#include "cryptopro.h"

#include "base64.h"
#include "capi.h"
#include "library.h"
#include "logger.h"

#define SHA1_SIZE           20

static const char* CERT_TRUST_IS_UNTRUSTED_ROOT_ERR_CODE = "CERT_TRUST_IS_UNTRUSTED_ROOT";
static const char* CERT_TRUST_REVOCATION_STATUS_UNKNOWN_ERR_CODE = "CERT_TRUST_REVOCATION_STATUS_UNKNOWN";
static const char* CERT_TRUST_IS_NOT_TIME_VALID_ERR_CODE = "CERT_TRUST_IS_NOT_TIME_VALID";
static const char* CERT_TRUST_IS_PARTIAL_CHAIN_ERR_CODE = "CERT_TRUST_IS_PARTIAL_CHAIN";

static capi_function_list_t cp_function_list;
static library_t libcapi;

static int sign_hash_data(const cryptopro_context_t *ctx, const str_t *data, 
                            /*out*/ str_t *sign, /*out*/ const char **error_code);

static int reverse_sign(const str_t *sign, /*out*/ str_t *sign_reversed);

static HCERTSTORE cert_open_store();
static void cert_close_store(HCERTSTORE hStoreHandle);

static PCCERT_CONTEXT get_signer_cert(const cryptopro_context_t *ctx, HCERTSTORE hStoreHandle);

static int set_password(PCCERT_CONTEXT cert_ctx, const str_t *password);

static bool get_subject_name(PCCERT_CONTEXT cert, /*out*/ char **subject_name);

static bool get_issuer_name(PCCERT_CONTEXT cert, /*out*/ char **issuer_name);

bool
cryptopro_init(const char* cp_file)
{
    static bool is_initialized = false;

    if (!is_initialized) {
        library_init(&libcapi, cp_file);
        if (!capi_function_list_init(&libcapi, &cp_function_list)) {
            LOG_ERROR("capi_function_list_init failed");
            return false;
        }
        is_initialized = true;
        LOG_INFO("Cryptographic Provider initialized");
    }
    return true;
}

int 
cryptopro_sign(const cryptopro_context_t *ctx, const str_t *data, 
                /*out*/ str_t *sign, /*out*/ const char **error_code)
{
    str_t signed_data = str_t_null; 
    str_t sign_reversed = str_t_null; 

    LOG_TRACE("cryptopro_sign enter");

    assert(ctx != NULL);
    assert(!str_t_is_null(*ctx->cert_thumbprint));
    assert(ctx->password != NULL);
    assert(data != NULL && !str_t_is_null(*data));
    assert(sign != NULL);

    if (sign_hash_data(ctx, data, &signed_data, error_code)) {
        goto error;
    }

    if (reverse_sign(&signed_data, &sign_reversed)) {
        goto error;
    }

    sign->len = base64_encoded_length(sign_reversed.len);
    sign->data = calloc(1, sign->len + 1);
    if (sign->data == NULL) {
        LOG_ERROR("Could not allocate memory for sign (%zu bytes)", sign->len + 1);
        goto error;
    }

    encode_base64_url(sign, &sign_reversed);

    str_t_clear(&signed_data);
    str_t_clear(&sign_reversed);

    LOG_TRACE("cryptopro_sign exit");
    return 0;

error:
    str_t_clear(&signed_data);
    str_t_clear(&sign_reversed);
    LOG_ERROR("cryptopro_sign exit with error (sign_cert_thumbprint = '%.*s')", 
                (int) ctx->cert_thumbprint->len, ctx->cert_thumbprint->data);
    return -1;
}

static void
free_cert_chain(PCCERT_CHAIN_CONTEXT chain_ctx)
{
    LOG_TRACE("free_cert_chain enter");

    if (chain_ctx) {
        cp_function_list.CertFreeCertificateChain(chain_ctx);
    }

    LOG_TRACE("free_cert_chain exit");
}

static void
print_crl_urls_from_certificate(PCCERT_CONTEXT cert)
{
    LOG_TRACE("print_crl_urls_from_certificate enter");
    
    PCERT_EXTENSION extension = cp_function_list.CertFindExtension(
        szOID_CRL_DIST_POINTS,
        cert->pCertInfo->cExtension,
        cert->pCertInfo->rgExtension
    );
    
    if (!extension) {
        LOG_WARN("CRL Distribution Points extension not found");
        goto error;
    }
    
    DWORD info_size = 0;
    CRL_DIST_POINTS_INFO *crl_dist_points = NULL;
    
    if (!cp_function_list.CryptDecodeObjectEx(
        X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
        X509_CRL_DIST_POINTS,
        extension->Value.pbData,
        extension->Value.cbData,
        CRYPT_DECODE_ALLOC_FLAG | CRYPT_DECODE_NOCOPY_FLAG,
        NULL,
        &crl_dist_points,
        &info_size
    )) {
        LOG_ERROR("CryptDecodeObjectEx failed. Error code: 0x%08x", cp_function_list.GetLastError());
        goto error;
    }
    
    if (crl_dist_points && crl_dist_points->cDistPoint > 0) {
        for (DWORD i = 0; i < crl_dist_points->cDistPoint; i++) {
            PCRL_DIST_POINT pDistPoint = &crl_dist_points->rgDistPoint[i];
            
            if (pDistPoint->DistPointName.dwDistPointNameChoice == CRL_DIST_POINT_FULL_NAME) {
                PCERT_ALT_NAME_ENTRY pAltNameEntry = pDistPoint->DistPointName._empty_union_.FullName.rgAltEntry;
                
                for (DWORD j = 0; j < pDistPoint->DistPointName._empty_union_.FullName.cAltEntry; j++) {
                    if (pAltNameEntry[j].dwAltNameChoice == CERT_ALT_NAME_URL) {
                        LOG_INFO("CRL URL: %ls", pAltNameEntry[j]._empty_union_.pwszURL);
                    }
                }
            }
        }
    }
    
    if (crl_dist_points) {
        cp_function_list.LocalFree(crl_dist_points);
    }

