/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set et sw=2 ts=2: */
/***************************************************************************
 *            lrtp.cc
 *
 *  Wed Aug 28 09:50:55 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 General Public License as published by
 *  the Free Software Foundation; either version 2 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with lrtp; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
 */
#include "lrtp.h"

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

#include "rtp_profile.h"
#include "rtp_profile_amrwb.h"
#include "rtp_profile_opus.h"
#include "rtp_profile_raw.h"
#include "rtp_profile_l16.h"
#include "rtp_profile_jpeg.h"

#include "srtp.h"

#ifdef __cplusplus
extern "C" {
#endif

#define MAGIC 0x726c7074

// Check if 'h' is a valid smtl handle and report/return error if not.
#define CHECK_HANDLE(h)                         \
  do {                                          \
    if(!h || h->magic != MAGIC) {               \
      return LRTP_MISSING_HANDLE;               \
    }                                           \
  } while(0)

typedef std::map<csrc_t, lrtp_profile_t *> profile_map_t;

struct lrtp_t {
  unsigned int magic;

  SRTP *srtp;
  csrc_t ssrc;
  unsigned short seq;
  profile_map_t profiles;

  csrc_t next_csrc; // for frame iterator (see get_next_frame)

  oframelist_t framelist;
};

typedef struct {
  lrtp_profile_id_t id;
  struct lrtp_profile_t *(*create)(struct lrtp_t *lrtp, unsigned int csrc,
                                   va_list ap);
} profile_class_t;

static const profile_class_t registered_profiles[] = {
  { PROFILE_AMRWB, profile_amrwb_create },
  { PROFILE_OPUS, profile_opus_create },
  { PROFILE_RAW, profile_raw_create },
  { PROFILE_L16, profile_raw_create },
  { PROFILE_JPEG, profile_jpeg_create },
  { }
};

EXPORT
struct lrtp_t *lrtp_init(enum lrtp_status_t *status,
                         const char *key, unsigned int ssrc)
{
  if(status == NULL) return NULL;

  *status = LRTP_OK;

  struct lrtp_t *lrtp = new (std::nothrow) struct lrtp_t;
  if(!lrtp) {
    *status = LRTP_OUT_OF_MEMORY;
    return NULL;
  }

  try {
    lrtp->srtp = new SRTP(key, ssrc);
  } catch(enum lrtp_status_t s) {
    *status = s;
    delete lrtp;
    return NULL;
  }
  
  lrtp->ssrc = ssrc;
  lrtp->seq = 0;

  lrtp->magic = MAGIC;

  return lrtp;
}

EXPORT
enum lrtp_status_t lrtp_close(struct lrtp_t *lrtp)
{
  CHECK_HANDLE(lrtp);

  enum lrtp_status_t status = LRTP_OK;

  try {
    if(lrtp->srtp) delete lrtp->srtp;
    lrtp->srtp = NULL;
  } catch(enum lrtp_status_t s) {
    status = s;
  }

  lrtp->magic = 0;

  try {
    delete lrtp;
  } catch(enum lrtp_status_t s) {
    status = s;
  }

  return status;
}

EXPORT
enum lrtp_status_t lrtp_create_profile(struct lrtp_t *lrtp,
                                       lrtp_profile_id_t profile_id,
                                       unsigned int csrc, ...)
{
  CHECK_HANDLE(lrtp);

  struct lrtp_profile_t *profile = NULL;

  if(lrtp->profiles.find(csrc) != lrtp->profiles.end()) {
    return LRTP_CSRC_ALREADY_ACTIVE;
  }

  va_list ap;
  va_start(ap, csrc);

  const profile_class_t *p = registered_profiles;
  while(p->create) {
    if(p->id == profile_id) {
      profile = p->create(lrtp, csrc, ap);
      profile->process_finished = NULL; // TODO: Figure out a way to set non-profile specific options.
      break;
    }
    p++;
  }

  va_end(ap);

  if(!profile) {
    return LRTP_MISSING_PROFILE;
  }

  profile->id = profile_id;
  profile->lrtp = lrtp;
  profile->csrc = csrc;

  lrtp->profiles[csrc] = profile;
  
  return LRTP_OK;
}

EXPORT
enum lrtp_status_t lrtp_destroy_profile(struct lrtp_t *lrtp, unsigned int csrc)
{
  CHECK_HANDLE(lrtp);

  if(lrtp->profiles.find(csrc) == lrtp->profiles.end()) {
    return LRTP_MISSING_CSRC;
  }

  struct lrtp_profile_t *profile = lrtp->profiles[csrc];
  profile->destroy(profile);
  lrtp->profiles.erase(csrc);

  return LRTP_OK;
}

EXPORT
enum lrtp_status_t lrtp_enqueue_frame(struct lrtp_t *lrtp, unsigned int csrc,
                                      char *data, size_t size,
                                      unsigned long int timestamp,
                                      int flags)
{
  CHECK_HANDLE(lrtp);

  if(lrtp->profiles.find(csrc) == lrtp->profiles.end()) {
    return LRTP_MISSING_CSRC;
  }

  struct lrtp_profile_t *profile = lrtp->profiles[csrc];

  inputframe_t *frame = new inputframe_t();

  if((flags & LRTP_TAKE_OWNERSHIP) == LRTP_TAKE_OWNERSHIP) {
    frame->owned = true;
    frame->data = data;
  } else if((flags & LRTP_COPY) == LRTP_COPY) {
    frame->owned = true;
    frame->data = (char*)malloc(size);
    memcpy(frame->data, data, size);
  } else {
    frame->owned = false;
    frame->data = data;
  }
  
  frame->size = size;
  frame->offset = 0;
  frame->timestamp = timestamp;

