/*
 * Secure eXtended Message Passing framework
 * Secure eXtended Transport layer implementation: (libsxt)
 * - very similar to SSH2/TLS
 * - using already proven and tested crypto algos
 * - better than TLS for message passing
 *
 * Ciphers API
 *
 * (c) Alexander Vdolainen 2016 <avdolainen@zoho.com>
 *
 * libsxmp 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.
 *
 * libsxmp 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 this program.  If not, see <http://www.gnu.org/licenses/>.";
 *
 */

#include <stdlib.h>
#include <string.h>

#include <sxt/errno.h>
#include <sxt/ciphers.h>
#include <sxt/lcrypt.h>

#include <tdata/list.h>

static list_head_t cipher_listhead;
static int __list_initied = 0;

struct cipher_tbl {
  sxt_cipher_t *cipher;
  list_node_t node;
};

static sxt_cipher_t *__alloc_cipher(const char *name, unsigned int blksize,
                                    unsigned int keylen, struct _cipher_ops *f)
{
  sxt_cipher_t *n = NULL;

  if(!name || !f) return NULL;

  if(!(n = malloc(sizeof(sxt_cipher_t)))) return NULL;
  if(!(n->name = strdup(name))) {
    free(n);
    return NULL;
  }

  n->blksize = blksize;
  n->keylen = keylen;
  n->f = f;

  return n;
}

/* API for workout with table */
sxt_cipher_t *sxt_cipher_get(const char *name)
{
  sxt_cipher_t *sc = NULL, *nn = NULL;
  struct cipher_tbl *entry = NULL;
  list_node_t *iter, *siter;

  if(!__list_initied || !name) return NULL;

  list_for_each_safe(&cipher_listhead, iter, siter) {
    entry = list_entry(iter, struct cipher_tbl, node);
    sc = entry->cipher;
    if(!strcmp(sxt_cipher_getname(sc), name)) break;
    else sc = NULL;
  }

  if(sc) {
    nn = malloc(sizeof(sxt_cipher_t));
    if(!nn) return NULL;
    else memset(nn, 0, sizeof(sxt_cipher_t));
    nn->name = sc->name;
    nn->f = sc->f;
    nn->blksize = sc->blksize;
    nn->keylen = sc->keylen;
    nn->keysize = sc->keysize;
    if(lcrypt_alloc_keystub(nn)) {
      free(nn);
      nn = NULL;
    }
  }

  return nn;
}

void sxt_cipher_free(sxt_cipher_t *c)
{
  if(!c) return;

  lcrypt_cleanup_keystub(c);
  memset(c, 0, sizeof(sxt_cipher_t));
  free(c);

  return;
}

int sxt_cipher_add(const char *name, unsigned int blksize, unsigned int keylen,
                   unsigned int keysz, struct _cipher_ops *f)
{
  struct cipher_tbl *ne = NULL;
  sxt_cipher_t *nec = NULL;

  /* take a check for head first */
  if(!__list_initied) {
    list_init_head(&cipher_listhead);
    __list_initied = 1;
  }

  if(!f) return SXT_EINVAL;
  if(!(ne = malloc(sizeof(struct cipher_tbl)))) return SXT_ENOMEM;
  else {
    nec = __alloc_cipher(name, blksize, keylen, f);
    if(!nec) {
      free(ne);
      return SXT_ENOMEM;
    } else nec->keysize = keysz;

    ne->cipher = nec;
    list_init_node(&ne->node);
    list_add2tail(&cipher_listhead, &ne->node);
  }

  return SXT_SUCCESS;
}

/* API to deal with cipher */
const char *sxt_cipher_getname(sxt_cipher_t *c)
{
  if(!c || !c->name) return "none";
  else return c->name;
}

int sxt_cipher_set_encrypt_key(sxt_cipher_t *c, void *key, void *ivec)
{
  if(!c || !key) return SXT_EINVAL;
  if(!ivec) return SXT_EINVAL;

  return c->f->set_encrypt_key(c, key, ivec);
}

int sxt_cipher_set_decrypt_key(sxt_cipher_t *c, void *key, void *ivec)
{
  if(!c || !key) return SXT_EINVAL;
  if(!ivec) return SXT_EINVAL;

  return c->f->set_decrypt_key(c, key, ivec);
}

void sxt_cipher_encrypt(sxt_cipher_t *c, void *in, void *out, unsigned long size)
{
  if(!c || !size) return;
  if(!in || !out) return;

  c->f->encrypt(c, in, out, size);

  return;
}

void sxt_cipher_decrypt(sxt_cipher_t *c, void *in, void *out, unsigned long size)
{
  if(!c || !size) return;
  if(!in || !out) return;

  c->f->decrypt(c, in, out, size);

  return;
}