#include "hash.h"
#include "digest.h"

#define MD5_CTX_LEN       (sizeof(MD5_CTX))
#define MD4_CTX_LEN       (sizeof(MD4_CTX))
#define RIPEMD160_CTX_LEN (sizeof(RIPEMD160_CTX))

#if OPENSSL_VERSION_NUMBER >= PACKED_OPENSSL_VERSION_PLAIN(1,0,0)
/* Define resource types for OpenSSL context structures. */
ErlNifResourceType* evp_md_ctx_rtype;

void evp_md_ctx_dtor(ErlNifEnv* env, struct evp_md_ctx *ctx) {
    EVP_MD_CTX_free(ctx->ctx);
}
#endif

ERL_NIF_TERM hash_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Type, Data) */
    struct digest_type_t *digp = NULL;
    const EVP_MD         *md;
    ErlNifBinary         data;
    ERL_NIF_TERM         ret;
    unsigned             ret_size;

    digp = get_digest_type(argv[0]);
    if (!digp ||
        !enif_inspect_iolist_as_binary(env, argv[1], &data)) {
	return enif_make_badarg(env);
    }
    md = digp->md.p;
    if (!md) {
	return atom_notsup;
    }

    ret_size = (unsigned)EVP_MD_size(md);
    ASSERT(0 < ret_size && ret_size <= EVP_MAX_MD_SIZE);
    if (!EVP_Digest(data.data, data.size,
                    enif_make_new_binary(env, ret_size, &ret), &ret_size,
                    md, NULL)) {
        return atom_notsup;
    }
    ASSERT(ret_size == (unsigned)EVP_MD_size(md));

    CONSUME_REDS(env, data);
    return ret;
}

#if OPENSSL_VERSION_NUMBER >= PACKED_OPENSSL_VERSION_PLAIN(1,0,0)

ERL_NIF_TERM hash_init_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Type) */
    struct digest_type_t *digp = NULL;
    struct evp_md_ctx    *ctx;
    ERL_NIF_TERM         ret;

    digp = get_digest_type(argv[0]);
    if (!digp) {
	return enif_make_badarg(env);
    }
    if (!digp->md.p) {
	return atom_notsup;
    }

    ctx = enif_alloc_resource(evp_md_ctx_rtype, sizeof(struct evp_md_ctx));
    ctx->ctx = EVP_MD_CTX_new();
    if (!EVP_DigestInit(ctx->ctx, digp->md.p)) {
        enif_release_resource(ctx);
        return atom_notsup;
    }
    ret = enif_make_resource(env, ctx);
    enif_release_resource(ctx);
    return ret;
}

ERL_NIF_TERM hash_update_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Context, Data) */
    struct evp_md_ctx   *ctx, *new_ctx;
    ErlNifBinary data;
    ERL_NIF_TERM ret;

    if (!enif_get_resource(env, argv[0], evp_md_ctx_rtype, (void**)&ctx) ||
        !enif_inspect_iolist_as_binary(env, argv[1], &data)) {
        return enif_make_badarg(env);
    }

    new_ctx = enif_alloc_resource(evp_md_ctx_rtype, sizeof(struct evp_md_ctx));
    new_ctx->ctx = EVP_MD_CTX_new();
    if (!EVP_MD_CTX_copy(new_ctx->ctx, ctx->ctx) ||
        !EVP_DigestUpdate(new_ctx->ctx, data.data, data.size)) {
        enif_release_resource(new_ctx);
        return atom_notsup;
    }

    ret = enif_make_resource(env, new_ctx);
    enif_release_resource(new_ctx);
    CONSUME_REDS(env, data);
    return ret;
}