    LOG_TRACE("print_crl_urls_from_certificate exit");
    return;

error:
    LOG_ERROR("print_crl_urls_from_certificate exit with error");
    return;
}

static void
print_crt_urls_from_certificate(PCCERT_CONTEXT cert)
{
    LOG_TRACE("print_crt_urls_from_certificate enter");

    PCERT_EXTENSION extension = cp_function_list.CertFindExtension(
        szOID_AUTHORITY_INFO_ACCESS,
        cert->pCertInfo->cExtension,
        cert->pCertInfo->rgExtension
    );
    
    if (!extension) {
        LOG_WARN("Authority Info Access extension not found");
        goto error;
    }

    DWORD info_size = 0;
    PCERT_AUTHORITY_INFO_ACCESS info_access = NULL;
    
    if (!cp_function_list.CryptDecodeObjectEx(
        X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
        X509_AUTHORITY_INFO_ACCESS,
        extension->Value.pbData,
        extension->Value.cbData,
        CRYPT_DECODE_ALLOC_FLAG | CRYPT_DECODE_NOCOPY_FLAG,
        NULL,
        &info_access,
        &info_size
    )) {
        LOG_ERROR("CryptDecodeObjectEx failed. Error code: 0x%08x", cp_function_list.GetLastError());
        goto error;
    }

    if (info_access && info_access->cAccDescr > 0) {
        for (DWORD i = 0; i < info_access->cAccDescr; i++) {
            if (strcmp(info_access->rgAccDescr[i].pszAccessMethod, szOID_PKIX_CA_ISSUERS) == 0) {
                if (info_access->rgAccDescr[i].AccessLocation.dwAltNameChoice == CERT_ALT_NAME_URL) {
                    LOG_INFO("CA Issuers URL: %ls", info_access->rgAccDescr[i].AccessLocation._empty_union_.pwszURL);
                }
            }
        }
    }

    if (info_access) {
        cp_function_list.LocalFree(info_access);
    }

    LOG_TRACE("print_crt_urls_from_certificate exit");
    return;

error:
    LOG_ERROR("print_crt_urls_from_certificate exit with error");
    return;
}

static char*
bin_to_hex(const BYTE *bytes, DWORD len)
{
    char* hex = NULL;

    hex = malloc(len * 2 + 1);
    if (hex == NULL) {
        LOG_ERROR("bin_to_hex exit with error: could not allocate memory for hex (%d bytes)", len * 2 + 1);
        return NULL;
    }

    for (DWORD i = 0; i < len; i++) {
        sprintf(hex + i * 2, "%02x", bytes[i]);
    }

    return hex;
}

static bool 
get_thumbprint(PCCERT_CONTEXT cert, /*out*/ char** thumbprint)
{
    LOG_TRACE("get_thumbprint enter");

    BYTE sha1_hash[SHA1_SIZE];
    DWORD sha1_hash_size = sizeof(sha1_hash);

    if (!cp_function_list.CertGetCertificateContextProperty(
        cert, 
        CERT_SHA1_HASH_PROP_ID, 
        sha1_hash, 
        &sha1_hash_size)) {
        LOG_ERROR("CertGetCertificateContextProperty(CERT_SHA1_HASH_PROP_ID) failed. Error code: 0x%08x",
                    cp_function_list.GetLastError());
        goto error;
    }
        
    *thumbprint = bin_to_hex(sha1_hash, sha1_hash_size);
    if (*thumbprint == NULL) {
        goto error;
    }

    LOG_DEBUG("thumbprint: '%s'", *thumbprint);

    LOG_TRACE("get_thumbprint exit");
    return true;

error:
    LOG_ERROR("get_thumbprint exit with error");
    return false;
}

static void
print_cert_time_validity(PCCERT_CONTEXT cert)
{
    SYSTEMTIME st;

    LOG_TRACE("print_cert_time_validity enter");

    if (cp_function_list.FileTimeToSystemTime(&cert->pCertInfo->NotBefore, &st)) {
        LOG_INFO("Not valid before: %02d.%02d.%04d", st.wDay, st.wMonth, st.wYear);
    }
    
    if (cp_function_list.FileTimeToSystemTime(&cert->pCertInfo->NotAfter, &st)) {
        LOG_INFO("Not valid after:  %02d.%02d.%04d", st.wDay, st.wMonth, st.wYear);
    }

    LOG_TRACE("print_cert_time_validity exit");
}

static void 
print_common_cert_info(PCCERT_CONTEXT cert) 
{
    char* subject = NULL;
    char* issuer = NULL;
    char* thumbprint = NULL;
    
    LOG_TRACE("print_common_cert_info enter");
    
    if (get_thumbprint(cert, &thumbprint)) {
        LOG_INFO("SHA1 Hash: %s", thumbprint);
    }

    if (get_subject_name(cert, &subject)) {
        LOG_INFO("Subject: %s", subject);
    }

    if (get_issuer_name(cert, &issuer)) {
        LOG_INFO("Issuer: %s", issuer);
    }

    free(subject);
    free(issuer);
    free(thumbprint);

