/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set et sw=2 ts=2: */
/***************************************************************************
 *            rtp.cc
 *
 *  Mon Sep  2 15:24:09 CEST 2013
 *  Copyright 2013 Bent Bisballe Nyeng
 *  deva@aasimon.org
 ****************************************************************************/

/*
 *  This file is part of lrtp.
 *
 * lrtp 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.
 *
 * lrtp 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 lrtp; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
#include "rtp.h"

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

// For ntoh et al.
#ifdef WIN32
#include <winsock2.h>
#else
#include <arpa/inet.h>
#endif

RTP::RTP()
{
  memset(&header, 0, sizeof(header));
  pads = 0;

  header.version = 2;

  memset(pload, 0, sizeof(pload));
  pload_size = 0;

  is_valid = false;
}

void RTP::setPadding(unsigned char padding)
{
  if(padding == 0) {
    header.p = 0;
    pads = 0;
    return;
  }
  header.p = 1;
  pads = padding;
}

unsigned char RTP::padding() const
{
  return pads;
}

void RTP::setPayloadType(unsigned char pt)
{
  header.pt = pt;
}

unsigned char RTP::payloadType() const
{
  return header.pt;
}

void RTP::setMarker(bool bit)
{
  header.m = bit?1:0;
}

bool RTP::marker() const
{
  return header.m;
}

void RTP::setSeq(uint16_t seq)
{
  header.seq = htons(seq);
}

uint16_t RTP::seq() const
{
  return ntohs(header.seq);
}

void RTP::setTimestamp(uint32_t ts)
{
  header.ts = htonl(ts);
}

uint32_t RTP::timestamp() const
{
  return ntohl(header.ts);
}

void RTP::setSSrc(uint32_t ssrc)
{
  header.ssrc = htonl(ssrc);
}

uint32_t RTP::SSrc() const
{
  return ntohl(header.ssrc);
}

void RTP::addCSrc(csrc_t csrc)
{
  if(csrcs.size() == 15) {
    printf("ERROR: Too many CSRCs (max 15).\n");
    return; // TODO: Report error!
  }
  csrcs.push_back(csrc);
  header.cc = csrcs.size();
}

std::list<csrc_t> RTP::getCSrcs() const
{
  return csrcs;
}

void RTP::removeCSrc(csrc_t csrc)
{
  csrcs.remove(csrc);
  header.cc = csrcs.size();
}

void RTP::clearCSrcs()
{
  csrcs.clear();
  header.cc = csrcs.size();
}

int RTP::setPayload(const char *pl, size_t size)
{
  if(size > MAX_RTP_PAYLOAD_SIZE) {
    printf("ERROR: Payload is too big for RTP packet (%d bytes, max is %d).\n",
           size, MAX_RTP_PAYLOAD_SIZE);
    // TODO: Report error.
    return -1;
  }

  memcpy(pload, pl, size);
  pload_size = size;

  setValid(true);

  return size;
}

size_t RTP::payload(char *payload, size_t maxsize) const
{
  if(pload_size > maxsize) {
    printf("ERROR: Payload is too big for the buffer.\n");
    return 0; // TODO: Report error.
  }

  memcpy(payload, pload, pload_size);
  return pload_size;
}

size_t RTP::payloadSize() const
{
  return pload_size;
}

const char *RTP::payloadData() const
{
  return pload;
}

size_t RTP::packet(char *packet, size_t maxsize) const
{
  memset(packet, 0, maxsize);

  size_t total_packet_size =
    sizeof(header) + sizeof(csrc_t) * csrcs.size() + pload_size + pads;

  if(total_packet_size > maxsize) {
    printf("ERROR: Packet is too big for the buffer.\n");
    return 0; // TODO: Report error.
  }

  char *p = packet;

  // Copy header fields.
  memcpy(p, &header, sizeof(header));

  p += sizeof(header);

  // Write CSrcs to packet
  csrc_t *pcsrc = (csrc_t*)p;
  std::list<csrc_t>::const_iterator i = csrcs.begin();
  while(i != csrcs.end()) {
    *pcsrc++ = htonl(*i);
    i++;
  }

  p += sizeof(csrc_t) * csrcs.size();

  // TODO: Insert header extension here (if it exists)

  // Write payload to body.
  memcpy(p, pload, pload_size);

  p += pload_size;

  if(pads) {
    for(int i = 0; i < pads - 1; i++) *p++ = '\0';
    *p++ = (unsigned char)pads;
  }

  return p - packet;
}

int RTP::fromPacket(const char *packet, size_t size)
{
  rtp_header_t *hdr =  (rtp_header_t *)packet;

  if(hdr->version != 2) {
    printf("ERROR: Wrong RTP header version.\n");
    return -1; // TODO: Invalid RTP version error
  }

  setMarker(hdr->m);
  setPayloadType(hdr->pt);
  setSeq(ntohs(hdr->seq));
  setTimestamp(ntohl(hdr->ts));
  setSSrc(ntohl(hdr->ssrc));

  if(hdr->p) {
    setPadding(*(unsigned char*)&packet[size - 1]);
  }

  // TODO: Use header extension flag: hdr->x

  // Read out CSrc's:
  csrc_t *pcsrc = (csrc_t*)(packet + sizeof(rtp_header_t));
  for(int i = 0; i < hdr->cc; i++) {
    addCSrc(ntohl(*pcsrc));
    pcsrc++;
  }

  // Read out payload
  size_t plsz = size - (sizeof(rtp_header_t) + hdr->cc*sizeof(csrc_t) + pads);
  char *pl = (char*)pcsrc;
  if(setPayload(pl, plsz) < 0) return -1;

  setValid(true);

  return size;
}

bool RTP::isValid()
{
  return is_valid;
}

void RTP::setValid(bool valid)
{
  is_valid = valid;
}