/*
    This file is part of Pretty Curved Privacy (pcp1).

    Copyright (C) 2013 T.Linden.

    This program 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 3 of the License, or
    (at your option) any later version.

    This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.

    You can contact me by mail: <tlinden AT cpan DOT org>.
*/

#include "sign++.h"

using namespace std;
using namespace pcp;

Signature::Signature(Key &skey) {
  S = skey;
  havevault = false;
  sig = NULL;
}

Signature::Signature(PubKey &pkey) {
  P = pkey;
  havevault = false;
  sig = NULL;
}

Signature::Signature(Key &skey, PubKey &pkey) {
  P = pkey;
  S = skey;
  havevault = false;
  sig = NULL;
}

Signature::Signature(Vault &v) {
  vault = v;
  havevault = true;
  sig = NULL;
  S = vault.get_primary();
}

Signature::~Signature() {
  if(sig != NULL)
    free(sig);
}

unsigned char *Signature::sign(std::vector<unsigned char> message) {
  if(! S)
    throw exception("Error: cannot sign without a secret key, use another constructor.");

  if(S.is_encrypted())
    throw exception("Error: cannot sign with an encrypted secret key, decrypt it before using.");

  char n[] = "signvec";
  Buffer *m = buffer_new(32, n);

  for(size_t i=0; i<message.size(); ++i)
    buffer_add(m, (void *)message[i], 1);

  Pcpstream *p = ps_new_inbuffer(m);
  unsigned char *sig = Signature::sign(p);
  ps_close(p);
  buffer_free(m);

  if(sig == NULL)
    throw exception();

  return sig;
}

unsigned char *Signature::sign(unsigned char *message, size_t mlen) {
  if(! S)
    throw exception("Error: cannot sign without a secret key, use another constructor.");

  if(S.is_encrypted())
    throw exception("Error: cannot sign with an encrypted secret key, decrypt it before using.");

  char n[] = "signchar";
  Buffer *m = buffer_new(32, n);
  buffer_add(m, message, mlen);
  Pcpstream *p = ps_new_inbuffer(m);

  unsigned char *sig = Signature::sign(p);
  ps_close(p);
  buffer_free(m);

  if(sig == NULL)
    throw exception();

  return sig;
}

unsigned char *Signature::sign(Pcpstream *message) {
  Pcpstream *out = ps_new_outbuffer();
  unsigned char *sig = NULL;

  size_t sigsize = pcp_ed_sign_buffered(message, out, S.K, 1);

  if(sigsize > 0) {
    Buffer *o = ps_buffer(out);
    sigsize = buffer_size(o);
    buffer_dump(o);
    sig = (unsigned char*)ucmalloc(sigsize);
    buffer_get_chunk(o, sig, sigsize);
  }

  ps_close(out);

  return sig;
}

bool Signature::verify(vector<unsigned char> message) {
  unsigned char *m = (unsigned char *)ucmalloc(message.size());
  for(size_t i=0; i<message.size(); ++i)
    m[i] = message[i];
  bool _b = Signature::verify(m, message.size());
  free(m);
  return _b;
}

bool Signature::verify(unsigned char *signature, size_t mlen) {
  if(!P) {
    throw exception("No public key specified, unable to verify.");
  }

  char n[] = "verify";
  Buffer *m = buffer_new(32, n);
  buffer_add(m, signature, mlen);
  Pcpstream *p = ps_new_inbuffer(m);

  pcp_pubkey_t *pub = pcp_ed_verify_buffered(p, P.K);

  ps_close(p);
  

  if(pub != NULL) {
    Signedby = PubKey(pub);
    return true;
  }
  else {
    throw exception();
  }
}