    LOG_TRACE("print_common_cert_info exit");
}

static void
print_cert_info(PCCERT_CONTEXT cert)
{
    LOG_INFO("=========== Certificate Info: ===========");
    print_common_cert_info(cert);
    print_cert_time_validity(cert);
    print_crt_urls_from_certificate(cert);
    print_crl_urls_from_certificate(cert);
    LOG_INFO("=========================================");
}

static void
process_trust_status_error(PCCERT_CONTEXT cert, DWORD status, /*out*/ const char **error_code)
{
    LOG_TRACE("process_trust_status_error enter");

    switch (status) {
        case CERT_TRUST_REVOCATION_STATUS_UNKNOWN:
            *error_code = CERT_TRUST_REVOCATION_STATUS_UNKNOWN_ERR_CODE;
            break;
        case CERT_TRUST_IS_UNTRUSTED_ROOT:
            *error_code = CERT_TRUST_IS_UNTRUSTED_ROOT_ERR_CODE;
            break;
        case CERT_TRUST_IS_NOT_TIME_VALID:
            *error_code = CERT_TRUST_IS_NOT_TIME_VALID_ERR_CODE;
            break;
        case CERT_TRUST_IS_PARTIAL_CHAIN:
            *error_code = CERT_TRUST_IS_PARTIAL_CHAIN_ERR_CODE;
            break;
        default:
            *error_code = NULL;
            break;
    }

    if (*error_code) {
        LOG_WARN("The certificate is not trusted. CERT_TRUST_STATUS: '0x%08x' (%s)", 
                    status, *error_code);
    } else {
        LOG_WARN("The certificate is not trusted. CERT_TRUST_STATUS: '0x%08x'", status);
    }

    print_cert_info(cert);

    LOG_TRACE("process_trust_status_error exit");
}

static PCCERT_CHAIN_CONTEXT
get_cert_chain(PCCERT_CONTEXT certificate, /*out*/ const char **error_code)
{
    LOG_TRACE("get_cert_chain enter");

    CERT_CHAIN_PARA chain_para = {0};
    chain_para.cbSize = sizeof(CERT_CHAIN_PARA);

    PCCERT_CHAIN_CONTEXT chain_ctx = NULL;


    if (!cp_function_list.CertGetCertificateChain(NULL, 
                    certificate, 
                    NULL, 
                    NULL, 
                    &chain_para,
                    (CERT_CHAIN_CACHE_END_CERT | CERT_CHAIN_REVOCATION_CHECK_CHAIN_EXCLUDE_ROOT),
                    NULL, 
                    &chain_ctx)) {
        LOG_ERROR("CertGetCertificateChain() failed");
        goto error;
    }

    if (chain_ctx->TrustStatus.dwErrorStatus) {
        process_trust_status_error(certificate, chain_ctx->TrustStatus.dwErrorStatus, error_code);
        goto error;
    }

    LOG_TRACE("get_cert_chain exit");
    return chain_ctx;

error:
    free_cert_chain(chain_ctx);
    LOG_ERROR("get_cert_chain exit with error");
    return NULL;
}

static bool
check_cert_chain_policy(PCCERT_CHAIN_CONTEXT chain_ctx)
{
    LOG_TRACE("check_cert_chain_policy enter");

    bool is_valid = false;

    CERT_CHAIN_POLICY_PARA policy_para = {0};
    policy_para.cbSize = sizeof(policy_para);

    CERT_CHAIN_POLICY_STATUS status = {0};
    status.cbSize = sizeof(status);

    CPSIGNATURE_EXTRA_CERT_CHAIN_POLICY_STATUS extraStatus = {0};
    extraStatus.cbSize = sizeof(extraStatus);

    status.pvExtraPolicyStatus = &extraStatus;

    if (!cp_function_list.CertVerifyCertificateChainPolicy(
            CERT_CHAIN_POLICY_BASE,
            chain_ctx, 
            &policy_para,
            &status)) {
        LOG_ERROR("CertVerifyCertificateChainPolicy() failed. Error code: 0x%08x", 
                    cp_function_list.GetLastError());
        goto exit;
    }

    if (status.dwError != 0) {
        LOG_WARN("The certificate chain cannot be validated. "
                 "CERT_CHAIN_POLICY_STATUS: '0x%08x'", status.dwError);
        goto exit;
    }

    if (extraStatus.dwError != 0) {
        LOG_WARN("The certificate chain cannot be validated. "
                 "CPSIGNATURE_EXTRA_CERT_CHAIN_POLICY_STATUS: '0x%08x'", extraStatus.dwError);
        goto exit;
    }

    is_valid = true;

exit:
    LOG_TRACE("check_cert_chain_policy exit");
    return is_valid;
}

static bool
verify_cert_chain(PCCERT_CONTEXT certificate, timer_context_t *timer_ctx, /*out*/ const char **error_code)
{
    bool is_verified = false;

    LOG_TRACE("verify_cert_chain enter");

    timer_on_verify_cert_chain_enter(timer_ctx);

    timer_on_get_cert_chain_enter(timer_ctx);

