include/json_html_serializer.hpp

#ifndef THIRD_PARTY_GBMCWEB_INCLUDE_JSON_HTML_SERIALIZER_H_
#define THIRD_PARTY_GBMCWEB_INCLUDE_JSON_HTML_SERIALIZER_H_

#include <algorithm>
#include <array>
#include <cstddef>
#include <cstdint>
#include <cstdio>
#include <limits>
#include <string>
#include <type_traits>

#include <nlohmann/json.hpp>

namespace json_html_util {

static constexpr uint8_t utf8Accept = 0;
static constexpr uint8_t utf8Reject = 1;

// NOLINTBEGIN
inline uint8_t decode(uint8_t& state, uint32_t& codePoint,
                      const uint8_t byte) noexcept {
  // clang-format off
    static const std::array<std::uint8_t, 400> utf8d =
    {
        {
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 00..1F
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 20..3F
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 40..5F
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 60..7F
            1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 80..9F
            7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, // A0..BF
            8, 8, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, // C0..DF
            0xA, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x4, 0x3, 0x3, // E0..EF
            0xB, 0x6, 0x6, 0x6, 0x5, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, // F0..FF
            0x0, 0x1, 0x2, 0x3, 0x5, 0x8, 0x7, 0x1, 0x1, 0x1, 0x4, 0x6, 0x1, 0x1, 0x1, 0x1, // s0..s0
            1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, // s1..s2
            1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, // s3..s4
            1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1, 1, // s5..s6
            1, 3, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 // s7..s8
        }
    };
  // clang-format on

  if (state > 0x8) {
    return state;
  }

  const uint8_t type = utf8d[byte];

  codePoint = (state != utf8Accept)
                  ? (byte & 0x3fU) | (codePoint << 6)
                  : static_cast<uint32_t>(0xff >> type) & (byte);

  state = utf8d[256U + state * 16U + type];
  return state;
}

inline void dumpEscaped(std::string& out, const std::string& str) {
  std::array<char, 512> stringBuffer{{}};
  uint32_t codePoint = 0;
  uint8_t state = utf8Accept;
  std::size_t bytes = 0;  // number of bytes written to string_buffer

  // number of bytes written at the point of the last valid byte
  std::size_t bytesAfterLastAccept = 0;
  std::size_t undumpedChars = 0;

  for (std::size_t i = 0; i < str.size(); ++i) {
    const uint8_t byte = static_cast<uint8_t>(str[i]);

    switch (decode(state, codePoint, byte)) {
      case utf8Accept:  // decode found a new code point
      {
        switch (codePoint) {
          case 0x08:  // backspace
          {
            stringBuffer[bytes++] = '\\';
            stringBuffer[bytes++] = 'b';
            break;
          }

          case 0x09:  // horizontal tab
          {
            stringBuffer[bytes++] = '\\';
            stringBuffer[bytes++] = 't';
            break;
          }

          case 0x0A:  // newline
          {
            stringBuffer[bytes++] = '\\';
            stringBuffer[bytes++] = 'n';
            break;
          }

          case 0x0C:  // formfeed
          {
            stringBuffer[bytes++] = '\\';
            stringBuffer[bytes++] = 'f';
            break;
          }

          case 0x0D:  // carriage return
          {
            stringBuffer[bytes++] = '\\';
            stringBuffer[bytes++] = 'r';
            break;
          }

          case 0x22:  // quotation mark
          {
            stringBuffer[bytes++] = '&';
            stringBuffer[bytes++] = 'q';
            stringBuffer[bytes++] = 'u';
            stringBuffer[bytes++] = 'o';
            stringBuffer[bytes++] = 't';
            stringBuffer[bytes++] = ';';
            break;
          }

          case 0x27:  // apostrophe
          {
            stringBuffer[bytes++] = '&';
            stringBuffer[bytes++] = 'a';
            stringBuffer[bytes++] = 'p';
            stringBuffer[bytes++] = 'o';
            stringBuffer[bytes++] = 's';
            stringBuffer[bytes++] = ';';
            break;
          }

          case 0x26:  // ampersand
          {
            stringBuffer[bytes++] = '&';
            stringBuffer[bytes++] = 'a';
            stringBuffer[bytes++] = 'm';
            stringBuffer[bytes++] = 'p';
            stringBuffer[bytes++] = ';';
            break;
          }

          case 0x3C:  // less than
          {
            stringBuffer[bytes++] = '\\';
            stringBuffer[bytes++] = 'l';
            stringBuffer[bytes++] = 't';
            stringBuffer[bytes++] = ';';
            break;
          }

