/*!@file
  \brief  Password Encyption and Storing
  \details hashes password using SHA256 and saves result in a file on VFS using
           hashing algorithm provided by wolfcrypt(wc), a subsystem of wolfSSL
  \author  JEL
  \date    2016
  -----------------------------------------------------------------------------*/
#include <stddef.h>
#include <stdio.h>
#include <wolfssl/wolfcrypt/sha256.h>
#ifdef __EMSCRIPTEN__
#include <emscripten.h>
#endif

word32 str_len(const char*);
int auth_encrypt(int argc, char** argv);
void store_password(byte*);

/* Should come with wolfcrypt type.h */
/* typedef unsigned int word32; */

word32
str_len (const char* str)
{
  const char* strl;

  for (strl = str; *strl != '\0'; ++strl)
  {
  /* nothing to be done */;
  }
  return strl - str;
}


/* Takes a string and hashes it, returning
   the encrypted string as a result */

int
auth_encrypt(int argc, char** argv)
{
  /* Determine length of password */
  word32 len = 0;
  char* password;
  byte hash[32]; /* 32bytes * 8 = 256, the # bits of hash */
  const unsigned char c_password[32]; /* Passwords are between 8-32 chars */
  Sha256 sha256[1]; /* Init a Sha256 type for wc */


  password = argv[0];
  len = str_len(password);

  /* Converting password to unsigned const char* for wc_functions */
  memcpy( (void*) c_password, (void*) password, len+1);

  if (wc_InitSha256(sha256) != 0 )
   {
     printf("wc_InitSha256 failed\n");
   }
   else
   {
     wc_Sha256Update(sha256, c_password, len);
     wc_Sha256Final(sha256, hash);
   }

  printf("password is: %s\n", c_password);
  printf("password length is: %d\n", len);
  for(len = 0; len < 32; len++){
    printf("hash is %x\n",hash[len]);
  }

  store_password(hash);
  //free((void*) c_password);


  return 0;
}

void
store_password(byte* hash)
{
  byte b;
  /* Save hash to a file on emscripten VFS */
  FILE *fp;
  int i;
  byte buff[32] = {0};

  printf("=====Storing Password in auth/password========\n");
  /* for(i = 0; i < 32; i++){ */
  /*   printf("hash is %x\n",hash[i]); */
  /* } */

  fp = fopen("/auth/password", "w+");
  if(!fp)
  {
    printf("cannot open file\n");
  }
  else
  {
    fwrite(hash, 1, 32, fp);
  }

  printf("========Stored Password=========\n");

  fseek(fp, 0, SEEK_SET);

  for(i = 0; i < 32; i++)
  {
    fread(buff, 1, 32, fp) ;
    printf("buff is %x\n",buff[i]);
  }

  fclose(fp);
}