    PCCERT_CHAIN_CONTEXT chain_ctx = get_cert_chain(certificate, error_code);
    if (chain_ctx == NULL) {
        goto exit;
    }

    timer_on_get_cert_chain_exit(timer_ctx);

    if (!check_cert_chain_policy(chain_ctx)) {
        goto exit;
    }

    is_verified = true;

exit:
    free_cert_chain(chain_ctx);

    LOG_DEBUG("cert_chain: %s", is_verified ? "verified" : "failed");

    timer_on_verify_cert_chain_exit(timer_ctx);

    LOG_DEBUG("verify_cert_chain exit");
    return is_verified;
}

static bool
check_cert_key_usage(PCCERT_CONTEXT certificate)
{
    bool is_digital_signature_key_usage = false;
    BYTE key_usage;

    LOG_TRACE("check_cert_key_usage enter");

    if (cp_function_list.CertGetIntendedKeyUsage(
                            X509_ASN_ENCODING | PKCS_7_ASN_ENCODING, 
                            certificate->pCertInfo,
                            &key_usage, 
                            sizeof(key_usage))) {
        if (key_usage & CERT_DIGITAL_SIGNATURE_KEY_USAGE) {
            is_digital_signature_key_usage = true;
        } 
    } else {
        LOG_ERROR("CertGetIntendedKeyUsage failed: 0x%08x", cp_function_list.GetLastError());
    }

    if (is_digital_signature_key_usage) {
        LOG_DEBUG("Certificate KeyUsage contains digitalSignature");
    } else {
        LOG_ERROR("Certificate KeyUsage does not contain digitalSignature");
    }

    LOG_TRACE("check_cert_key_usage exit");
    return is_digital_signature_key_usage;
}

int 
open_signer_cert(cryptopro_context_t *ctx)
{
    LOG_TRACE("open_signer_cert enter");

    ctx->cert_store = cert_open_store();
    if (ctx->cert_store == NULL) {
        goto error;
    }

    ctx->signer_cert = get_signer_cert(ctx, ctx->cert_store);
    if (ctx->signer_cert == NULL) {
        goto error;
    }

    if (!check_cert_key_usage(ctx->signer_cert)) {
        goto error;
    }

    LOG_TRACE("open_signer_cert exit");

    return 0;

error:
    LOG_ERROR("open_signer_cert exit with error. Last error code: 0x%08x", 
                cp_function_list.GetLastError());
    close_signer_cert(ctx);
    return -1;
}

void
close_signer_cert(cryptopro_context_t *ctx)
{
    LOG_TRACE("close_signer_cert enter");

    if (ctx->signer_cert) {
        cp_function_list.CertFreeCertificateContext(ctx->signer_cert);
        ctx->signer_cert = NULL;
    }

    cert_close_store(ctx->cert_store);
    ctx->cert_store = NULL;

    LOG_TRACE("close_signer_cert exit");
}

static void
log_sign_hash_data_last_error()
{
    DWORD error = cp_function_list.GetLastError();

    switch (error) {
    case ERROR_FUNCTION_FAILED:
        LOG_ERROR("sign_hash_data exit with error. Last error code: "
                    "license is expired or not yet valid (0x%08x)", error);
        break;

    case SCARD_W_WRONG_CHV:
        LOG_ERROR("sign_hash_data exit with error. Last error code: "
                    "the wrong PIN was presented (0x%08x)", error);
        break;
        
    default:
        LOG_ERROR("sign_hash_data exit with error. Last error code: 0x%08x", error);
        break;
    }
}

static int 
sign_hash_data(const cryptopro_context_t *ctx, const str_t *data, /*out*/ str_t *sign, /*out*/ const char **error_code)
{
    int rc = -1;
    BOOL bReleaseContext = FALSE;
    HCRYPTPROV hCryptProv;
    HCRYPTHASH hash = 0;
    BYTE *pbSignedMessageBlob;
    DWORD cbSignedMessageBlob;

    if (!verify_cert_chain(ctx->signer_cert, ctx->timer_ctx, error_code)) {
        goto exit;
    }

    timer_on_acquire_private_key_enter(ctx->timer_ctx);

    if (!cp_function_list.CryptAcquireCertificatePrivateKey(
            ctx->signer_cert,
            CRYPT_ACQUIRE_SILENT_FLAG | CRYPT_ACQUIRE_CACHE_FLAG,
            NULL,
            &hCryptProv,
            NULL,
            &bReleaseContext)) {
        LOG_ERROR("Cannot acquire the certificate private key");
        goto exit;
    }

    timer_on_acquire_private_key_exit(ctx->timer_ctx);

    if (!cp_function_list.CryptCreateHash(hCryptProv, CALG_GR3411_2012_256, 0, 0, &hash)) {
        LOG_ERROR("CryptCreateHash() failed");
        goto exit;
    }
            
    if (!cp_function_list.CryptHashData(hash, (BYTE *)data->data, data->len, 0)) {
        LOG_ERROR("CryptHashData() failed");
        goto exit;
    }

    timer_on_sign_hash_enter(ctx->timer_ctx);
    
    if (!cp_function_list.CryptSignHash(hash, AT_KEYEXCHANGE, NULL, 0, NULL, &cbSignedMessageBlob)) {
        LOG_ERROR("CryptSignHash() failed");
        goto exit;
    }
    
    pbSignedMessageBlob = malloc(cbSignedMessageBlob * sizeof(BYTE));
    if (pbSignedMessageBlob == NULL) {
        LOG_ERROR("Could not allocate memory for pbSignedMessageBlob (%zd bytes)", cbSignedMessageBlob * sizeof(BYTE));
        goto exit;
    }
    
