# build_ffi.py
#
# Copyright (C) 2006-2022 wolfSSL Inc.
#
# This file is part of wolfSSL. (formerly known as CyaSSL)
#
# wolfSSL 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 2 of the License, or
# (at your option) any later version.
#
# wolfSSL 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, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA

import os
import sys
import re
import subprocess
from contextlib import contextmanager
from distutils.util import get_platform
from cffi import FFI
import shutil
import glob
from wolfcrypt._version import __wolfssl_version__ as version

def local_path(path):
    """ Return path relative to the root of this project
    """
    current = os.path.abspath(os.getcwd())
    return os.path.abspath(os.path.join(current, path))

WOLFSSL_SRC_PATH = local_path("lib/wolfssl")

def wolfssl_inc_dirs(local_wolfssl=None, fips=False):
    """Returns the wolfSSL include directories needed to build the CFFI.
    """
    include_paths = []
    if local_wolfssl:
        include_dir = os.path.join(local_wolfssl, "include")
        # If an include subdirectory exists under local_wolfssl, use that.
        # Otherwise, use local_wolfssl (e.g. local_wolfssl may point to a
        # wolfssl source code directory).
        if os.path.exists(include_dir):
            include_paths.append(include_dir)
        else:
            include_paths.append(local_wolfssl)
            if sys.platform == "win32":
                # Add the user_settings.h directory.
                if fips:
                    include_paths.append(os.path.join(local_wolfssl, "IDE",
                        "WIN10"))
                else:
                    include_paths.append(os.path.join(local_wolfssl, "IDE",
                        "WIN"))
    else:
        include_paths.append(os.path.join(WOLFSSL_SRC_PATH, get_platform(),
            version, "include"))
        if sys.platform == "win32":
            # Add the user_settings.h directory.
            include_paths.append(os.path.join(WOLFSSL_SRC_PATH, "build"))

    return include_paths

def wolfssl_lib_dir(local_wolfssl=None, fips=False):
    """Returns the directory containg the wolfSSL library.
    """
    lib_dir = None

    if local_wolfssl:
        lib_names = []
        if sys.platform == "win32":
            lib_names.append("wolfssl-fips.dll")
            lib_names.append("wolfssl.lib")
        else:
            lib_names.append("libwolfssl.a")
            lib_names.append("libwolfssl.so")

        found = False
        for root, dirs, files in os.walk(local_wolfssl):
            for name in lib_names:
                if name in files:
                    lib_dir = root
                    found = True
                    break

            if found:
                break
    else:
        lib_dir = os.path.join(WOLFSSL_SRC_PATH, get_platform(), version, "lib")

    if not lib_dir:
        e = ("Unable to find wolfSSL library. If using USE_LOCAL_WOLFSSL, "
             "ensure wolfSSL has been built.")
        raise FileNotFoundError(e)

    return lib_dir

def call(cmd):
    print("Calling: '{}' from working directory {}".format(cmd, os.getcwd()))

    old_env = os.environ["PATH"]
    os.environ["PATH"] = "{}:{}".format(WOLFSSL_SRC_PATH, old_env)
    subprocess.check_call(cmd, shell=True, env=os.environ)
    os.environ["PATH"] = old_env

@contextmanager
def chdir(new_path, mkdir=False):
    old_path = os.getcwd()

    if mkdir:
        try:
            os.mkdir(new_path)
        except OSError:
            pass

    try:
        yield os.chdir(new_path)
    finally:
        os.chdir(old_path)


def checkout_version(version):
    """ Ensure that we have the right version.
    """
    with chdir(WOLFSSL_SRC_PATH):
        current = ""
        try:
            current = subprocess.check_output(
                ["git", "describe", "--all", "--exact-match"]
            ).strip().decode().split('/')[-1]
        except:
            pass

        if current != version:
            tags = subprocess.check_output(
                ["git", "tag"]
            ).strip().decode().split("\n")

            if version != "master" and version not in tags:
                call("git fetch --depth=1 origin tag {}".format(version))

            call("git checkout --force {}".format(version))

            return True  # rebuild needed

    return False


def ensure_wolfssl_src(ref):
    """ Ensure that wolfssl sources are presents and up-to-date.
    """

    if not os.path.isdir("lib"):
        os.mkdir("lib")
        with chdir("lib"):
            subprocess.run(["git", "clone", "--depth=1", "https://github.com/wolfssl/wolfssl"])

    if not os.path.isdir(os.path.join(WOLFSSL_SRC_PATH, "wolfssl")):
        subprocess.run(["git", "submodule", "update", "--init", "--depth=1"])

    return checkout_version(version)


def make_flags(prefix):
    """ Returns compilation flags.
    """
    if sys.platform == "win32":
        flags = []
        flags.append("-DCMAKE_INSTALL_PREFIX={}".format(prefix))
        flags.append("-DWOLFSSL_CRYPT_TESTS=no")
        flags.append("-DWOLFSSL_EXAMPLES=no")
        flags.append("-DBUILD_SHARED_LIBS=no")
        flags.append("-DWOLFSSL_USER_SETTINGS=yes")
        return " ".join(flags)
    else:
        flags = []

        if get_platform() in ["linux-x86_64", "linux-i686"]:
            flags.append("CFLAGS=-fPIC")

