#pragma once

#include <algorithm> // reverse, remove, fill, find, none_of
#include <array> // array
#include <cassert> // assert
#include <ciso646> // and, or
#include <clocale> // localeconv, lconv
#include <cmath> // labs, isfinite, isnan, signbit
#include <cstddef> // size_t, ptrdiff_t
#include <cstdint> // uint8_t
#include <cstdio> // snprintf
#include <limits> // numeric_limits
#include <string> // string
#include <type_traits> // is_same

#include <nlohmann/detail/exceptions.hpp>
#include <nlohmann/detail/conversions/to_chars.hpp>
#include <nlohmann/detail/macro_scope.hpp>
#include <nlohmann/detail/meta.hpp>
#include <nlohmann/detail/output/output_adapters.hpp>
#include <nlohmann/detail/value_t.hpp>

namespace nlohmann
{
namespace detail
{
///////////////////
// serialization //
///////////////////

template<typename BasicJsonType>
class primitive_serializer
{
    using string_t = typename BasicJsonType::string_t;
    using number_float_t = typename BasicJsonType::number_float_t;
    using number_integer_t = typename BasicJsonType::number_integer_t;
    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
    static constexpr uint8_t UTF8_ACCEPT = 0;
    static constexpr uint8_t UTF8_REJECT = 1;
    using output_adapter_protocol_t = output_adapter_protocol<char>;

  public:
    /*!
    @param[in] s  output stream to serialize to
    @param[in] ichar  indentation character to use
    */
    primitive_serializer()
        : loc(std::localeconv()),
          thousands_sep(loc->thousands_sep == nullptr ? '\0' : * (loc->thousands_sep)),
          decimal_point(loc->decimal_point == nullptr ? '\0' : * (loc->decimal_point))
    {}

    // delete because of pointer members
    primitive_serializer(const primitive_serializer&) = delete;
    primitive_serializer& operator=(const primitive_serializer&) = delete;

    /*!
    @brief dump escaped string

    Escape a string by replacing certain special characters by a sequence of an
    escape character (backslash) and another character and other control
    characters by a sequence of "\u" followed by a four-digit hex
    representation. The escaped string is written to output stream @a o.

    @param[in] s  the string to escape
    @param[in] ensure_ascii  whether to escape non-ASCII characters with
                             \uXXXX sequences

    @complexity Linear in the length of string @a s.
    */
    void dump_escaped(output_adapter_protocol_t& o, const string_t& s, const bool ensure_ascii)
    {
        uint32_t codepoint;
        uint8_t state = UTF8_ACCEPT;
        std::size_t bytes = 0;  // number of bytes written to string_buffer

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

            switch (decode(state, codepoint, byte))
            {
                case UTF8_ACCEPT:  // decode found a new code point
                {
                    switch (codepoint)
                    {
                        case 0x08: // backspace
                        {
                            string_buffer[bytes++] = '\\';
                            string_buffer[bytes++] = 'b';
                            break;
                        }

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

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

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

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

                        case 0x22: // quotation mark
                        {
                            string_buffer[bytes++] = '\\';
                            string_buffer[bytes++] = '\"';
                            break;
                        }

                        case 0x5C: // reverse solidus
                        {
                            string_buffer[bytes++] = '\\';
                            string_buffer[bytes++] = '\\';
                            break;
                        }

                        default:
                        {
                            // escape control characters (0x00..0x1F) or, if
                            // ensure_ascii parameter is used, non-ASCII characters
                            if ((codepoint <= 0x1F) or (ensure_ascii and (codepoint >= 0x7F)))
                            {
                                if (codepoint <= 0xFFFF)
                                {
                                    std::snprintf(string_buffer.data() + bytes, 7, "\\u%04x",
                                                  static_cast<uint16_t>(codepoint));
                                    bytes += 6;
                                }
                                else
                                {
                                    std::snprintf(string_buffer.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)
                                string_buffer[bytes++] = s[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 (string_buffer.size() - bytes < 13)
                    {
                        o.write_characters(string_buffer.data(), bytes);
                        bytes = 0;
                    }
                    break;
                }

                case UTF8_REJECT:  // decode found invalid UTF-8 byte
                {
                    std::string sn(3, '\0');
                    snprintf(&sn[0], sn.size(), "%.2X", byte);
                    JSON_THROW(type_error::create(316, "invalid UTF-8 byte at index " + std::to_string(i) + ": 0x" + sn));
                }