    if (!cp_function_list.CryptSignHash(hash, AT_KEYEXCHANGE, NULL, 0, pbSignedMessageBlob, &cbSignedMessageBlob)) {
        LOG_ERROR("CryptSignHash() failed");
        free(pbSignedMessageBlob);
        goto exit;
    }

    timer_on_sign_hash_exit(ctx->timer_ctx);

    sign->data = (char*)pbSignedMessageBlob;
    sign->len = (size_t)cbSignedMessageBlob;

    rc = 0;

exit:
    if (hash) {
        if (!cp_function_list.CryptDestroyHash(hash)) {
            LOG_ERROR("CryptDestroyHash() failed");
            rc = -1;
        }
    }

    if (bReleaseContext) {
        if (!cp_function_list.CryptReleaseContext(hCryptProv, 0)) {
            LOG_ERROR("CryptReleaseContext() failed");
            rc = -1;
        }
    }


    if (rc) {
        log_sign_hash_data_last_error();
    }

    return rc;
}

static int 
reverse_sign(const str_t *sign, /*out*/ str_t *sign_reversed)
{
    size_t i;

    sign_reversed->data = malloc(sign->len);
    if (sign_reversed->data == NULL) {
        LOG_ERROR("Could not allocate memory for reversed sign (%zd bytes)", sign->len);
        return -1;
    }

    for (i = 0; i < sign->len; i++) {
        sign_reversed->data[i] = sign->data[sign->len - i - 1];
    }

    sign_reversed->len = sign->len;

    return 0;
}

static HCERTSTORE 
cert_open_store()
{
    HCERTSTORE hStoreHandle;

    LOG_TRACE("cert_open_store enter");

    hStoreHandle = cp_function_list.CertOpenStore(CERT_STORE_PROV_SYSTEM,
                                    0,
                                    0,
                                    CERT_SYSTEM_STORE_CURRENT_USER | CERT_STORE_OPEN_EXISTING_FLAG,
                                    L"MY");
    
    if (hStoreHandle == NULL) {
        LOG_ERROR("The store could not be opened");
        return NULL;
    }

    LOG_DEBUG("The MY store is open");
    LOG_TRACE("cert_open_store exit");
    return hStoreHandle;
}


static void
cert_close_store(HCERTSTORE hStoreHandle)
{
    LOG_TRACE("cert_close_store enter");

    if (hStoreHandle) {
        if (!cp_function_list.CertCloseStore(hStoreHandle, CERT_CLOSE_STORE_CHECK_FLAG)) {
            LOG_ERROR("CertCloseStore() failed");
        }
    }

    LOG_TRACE("cert_close_store exit");
}

static PCCERT_CONTEXT 
get_cert_by_thumbprint(HCERTSTORE hStoreHandle, const str_t* thumbprint)
{
    str_t thumbprint_bin = str_t_null;

    LOG_TRACE("get_cert_by_thumbprint enter");

    if (hex_to_bin(thumbprint, &thumbprint_bin)) {
        goto error;
    }

    CRYPT_HASH_BLOB hash = {
        .pbData = (BYTE*)thumbprint_bin.data,
        .cbData = thumbprint_bin.len
    };

    PCCERT_CONTEXT cert = cp_function_list.CertFindCertificateInStore(hStoreHandle,
                                                X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
                                                0,
                                                CERT_FIND_HASH,
                                                &hash,
                                                NULL);
    if (cert == NULL) {
        LOG_ERROR("Could not find certificate in store");
        goto error;
    }

    str_t_clear(&thumbprint_bin);

    LOG_TRACE("get_cert_by_thumbprint exit");

    return cert;

error:
    str_t_clear(&thumbprint_bin);
    LOG_ERROR("get_cert_by_thumbprint exit with error");
    return NULL;
}

static PCCERT_CONTEXT 
get_signer_cert(const cryptopro_context_t *ctx, HCERTSTORE hStoreHandle)
{
    PCCERT_CONTEXT cert_ctx = get_cert_by_thumbprint(hStoreHandle, ctx->cert_thumbprint);
    if (cert_ctx == NULL) {
        goto error;
    }

    if (!str_t_is_null(*ctx->password)) {
        if (set_password(cert_ctx, ctx->password)) {
            goto error;
        }
    }

    LOG_DEBUG("The signer's certificate was found");
    return cert_ctx;

error:
    if (cert_ctx) {
        cp_function_list.CertFreeCertificateContext(cert_ctx);
    }
    LOG_ERROR("get_signer_cert exit with error");
    return NULL;
}

static int
set_password(PCCERT_CONTEXT cert_ctx, const str_t *password)
{
    DWORD dwSize;
    if (!cp_function_list.CertGetCertificateContextProperty(
             cert_ctx, 
             CERT_KEY_PROV_INFO_PROP_ID, 
             NULL,
             &dwSize)) {
        LOG_ERROR("Error getting key property");
        LOG_ERROR("set_password exit with error. Last error code: 0x%08x", cp_function_list.GetLastError());
        return -1;
    }

    unsigned char pKeyInfoBuffer[dwSize];
    CRYPT_KEY_PROV_INFO* pKeyInfo = (CRYPT_KEY_PROV_INFO*) pKeyInfoBuffer;

    if (!cp_function_list.CertGetCertificateContextProperty(
            cert_ctx,
            CERT_KEY_PROV_INFO_PROP_ID,
            pKeyInfo,
            &dwSize)){
        LOG_ERROR("The second call to the function failed");
        goto error;
    }