          case 0x3E:  // greater than
          {
            stringBuffer[bytes++] = '\\';
            stringBuffer[bytes++] = 'g';
            stringBuffer[bytes++] = 't';
            stringBuffer[bytes++] = ';';
            break;
          }

          default: {
            // escape control characters (0x00..0x1F)
            if ((codePoint <= 0x1F) or (codePoint >= 0x7F)) {
              if (codePoint <= 0xFFFF) {
                // NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg)
                std::snprintf(stringBuffer.data() + bytes, 7, "\\u%04x",
                              static_cast<uint16_t>(codePoint));
                bytes += 6;
              } else {
                // NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg)
                std::snprintf(
                    stringBuffer.data() + bytes, 13, "\\u%04x\\u%04x",
                    static_cast<uint16_t>(0xD7C0 + (codePoint >> 10)),
                    static_cast<uint16_t>(0xDC00 + (codePoint & 0x3FF)));
                bytes += 12;
              }
            } else {
              // copy byte to buffer (all previous bytes
              // been copied have in default case above)
              stringBuffer[bytes++] = str[i];
            }
            break;
          }
        }

        // write buffer and reset index; there must be 13 bytes
        // left, as this is the maximal number of bytes to be
        // written ("\uxxxx\uxxxx\0") for one code point
        if (stringBuffer.size() - bytes < 13) {
          out.append(stringBuffer.data(), bytes);
          bytes = 0;
        }

        // remember the byte position of this accept
        bytesAfterLastAccept = bytes;
        undumpedChars = 0;
        break;
      }

      case utf8Reject:  // decode found invalid UTF-8 byte
      {
        // in case we saw this character the first time, we
        // would like to read it again, because the byte
        // may be OK for itself, but just not OK for the
        // previous sequence
        if (undumpedChars > 0) {
          --i;
        }

        // reset length buffer to the last accepted index;
        // thus removing/ignoring the invalid characters
        bytes = bytesAfterLastAccept;

        stringBuffer[bytes++] = '\\';
        stringBuffer[bytes++] = 'u';
        stringBuffer[bytes++] = 'f';
        stringBuffer[bytes++] = 'f';
        stringBuffer[bytes++] = 'f';
        stringBuffer[bytes++] = 'd';

        bytesAfterLastAccept = bytes;

        undumpedChars = 0;

        // continue processing the string
        state = utf8Accept;
        break;

        break;
      }

      default:  // decode found yet incomplete multi-byte code point
      {
        ++undumpedChars;
        break;
      }
    }
  }

  // we finished processing the string
  if (state == utf8Accept) {
    // write buffer
    if (bytes > 0) {
      out.append(stringBuffer.data(), bytes);
    }
  } else {
    // write all accepted bytes
    out.append(stringBuffer.data(), bytesAfterLastAccept);
    out += "\\ufffd";
  }
}

inline unsigned int countDigits(uint64_t number) noexcept {
  unsigned int nDigits = 1;
  for (;;) {
    if (number < 10) {
      return nDigits;
    }
    if (number < 100) {
      return nDigits + 1;
    }
    if (number < 1000) {
      return nDigits + 2;
    }
    if (number < 10000) {
      return nDigits + 3;
    }
    number = number / 10000U;
    nDigits += 4;
  }
}

template <typename NumberType,
          std::enable_if_t<std::is_same<NumberType, uint64_t>::value or
                               std::is_same<NumberType, int64_t>::value,
                           int> = 0>
void dumpInteger(std::string& out, NumberType number) {
  std::array<char, 64> numberbuffer{{}};

