#pragma once

#include <memory>
#include <openssl/evp.h>
#include <openssl/hmac.h>
#include <openssl/sha.h>

#include <rublon/utils.hpp>

namespace rublon {

struct EVP_MD_CTX_deleter{
    void operator()(EVP_MD_CTX *ctx)const{
        EVP_MD_CTX_free(ctx);
    }
};

inline StaticString< SHA256_DIGEST_LENGTH * 2 > fileSHA256(const char * const path) {
    std::string fileContent;
    readFile(path, fileContent);

    StaticString< SHA256_DIGEST_LENGTH * 2 > xRublon{};
    std::array< unsigned char, SHA256_DIGEST_LENGTH + 1 > hash{};

    auto ctx = std::unique_ptr<EVP_MD_CTX, EVP_MD_CTX_deleter>{EVP_MD_CTX_new()};
    
    if(not ctx)
        goto out;

    // EVP_X methods return 1 on success, so does this function
    // Any values other than 1 denote error
    if(not EVP_DigestInit(ctx.get(), EVP_sha256()))
        goto out;
    
    if(not EVP_DigestUpdate(ctx.get(), fileContent.data(), fileContent.size()))
        goto out;

    // Provide uint* instead of NULL to get nBytes written, 32 for SHA256
    if(not EVP_DigestFinal(ctx.get(), hash.data(), NULL))
        goto out;

out:
    for(unsigned int i = 0; i < SHA256_DIGEST_LENGTH; i++)
        sprintf(&xRublon[i * 2], "%02x", ( unsigned int ) hash[i]);

    return xRublon;
}

// +1 for \0
inline StaticString< SHA256_DIGEST_LENGTH * 2 > signData(std::string_view data, std::string_view secretKey) {
    StaticString< SHA256_DIGEST_LENGTH * 2 > xRublon;
    std::array< unsigned char, EVP_MAX_MD_SIZE > md{};
    unsigned int md_len{};

    HMAC(EVP_sha256(), secretKey.data(), secretKey.size(), ( unsigned const char * ) data.data(), data.size(), md.data(), &md_len);

    for(unsigned int i = 0; i < md_len; i++)
        sprintf(&xRublon[i * 2], "%02x", ( unsigned int ) md[i]);

    return xRublon;
}

} // namespace rublon