  //printf("lrtp_enqueue_frame: frame->size: %d\n", frame->size);

  profile->framelist.push_back(frame);

  return LRTP_OK;
}

// Assume we have at least one csrc in the list
static csrc_t get_next_csrc(struct lrtp_t *lrtp)
{
  profile_map_t::iterator i = lrtp->profiles.find(lrtp->next_csrc);

  if(i == lrtp->profiles.end()) {
    // If we haven't got a valid csrc start from the beginning.
    i = lrtp->profiles.begin();
  } else {
    // Otherwise increase the iterator, potentially wrapping.
    i++;
    if(i == lrtp->profiles.end()) i = lrtp->profiles.begin();
  }

  lrtp->next_csrc = i->second->csrc;

  return lrtp->next_csrc;
}

static lrtp_profile_t *get_next_profile(struct lrtp_t *lrtp)
{
  if(lrtp->profiles.size() == 0) return NULL; // No profiles

  csrc_t start = get_next_csrc(lrtp);
  csrc_t cur = start;
  do {
    if(lrtp->profiles.find(cur) == lrtp->profiles.end()) {
      printf("ERROR: This shouldn't happen."
             " Selected profile is not in the list\n");
      break;
    }

    struct lrtp_profile_t *profile = lrtp->profiles.find(cur)->second;
    if(profile->framelist.size()) return profile;

    cur = get_next_csrc(lrtp);

  } while(cur != start);

  return NULL;
}

EXPORT
int lrtp_pack(struct lrtp_t *lrtp, char *packet, size_t maxsize)
{
  CHECK_HANDLE(lrtp);

  struct lrtp_profile_t *profile = get_next_profile(lrtp);

  if(profile == NULL || profile->framelist.size() == 0) return 0;

  inputframe_t *frame = profile->framelist.front();

  RTP rtp;
  rtp.setSSrc(lrtp->ssrc);
  rtp.setTimestamp(frame->timestamp);
  rtp.setSeq(lrtp->seq);
  rtp.addCSrc(profile->csrc);

  int ret = profile->pack(profile,
                          frame->data + frame->offset,
                          frame->size - frame->offset,
                          rtp);

  if(ret < 0) return ret;

  frame->offset += ret;

  if(frame->size == frame->offset) {
    if(profile->process_finished) {
      profile->process_finished(profile, frame->data,
                                profile->process_finished_ptr);
    }
    profile->framelist.pop_front();
    if(frame->owned) free(frame->data);
    delete frame;
  }

  if(rtp.isValid()) {
    size_t size = rtp.packet(packet, maxsize);
    size = lrtp->srtp->encrypt(packet, size);
    lrtp->seq++;
    return size;
  }

  return 0;
}

EXPORT
int lrtp_dequeue_frame(struct lrtp_t *lrtp,
                       char *frame, size_t maxsize,
                       unsigned int *csrc, unsigned int *ts)
{
  CHECK_HANDLE(lrtp);

  if(lrtp->framelist.size() == 0) return 0;

  outputframe_t *f = lrtp->framelist.front();

  if(f->size > maxsize) {
    printf("Buffer is too small\n");
    return -1; // Buffer too small.
  }

  size_t framesize = f->size;
  memcpy(frame, f->data, f->size);

  if(csrc) *csrc = f->csrc;
  if(ts) *ts = f->ts;

  lrtp->framelist.pop_front();

  //printf("%d frames left in framelist.\n", lrtp->framelist.size());

  free(f->data);
  delete f;

  return framesize;
}

EXPORT
enum lrtp_status_t lrtp_unpack(struct lrtp_t *lrtp,
                               const char *packet, size_t size)
{
  CHECK_HANDLE(lrtp);

  char *pkg = (char*)malloc(size);
  memcpy(pkg, packet, size);

  int ret = 0;

  try {
    ret = lrtp->srtp->decrypt(pkg, size);
    size = ret;
  } catch(enum lrtp_status_t s) {
    free(pkg);
    return s;
  }

  RTP rtp;
  rtp.fromPacket(pkg, size);
  std::list<csrc_t> csrcs = rtp.getCSrcs();
  if(csrcs.size() == 0) {
    free(pkg);
    return LRTP_MISSING_CSRC;
  }
  if(csrcs.size() > 1) {
    free(pkg);
    return LRTP_TOO_MANY_CSRCS;
  }

  csrc_t csrc = *csrcs.begin();

  struct lrtp_profile_t *profile = NULL;
  if(lrtp->profiles.find(csrc) == lrtp->profiles.end()) {
    free(pkg);
    return LRTP_MISSING_PROFILE;
  }

  profile = lrtp->profiles[csrc];

  oframelist_t framelist;
  ret = profile->unpack(profile, rtp, framelist);

  if(ret < 0) {
    printf("lrtp_unpack::Profile unpack failed: %d\n", ret);
    free(pkg);
    return (enum lrtp_status_t)ret;
  }

  // Make sure all frames in the list have the correct csrc.
  oframelist_t::iterator fi = framelist.begin();
  while(fi != framelist.end()) {
    (*fi)->csrc = csrc;
    fi++;
  }

  lrtp->framelist.splice(lrtp->framelist.end(), framelist);

  free(pkg);

  return LRTP_OK;
}

// NOTE: lrtp_strerror implemented in error.cc

#ifdef __cplusplus
}
#endif