#ifndef LLARP_ENDIAN_HPP
#define LLARP_ENDIAN_HPP

// adapted from libi2pd

#include <cinttypes>
#include <cstring>
#include <absl/numeric/int128.h>

#if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__)
#include <sys/endian.h>
#elif defined(__sun)
#include <sys/byteorder.h>
#define htobe16(x) htons(x)
#define htole16(x) (x)
#define be16toh(x) ntohs(x)
#define le16toh(x) (x)

#define htobe32(x) htonl(x)
#define htole32(x) (x)
#define be32toh(x) ntohl(x)
#define le32toh(x) (x)

#define htobe64(x)                                        \
  (((uint64_t)htonl(((uint32_t)(((uint64_t)(x)) >> 32)))) \
   | (((uint64_t)htonl(((uint32_t)(x)))) << 32))
#define htole64(x) (x)
#define be64toh(x)                                        \
  (((uint64_t)ntohl(((uint32_t)(((uint64_t)(x)) >> 32)))) \
   | (((uint64_t)ntohl(((uint32_t)(x)))) << 32))
#define le64toh(x) (x)
#elif defined(__linux__) || defined(__FreeBSD_kernel__) || defined(__GLIBC__)
#include <endian.h>
#elif defined(__APPLE__) && defined(__MACH__)
#include <libkern/OSByteOrder.h>
#define htobe16(x) OSSwapHostToBigInt16(x)
#define htole16(x) OSSwapHostToLittleInt16(x)
#define be16toh(x) OSSwapBigToHostInt16(x)
#define le16toh(x) OSSwapLittleToHostInt16(x)

#define htobe32(x) OSSwapHostToBigInt32(x)
#define htole32(x) OSSwapHostToLittleInt32(x)
#define be32toh(x) OSSwapBigToHostInt32(x)
#define le32toh(x) OSSwapLittleToHostInt32(x)

#define htobe64(x) OSSwapHostToBigInt64(x)
#define htole64(x) OSSwapHostToLittleInt64(x)
#define be64toh(x) OSSwapBigToHostInt64(x)
#define le64toh(x) OSSwapLittleToHostInt64(x)
#elif defined(_WIN32)
#include <winsock2.h>
#define htobe16(x) htons(x)
#define htole16(x) (x)
#define be16toh(x) ntohs(x)
#define le16toh(x) (x)

#define htobe32(x) htonl(x)
#define htole32(x) (x)
#define be32toh(x) ntohl(x)
#define le32toh(x) (x)

#define htobe64(x)                                        \
  (((uint64_t)htonl(((uint32_t)(((uint64_t)(x)) >> 32)))) \
   | (((uint64_t)htonl(((uint32_t)(x)))) << 32))
#define htole64(x) (x)
#define be64toh(x)                                        \
  (((uint64_t)ntohl(((uint32_t)(((uint64_t)(x)) >> 32)))) \
   | (((uint64_t)ntohl(((uint32_t)(x)))) << 32))
#define le64toh(x) (x)
#else
#define NEEDS_LOCAL_ENDIAN
#include <cstdint>
uint16_t
htobe16(uint16_t int16);
uint32_t
htobe32(uint32_t int32);
uint64_t
htobe64(uint64_t int64);

uint16_t
be16toh(uint16_t big16);
uint32_t
be32toh(uint32_t big32);
uint64_t
be64toh(uint64_t big64);

// assume LittleEndine
#define htole16
#define htole32
#define htole64
#define le16toh
#define le32toh
#define le64toh

#endif

#if !defined(__LITTLE_ENDIAN__) && defined(__BYTE_ORDER) \
    && defined(__LITTLE_ENDIAN) && __BYTE_ORDER == __LITTLE_ENDIAN
#define __LITTLE_ENDIAN__
#elif !defined(__BIG_ENDIAN__) && defined(__BYTE_ORDER) \
    && defined(__BIG_ENDIAN) && __BYTE_ORDER == __BIG_ENDIAN
#define __BIG_ENDIAN__
#elif !defined(__LITTLE_ENDIAN__) && !defined(__BIG_ENDIAN__)
#error "Error: don't know which endian this is"
#endif

inline uint16_t
buf16toh(const void *buf)
{
  uint16_t b16;
  memcpy(&b16, buf, sizeof(uint16_t));
  return b16;
}

inline uint32_t
buf32toh(const void *buf)
{
  uint32_t b32;
  memcpy(&b32, buf, sizeof(uint32_t));
  return b32;
}

inline uint64_t
buf64toh(const void *buf)
{
  uint64_t b64;
  memcpy(&b64, buf, sizeof(uint64_t));
  return b64;
}

inline uint16_t
bufbe16toh(const void *buf)
{
  return be16toh(buf16toh(buf));
}

inline uint32_t
bufbe32toh(const void *buf)
{
  return be32toh(buf32toh(buf));
}

inline uint64_t
bufbe64toh(const void *buf)
{
  return be64toh(buf64toh(buf));
}

inline void
htobuf16(void *buf, uint16_t b16)
{
  memcpy(buf, &b16, sizeof(uint16_t));
}

inline void
htobuf32(void *buf, uint32_t b32)
{
  memcpy(buf, &b32, sizeof(uint32_t));
}

inline void
htobuf64(void *buf, uint64_t b64)
{
  memcpy(buf, &b64, sizeof(uint64_t));
}

inline void
htobe16buf(void *buf, uint16_t big16)
{
  htobuf16(buf, htobe16(big16));
}

inline void
htobe32buf(void *buf, uint32_t big32)
{
  htobuf32(buf, htobe32(big32));
}

inline void
htobe64buf(void *buf, uint64_t big64)
{
  htobuf64(buf, htobe64(big64));
}

inline void
htole16buf(void *buf, uint16_t big16)
{
  htobuf16(buf, htole16(big16));
}

inline void
htole32buf(void *buf, uint32_t big32)
{
  htobuf32(buf, htole32(big32));
}

inline void
htole64buf(void *buf, uint64_t big64)
{
  htobuf64(buf, htole64(big64));
}

inline absl::uint128
ntoh128(absl::uint128 i)
{
#ifdef __BIG_ENDIAN__
  return i;
#else
  const auto loSwapped = htobe64(absl::Uint128Low64(i));
  const auto hiSwapped = htobe64(absl::Uint128High64(i));
  return absl::MakeUint128(loSwapped, hiSwapped);
#endif
}

#endif