_packet(s, pkt);

     if (ret < 0) {

         if (ret == AVERROR(ETIMEDOUT) && !rt->packets) {

             if (rt->lower_transport == RTSP_LOWER_TRANSPORT_UDP &&
                 rt->lower_transport_mask & (1 << RTSP_LOWER_TRANSPORT_TCP)) {
                 RTSPMessageHeader reply1, *reply = &reply1;
                 av_log(s, AV_LOG_WARNING, "UDP timeout, retrying with TCP\n");
                 if (rtsp_read_pause(s) != 0)
                     return -1;
                 // TEARDOWN is required on Real-RTSP, but might make
                 // other servers close the connection.
                 if (rt->server_type == RTSP_SERVER_REAL)
                     ff_rtsp_send_cmd(s, "TEARDOWN", rt->control_uri, NULL,
                                      reply, NULL);
                 rt->session_id[0] = '\0';
                 if (resetup_tcp(s) == 0) {
                     rt->state = RTSP_STATE_IDLE;
                     rt->need_subscription = 1;
                     if (rtsp_read_play(s) != 0)
                         return -1;
                     goto retry;
                 }
             }
         }

         return ret;

     }
     rt->packets++;

 
     /* send dummy request to keep TCP connection alive */
     if ((av_gettime() - rt->last_cmd_time) / 1000000 >= rt->timeout / 2) {

         if (rt->server_type == RTSP_SERVER_WMS ||
            (rt->server_type != RTSP_SERVER_REAL &&
             rt->get_parameter_supported)) {

             ff_rtsp_send_cmd_async(s, "GET_PARAMETER", rt->control_uri, NULL);
         } else {
             ff_rtsp_send_cmd_async(s, "OPTIONS", "*", NULL);
         }
     }
 
     return 0;
 }
 
 static int rtsp_read_seek(AVFormatContext *s, int stream_index,
                           int64_t timestamp, int flags)
 {
     RTSPState *rt = s->priv_data;
 
     rt->seek_timestamp = av_rescale_q(timestamp,
                                       s->streams[stream_index]->time_base,
                                       AV_TIME_BASE_Q);
     switch(rt->state) {
     default:
     case RTSP_STATE_IDLE:
         break;
     case RTSP_STATE_STREAMING:
         if (rtsp_read_pause(s) != 0)
             return -1;
         rt->state = RTSP_STATE_SEEKING;
         if (rtsp_read_play(s) != 0)
             return -1;
         break;
     case RTSP_STATE_PAUSED:
         rt->state = RTSP_STATE_IDLE;
         break;
     }
     return 0;
 }
 
 static int rtsp_read_close(AVFormatContext *s)
 {
     RTSPState *rt = s->priv_data;
 
     ff_rtsp_send_cmd_async(s, "TEARDOWN", rt->control_uri, NULL);
 
     ff_rtsp_close_streams(s);
     ff_rtsp_close_connections(s);
     ff_network_close();
     rt->real_setup = NULL;
     av_freep(&rt->real_setup_cache);
     return 0;
 }
 

 const AVClass rtsp_demuxer_class = {
     .class_name     = "RTSP demuxer",
     .item_name      = av_default_item_name,

     .option         = ff_rtsp_options,

     .version        = LIBAVUTIL_VERSION_INT,
 };
 

 AVInputFormat ff_rtsp_demuxer = {

     .name           = "rtsp",
     .long_name      = NULL_IF_CONFIG_SMALL("RTSP input format"),
     .priv_data_size = sizeof(RTSPState),
     .read_probe     = rtsp_probe,
     .read_header    = rtsp_read_header,
     .read_packet    = rtsp_read_packet,
     .read_close     = rtsp_read_close,
     .read_seek      = rtsp_read_seek,

     .flags = AVFMT_NOFILE,
     .read_play = rtsp_read_play,
     .read_pause = rtsp_read_pause,

     .priv_class = &rtsp_demuxer_class,

 };