ERL_NIF_TERM hash_final_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Context) */
    struct evp_md_ctx *ctx;
    EVP_MD_CTX        *new_ctx;
    ERL_NIF_TERM  ret;
    unsigned      ret_size;

    if (!enif_get_resource(env, argv[0], evp_md_ctx_rtype, (void**)&ctx)) {
        return enif_make_badarg(env);
    }

    ret_size = (unsigned)EVP_MD_CTX_size(ctx->ctx);
    ASSERT(0 < ret_size && ret_size <= EVP_MAX_MD_SIZE);

    new_ctx = EVP_MD_CTX_new();
    if (!EVP_MD_CTX_copy(new_ctx, ctx->ctx) ||
        !EVP_DigestFinal(new_ctx,
                         enif_make_new_binary(env, ret_size, &ret),
                         &ret_size)) {
	EVP_MD_CTX_free(new_ctx);
        return atom_notsup;
    }
    EVP_MD_CTX_free(new_ctx);
    ASSERT(ret_size == (unsigned)EVP_MD_CTX_size(ctx->ctx));

    return ret;
}

#else /* if OPENSSL_VERSION_NUMBER < 1.0 */

ERL_NIF_TERM hash_init_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Type) */
    typedef int (*init_fun)(unsigned char*);
    struct digest_type_t *digp = NULL;
    ERL_NIF_TERM         ctx;
    size_t               ctx_size = 0;
    init_fun             ctx_init = 0;

    digp = get_digest_type(argv[0]);
    if (!digp) {
	return enif_make_badarg(env);
    }
    if (!digp->md.p) {
	return atom_notsup;
    }

    switch (EVP_MD_type(digp->md.p))
    {
    case NID_md4:
        ctx_size = MD4_CTX_LEN;
        ctx_init = (init_fun)(&MD4_Init);
        break;
    case NID_md5:
        ctx_size = MD5_CTX_LEN;
        ctx_init = (init_fun)(&MD5_Init);
        break;
    case NID_ripemd160:
        ctx_size = RIPEMD160_CTX_LEN;
        ctx_init = (init_fun)(&RIPEMD160_Init);
        break;
    case NID_sha1:
        ctx_size = sizeof(SHA_CTX);
        ctx_init = (init_fun)(&SHA1_Init);
        break;
#ifdef HAVE_SHA224
    case NID_sha224:
        ctx_size = sizeof(SHA256_CTX);
        ctx_init = (init_fun)(&SHA224_Init);
        break;
#endif
#ifdef HAVE_SHA256
    case NID_sha256:
        ctx_size = sizeof(SHA256_CTX);
        ctx_init = (init_fun)(&SHA256_Init);
        break;
#endif
#ifdef HAVE_SHA384
    case NID_sha384:
        ctx_size = sizeof(SHA512_CTX);
        ctx_init = (init_fun)(&SHA384_Init);
        break;
#endif
#ifdef HAVE_SHA512
    case NID_sha512:
        ctx_size = sizeof(SHA512_CTX);
        ctx_init = (init_fun)(&SHA512_Init);
        break;
#endif
    default:
        return atom_notsup;
    }
    ASSERT(ctx_size);
    ASSERT(ctx_init);

    ctx_init(enif_make_new_binary(env, ctx_size, &ctx));
    return enif_make_tuple2(env, argv[0], ctx);
}

ERL_NIF_TERM hash_update_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* ({Type, Context}, Data) */
    typedef int (*update_fun)(unsigned char*, const unsigned char*, size_t);
    ERL_NIF_TERM         new_ctx;
    ErlNifBinary         ctx, data;
    const ERL_NIF_TERM   *tuple;
    int                  arity;
    struct digest_type_t *digp = NULL;
    unsigned char        *ctx_buff;
    size_t               ctx_size   = 0;
    update_fun           ctx_update = 0;

    if (!enif_get_tuple(env, argv[0], &arity, &tuple) ||
        arity != 2 ||
        !(digp = get_digest_type(tuple[0])) ||
        !enif_inspect_binary(env, tuple[1], &ctx) ||
        !enif_inspect_iolist_as_binary(env, argv[1], &data)) {
        return enif_make_badarg(env);
    }
    if (!digp->md.p) {
	return atom_notsup;
    }

