#include <iostream>
//#include <endian.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <inttypes.h>
// #include "bignum.h"

#include "BigInteger/BigInteger.h"

extern "C" {
//#include "tfm.h"
}


const char* secretMessage =
	"b3bb321dd5ba49a6dc3003d47d769e0b8001154fb7e785c567e68986"
	"cf6caadd1f57c8f0b5bd33553ab25b519f8f59637d2913e21ba6c2c4"
	"f8cc1e4b933507191352acbbbca4774b82471bd052dfd9f95f17e644"
	"cd0efdfbe692ea54d78fcdb79e6aa6ae9d6c100d7dd1f72bb68ae8e7"
	"2fe3886e90aa89268c5c8eb961df316b568acd8c1e78cb20ec1ebd3e"
	"ef01828e271093a9c83380b62187f2a92f0d191ba463307de661c5ad"
	"0ac229cc347d8dd932a639dc1d724a707d2f5528ca75005a126877e9"
	"b58e7e139854dae90e43dcdfb3d2373f412aafa2e1a977addc9be9a8"
	"c1e959af236dcd42e76f1fefd577c6211f7b033da9c2b683f131a7c7"
	"0d96038b";


const char* publicModulus =
	"C595751A3ECF23F251F42D53053E2A88B195F79FAA370EBDA69D4C0E"
	"8535E9DCBD1A28CD726CB097504B041807FB0755228B180F4EC82907"
	"2BF716A4DD0948917B09308509916A7AB1F4D5C2D65444284FB734AB"
	"7F161AE2FACC6962EC0CF12559BD81E34E945B8A5BDE6276EAD96F7B"
	"1ECBE0BFD1D8266261AF6C6CF6D72F0962002FC774A0FB43C5A7EA3E"
	"FFBFC5EF95703CB408BA414E0C280611F03A8423C3A5A827D49B8CB8"
	"5E92513C7A68870701B16D0511EE1A8EA1998A519DAA3BFFCB926236"
	"D94658C57E413B49E8F7881B7000DF05655487E9B0D9D82F077EEC1F"
	"8533816D074AE6B347430C5F3F98E5350A0A3121B243ED1C1CFA9408"
	"BA64E00D";


const char* publicExponent = "010001";


unsigned int hexCharToInt(unsigned char ch)
{
	unsigned int c = tolower(ch);
	if (c >= 'a')
		return c - 'a' + 10;
	return c - '0';
}

#if 0
uint8_t bnCreateFromString(BN* bn, const char* str)
{
	int len = strlen(str);
	int byteLen = len / 2;
	bn->nbytes = byteLen - 1;
	bn->data = (uint8_t*)malloc((int)byteLen+2);
	if (!bn->data)
		return 0;
	for (int i = 0; i < byteLen; i++)
	{
		int val = 0;
		val = hexCharToInt(str[i * 2 +1]);
		val |= hexCharToInt(str[i * 2]) << 4;
		//val = hexCharToInt(str[(len - 1) - i * 2]);
		//val |= hexCharToInt(str[(len - 2) - i * 2]) << 4;
		bn->data[i] = val;
	}
	return 1;
}

void printBigNum(const char* name, BN* bn)
{
	printf("%s", name);
	for (int i = 0; i <= bn->nbytes; i++)
		printf("%02X ", bn->data[i]);
	printf("\n");
}

void fpCreateFromString(fp_int* n, const char* str)
{
  int len = strlen(str);
  char* writable = (char*)memcpy(malloc(len + 1), str, len + 1);
  //fp_reverse((unsigned char*)writable, len);
  fp_read_radix(n, writable, 16);
  free(writable);
  //fp_reverse(s.c_str(), s.length());
  //fp_read_radix(n, (char*)s.c_str(), 16);
}

void rsa_test()
{
  fp_int d, e, n, c, m, e_m;
  /* read in the parameters */
  fpCreateFromString(&m, secretMessage);
  fpCreateFromString(&e, publicExponent);
  fpCreateFromString(&n, publicModulus);
  /* test it */
  fp_exptmod(&m, &e, &n, &e_m);

  char buf[512];
  memset(buf, 0, 512);
  fp_toradix_n(&e_m, buf, 16, 512);
  //printf("text = %s\n", buf);
  for (int i = 0; i < 256; i++)
  {
	unsigned int val = 0;
	val = hexCharToInt(buf[i * 2 + 1]) << 4;
	val |= hexCharToInt(buf[i * 2 + 2]);
	if (isprint(val) || isspace(val))
		printf("%c", val);
  }

  printf("res: ");
  for (int i = 0; i < 512; i++)
  {
    printf("%c", buf[i]);
  }
}
#endif

void bignum_tests()
{
    // TODO: need some helpers to reverse the order, construct from an int
    // need helper to print out in reverse order or be able to convert back to an int
    // then can make a set of unit tests which can be compared against normal int math results
	BigInteger a = 0x40512F; // reverse endian order
	BigInteger b = 0xE1E30F;
    BigInteger c = a * b;
	printf("\n %" PRIx64 " x %" PRIx64 " = %" PRIx64 " ", (uint64_t)a, (uint64_t)b, (uint64_t)c);
	printf("\n %x x %x = %llx", 0x40512F, 0xE1E30F, 0x40512FLL*0xE1E30FLL);

	printf("\n 0x40512F x 0x03 =   "); BigInteger(BigInteger(0x40512F) * BigInteger(0x03)).Print();
	printf("\n 0x40512F x 0x03 =   %llx", 0x40512FLL*0x03LL);

	printf("\n 0x40512F x 0x03 =   "); BigInteger(BigInteger("03") * BigInteger("40512F")).Print();
	printf("\n 0x40512F x 0x03 =   %llx", 0x40512FLL*0x03LL);

	a = BigInteger("012F"); // reverse endian order
	b = BigInteger("FF");