    DWORD keyType = (pKeyInfo->dwKeySpec == AT_SIGNATURE) ? PP_SIGNATURE_PIN
                                                          : PP_KEYEXCHANGE_PIN;

    CRYPT_KEY_PROV_PARAM keyProvParam;
    memset(&keyProvParam, 0, sizeof(CRYPT_KEY_PROV_PARAM));
    keyProvParam.dwFlags = 0;
    keyProvParam.dwParam = keyType;
    keyProvParam.cbData  = (DWORD)(password->len + 1);
    keyProvParam.pbData  = (BYTE*) password->data;

    pKeyInfo->cProvParam = 1;
    pKeyInfo->rgProvParam = &keyProvParam;

    if (!cp_function_list.CertSetCertificateContextProperty(
                cert_ctx,
                CERT_KEY_PROV_INFO_PROP_ID,
                0,
                pKeyInfo)) {
        LOG_ERROR("Error setting key property");
        goto error;
    }

    return 0;

error:
    LOG_ERROR("set_password exit with error. Last error code: 0x%08x", cp_function_list.GetLastError());
    return -1;
}

static void
set_unknown_alg_error(/*out*/ char** verify_error, const str_t* alg)
{
    LOG_TRACE("set_unknown_alg_error enter");

    const str_t err_format = str_t_const("Unknown alg: '%.*s'");

    size_t size = err_format.len + alg->len;

    *verify_error = malloc(size);
    if (*verify_error == NULL) {
        LOG_ERROR("set_unknown_alg_error failed. Could not allocate memory for error string "
                "(%zd bytes)", size);
        goto exit;
    }

    int n = snprintf(*verify_error, size, err_format.data, (int) alg->len, alg->data);

    if (n < 0 || (size_t)n >= size) {
        LOG_ERROR("set_unknown_alg_error failed. Error occurred in concatenation err_string");
        free(*verify_error);
        *verify_error = NULL;
        goto exit;
    }

    LOG_ERROR("%s", *verify_error);

exit:
    LOG_TRACE("set_unknown_alg_error exit");
}

static int
alg_id_from_str(const str_t* alg, /*out*/ ALG_ID* alg_id, /*out*/ char** verify_error)
{
    LOG_TRACE("alg_id_from_str enter");

    if (strncmp(alg->data, "GOST3410_2012_256", alg->len) == 0) {
        *alg_id = CALG_GR3411_2012_256;
    } else if (strncmp(alg->data, "GOST3410_2012_512", alg->len) == 0) {
        *alg_id = CALG_GR3411_2012_512;
    } else {
        set_unknown_alg_error(verify_error, alg);
        LOG_ERROR("alg_id_from_str exit with error");
        return -1;
    }

    LOG_TRACE("alg_id_from_str exit");
    return 0;
}

static void
get_verify_error(char** verify_error)
{
    LOG_TRACE("get_verify_error enter");

    DWORD err = cp_function_list.GetLastError();

    const char* err_string;

    switch (err) {
    case NTE_BAD_SIGNATURE:
        err_string = "sign is invalid: bad signature (0x%08x)";
        break;

    case NTE_BAD_ALGID:
        err_string = "sign is invalid: bad alg id (0x%08x)";
        break;
    
    default:
        err_string = "sign is invalid. Last error code: 0x%08x";
        break;
    }

    size_t size = strlen(err_string) + 4 /*error code*/ + 1 /*terminating null*/;

    if (*verify_error != NULL) {
        free(*verify_error); // в ответе отдаем последнюю ошибку
    }

    *verify_error = malloc(size);
    if (*verify_error == NULL) {
        LOG_ERROR("get_verify_error failed. Could not allocate memory for error string "
                    "(%zd bytes)", size);
        return;
    }

    int n = snprintf(*verify_error, size, err_string, err);
    
    if (n < 0 || (size_t)n >= size) {
        LOG_ERROR("get_verify_error failed. Error occurred in concatenation err_string");
        free(*verify_error);
        *verify_error = NULL;
        return;
    }

    LOG_DEBUG("verify error: %s", *verify_error);

    LOG_TRACE("get_verify_error exit");
}

int 
cryptopro_verify(cryptopro_context_t* ctx, const str_t* alg, const str_t* data, 
                    const str_t* sign, bool* is_verified, char** verify_error, const char** error_code)
{
    int rc = -1;
    HCERTSTORE hStoreHandle = NULL;
    PCCERT_CONTEXT certificate = NULL;
    HCRYPTPROV hCryptProv = 0;
    HCRYPTHASH hash = 0;
    HCRYPTKEY hPubKey = 0;
    str_t sign_reversed = str_t_null;
    ALG_ID alg_id;

    LOG_TRACE("cryptopro_verify enter");

    timer_on_cryptopro_verify_enter(ctx->timer_ctx);

    *is_verified = false;

    if (alg_id_from_str(alg, &alg_id, verify_error)) {
        goto exit;
    }

    if (reverse_sign(sign, &sign_reversed)) {
        goto exit;
    }

    hStoreHandle = cert_open_store();
    if (hStoreHandle == NULL) {
        goto exit;
    }

    certificate = get_cert_by_thumbprint(hStoreHandle, ctx->cert_thumbprint);
    if (certificate == NULL) {
        goto exit;
    }

    if (!verify_cert_chain(certificate, ctx->timer_ctx, error_code)) {
        goto exit;
    }