        # install location
        flags.append("--prefix={}".format(prefix))

        # crypt only, lib only
        flags.append("--enable-cryptonly")
        flags.append("--disable-crypttests")
        flags.append("--disable-shared")

        # symmetric ciphers
        flags.append("--enable-aes")
        flags.append("--enable-aesctr")
        flags.append("--enable-des3")
        flags.append("--enable-chacha")

        flags.append("--enable-aesgcm-stream")

        flags.append("--enable-aesgcm")

        # hashes and MACs
        flags.append("--enable-sha")
        flags.append("--enable-sha384")
        flags.append("--enable-sha512")
        flags.append("--enable-sha3")
        flags.append("--enable-hkdf")

        flags.append("--disable-md5")
        flags.append("--disable-sha224")
        flags.append("--disable-poly1305")

        # asymmetric ciphers
        flags.append("--enable-rsa")
        flags.append("--enable-rsapss")
        flags.append("--enable-ecc")
        flags.append("--enable-ed25519")
        flags.append("--enable-ed448")
        flags.append("--enable-curve25519")
        flags.append("--enable-keygen")

        flags.append("--disable-dh")

        # pwdbased
        flags.append("--enable-pwdbased")
        flags.append("--enable-pkcs7")

        # disabling other configs enabled by default
        flags.append("--disable-oldtls")
        flags.append("--disable-oldnames")
        flags.append("--disable-extended-master")
        flags.append("--disable-errorstrings")

        return " ".join(flags)


def make(configure_flags, fips=False):
    """ Create a release of wolfSSL C library
    """
    if sys.platform == 'win32':
        build_path = os.path.join(WOLFSSL_SRC_PATH, "build")
        if not os.path.isdir(build_path):
            os.mkdir(build_path)

        if not fips:
            shutil.copy(local_path("windows/non_fips/user_settings.h"),
                        build_path)
        else:
            raise Exception("Cannot build wolfSSL FIPS from git repo.")

        with chdir(build_path):
            call("cmake {} ..".format(configure_flags))
            call("cmake --build . --config Release")
            call("cmake --install . --config Release")
    else:
        with chdir(WOLFSSL_SRC_PATH):
            call("git clean -fdX")

            try:
                call("./autogen.sh")
            except subprocess.CalledProcessError:
                call("libtoolize")
                call("./autogen.sh")

            call("./configure {}".format(configure_flags))
            call("make")
            call("make install")

def get_libwolfssl():
    if sys.platform == "win32":
        libwolfssl_path = os.path.join(wolfssl_lib_dir(), "wolfssl.lib")
        if not os.path.exists(libwolfssl_path):
            return False
        else:
            return True
    else:
        libwolfssl_path = os.path.join(wolfssl_lib_dir(), "libwolfssl.a")
        if not os.path.exists(libwolfssl_path):
            libwolfssl_path = os.path.join(wolfssl_lib_dir(), "libwolfssl.so")
            if not os.path.exists(libwolfssl_path):
                return False
            else:
                return True
        else:
            return True

def generate_libwolfssl():
    ensure_wolfssl_src(version)
    prefix = os.path.join(WOLFSSL_SRC_PATH, get_platform(), version)
    make(make_flags(prefix))

def get_features(local_wolfssl, features):
    fips = False

    if sys.platform == "win32":
        # On Windows, we assume the local_wolfssl path is to a wolfSSL source
        # directory where the library has been built.
        fips_file = os.path.join(local_wolfssl, "wolfssl", "wolfcrypt",
            "fips.h")
    else:
        # On non-Windows platforms, first assume local_wolfssl is an
        # installation directory with an include subdirectory.
        fips_file = os.path.join(local_wolfssl, "include", "wolfssl",
            "wolfcrypt", "fips.h")
        if not os.path.exists(fips_file):
            # Try assuming local_wolfssl is a wolfSSL source directory.
            fips_file = os.path.join(local_wolfssl, "wolfssl", "wolfcrypt",
                "fips.h")

    if os.path.exists(fips_file):
        with open(fips_file, "r") as f:
            contents = f.read()
            if not contents.isspace():
                fips = True

    include_dirs = wolfssl_inc_dirs(local_wolfssl, fips)
    defines_files = []

    for d in include_dirs:
        if not os.path.exists(d):
            e = "Invalid wolfSSL include dir: .".format(d)
            raise FileNotFoundError(e)

        options = os.path.join(d, "wolfssl", "options.h")
        if os.path.exists(options):
            defines_files.append(options)
        user_settings = os.path.join(d, "user_settings.h")
        if os.path.exists(user_settings):
            defines_files.append(user_settings)