    switch (EVP_MD_type(digp->md.p))
    {
    case NID_md4:
        ctx_size   = MD4_CTX_LEN;
        ctx_update = (update_fun)(&MD4_Update);
        break;
    case NID_md5:
        ctx_size   = MD5_CTX_LEN;
        ctx_update = (update_fun)(&MD5_Update);
        break;
    case NID_ripemd160:
        ctx_size   = RIPEMD160_CTX_LEN;
        ctx_update = (update_fun)(&RIPEMD160_Update);
        break;
    case NID_sha1:
        ctx_size   = sizeof(SHA_CTX);
        ctx_update = (update_fun)(&SHA1_Update);
        break;
#ifdef HAVE_SHA224
    case NID_sha224:
        ctx_size   = sizeof(SHA256_CTX);
        ctx_update = (update_fun)(&SHA224_Update);
        break;
#endif
#ifdef HAVE_SHA256
    case NID_sha256:
        ctx_size   = sizeof(SHA256_CTX);
        ctx_update = (update_fun)(&SHA256_Update);
        break;
#endif
#ifdef HAVE_SHA384
    case NID_sha384:
        ctx_size   = sizeof(SHA512_CTX);
        ctx_update = (update_fun)(&SHA384_Update);
        break;
#endif
#ifdef HAVE_SHA512
    case NID_sha512:
        ctx_size   = sizeof(SHA512_CTX);
        ctx_update = (update_fun)(&SHA512_Update);
        break;
#endif
    default:
        return atom_notsup;
    }
    ASSERT(ctx_size);
    ASSERT(ctx_update);

    if (ctx.size != ctx_size) {
        return enif_make_badarg(env);
    }

    ctx_buff = enif_make_new_binary(env, ctx_size, &new_ctx);
    memcpy(ctx_buff, ctx.data, ctx_size);
    ctx_update(ctx_buff, data.data, data.size);

    CONSUME_REDS(env, data);
    return enif_make_tuple2(env, tuple[0], new_ctx);
}

ERL_NIF_TERM hash_final_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* ({Type, Context}) */
    typedef int (*final_fun)(unsigned char*, void*);
    ERL_NIF_TERM         ret;
    ErlNifBinary         ctx;
    const ERL_NIF_TERM   *tuple;
    int                  arity;
    struct digest_type_t *digp = NULL;
    const EVP_MD         *md;
    void                 *new_ctx;
    size_t               ctx_size  = 0;
    final_fun            ctx_final = 0;

    if (!enif_get_tuple(env, argv[0], &arity, &tuple) ||
        arity != 2 ||
        !(digp = get_digest_type(tuple[0])) ||
        !enif_inspect_binary(env, tuple[1], &ctx)) {
        return enif_make_badarg(env);
    }
    md = digp->md.p;
    if (!md) {
	return atom_notsup;
    }

    switch (EVP_MD_type(md))
    {
    case NID_md4:
        ctx_size  = MD4_CTX_LEN;
        ctx_final = (final_fun)(&MD4_Final);
        break;
    case NID_md5:
        ctx_size  = MD5_CTX_LEN;
        ctx_final = (final_fun)(&MD5_Final);
        break;
    case NID_ripemd160:
        ctx_size  = RIPEMD160_CTX_LEN;
        ctx_final = (final_fun)(&RIPEMD160_Final);
        break;
    case NID_sha1:
        ctx_size  = sizeof(SHA_CTX);
        ctx_final = (final_fun)(&SHA1_Final);
        break;
#ifdef HAVE_SHA224
    case NID_sha224:
        ctx_size  = sizeof(SHA256_CTX);
        ctx_final = (final_fun)(&SHA224_Final);
        break;
#endif
#ifdef HAVE_SHA256
    case NID_sha256:
        ctx_size  = sizeof(SHA256_CTX);
        ctx_final = (final_fun)(&SHA256_Final);
        break;
#endif
#ifdef HAVE_SHA384
    case NID_sha384:
        ctx_size  = sizeof(SHA512_CTX);
        ctx_final = (final_fun)(&SHA384_Final);
        break;
#endif
#ifdef HAVE_SHA512
    case NID_sha512:
        ctx_size  = sizeof(SHA512_CTX);
        ctx_final = (final_fun)(&SHA512_Final);
        break;
#endif
    default:
        return atom_notsup;
    }
    ASSERT(ctx_size);
    ASSERT(ctx_final);

    if (ctx.size != ctx_size) {
        return enif_make_badarg(env);
    }

    new_ctx = enif_alloc(ctx_size);
    memcpy(new_ctx, ctx.data, ctx_size);
    ctx_final(enif_make_new_binary(env, (size_t)EVP_MD_size(md), &ret),
              new_ctx);
    enif_free(new_ctx);

    return ret;
}

#endif  /* OPENSSL_VERSION_NUMBER < 1.0 */