    LOG_DEBUG("provider: '%s', prov_type: %u", ctx->provider, ctx->prov_type);

    if (!cp_function_list.CryptAcquireContext(&hCryptProv, NULL, ctx->provider, ctx->prov_type, 
                                                CRYPT_VERIFYCONTEXT)) {
        LOG_ERROR("CryptAcquireContext() failed. provider: '%s', prov_type: %u", 
                        ctx->provider, ctx->prov_type);
        goto exit;
    }

    if (!cp_function_list.CryptImportPublicKeyInfo(hCryptProv, X509_ASN_ENCODING,
                                                    &certificate->pCertInfo->SubjectPublicKeyInfo, 
                                                    &hPubKey)) {
        LOG_ERROR("CryptImportPublicKeyInfo() failed");
        goto exit;
    }

    if (!cp_function_list.CryptCreateHash(hCryptProv, alg_id, 0, 0, &hash)) {
        LOG_ERROR("CryptCreateHash() failed");
        goto exit;
    }
            
    if (!cp_function_list.CryptHashData(hash, (CONST BYTE *) data->data, data->len, 0)) {
        LOG_ERROR("CryptHashData() failed");
        goto exit;
    }

    if (cp_function_list.CryptVerifySignature(hash, 
                                                (CONST BYTE *) sign_reversed.data, 
                                                sign_reversed.len, 
                                                hPubKey,
                                                NULL, 
                                                0)) {
        LOG_DEBUG("sign is valid");
        *is_verified = true;
    } else {
        get_verify_error(verify_error);
        if (*verify_error == NULL) {
            goto exit;
        }
        LOG_WARN("%s, cert_thumbprint: %.*s", *verify_error, 
                    (int) ctx->cert_thumbprint->len, ctx->cert_thumbprint->data);
    }

exit:

    if (*is_verified || *verify_error) {
        rc = 0;
    }

    str_t_clear(&sign_reversed);

    if (hash) {
        if (!cp_function_list.CryptDestroyHash(hash)) {
            LOG_ERROR("CryptDestroyHash() failed");
            rc = -1;
        }
    }

    if (hPubKey) {
        if (!cp_function_list.CryptDestroyKey(hPubKey)) {
            LOG_ERROR("CryptDestroyKey() failed");
            rc = -1;
        }
    }

    if (hCryptProv) {
        if (!cp_function_list.CryptReleaseContext(hCryptProv, 0)) {
            LOG_ERROR("CryptReleaseContext() failed");
            rc = -1;
        }
    }

    if (certificate) {
        cp_function_list.CertFreeCertificateContext(certificate);
    }

    cert_close_store(hStoreHandle);

    if (rc == 0) {
        LOG_TRACE("cryptopro_verify exit");
    } else {
        LOG_ERROR("cryptopro_verify exit with error. Last error code: 0x%08x", 
                    cp_function_list.GetLastError());
    }

    timer_on_cryptopro_verify_exit(ctx->timer_ctx);
    timer_log_verify(ctx->timer_ctx);

    return rc;  
}

static bool
get_subject_name(PCCERT_CONTEXT cert, /*out*/ char **subject_name)
{
    LOG_TRACE("get_subject_name enter");

    DWORD dwFlags = CERT_X500_NAME_STR | CERT_NAME_STR_NO_QUOTING_FLAG;

    DWORD len = cp_function_list.CertNameToStr(
        cert->dwCertEncodingType,
        &cert->pCertInfo->Subject,
        dwFlags,
        NULL,
        0
    );

    *subject_name = malloc(len);
    if (*subject_name == NULL) {
        LOG_ERROR("Could not allocate memory for Subject Name str (%d bytes)", len);
        goto error;
    }

    cp_function_list.CertNameToStr(
        cert->dwCertEncodingType,
        &cert->pCertInfo->Subject,
        dwFlags,
        *subject_name,
        len
    );

    LOG_DEBUG("Subject Name: %s", *subject_name);

    LOG_TRACE("get_subject_name exit");
    return true;

error:
    free(*subject_name);
    LOG_ERROR("get_subject_name exit with error");
    return false;
}

static bool
get_issuer_name(PCCERT_CONTEXT cert, /*out*/ char **issuer_name)
{
    LOG_TRACE("get_issuer_name enter");

    DWORD dwFlags = CERT_X500_NAME_STR | CERT_NAME_STR_NO_QUOTING_FLAG;

    DWORD len = cp_function_list.CertNameToStr(
        cert->dwCertEncodingType,
        &cert->pCertInfo->Issuer,
        dwFlags,
        NULL,
        0
    );

    *issuer_name = malloc(len);
    if (*issuer_name == NULL) {
        LOG_ERROR("Could not allocate memory for Issuer Name str (%d bytes)", len);
        goto error;
    }

    cp_function_list.CertNameToStr(
        cert->dwCertEncodingType,
        &cert->pCertInfo->Issuer,
        dwFlags,
        *issuer_name,
        len
    );

    LOG_DEBUG("Issuer Name: %s", *issuer_name);

    LOG_TRACE("get_issuer_name exit");
    return true;

error:
    free(*issuer_name);
    LOG_ERROR("get_issuer_name exit with error");
    return false;
}

static bool 
get_signer_cert_info(PCCERT_CONTEXT signer_cert, cert_info_t *signer_cert_info) 
{
    LOG_TRACE("get_signer_cert_info enter");

    if (!get_subject_name(signer_cert, &signer_cert_info->subject)) {
        goto error;
    }
    
    if (!get_issuer_name(signer_cert, &signer_cert_info->issuer)) {
        goto error;
    }