  static constexpr std::array<std::array<char, 2>, 100> digitsTo99{{
      {'0', '0'}, {'0', '1'}, {'0', '2'}, {'0', '3'}, {'0', '4'}, {'0', '5'},
      {'0', '6'}, {'0', '7'}, {'0', '8'}, {'0', '9'}, {'1', '0'}, {'1', '1'},
      {'1', '2'}, {'1', '3'}, {'1', '4'}, {'1', '5'}, {'1', '6'}, {'1', '7'},
      {'1', '8'}, {'1', '9'}, {'2', '0'}, {'2', '1'}, {'2', '2'}, {'2', '3'},
      {'2', '4'}, {'2', '5'}, {'2', '6'}, {'2', '7'}, {'2', '8'}, {'2', '9'},
      {'3', '0'}, {'3', '1'}, {'3', '2'}, {'3', '3'}, {'3', '4'}, {'3', '5'},
      {'3', '6'}, {'3', '7'}, {'3', '8'}, {'3', '9'}, {'4', '0'}, {'4', '1'},
      {'4', '2'}, {'4', '3'}, {'4', '4'}, {'4', '5'}, {'4', '6'}, {'4', '7'},
      {'4', '8'}, {'4', '9'}, {'5', '0'}, {'5', '1'}, {'5', '2'}, {'5', '3'},
      {'5', '4'}, {'5', '5'}, {'5', '6'}, {'5', '7'}, {'5', '8'}, {'5', '9'},
      {'6', '0'}, {'6', '1'}, {'6', '2'}, {'6', '3'}, {'6', '4'}, {'6', '5'},
      {'6', '6'}, {'6', '7'}, {'6', '8'}, {'6', '9'}, {'7', '0'}, {'7', '1'},
      {'7', '2'}, {'7', '3'}, {'7', '4'}, {'7', '5'}, {'7', '6'}, {'7', '7'},
      {'7', '8'}, {'7', '9'}, {'8', '0'}, {'8', '1'}, {'8', '2'}, {'8', '3'},
      {'8', '4'}, {'8', '5'}, {'8', '6'}, {'8', '7'}, {'8', '8'}, {'8', '9'},
      {'9', '0'}, {'9', '1'}, {'9', '2'}, {'9', '3'}, {'9', '4'}, {'9', '5'},
      {'9', '6'}, {'9', '7'}, {'9', '8'}, {'9', '9'},
  }};

  // special case for "0"
  if (number == 0) {
    out += '0';
    return;
  }

  // use a pointer to fill the buffer
  auto* bufferPtr = begin(numberbuffer);

  const bool isNegative = std::is_same<NumberType, int64_t>::value &&
                          !(number >= 0);  // see issue #755
  uint64_t absValue = 0;

  unsigned int nChars = 0;

  if (isNegative) {
    *bufferPtr = '-';
    absValue = static_cast<uint64_t>(0 - number);

    // account one more byte for the minus sign
    nChars = 1 + countDigits(absValue);
  } else {
    absValue = static_cast<uint64_t>(number);
    nChars = countDigits(absValue);
  }

  // spare 1 byte for '\0'
  if (nChars >= numberbuffer.size() - 1) {
    return;
  }

  // jump to the end to generate the string from backward
  // so we later avoid reversing the result
  // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-pointer-arithmetic)
  bufferPtr += nChars;

  // Fast int2ascii implementation inspired by "Fastware" talk by Andrei
  // Alexandrescu See: https://www.youtube.com/watch?v=o4-CwDo2zpg
  while (absValue >= 100) {
    const auto digitsIndex = static_cast<unsigned>((absValue % 100));
    absValue /= 100;
    // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-pointer-arithmetic)
    *(--bufferPtr) = digitsTo99[digitsIndex][1];
    // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-pointer-arithmetic)
    *(--bufferPtr) = digitsTo99[digitsIndex][0];
  }

  if (absValue >= 10) {
    const auto digitsIndex = static_cast<unsigned>(absValue);
    // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-pointer-arithmetic)
    *(--bufferPtr) = digitsTo99[digitsIndex][1];
    // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-pointer-arithmetic)
    *(--bufferPtr) = digitsTo99[digitsIndex][0];
  } else {
    // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-pointer-arithmetic)
    *(--bufferPtr) = static_cast<char>('0' + absValue);
  }

  out.append(numberbuffer.data(), nChars);
}

inline void dumpfloat(std::string& out, double number,
                      std::true_type /*isIeeeSingleOrDouble*/) {
  std::array<char, 64> numberbuffer{{}};
  char* begin = numberbuffer.data();

  // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-pointer-arithmetic)
  ::nlohmann::detail::to_chars(begin, begin + numberbuffer.size(), number);

  out += begin;
}

inline void dumpfloat(std::string& out, double number,
                      std::false_type /*isIeeeSingleOrDouble*/) {
  std::array<char, 64> numberbuffer{{}};
  // get number of digits for a float -> text -> float round-trip
  static constexpr auto d = std::numeric_limits<double>::max_digits10;

  // the actual conversion
  // NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg)
  std::ptrdiff_t len = std::snprintf(numberbuffer.data(), numberbuffer.size(),
                                     "%.*g", d, number);

  // negative value indicates an error
  if (len <= 0) {
    return;
  }

  // check if buffer was large enough
  if (numberbuffer.size() < static_cast<std::size_t>(len)) {
    return;
  }

  std::array<char, 64>::iterator end =
      std::remove(numberbuffer.begin(), numberbuffer.begin() + len, ',');
  std::fill(end, numberbuffer.end(), '\0');

  if ((end - numberbuffer.begin()) > len) {
    return;
  }
  len = (end - numberbuffer.begin());

  out.append(numberbuffer.data(), static_cast<std::size_t>(len));

