// Copyright 2017 Dolphin Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later

#pragma once

#include <array>
#include <limits>
#include <memory>
#include <span>
#include <string_view>
#include <type_traits>
#include <vector>

#include "Common/Assert.h"
#include "Common/CommonTypes.h"

namespace Common::SHA1
{
using Digest = std::array<u8, 160 / 8>;
static constexpr size_t DIGEST_LEN = sizeof(Digest);

class Context
{
public:
  virtual ~Context() = default;
  virtual void Update(const u8* msg, size_t len) = 0;
  void Update(std::span<const u8> msg) { return Update(msg.data(), msg.size()); }
  void Update(std::string_view msg)
  {
    return Update(reinterpret_cast<const u8*>(msg.data()), msg.size());
  }
  virtual Digest Finish() = 0;
  virtual bool HwAccelerated() const = 0;
};

std::unique_ptr<Context> CreateContext();

Digest CalculateDigest(const u8* msg, size_t len);

template <typename T>
inline Digest CalculateDigest(const std::vector<T>& msg)
{
  static_assert(std::is_trivially_copyable_v<T>);
  ASSERT(std::numeric_limits<size_t>::max() / sizeof(T) >= msg.size());
  return CalculateDigest(reinterpret_cast<const u8*>(msg.data()), sizeof(T) * msg.size());
}

inline Digest CalculateDigest(const std::string_view& msg)
{
  return CalculateDigest(reinterpret_cast<const u8*>(msg.data()), msg.size());
}

template <typename T, size_t Size>
inline Digest CalculateDigest(const std::array<T, Size>& msg)
{
  static_assert(std::is_trivially_copyable_v<T>);
  return CalculateDigest(reinterpret_cast<const u8*>(msg.data()), sizeof(msg));
}

std::string DigestToString(const Digest& digest);

constexpr Digest StringToDigest(std::string_view str)
{
  Digest digest{};
  ASSERT(str.size() == digest.size() * 2);

  for (size_t i = 0; i < str.size(); ++i)
  {
    const char c = str[i];
    u8 quartet;
    if (c >= '0' && c <= '9')
      quartet = c - '0';
    else if (c >= 'A' && c <= 'F')
      quartet = c - 'A' + 10;
    else if (c >= 'a' && c <= 'f')
      quartet = c - 'a' + 10;
    else
      ASSERT(false);

    if (i % 2 == 0)
      digest[i / 2] = quartet << 4;
    else
      digest[i / 2] |= quartet;
  }
  return digest;
}
}  // namespace Common::SHA1