/*
  * RTMP HTTP network protocol
  * Copyright (c) 2012 Samuel Pitoiset
  *

  * 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
  */
 
 /**
  * @file
  * RTMP HTTP protocol
  */
 
 #include "libavutil/avstring.h"
 #include "libavutil/intfloat.h"
 #include "libavutil/opt.h"

 #include "libavutil/time.h"

 #include "internal.h"
 #include "http.h"

 #include "rtmp.h"

 
 #define RTMPT_DEFAULT_PORT 80

 #define RTMPTS_DEFAULT_PORT RTMPS_DEFAULT_PORT

 
 /* protocol handler context */
 typedef struct RTMP_HTTPContext {

     const AVClass *class;

     URLContext   *stream;           ///< HTTP stream
     char         host[256];         ///< hostname of the server
     int          port;              ///< port to connect (default is 80)
     char         client_id[64];     ///< client ID used for all requests except the first one
     int          seq;               ///< sequence ID used for all requests
     uint8_t      *out_data;         ///< output buffer
     int          out_size;          ///< current output buffer size
     int          out_capacity;      ///< current output buffer capacity
     int          initialized;       ///< flag indicating when the http context is initialized
     int          finishing;         ///< flag indicating when the client closes the connection

     int          nb_bytes_read;     ///< number of bytes read since the last request

     int          tls;               ///< use Transport Security Layer (RTMPTS)

 } RTMP_HTTPContext;
 
 static int rtmp_http_send_cmd(URLContext *h, const char *cmd)
 {
     RTMP_HTTPContext *rt = h->priv_data;
     char uri[2048];
     uint8_t c;
     int ret;
 
     ff_url_join(uri, sizeof(uri), "http", NULL, rt->host, rt->port,
                 "/%s/%s/%d", cmd, rt->client_id, rt->seq++);
 
     av_opt_set_bin(rt->stream->priv_data, "post_data", rt->out_data,
                    rt->out_size, 0);
 
     /* send a new request to the server */
     if ((ret = ff_http_do_new_request(rt->stream, uri)) < 0)
         return ret;
 
     /* re-init output buffer */
     rt->out_size = 0;
 
     /* read the first byte which contains the polling interval */
     if ((ret = ffurl_read(rt->stream, &c, 1)) < 0)
         return ret;
 

     /* re-init the number of bytes read */
     rt->nb_bytes_read = 0;
 

     return ret;
 }
 
 static int rtmp_http_write(URLContext *h, const uint8_t *buf, int size)
 {
     RTMP_HTTPContext *rt = h->priv_data;
     void *ptr;
 
     if (rt->out_size + size > rt->out_capacity) {
         rt->out_capacity = (rt->out_size + size) * 2;
         ptr = av_realloc(rt->out_data, rt->out_capacity);
         if (!ptr)
             return AVERROR(ENOMEM);
         rt->out_data = ptr;
     }
 
     memcpy(rt->out_data + rt->out_size, buf, size);
     rt->out_size += size;
 
     return size;
 }
 
 static int rtmp_http_read(URLContext *h, uint8_t *buf, int size)
 {
     RTMP_HTTPContext *rt = h->priv_data;
     int ret, off = 0;
 
     /* try to read at least 1 byte of data */
     do {
         ret = ffurl_read(rt->stream, buf + off, size);
         if (ret < 0 && ret != AVERROR_EOF)
             return ret;
 
         if (ret == AVERROR_EOF) {
             if (rt->finishing) {
                 /* Do not send new requests when the client wants to
                  * close the connection. */
                 return AVERROR(EAGAIN);
             }
 
             /* When the client has reached end of file for the last request,
              * we have to send a new request if we have buffered data.
              * Otherwise, we have to send an idle POST. */
             if (rt->out_size > 0) {
                 if ((ret = rtmp_http_send_cmd(h, "send")) < 0)
                     return ret;
             } else {

                 if (rt->nb_bytes_read == 0) {
                     /* Wait 50ms before retrying to read a server reply in
                      * order to reduce the number of idle requets. */

                     av_usleep(50000);

                 }
 

                 if ((ret = rtmp_http_write(h, "", 1)) < 0)
                     return ret;
 
                 if ((ret = rtmp_http_send_cmd(h, "idle")) < 0)
                     return ret;
             }
 
             if (h->flags & AVIO_FLAG_NONBLOCK) {
                 /* no incoming data to handle in nonblocking mode */
                 return AVERROR(EAGAIN);
             }
         } else {
             off  += ret;
             size -= ret;

             rt->nb_bytes_read += ret;