    LOG_TRACE("get_signer_cert_info exit");
    return true;

error:
    LOG_ERROR("get_signer_cert_info exit with error");
    return false;
}

/*
 * Проверка количества подписантов сообщения
 * Предполагается, что количество подписантов должно быть равно 1
 */
static bool
check_message_signer_count(const str_t *sign)
{
    int signer_count = cp_function_list.CryptGetMessageSignerCount(
                                            PKCS_7_ASN_ENCODING | X509_ASN_ENCODING,
                                            (const BYTE *) sign->data,
                                            (DWORD) sign->len);
    
    LOG_DEBUG("signer count = %d", signer_count);

    if (signer_count == 1) {
        LOG_DEBUG("signer count is ok");
        return true;
    }

    if (signer_count < 0) {
        LOG_ERROR("Could not get signer count. Last error code: 0x%08x", 
                cp_function_list.GetLastError());
    } else {
        LOG_ERROR("Invalid signer count: %d", signer_count);
    }

    return false;
}

/*
 * Проверка подписи и извлечение сертификата подписанта
 * Предполагается, что количество подписантов проверено и равно 1
 */
static bool
verify_detached_message_signature(const str_t *data, const str_t *sign, 
                                    timer_context_t *timer_ctx,
                                    /*out*/ PCCERT_CONTEXT *signer_cert)
{
    LOG_TRACE("verify_detached_message_signature enter");

    timer_on_verify_detached_message_signature_enter(timer_ctx);

    CRYPT_VERIFY_MESSAGE_PARA verifyParams = {
        .cbSize = sizeof(CRYPT_VERIFY_MESSAGE_PARA),
        .dwMsgAndCertEncodingType = PKCS_7_ASN_ENCODING | X509_ASN_ENCODING
    };

    BOOL r = cp_function_list.CryptVerifyDetachedMessageSignature(
        &verifyParams,
        0, // индекс проверяемой подписи
        (CONST BYTE *) sign->data,
        sign->len,
        1, // количество подписанных сообщений
        (const BYTE **) &(data->data),
        (DWORD*) &(data->len),
        signer_cert
    );

    timer_on_verify_detached_message_signature_exit(timer_ctx);

    LOG_TRACE("verify_detached_message_signature exit");
    return r;
}

int 
cryptopro_verify_detached(cryptopro_context_t *ctx, const str_t *data, const str_t *sign, 
                                bool *is_verified, /*out*/ cert_info_t *signer_cert_info,
                                /*out*/ char **verify_error, /*out*/ const char **error_code)
{
    LOG_TRACE("cryptopro_verify_detached enter");

    timer_on_cryptopro_verify_detached_enter(ctx->timer_ctx);

    *is_verified = false;
    PCCERT_CONTEXT signer_cert = NULL;

    if (!check_message_signer_count(sign)) {
        goto error;
    }

    if (verify_detached_message_signature(data, sign, ctx->timer_ctx, &signer_cert)) {
        LOG_DEBUG("sign is valid");

        if (!check_cert_key_usage(signer_cert)) {
            goto error;
        }

        if (!verify_cert_chain(signer_cert, ctx->timer_ctx, error_code)) {
            goto error;
        }

        if (!get_signer_cert_info(signer_cert, signer_cert_info)) {
            goto error;
        }

        *is_verified = true;
        
    } else {
        LOG_DEBUG("sign is invalid");
        get_verify_error(verify_error);
    }

    if (signer_cert != NULL) {
        cp_function_list.CertFreeCertificateContext(signer_cert);
    }

    timer_on_cryptopro_verify_detached_exit(ctx->timer_ctx);

    LOG_TRACE("cryptopro_verify_detached exit");
    return 0;

error:
    if (signer_cert != NULL) {
        cp_function_list.CertFreeCertificateContext(signer_cert);
    }

    LOG_ERROR("cryptopro_verify_detached exit with error. Last error code: 0x%08x", 
                    cp_function_list.GetLastError());
    return -1;
}

int 
cryptopro_gen_random(const cryptopro_context_t *ctx, unsigned char* data, size_t len)
{
    HCRYPTPROV hCryptProv = 0;

    LOG_TRACE("cryptopro_gen_random enter");

    if (!cp_function_list.CryptAcquireContext(&hCryptProv, NULL, ctx->provider, ctx->prov_type, 
                                                CRYPT_VERIFYCONTEXT)) {
        LOG_ERROR("CryptAcquireContext() failed. provider: '%s', prov_type: %u", 
                        ctx->provider, ctx->prov_type);
        goto error;
    }

    if (!cp_function_list.CryptGenRandom(hCryptProv, len, data)) {
        LOG_ERROR("CryptGenRandom() failed");
        goto error;
    }

    if (!cp_function_list.CryptReleaseContext(hCryptProv, 0)) {
        LOG_ERROR("CryptReleaseContext() failed");
        hCryptProv = 0;
        goto error;
    }

    LOG_TRACE("cryptopro_gen_random exit");
    return 0;

error:
    if (hCryptProv) {
        if (!cp_function_list.CryptReleaseContext(hCryptProv, 0)) {
            LOG_ERROR("CryptReleaseContext() failed");
        }
    }

    LOG_ERROR("cryptopro_gen_random exit with error. Last error code: 0x%08x", 
                cp_function_list.GetLastError());
    return -1;
}