/*
 * ---------------------------------------------------------------------------
 * OpenAES License
 * ---------------------------------------------------------------------------
 * Copyright (c) 2012, Nabil S. Al Ramli, www.nalramli.com
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   - Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * ---------------------------------------------------------------------------
 */

#ifndef _OAES_LIB_H
#define _OAES_LIB_H

#include <stdint.h>
#include <stdlib.h>

#ifdef __cplusplus
extern "C"
{
#endif

#ifdef _WIN32
#ifdef OAES_SHARED
#ifdef oaes_lib_EXPORTS
#define OAES_API __declspec(dllexport)
#else
#define OAES_API __declspec(dllimport)
#endif
#else
#define OAES_API
#endif
#else
#define OAES_API
#endif // WIN32

#define OAES_VERSION "0.8.1"
#define OAES_BLOCK_SIZE 16

    typedef void OAES_CTX;

    typedef enum
    {
        OAES_RET_FIRST = 0,
        OAES_RET_SUCCESS = 0,
        OAES_RET_UNKNOWN,
        OAES_RET_ARG1,
        OAES_RET_ARG2,
        OAES_RET_ARG3,
        OAES_RET_ARG4,
        OAES_RET_ARG5,
        OAES_RET_NOKEY,
        OAES_RET_MEM,
        OAES_RET_BUF,
        OAES_RET_HEADER,
        OAES_RET_COUNT
    } OAES_RET;

/*
 * oaes_set_option() takes one of these values for its [option] parameter
 * some options accept either an optional or a required [value] parameter
 */
// no option
#define OAES_OPTION_NONE 0
// enable ECB mode, disable CBC mode
#define OAES_OPTION_ECB 1
// enable CBC mode, disable ECB mode
// value is optional, may pass uint8_t iv[OAES_BLOCK_SIZE] to specify
// the value of the initialization vector, iv
#define OAES_OPTION_CBC 2

#ifdef OAES_DEBUG
    typedef int (
        *oaes_step_cb)(const uint8_t state[OAES_BLOCK_SIZE], const char *step_name, int step_count, void *user_data);
// enable state stepping mode
// value is required, must pass oaes_step_cb to receive the state at each step
#define OAES_OPTION_STEP_ON 4
// disable state stepping mode
#define OAES_OPTION_STEP_OFF 8
#endif // OAES_DEBUG

    typedef uint16_t OAES_OPTION;

    typedef struct _oaes_key
    {
        size_t data_len;
        uint8_t *data;
        size_t exp_data_len;
        uint8_t *exp_data;
        size_t num_keys;
        size_t key_base;
    } oaes_key;

    typedef struct _oaes_ctx
    {
#ifdef OAES_HAVE_ISAAC
        randctx *rctx;
#endif // OAES_HAVE_ISAAC

#ifdef OAES_DEBUG
        oaes_step_cb step_cb;
#endif // OAES_DEBUG

        oaes_key *key;
        OAES_OPTION options;
        uint8_t iv[OAES_BLOCK_SIZE];
    } oaes_ctx;
    /*
     * // usage:
     *
     * OAES_CTX * ctx = oaes_alloc();
     * .
     * .
     * .
     * {
     *   oaes_gen_key_xxx( ctx );
     *   {
     *     oaes_key_export( ctx, _buf, &_buf_len );
     *     // or
     *     oaes_key_export_data( ctx, _buf, &_buf_len );\
     *   }
     * }
     * // or
     * {
     *   oaes_key_import( ctx, _buf, _buf_len );
     *   // or
     *   oaes_key_import_data( ctx, _buf, _buf_len );
     * }
     * .
     * .
     * .
     * oaes_encrypt( ctx, m, m_len, c, &c_len );
     * .
     * .
     * .
     * oaes_decrypt( ctx, c, c_len, m, &m_len );
     * .
     * .
     * .
     * oaes_free( &ctx );
     */

    OAES_API OAES_CTX *oaes_alloc(void);

    OAES_API OAES_RET oaes_free(OAES_CTX **ctx);

    OAES_API OAES_RET oaes_set_option(OAES_CTX *ctx, OAES_OPTION option, const void *value);

    OAES_API OAES_RET oaes_key_gen_128(OAES_CTX *ctx);

    OAES_API OAES_RET oaes_key_gen_192(OAES_CTX *ctx);

    OAES_API OAES_RET oaes_key_gen_256(OAES_CTX *ctx);

    // export key with header information
    // set data == NULL to get the required data_len
    OAES_API OAES_RET oaes_key_export(OAES_CTX *ctx, uint8_t *data, size_t *data_len);

    // directly export the data from key
    // set data == NULL to get the required data_len
    OAES_API OAES_RET oaes_key_export_data(OAES_CTX *ctx, uint8_t *data, size_t *data_len);

    // import key with header information
    OAES_API OAES_RET oaes_key_import(OAES_CTX *ctx, const uint8_t *data, size_t data_len);

    // directly import data into key
    OAES_API OAES_RET oaes_key_import_data(OAES_CTX *ctx, const uint8_t *data, size_t data_len);

    // set c == NULL to get the required c_len
    OAES_API OAES_RET oaes_encrypt(OAES_CTX *ctx, const uint8_t *m, size_t m_len, uint8_t *c, size_t *c_len);

    // set m == NULL to get the required m_len
    OAES_API OAES_RET oaes_decrypt(OAES_CTX *ctx, const uint8_t *c, size_t c_len, uint8_t *m, size_t *m_len);

    // set buf == NULL to get the required buf_len
    OAES_API OAES_RET oaes_sprintf(char *buf, size_t *buf_len, const uint8_t *data, size_t data_len);

    OAES_API OAES_RET oaes_encryption_round(const uint8_t *key, uint8_t *c);

    OAES_API OAES_RET oaes_pseudo_encrypt_ecb(OAES_CTX *ctx, uint8_t *c);

#ifdef __cplusplus
}
#endif

#endif // _OAES_LIB_H