    if len(defines_files) == 0:
        e = "No options.h or user_settings.h found for feature detection."
        raise RuntimeError(e)

    defines = ""
    for file in defines_files:
        with open(file, 'r') as f:
            defines += f.read()

    features["MPAPI"] = 1 if '#define WOLFSSL_PUBLIC_MP' in defines else 0
    features["SHA"] = 0 if '#define NO_SHA' in defines else 1
    features["SHA256"] = 0 if '#define NO_SHA256' in defines else 1
    features["SHA384"] = 1 if '#define WOLFSSL_SHA384' in defines else 0
    features["SHA512"] = 1 if '#define WOLFSSL_SHA512' in defines else 0
    features["SHA3"] = 1 if '#define WOLFSSL_SHA3' in defines else 0
    features["DES3"] = 0 if '#define NO_DES3' in defines else 1
    features["AES"] = 0 if '#define NO_AES' in defines else 1
    features["CHACHA"] = 1 if '#define HAVE_CHACHA' in defines else 0
    features["HMAC"] = 0 if '#define NO_HMAC' in defines else 1
    features["RSA"] = 0 if '#define NO_RSA' in defines else 1
    features["ECC_TIMING_RESISTANCE"] = 1 if '#define ECC_TIMING_RESISTANT' in defines else 0
    features["RSA_BLINDING"] = 1 if '#define WC_RSA_BLINDING' in defines else 0
    features["ECC"] = 1 if '#define HAVE_ECC' in defines else 0
    features["ED25519"] = 1 if '#define HAVE_ED25519' in defines else 0
    features["ED448"] = 1 if '#define HAVE_ED448' in defines else 0
    features["KEYGEN"] = 1 if '#define WOLFSSL_KEY_GEN' in defines else 0
    features["PWDBASED"] = 0 if '#define NO_PWDBASED' in defines else 1
    features["ERROR_STRINGS"] = 0 if '#define NO_ERROR_STRINGS' in defines else 1
    features["ASN"] = 0 if '#define NO_ASN' in defines else 1
    features["WC_RNG_SEED_CB"] = 1 if '#define WC_RNG_SEED_CB' in defines else 0
    features["AESGCM_STREAM"] = 1 if '#define WOLFSSL_AESGCM_STREAM' in defines else 0
    features["RSA_PSS"] = 1 if '#define WC_RSA_PSS' in defines else 0

    if '#define HAVE_FIPS' in defines:
        if not fips:
            e = "fips.c empty but HAVE_FIPS defined."
            raise RuntimeError(e)

        features["FIPS"] = 1
        version_match = re.search(r'#define HAVE_FIPS_VERSION\s+(\d+)', defines)
        if version_match is not None:
            features["FIPS_VERSION"] = int(version_match.group(1))
        else:
            e = "Saw #define HAVE_FIPS but no FIPS version found."
            raise RuntimeError(e)

    return features

def build_ffi(local_wolfssl, features):
    cffi_include_dirs = wolfssl_inc_dirs(local_wolfssl, features["FIPS"])
    cffi_libraries = []

    if sys.platform == 'win32':
        if features["FIPS"]:
            # To use the CFFI library, we need wolfssl-fips.dll. It should exist
            # alongside the .pyd created by CFFI, so we copy it over here.
            shutil.copy(os.path.join(wolfssl_lib_dir(local_wolfssl,
                features["FIPS"]), "wolfssl-fips.dll"),
                local_path("wolfcrypt/"))
            cffi_libraries.append("wolfssl-fips")
        else:
            cffi_libraries.append("wolfssl")

        # Needed for WIN32 functions in random.c.
        cffi_libraries.append("Advapi32")
    else:
        cffi_libraries.append("wolfssl")

    includes_string = ""

    if sys.platform == 'win32':
        includes_string += """
        #ifndef WOLFSSL_USER_SETTINGS
        #define WOLFSSL_USER_SETTINGS
        #endif

        #include \"user_settings.h\"\n
        """
    else:
        includes_string += "#include  <wolfssl/options.h>\n"

    includes_string += """
        #include <wolfssl/wolfcrypt/settings.h>

        #include <wolfssl/wolfcrypt/sha.h>
        #include <wolfssl/wolfcrypt/sha256.h>
        #include <wolfssl/wolfcrypt/sha512.h>
        #include <wolfssl/wolfcrypt/sha3.h>

        #include <wolfssl/wolfcrypt/hmac.h>

        #include <wolfssl/wolfcrypt/aes.h>
        #include <wolfssl/wolfcrypt/chacha.h>
        #include <wolfssl/wolfcrypt/des3.h>
        #include <wolfssl/wolfcrypt/asn.h>
        #include <wolfssl/wolfcrypt/pwdbased.h>