         }
     } while (off <= 0);
 
     return off;
 }
 
 static int rtmp_http_close(URLContext *h)
 {
     RTMP_HTTPContext *rt = h->priv_data;
     uint8_t tmp_buf[2048];
     int ret = 0;
 
     if (rt->initialized) {
         /* client wants to close the connection */
         rt->finishing = 1;
 
         do {
             ret = rtmp_http_read(h, tmp_buf, sizeof(tmp_buf));
         } while (ret > 0);
 
         /* re-init output buffer before sending the close command */
         rt->out_size = 0;
 
         if ((ret = rtmp_http_write(h, "", 1)) == 1)
             ret = rtmp_http_send_cmd(h, "close");
     }
 
     av_freep(&rt->out_data);
     ffurl_close(rt->stream);
 
     return ret;
 }
 
 static int rtmp_http_open(URLContext *h, const char *uri, int flags)
 {
     RTMP_HTTPContext *rt = h->priv_data;
     char headers[1024], url[1024];
     int ret, off = 0;
 
     av_url_split(NULL, 0, NULL, 0, rt->host, sizeof(rt->host), &rt->port,
                  NULL, 0, uri);
 
     /* This is the first request that is sent to the server in order to
      * register a client on the server and start a new session. The server
      * replies with a unique id (usually a number) that is used by the client
      * for all future requests.
      * Note: the reply doesn't contain a value for the polling interval.
      * A successful connect resets the consecutive index that is used
      * in the URLs. */

     if (rt->tls) {
         if (rt->port < 0)
             rt->port = RTMPTS_DEFAULT_PORT;
         ff_url_join(url, sizeof(url), "https", NULL, rt->host, rt->port, "/open/1");
     } else {
         if (rt->port < 0)
             rt->port = RTMPT_DEFAULT_PORT;
         ff_url_join(url, sizeof(url), "http", NULL, rt->host, rt->port, "/open/1");
     }

 
     /* alloc the http context */
     if ((ret = ffurl_alloc(&rt->stream, url, AVIO_FLAG_READ_WRITE, NULL)) < 0)
         goto fail;
 
     /* set options */
     snprintf(headers, sizeof(headers),
              "Cache-Control: no-cache\r\n"
              "Content-type: application/x-fcs\r\n"
              "User-Agent: Shockwave Flash\r\n");
     av_opt_set(rt->stream->priv_data, "headers", headers, 0);
     av_opt_set(rt->stream->priv_data, "multiple_requests", "1", 0);
     av_opt_set_bin(rt->stream->priv_data, "post_data", "", 1, 0);
 
     /* open the http context */
     if ((ret = ffurl_connect(rt->stream, NULL)) < 0)
         goto fail;
 
     /* read the server reply which contains a unique ID */
     for (;;) {
         ret = ffurl_read(rt->stream, rt->client_id + off, sizeof(rt->client_id) - off);
         if (ret == AVERROR_EOF)
             break;
         if (ret < 0)
             goto fail;
         off += ret;
         if (off == sizeof(rt->client_id)) {
             ret = AVERROR(EIO);
             goto fail;
         }
     }
     while (off > 0 && isspace(rt->client_id[off - 1]))
         off--;
     rt->client_id[off] = '\0';
 
     /* http context is now initialized */
     rt->initialized = 1;
     return 0;
 
 fail:
     rtmp_http_close(h);
     return ret;
 }
 

 #define OFFSET(x) offsetof(RTMP_HTTPContext, x)
 #define DEC AV_OPT_FLAG_DECODING_PARAM
 
 static const AVOption ffrtmphttp_options[] = {

     {"ffrtmphttp_tls", "Use a HTTPS tunneling connection (RTMPTS).", OFFSET(tls), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, DEC},

     { NULL },
 };
 
 static const AVClass ffrtmphttp_class = {
     .class_name = "ffrtmphttp",
     .item_name  = av_default_item_name,
     .option     = ffrtmphttp_options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 

 URLProtocol ff_ffrtmphttp_protocol = {
     .name           = "ffrtmphttp",

     .url_open       = rtmp_http_open,
     .url_read       = rtmp_http_read,
     .url_write      = rtmp_http_write,
     .url_close      = rtmp_http_close,
     .priv_data_size = sizeof(RTMP_HTTPContext),
     .flags          = URL_PROTOCOL_FLAG_NETWORK,

     .priv_data_class= &ffrtmphttp_class,

 };