  // determine if need to append ".0"
  const bool valueIsIntLike =
      std::none_of(numberbuffer.begin(), numberbuffer.begin() + len + 1,
                   [](char c) { return (c == '.' or c == 'e'); });

  if (valueIsIntLike) {
    out += ".0";
  }
}

inline void dumpfloat(std::string& out, double number) {
  // NaN / inf
  if (!std::isfinite(number)) {
    out += "null";
    return;
  }

  // If float is an IEEE-754 single or double precision number,
  // use the Grisu2 algorithm to produce short numbers which are
  // guaranteed to round-trip, using strtof and strtod, resp.
  //
  // NB: The test below works if <long double> == <double>.
  static constexpr bool isIeeeSingleOrDouble =
      (std::numeric_limits<double>::is_iec559 and
       std::numeric_limits<double>::digits == 24 and
       std::numeric_limits<double>::max_exponent == 128) or
      (std::numeric_limits<double>::is_iec559 and
       std::numeric_limits<double>::digits == 53 and
       std::numeric_limits<double>::max_exponent == 1024);

  dumpfloat(out, number, std::integral_constant<bool, isIeeeSingleOrDouble>());
}

inline void dump(std::string& out, const nlohmann::json& val) {
  switch (val.type()) {
    case nlohmann::json::value_t::object: {
      if (val.empty()) {
        out += "{}";
        return;
      }

      out += "{";

      out += "<div class=tab>";
      for (auto i = val.begin(); i != val.end();) {
        out += "&quot";
        dumpEscaped(out, i.key());
        out += "&quot: ";

        bool inATag = false;
        if (i.key() == "@odata.id" || i.key() == "@odata.context" ||
            i.key() == "Members@odata.nextLink" || i.key() == "Uri") {
          inATag = true;
          out += "<a href=\"";
          dumpEscaped(out, i.value());
          out += "\">";
        }
        dump(out, i.value());
        if (inATag) {
          out += "</a>";
        }
        i++;
        if (i != val.end()) {
          out += ",";
        }
        out += "<br>";
      }
      out += "</div>";
      out += '}';

      return;
    }

    case nlohmann::json::value_t::array: {
      if (val.empty()) {
        out += "[]";
        return;
      }

      out += "[";

      out += "<div class=tab>";

      // first n-1 elements
      for (auto i = val.cbegin(); i != val.cend() - 1; ++i) {
        dump(out, *i);
        out += ",<br>";
      }

      // last element
      dump(out, val.back());

      out += "</div>";
      out += ']';

      return;
    }

    case nlohmann::json::value_t::string: {
      out += '\"';
      const std::string* ptr = val.get_ptr<const std::string*>();
      dumpEscaped(out, *ptr);
      out += '\"';
      return;
    }

    case nlohmann::json::value_t::boolean: {
      if (*(val.get_ptr<const bool*>())) {
        out += "true";
      } else {
        out += "false";
      }
      return;
    }

    case nlohmann::json::value_t::number_integer: {
      dumpInteger(out, *(val.get_ptr<const int64_t*>()));
      return;
    }

    case nlohmann::json::value_t::number_unsigned: {
      dumpInteger(out, *(val.get_ptr<const uint64_t*>()));
      return;
    }

    case nlohmann::json::value_t::number_float: {
      dumpfloat(out, *(val.get_ptr<const double*>()));
      return;
    }

    case nlohmann::json::value_t::discarded: {
      out += "<discarded>";
      return;
    }

    case nlohmann::json::value_t::null: {
      out += "null";
      return;
    }
    case nlohmann::json::value_t::binary: {
      // Do nothing;  Should never happen.
      return;
    }
  }
}

inline void dumpHtml(std::string& out, const nlohmann::json& json) {
  out +=
      "<html>\n"
      "<head>\n"
      "<title>Redfish API</title>\n"
      "<link href=\"/redfish.css\" rel=\"stylesheet\">\n"
      "</head>\n"
      "<body>\n"
      "<div class=\"container\">\n"
      "<img src=\"/DMTF_Redfish_logo_2017.svg\" alt=\"redfish\" "
      "height=\"406px\" "
      "width=\"576px\">\n"
      "<div class=\"content\">\n";
  dump(out, json);
  out +=
      "</div>\n"
      "</div>\n"
      "</body>\n"
      "</html>\n";
}
// NOLINTEND

}  // namespace json_html_util

#endif  // THIRD_PARTY_GBMCWEB_INCLUDE_JSON_HTML_SERIALIZER_H_