        #include <wolfssl/wolfcrypt/random.h>

        #include <wolfssl/wolfcrypt/rsa.h>
        #include <wolfssl/wolfcrypt/ecc.h>
        #include <wolfssl/wolfcrypt/ed25519.h>
        #include <wolfssl/wolfcrypt/ed448.h>
        #include <wolfssl/wolfcrypt/curve25519.h>
    """

    init_source_string = """
        #ifdef __cplusplus
        extern "C" {
        #endif
           """ + includes_string + """
        #ifdef __cplusplus
        }
        #endif

        int MPAPI_ENABLED = """ + str(features["MPAPI"]) + """;
        int SHA_ENABLED = """ + str(features["SHA"]) + """;
        int SHA256_ENABLED = """ + str(features["SHA256"]) + """;
        int SHA384_ENABLED = """ + str(features["SHA384"]) + """;
        int SHA512_ENABLED = """ + str(features["SHA512"]) + """;
        int SHA3_ENABLED = """ + str(features["SHA3"]) + """;
        int DES3_ENABLED = """ + str(features["DES3"]) + """;
        int AES_ENABLED = """ + str(features["AES"]) + """;
        int CHACHA_ENABLED = """ + str(features["CHACHA"]) + """;
        int HMAC_ENABLED = """ + str(features["HMAC"]) + """;
        int RSA_ENABLED = """ + str(features["RSA"]) + """;
        int RSA_BLINDING_ENABLED = """ + str(features["RSA_BLINDING"]) + """;
        int ECC_TIMING_RESISTANCE_ENABLED = """ + str(features["ECC_TIMING_RESISTANCE"]) + """;
        int ECC_ENABLED = """ + str(features["ECC"]) + """;
        int ED25519_ENABLED = """ + str(features["ED25519"]) + """;
        int ED448_ENABLED = """ + str(features["ED448"]) + """;
        int KEYGEN_ENABLED = """ + str(features["KEYGEN"]) + """;
        int PWDBASED_ENABLED = """ + str(features["PWDBASED"]) + """;
        int FIPS_ENABLED = """ + str(features["FIPS"]) + """;
        int FIPS_VERSION = """ + str(features["FIPS_VERSION"]) + """;
        int ASN_ENABLED = """ + str(features["ASN"]) + """;
        int WC_RNG_SEED_CB_ENABLED = """ + str(features["WC_RNG_SEED_CB"]) + """;
        int AESGCM_STREAM_ENABLED = """ + str(features["AESGCM_STREAM"]) + """;
        int RSA_PSS_ENABLED = """ + str(features["RSA_PSS"]) + """;
    """

    ffibuilder.set_source( "wolfcrypt._ffi", init_source_string,
        include_dirs=cffi_include_dirs,
        library_dirs=[wolfssl_lib_dir(local_wolfssl, features["FIPS"])],
        libraries=cffi_libraries)

    # TODO: change cdef to cdef.
    # cdef = ""
    cdef = """
        extern int MPAPI_ENABLED;
        extern int SHA_ENABLED;
        extern int SHA256_ENABLED;
        extern int SHA384_ENABLED;
        extern int SHA512_ENABLED;
        extern int SHA3_ENABLED;
        extern int DES3_ENABLED;
        extern int AES_ENABLED;
        extern int CHACHA_ENABLED;
        extern int HMAC_ENABLED;
        extern int RSA_ENABLED;
        extern int RSA_BLINDING_ENABLED;
        extern int ECC_TIMING_RESISTANCE_ENABLED;
        extern int ECC_ENABLED;
        extern int ED25519_ENABLED;
        extern int ED448_ENABLED;
        extern int KEYGEN_ENABLED;
        extern int PWDBASED_ENABLED;
        extern int FIPS_ENABLED;
        extern int FIPS_VERSION;
        extern int ASN_ENABLED;
        extern int WC_RNG_SEED_CB_ENABLED;
        extern int AESGCM_STREAM_ENABLED;
        extern int RSA_PSS_ENABLED;

        typedef unsigned char byte;
        typedef unsigned int word32;

        typedef struct { ...; } WC_RNG;
        typedef struct { ...; } OS_Seed;

        int wc_InitRng(WC_RNG*);
        int wc_RNG_GenerateBlock(WC_RNG*, byte*, word32);
        int wc_RNG_GenerateByte(WC_RNG*, byte*);
        int wc_FreeRng(WC_RNG*);

        int wc_GetPkcs8TraditionalOffset(byte* input, word32* inOutIdx, word32 sz);
    """

    if not features["FIPS"] or features["FIPS_VERSION"] > 2:
        cdef += """
        int wc_GenerateSeed(OS_Seed* os, byte* seed, word32 sz);
        """

    if features["MPAPI"]:
        cdef += """
        typedef struct { ...; } mp_int;

        int mp_init (mp_int * a);
        int mp_to_unsigned_bin (mp_int * a, unsigned char *b);
        int mp_read_unsigned_bin (mp_int * a, const unsigned char *b, int c);
        """

