#include "client.h"
#include <openssl/evp.h>
#include <openssl/err.h>

char* getSHA256(const char* filePath){
    int fd = open(filePath, O_RDONLY);

    EVP_MD_CTX* mdctx;
    const EVP_MD* md;
    unsigned char md_value[EVP_MAX_MD_SIZE];
    unsigned int md_len;
    unsigned char buf[1024];
    size_t bytes;

    OpenSSL_add_all_digests();
    md = EVP_get_digestbyname("SHA256");
    mdctx = EVP_MD_CTX_new();
    EVP_DigestInit_ex(mdctx, md, NULL);

    while ((bytes = read(fd, buf, sizeof(buf))) != 0){
        EVP_DigestUpdate(mdctx, buf, bytes);
    }

    EVP_DigestFinal_ex(mdctx, md_value, &md_len);
    EVP_MD_CTX_free(mdctx);
    close(fd);

    char* sha256_str = (char*)calloc(65, sizeof(char));

    for (unsigned int i = 0; i < md_len; i++) {
        sprintf(&sha256_str[i * 2], "%02x", md_value[i]);
    }

    EVP_cleanup();

    return sha256_str;
}