///  @file  sign.c
///  @brief the implementations for functions in api.h
///
///

#include "api.h"
#include "rainbow.h"
#include "rainbow_config.h"
#include "rainbow_keypair.h"
#include "randombytes.h"
#include "utils_hash.h"
#include <stdlib.h>
#include <string.h>



int
PQCLEAN_RAINBOWIACLASSIC_CLEAN_crypto_sign_keypair(unsigned char *pk, unsigned char *sk) {
    unsigned char sk_seed[LEN_SKSEED] = {0};
    randombytes( sk_seed, LEN_SKSEED );


    PQCLEAN_RAINBOWIACLASSIC_CLEAN_generate_keypair( (pk_t *) pk, (sk_t *) sk, sk_seed );

    return 0;
}





int
PQCLEAN_RAINBOWIACLASSIC_CLEAN_crypto_sign(unsigned char *sm, size_t *smlen, const unsigned char *m, size_t mlen, const unsigned char *sk) {
    unsigned char digest[_HASH_LEN];

    PQCLEAN_RAINBOWIACLASSIC_CLEAN_hash_msg( digest, _HASH_LEN, m, mlen );

    memcpy( sm, m, mlen );
    smlen[0] = mlen + _SIGNATURE_BYTE;


    return PQCLEAN_RAINBOWIACLASSIC_CLEAN_rainbow_sign( sm + mlen, (const sk_t *)sk, digest );



}






int
PQCLEAN_RAINBOWIACLASSIC_CLEAN_crypto_sign_open(unsigned char *m, size_t *mlen, const unsigned char *sm, size_t smlen, const unsigned char *pk) {
    //TODO: this should not copy out the message if verification fails
    if ( _SIGNATURE_BYTE > smlen ) {
        return -1;
    }
    memcpy( m, sm, smlen - _SIGNATURE_BYTE );
    mlen[0] = smlen - _SIGNATURE_BYTE;

    unsigned char digest[_HASH_LEN];
    PQCLEAN_RAINBOWIACLASSIC_CLEAN_hash_msg( digest, _HASH_LEN, m, *mlen );


    return PQCLEAN_RAINBOWIACLASSIC_CLEAN_rainbow_verify( digest, sm + mlen[0], (const pk_t *)pk );



}

int PQCLEAN_RAINBOWIACLASSIC_CLEAN_crypto_sign_signature(
    uint8_t *sig, size_t *siglen,
    const uint8_t *m, size_t mlen, const uint8_t *sk) {
    unsigned char digest[_HASH_LEN];

    PQCLEAN_RAINBOWIACLASSIC_CLEAN_hash_msg( digest, _HASH_LEN, m, mlen );
    *siglen = _SIGNATURE_BYTE;
    return PQCLEAN_RAINBOWIACLASSIC_CLEAN_rainbow_sign( sig, (const sk_t *)sk, digest );
}

int PQCLEAN_RAINBOWIACLASSIC_CLEAN_crypto_sign_verify(
    const uint8_t *sig, size_t siglen,
    const uint8_t *m, size_t mlen, const uint8_t *pk) {
    if (siglen != _SIGNATURE_BYTE) {
        return -1;
    }
    unsigned char digest[_HASH_LEN];
    PQCLEAN_RAINBOWIACLASSIC_CLEAN_hash_msg( digest, _HASH_LEN, m, mlen );
    return PQCLEAN_RAINBOWIACLASSIC_CLEAN_rainbow_verify( digest, sig, (const pk_t *)pk );

}