    if features["SHA"]:
        cdef += """
        typedef struct { ...; } wc_Sha;
        int wc_InitSha(wc_Sha*);
        int wc_ShaUpdate(wc_Sha*, const byte*, word32);
        int wc_ShaFinal(wc_Sha*, byte*);
        """

    if features["SHA256"]:
        cdef += """
        typedef struct { ...; } wc_Sha256;
        int wc_InitSha256(wc_Sha256*);
        int wc_Sha256Update(wc_Sha256*, const byte*, word32);
        int wc_Sha256Final(wc_Sha256*, byte*);
        """

    if features["SHA384"]:
        cdef += """
        typedef struct { ...; } wc_Sha384;
        int wc_InitSha384(wc_Sha384*);
        int wc_Sha384Update(wc_Sha384*, const byte*, word32);
        int wc_Sha384Final(wc_Sha384*, byte*);
        """

    if features["SHA512"]:
        cdef += """
        typedef struct { ...; } wc_Sha512;

        int wc_InitSha512(wc_Sha512*);
        int wc_Sha512Update(wc_Sha512*, const byte*, word32);
        int wc_Sha512Final(wc_Sha512*, byte*);
        """
    if features["SHA3"]:
        cdef += """
        typedef struct { ...; } wc_Sha3;
        int wc_InitSha3_224(wc_Sha3*, void *, int);
        int wc_InitSha3_256(wc_Sha3*, void *, int);
        int wc_InitSha3_384(wc_Sha3*, void *, int);
        int wc_InitSha3_512(wc_Sha3*, void *, int);
        int wc_Sha3_224_Update(wc_Sha3*, const byte*, word32);
        int wc_Sha3_256_Update(wc_Sha3*, const byte*, word32);
        int wc_Sha3_384_Update(wc_Sha3*, const byte*, word32);
        int wc_Sha3_512_Update(wc_Sha3*, const byte*, word32);
        int wc_Sha3_224_Final(wc_Sha3*, byte*);
        int wc_Sha3_256_Final(wc_Sha3*, byte*);
        int wc_Sha3_384_Final(wc_Sha3*, byte*);
        int wc_Sha3_512_Final(wc_Sha3*, byte*);
        """

    if features["DES3"]:
        cdef += """
            typedef struct { ...; } Des3;
            int wc_Des3_SetKey(Des3*, const byte*, const byte*, int);
            int wc_Des3_CbcEncrypt(Des3*, byte*, const byte*, word32);
            int wc_Des3_CbcDecrypt(Des3*, byte*, const byte*, word32);
        """

    if features["AES"]:
        cdef += """
        typedef struct { ...; } Aes;

        int wc_AesSetKey(Aes*, const byte*, word32, const byte*, int);
        int wc_AesCbcEncrypt(Aes*, byte*, const byte*, word32);
        int wc_AesCbcDecrypt(Aes*, byte*, const byte*, word32);
        int wc_AesCtrEncrypt(Aes*, byte*, const byte*, word32);
        """

    if features["AES"] and features["AESGCM_STREAM"]:
        cdef += """
        int  wc_AesInit(Aes* aes, void* heap, int devId);
        int wc_AesGcmInit(Aes* aes, const byte* key, word32 len,
            const byte* iv, word32 ivSz);
        int wc_AesGcmEncryptInit(Aes* aes, const byte* key, word32 len,
            const byte* iv, word32 ivSz);
        int wc_AesGcmEncryptInit_ex(Aes* aes, const byte* key, word32 len,
            byte* ivOut, word32 ivOutSz);
        int wc_AesGcmEncryptUpdate(Aes* aes, byte* out, const byte* in,
            word32 sz, const byte* authIn, word32 authInSz);
        int wc_AesGcmEncryptFinal(Aes* aes, byte* authTag,
            word32 authTagSz);
        int wc_AesGcmDecryptInit(Aes* aes, const byte* key, word32 len,
            const byte* iv, word32 ivSz);
        int wc_AesGcmDecryptUpdate(Aes* aes, byte* out, const byte* in,
            word32 sz, const byte* authIn, word32 authInSz);
        int wc_AesGcmDecryptFinal(Aes* aes, const byte* authTag,
            word32 authTagSz);
        """

    if features["CHACHA"]:
        cdef += """
        typedef struct { ...; } ChaCha;

        int wc_Chacha_SetKey(ChaCha*, const byte*, word32);
        int wc_Chacha_SetIV(ChaCha*, const byte*, word32);
        int wc_Chacha_Process(ChaCha*, byte*, const byte*,word32);
        """

    if features["HMAC"]:
        cdef += """
        typedef struct { ...; } Hmac;
        int wc_HmacInit(Hmac* hmac, void* heap, int devId);
        int wc_HmacSetKey(Hmac*, int, const byte*, word32);
        int wc_HmacUpdate(Hmac*, const byte*, word32);
        int wc_HmacFinal(Hmac*, byte*);
        """