    BigInteger d = a;
    d -= b;
	printf("\n 0x012F - 0xFF =   "); d.Print();
	printf("\n %x - %x = %x", 0x012F, 0xFF, 0x012F-0xFF);

	BigInteger bmod("03");
	BigInteger bexp("02");
	BigInteger bdat("1234");
	printf("\nbmod: "); bmod.Print();
	printf("\nbexp: "); bexp.Print();
	printf("\nbdat: "); bdat.Print();
	printf("\n");

	BigInteger bdst;

	bdst = BigInteger::ExpMod(bdat, bexp, bmod);
	printf("\n 0x1234 ^ 0x2 %% 0x3 =   "); bdst.Print();
	printf("\n %x ^ %x %% %x = %x", 0x1234, 0x2, 0x3, 0x1234*0x1234 % 0x3);

    bdst = bdat;
    bdst = bdat % BigInteger("07");
	printf("\n 0x1234 %% 0x0007 =   "); bdst.Print();
	printf("\n %x %% %x = %x", 0x1234, 0x0007, 0x1234 % 0x0007);

    bdst = bdat;
    bdst = bdat / BigInteger("07");
	printf("\n 0x1234 / 0x0007 =   "); bdst.Print();
	printf("\n %x / %x = %x", 0x1234, 0x0007, 0x1234 / 0x0007);

    bdst = bdat;
    bdst -= bmod;
	printf("\n 0x1234 - 0x3 =   "); bdst.Print();
	printf("\n %x - %x = %x", 0x1234, 0x3, 0x1234 - 0x3);

    bdst = bdat;
    bdst += bmod;
	printf("\n 0x1234 + 0x3 =   "); bdst.Print();
	printf("\n %x + %x = %x", 0x1234, 0x3, 0x1234 + 0x3);

    bdst = bdat;
    bdst >>= 3;//bmod;
	printf("\n 0x1234 >> 0x3 =   "); bdst.Print();
	printf("\n %x >> %x = %x", 0x1234, 0x3, 0x1234 >> 0x3);
	//printf("\n %x << %x = %x", 0x1234, 0x3, 0x1234 << 0x3);

    bdst = bdat;
    bdst <<= 3;//bmod;
	printf("\n 0x1234 << 0x3 =   "); bdst.Print();
	printf("\n %x << %x = %x", 0x1234, 0x3, 0x1234 << 0x3);
	//printf("\n %x << %x = %x", 0x1234, 0x3, 0x1234 << 0x3);

	printf("\n");
}

void rsa_test2()
{
	BigInteger bmod(publicModulus);
	BigInteger bexp(publicExponent);
	BigInteger bdat(secretMessage);

	printf("\nbmod: "); bmod.Print();
	printf("\nbexp: "); bexp.Print();
	printf("\nbdat: "); bdat.Print();
	printf("\n");

	BigInteger bdst = BigInteger::ExpMod(bdat, bexp, bmod);

	printf("\nbdst: "); bdst.Print();
	printf("\n");

    size_t siz = bdst.Size();
	printf("\nbdst size: %i\n", int(siz));
    for (size_t i = 0; i < siz; i++)
    {
	  unsigned int val = bdst[siz-1-i];
	  //printf("%x ", val);
	  if (isprint(val) || isspace(val))
        printf("%c", val);
    }
}

/*
void rsa_test3()
{
	BN bdst,bdat,bexp,bmod;
	bnCreateFromString(&bmod, publicModulus);
	printBigNum("bmod: ", &bmod);
	bnCreateFromString(&bexp, publicExponent);
	printBigNum("bexp: ", &bexp);
	bnCreateFromString(&bdat, secretMessage);
	printBigNum("bdat: ", &bdat);
	//bnCreate(&bdat,21,bunenc);
	//bnCreate(&bexp,3,bpublicExponent);
	//bnCreate(&bmod,128,bmodulus);
	bnExpMod(&bdst, &bdat, &bexp, &bmod);
	printBigNum("bdst: ", &bdst);
}
*/


int main()
{
    bignum_tests();

	//rsa_test();
	rsa_test2();
	//rsa_test3();

	// const char* paypal_pub_key = "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA3EdI1EOw/+ft6uywdUHi5P4CyIqCl5u31m88yuixkRHVYLGe/NLC8wjzOHkeN6kKjrdCMXhDcBK2CFnTKKptJdwmj25o3Kj3uqscN+jEzGaIy0hRvnFZ2FGr6MdQxMLI0xkC1fFiU22TCuwEJydxKtTQl";

	return 0;
}