// Copyright (C) 2007-2025 EQ2EMulator
// Licensed under GPL v3

#pragma once

#include <array>
#include <cstdint>
#include <string>
#include <string_view>

class SHA512
{
public:
    static constexpr unsigned int DIGEST_SIZE = 512 / 8;
    static constexpr unsigned int SHA384_512_BLOCK_SIZE = 1024 / 8;

    void init() noexcept;
    void update(const unsigned char* message, unsigned int len) noexcept;
    void final(unsigned char* digest) noexcept;

protected:
    using uint8 = std::uint8_t;
    using uint32 = std::uint32_t;
    using uint64 = std::uint64_t;

    static const std::array<uint64, 80> sha512_k;

    void transform(const unsigned char* message, unsigned int block_nb) noexcept;

    unsigned int m_tot_len{};
    unsigned int m_len{};
    std::array<unsigned char, 2 * SHA384_512_BLOCK_SIZE> m_block{};
    std::array<uint64, 8> m_h{};
};

[[nodiscard]] std::string sha512(std::string_view input) noexcept;

#define SHA2_SHFR(x, n)    (x >> n)
#define SHA2_ROTR(x, n)   ((x >> n) | (x << ((sizeof(x) << 3) - n)))
#define SHA2_ROTL(x, n)   ((x << n) | (x >> ((sizeof(x) << 3) - n)))
#define SHA2_CH(x, y, z)  ((x & y) ^ (~x & z))
#define SHA2_MAJ(x, y, z) ((x & y) ^ (x & z) ^ (y & z))
#define SHA512_F1(x) (SHA2_ROTR(x, 28) ^ SHA2_ROTR(x, 34) ^ SHA2_ROTR(x, 39))
#define SHA512_F2(x) (SHA2_ROTR(x, 14) ^ SHA2_ROTR(x, 18) ^ SHA2_ROTR(x, 41))
#define SHA512_F3(x) (SHA2_ROTR(x,  1) ^ SHA2_ROTR(x,  8) ^ SHA2_SHFR(x,  7))
#define SHA512_F4(x) (SHA2_ROTR(x, 19) ^ SHA2_ROTR(x, 61) ^ SHA2_SHFR(x,  6))
#define SHA2_UNPACK32(x, str)                 \
{                                             \
    *((str) + 3) = (uint8) ((x)      );       \
    *((str) + 2) = (uint8) ((x) >>  8);       \
    *((str) + 1) = (uint8) ((x) >> 16);       \
    *((str) + 0) = (uint8) ((x) >> 24);       \
}
#define SHA2_UNPACK64(x, str)                 \
{                                             \
    *((str) + 7) = (uint8) ((x)      );       \
    *((str) + 6) = (uint8) ((x) >>  8);       \
    *((str) + 5) = (uint8) ((x) >> 16);       \
    *((str) + 4) = (uint8) ((x) >> 24);       \
    *((str) + 3) = (uint8) ((x) >> 32);       \
    *((str) + 2) = (uint8) ((x) >> 40);       \
    *((str) + 1) = (uint8) ((x) >> 48);       \
    *((str) + 0) = (uint8) ((x) >> 56);       \
}
#define SHA2_PACK64(str, x)                   \
{                                             \
    *(x) =   ((uint64) *((str) + 7)      )    \
           | ((uint64) *((str) + 6) <<  8)    \
           | ((uint64) *((str) + 5) << 16)    \
           | ((uint64) *((str) + 4) << 24)    \
           | ((uint64) *((str) + 3) << 32)    \
           | ((uint64) *((str) + 2) << 40)    \
           | ((uint64) *((str) + 1) << 48)    \
           | ((uint64) *((str) + 0) << 56);   \
}