    if features["RSA"]:
        cdef += """
        static const int WC_RSA_PKCSV15_PAD;
        static const int WC_RSA_OAEP_PAD;
        static const int WC_RSA_PSS_PAD;
        static const int WC_RSA_NO_PAD;

        static const int WC_MGF1NONE;
        static const int WC_MGF1SHA1;
        static const int WC_MGF1SHA224;
        static const int WC_MGF1SHA256;
        static const int WC_MGF1SHA384;
        static const int WC_MGF1SHA512;

        static const int WC_HASH_TYPE_NONE;
        static const int WC_HASH_TYPE_MD2;
        static const int WC_HASH_TYPE_MD4;
        static const int WC_HASH_TYPE_MD5;
        static const int WC_HASH_TYPE_SHA;
        static const int WC_HASH_TYPE_SHA224;
        static const int WC_HASH_TYPE_SHA256;
        static const int WC_HASH_TYPE_SHA384;
        static const int WC_HASH_TYPE_SHA512;
        static const int WC_HASH_TYPE_MD5_SHA;
        static const int WC_HASH_TYPE_SHA3_224;
        static const int WC_HASH_TYPE_SHA3_256;
        static const int WC_HASH_TYPE_SHA3_384;
        static const int WC_HASH_TYPE_SHA3_512;
        static const int WC_HASH_TYPE_BLAKE2B;
        static const int WC_HASH_TYPE_BLAKE2S;
        typedef struct {...; } RsaKey;

        int wc_InitRsaKey(RsaKey* key, void*);
        int wc_FreeRsaKey(RsaKey* key);

        int wc_RsaPrivateKeyDecode(const byte*, word32*, RsaKey*, word32);
        int wc_RsaPublicKeyDecode(const byte*, word32*, RsaKey*, word32);
        int wc_RsaEncryptSize(RsaKey*);

        int wc_RsaPrivateDecrypt(const byte*, word32, byte*, word32,
                                RsaKey* key);
        int wc_RsaPublicEncrypt(const byte*, word32, byte*, word32,
                                RsaKey*, WC_RNG*);
        int wc_RsaPublicEncrypt_ex(const byte* in, word32 inLen, byte* out,
                   word32 outLen, RsaKey* key, WC_RNG* rng, int type,
                   enum wc_HashType hash, int mgf, byte* label, word32 labelSz);
        int wc_RsaPrivateDecrypt_ex(const byte* in, word32 inLen,
                   byte* out, word32 outLen, RsaKey* key, int type,
                   enum wc_HashType hash, int mgf, byte* label, word32 labelSz);
        """

        if features["RSA_PSS"]:
            cdef += """
            int wc_RsaPSS_Sign(const byte* in, word32 inLen, byte* out, word32 outLen,
                               enum wc_HashType hash, int mgf, RsaKey* key, WC_RNG* rng);
            int wc_RsaPSS_Verify(byte* in, word32 inLen, byte* out, word32 outLen,
                                   enum wc_HashType hash, int mgf, RsaKey* key);
            int wc_RsaPSS_CheckPadding(const byte* in, word32 inSz, byte* sig,
                                   word32 sigSz, enum wc_HashType hashType);
            int wc_RsaSSL_Sign(const byte*, word32, byte*, word32, RsaKey*, WC_RNG*);
            int wc_RsaSSL_Verify(const byte*, word32, byte*, word32, RsaKey*);
            """

        if features["RSA_BLINDING"]:
            cdef += """
            int wc_RsaSetRNG(RsaKey* key, WC_RNG* rng);
            """

        if features["KEYGEN"]:
            cdef += """
            int wc_MakeRsaKey(RsaKey* key, int size, long e, WC_RNG* rng);
            int wc_RsaKeyToDer(RsaKey* key, byte* output, word32 inLen);
            int wc_RsaKeyToPublicDer(RsaKey* key, byte* output, word32 inLen);

            """

    if features["ECC"]:
        cdef += """
        typedef struct {...; } ecc_key;

        int wc_ecc_init(ecc_key* ecc);
        void wc_ecc_free(ecc_key* ecc);

        int wc_ecc_make_key(WC_RNG* rng, int keysize, ecc_key* key);
        int wc_ecc_size(ecc_key* key);
        int wc_ecc_sig_size(ecc_key* key);

        int wc_EccPrivateKeyDecode(const byte*, word32*, ecc_key*, word32);
        int wc_EccKeyToDer(ecc_key*, byte* output, word32 inLen);

        int wc_EccPublicKeyDecode(const byte*, word32*, ecc_key*, word32);
        int wc_EccPublicKeyToDer(ecc_key*, byte* output,
                                 word32 inLen, int with_AlgCurve);

