#include "ffi_pedersen_hash.h"
#include "pedersen_hash.h"

#include <array>

#include "prime_field_element.h"
#include "ffi_utils.h"

#include "gsl-lite.hpp"

namespace starkware {

namespace {

using ValueType = PrimeFieldElement::ValueType;

constexpr size_t kElementSize = sizeof(ValueType);
constexpr size_t kOutBufferSize = 1024;
static_assert(kOutBufferSize >= kElementSize, "kOutBufferSize is not big enough");

}  // namespace

#ifdef __cplusplus
extern "C" {
#endif

int Hash(
    const gsl::byte in1[kElementSize], const gsl::byte in2[kElementSize],
    gsl::byte out[kOutBufferSize]) {
  try {
    auto hash = PedersenHash(
        PrimeFieldElement::FromBigInt(Deserialize(gsl::make_span(in1, kElementSize))),
        PrimeFieldElement::FromBigInt(Deserialize(gsl::make_span(in2, kElementSize))));
    Serialize(hash.ToStandardForm(), gsl::make_span(out, kElementSize));
  } catch (const std::exception& e) {
    return HandleError(e.what(), gsl::make_span(out, kOutBufferSize));
  } catch (...) {
    return HandleError("Unknown c++ exception.", gsl::make_span(out, kOutBufferSize));
  }
  return 0;
}

#ifdef __cplusplus
} // extern C
#endif 
}  // namespace starkware



int GoHash(const char* in1, const char* in2, char* out) {
	return starkware::Hash(
	reinterpret_cast<const gsl::byte *>(in1),
	reinterpret_cast<const gsl::byte *>(in2), 
	reinterpret_cast<gsl::byte *>(out));
}