        int wc_ecc_export_x963(ecc_key*, byte* out, word32* outLen);
        int wc_ecc_import_x963(const byte* in, word32 inLen, ecc_key* key);
        int wc_ecc_export_private_raw(ecc_key* key, byte* qx, word32* qxLen,
                                  byte* qy, word32* qyLen, byte* d, word32* dLen);
        int wc_ecc_import_unsigned(ecc_key* key, byte* qx, byte* qy,
                       byte* d, int curve_id);
        int wc_ecc_export_public_raw(ecc_key* key, byte* qx, word32* qxLen,
                                 byte* qy, word32* qyLen);


        int wc_ecc_shared_secret(ecc_key* private_key, ecc_key* public_key,
                                 byte* out, word32* outlen);

        int wc_ecc_sign_hash(const byte* in, word32 inlen,
                             byte* out, word32 *outlen,
                             WC_RNG* rng, ecc_key* key);
        int wc_ecc_verify_hash(const byte* sig, word32 siglen,
                               const byte* hash, word32 hashlen,
                               int* stat, ecc_key* key);
        """

        if features["MPAPI"]:
            cdef += """
            int wc_ecc_sign_hash_ex(const byte* in, word32 inlen, WC_RNG* rng,
                                 ecc_key* key, mp_int *r, mp_int *s);
            int wc_ecc_verify_hash_ex(mp_int *r, mp_int *s, const byte* hash,
                            word32 hashlen, int* res, ecc_key* key);
            """

        if features["ECC_TIMING_RESISTANCE"] and (not features["FIPS"] or
           features["FIPS_VERSION"] > 2):
            cdef += """
            int wc_ecc_set_rng(ecc_key* key, WC_RNG* rng);
            """


    if features["ED25519"]:
        cdef += """
        typedef struct {...; } ed25519_key;

        int wc_ed25519_init(ed25519_key* ed25519);
        void wc_ed25519_free(ed25519_key* ed25519);

        int wc_ed25519_make_key(WC_RNG* rng, int keysize, ed25519_key* key);
        int wc_ed25519_make_public(ed25519_key* key, unsigned char* pubKey,
                               word32 pubKeySz);
        int wc_ed25519_size(ed25519_key* key);
        int wc_ed25519_sig_size(ed25519_key* key);
        int wc_ed25519_sign_msg(const byte* in, word32 inlen, byte* out,
                            word32 *outlen, ed25519_key* key);
        int wc_ed25519_verify_msg(const byte* sig, word32 siglen, const byte* msg,
                              word32 msglen, int* stat, ed25519_key* key);
        int wc_Ed25519PrivateKeyDecode(const byte*, word32*, ed25519_key*, word32);
        int wc_Ed25519KeyToDer(ed25519_key*, byte* output, word32 inLen);

        int wc_Ed25519PublicKeyDecode(const byte*, word32*, ed25519_key*, word32);
        int wc_Ed25519PublicKeyToDer(ed25519_key*, byte* output,
                                 word32 inLen, int with_AlgCurve);

        int wc_ed25519_import_public(const byte* in, word32 inLen, ed25519_key* key);
        int wc_ed25519_import_private_only(const byte* priv, word32 privSz, ed25519_key* key);
        int wc_ed25519_import_private_key(const byte* priv, word32 privSz, const byte* pub, word32 pubSz, ed25519_key* key);
        int wc_ed25519_export_public(ed25519_key*, byte* out, word32* outLen);
        int wc_ed25519_export_private_only(ed25519_key* key, byte* out, word32* outLen);
        int wc_ed25519_export_private(ed25519_key* key, byte* out, word32* outLen);
        int wc_ed25519_export_key(ed25519_key* key, byte* priv, word32 *privSz, byte* pub, word32 *pubSz);
        int wc_ed25519_check_key(ed25519_key* key);
        int wc_ed25519_pub_size(ed25519_key* key);
        int wc_ed25519_priv_size(ed25519_key* key);
        """

    if features["ED448"]:
        cdef += """
        typedef struct {...; } ed448_key;

        int wc_ed448_init(ed448_key* ed448);
        void wc_ed448_free(ed448_key* ed448);

        int wc_ed448_make_key(WC_RNG* rng, int keysize, ed448_key* key);
        int wc_ed448_make_public(ed448_key* key, unsigned char* pubKey,
                               word32 pubKeySz);
        int wc_ed448_size(ed448_key* key);
        int wc_ed448_sig_size(ed448_key* key);
        int wc_ed448_sign_msg(const byte* in, word32 inlen, byte* out,
                            word32 *outlen, ed448_key* key, byte* ctx,
                            word32 ctx_len);
        int wc_ed448_verify_msg(const byte* sig, word32 siglen, const byte* msg,
                              word32 msglen, int* stat, ed448_key* key, byte *ctx,
                              word32 ctx_len);
        int wc_Ed448PrivateKeyDecode(const byte*, word32*, ed448_key*, word32);
        int wc_Ed448KeyToDer(ed448_key*, byte* output, word32 inLen);

        int wc_Ed448PublicKeyDecode(const byte*, word32*, ed448_key*, word32);
        int wc_Ed448PublicKeyToDer(ed448_key*, byte* output,
                                 word32 inLen, int with_AlgCurve);

        int wc_ed448_import_public(const byte* in, word32 inLen, ed448_key* key);
        int wc_ed448_import_private_only(const byte* priv, word32 privSz, ed448_key* key);
        int wc_ed448_import_private_key(const byte* priv, word32 privSz, const byte* pub, word32 pubSz, ed448_key* key);
        int wc_ed448_export_public(ed448_key*, byte* out, word32* outLen);
        int wc_ed448_export_private_only(ed448_key* key, byte* out, word32* outLen);
        int wc_ed448_export_private(ed448_key* key, byte* out, word32* outLen);
        int wc_ed448_export_key(ed448_key* key, byte* priv, word32 *privSz, byte* pub, word32 *pubSz);
        int wc_ed448_check_key(ed448_key* key);
        int wc_ed448_pub_size(ed448_key* key);
        int wc_ed448_priv_size(ed448_key* key);
        """

    if features["PWDBASED"]:
        cdef += """
        int wc_PBKDF2(byte* output, const byte* passwd, int pLen,
                      const byte* salt, int sLen, int iterations, int kLen,
                      int typeH);
        """

    if features["ASN"]:
        cdef += """
        static const long PRIVATEKEY_TYPE;
        static const long PUBLICKEY_TYPE;
        static const long CERT_TYPE;
        static const long MAX_DER_DIGEST_SZ;
        static const long SHAh;
        static const long SHA256h;
        static const long SHA384h;
        static const long SHA512h;

        typedef struct DerBuffer {
            byte*  buffer;
            void*  heap;
            word32 length;
            int    type;
            int    dynType;
        } DerBuffer;
        typedef struct { ...; } EncryptedInfo;

        int wc_PemToDer(const unsigned char* buff, long longSz, int type,
                        DerBuffer** pDer, void* heap, EncryptedInfo* info,
                        int* keyFormat);
        int wc_DerToPemEx(const byte* der, word32 derSz, byte* output, word32 outSz,
                          byte *cipher_info, int type);
        word32 wc_EncodeSignature(byte* out, const byte* digest, word32 digSz,
                                  int hashOID);
        """

    if features["WC_RNG_SEED_CB"]:
        cdef += """
        typedef int (*wc_RngSeed_Cb)(OS_Seed* os, byte* seed, word32 sz);

        int wc_SetSeed_Cb(wc_RngSeed_Cb cb);
        """

    if features["FIPS"] and features["FIPS_VERSION"] >= 5:
        cdef += """
        enum wc_KeyType {
            WC_KEYTYPE_ALL = 0
        };

        int wolfCrypt_SetPrivateKeyReadEnable_fips(int, enum wc_KeyType);
        int wolfCrypt_GetPrivateKeyReadEnable_fips(enum wc_KeyType);
        """

    ffibuilder.cdef(cdef)

def main(ffibuilder):
    # Default features.
    features = {
        "MPAPI": 1,
        "SHA": 1,
        "SHA256": 1,
        "SHA384": 1,
        "SHA512": 1,
        "SHA3": 1,
        "DES3": 1,
        "AES": 1,
        "HMAC": 1,
        "RSA": 1,
        "RSA_BLINDING": 1,
        "ECC_TIMING_RESISTANCE": 1,
        "ECC": 1,
        "ED25519": 1,
        "KEYGEN": 1,
        "CHACHA": 1,
        "PWDBASED": 1,
        "FIPS": 0,
        "FIPS_VERSION": 0,
        "ERROR_STRINGS": 1,
        "ASN": 1,
        "WC_RNG_SEED_CB": 0,
        "AESGCM_STREAM": 1,
        "RSA_PSS": 1,
    }

    # Ed448 requires SHAKE256, which isn't part of the Windows build, yet.
    if sys.platform == "win32":
        features["ED448"] = 0
    else:
        features["ED448"] = 1

    local_wolfssl = os.environ.get("USE_LOCAL_WOLFSSL")
    if local_wolfssl:
        print("Using local wolfSSL at {}.".format(local_wolfssl))
        if not os.path.exists(local_wolfssl):
            e = "Local wolfssl installation path {} doesn't exist.".format(local_wolfssl)
            raise FileNotFoundError(e)

        get_features(local_wolfssl, features)

    if features["RSA_BLINDING"] and features["FIPS"]:
        # These settings can't coexist. See settings.h.
        features["RSA_BLINDING"] = 0

    if not local_wolfssl:
        print("Building wolfSSL...")
        if not get_libwolfssl():
            generate_libwolfssl()

    build_ffi(local_wolfssl, features)


ffibuilder = FFI()
main(ffibuilder)

if __name__ == "__main__":
    ffibuilder.compile(verbose=True)