                default:  // decode found yet incomplete multi-byte code point
                {
                    if (not ensure_ascii)
                    {
                        // code point will not be escaped - copy byte to buffer
                        string_buffer[bytes++] = s[i];
                    }
                    break;
                }
            }
        }

        if (JSON_LIKELY(state == UTF8_ACCEPT))
        {
            // write buffer
            if (bytes > 0)
            {
                o.write_characters(string_buffer.data(), bytes);
            }
        }
        else
        {
            // we finish reading, but do not accept: string was incomplete
            std::string sn(3, '\0');
            snprintf(&sn[0], sn.size(), "%.2X", static_cast<uint8_t>(s.back()));
            JSON_THROW(type_error::create(316, "incomplete UTF-8 string; last byte: 0x" + sn));
        }
    }

    /*!
    @brief dump an integer

    Dump a given integer to output stream @a o. Works internally with
    @a number_buffer.

    @param[in] x  integer number (signed or unsigned) to dump
    @tparam NumberType either @a number_integer_t or @a number_unsigned_t
    */
    template<typename NumberType, detail::enable_if_t<
                 std::is_same<NumberType, number_unsigned_t>::value or
                 std::is_same<NumberType, number_integer_t>::value,
                 int> = 0>
    void dump_integer(output_adapter_protocol_t& o, NumberType x)
    {
        // special case for "0"
        if (x == 0)
        {
            o.write_character('0');
            return;
        }

        const bool is_negative = (x <= 0) and (x != 0);  // see issue #755
        std::size_t i = 0;

        while (x != 0)
        {
            // spare 1 byte for '\0'
            assert(i < number_buffer.size() - 1);

            const auto digit = std::labs(static_cast<long>(x % 10));
            number_buffer[i++] = static_cast<char>('0' + digit);
            x /= 10;
        }

        if (is_negative)
        {
            // make sure there is capacity for the '-'
            assert(i < number_buffer.size() - 2);
            number_buffer[i++] = '-';
        }

        std::reverse(number_buffer.begin(), number_buffer.begin() + i);
        o.write_characters(number_buffer.data(), i);
    }

    /*!
    @brief dump a floating-point number

    Dump a given floating-point number to output stream @a o. Works internally
    with @a number_buffer.

    @param[in] x  floating-point number to dump
    */
    void dump_float(output_adapter_protocol_t& o, number_float_t x)
    {
        // NaN / inf
        if (not std::isfinite(x))
        {
            o.write_characters("null", 4);
            return;
        }

        // If number_float_t 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 is_ieee_single_or_double
            = (std::numeric_limits<number_float_t>::is_iec559 and std::numeric_limits<number_float_t>::digits == 24 and std::numeric_limits<number_float_t>::max_exponent == 128) or
              (std::numeric_limits<number_float_t>::is_iec559 and std::numeric_limits<number_float_t>::digits == 53 and std::numeric_limits<number_float_t>::max_exponent == 1024);

        dump_float(o, x, std::integral_constant<bool, is_ieee_single_or_double>());
    }

  private:
    void dump_float(output_adapter_protocol_t& o, number_float_t x, std::true_type /*is_ieee_single_or_double*/)
    {
        char* begin = number_buffer.data();
        char* end = ::nlohmann::detail::to_chars(begin, begin + number_buffer.size(), x);

        o.write_characters(begin, static_cast<size_t>(end - begin));
    }

    void dump_float(output_adapter_protocol_t& o, number_float_t x, std::false_type /*is_ieee_single_or_double*/)
    {
        // get number of digits for a float -> text -> float round-trip
        static constexpr auto d = std::numeric_limits<number_float_t>::max_digits10;

        // the actual conversion
        std::ptrdiff_t len = snprintf(number_buffer.data(), number_buffer.size(), "%.*g", d, x);

        // negative value indicates an error
        assert(len > 0);
        // check if buffer was large enough
        assert(static_cast<std::size_t>(len) < number_buffer.size());

        // erase thousands separator
        if (thousands_sep != '\0')
        {
            const auto end = std::remove(number_buffer.begin(),
                                         number_buffer.begin() + len, thousands_sep);
            std::fill(end, number_buffer.end(), '\0');
            assert((end - number_buffer.begin()) <= len);
            len = (end - number_buffer.begin());
        }

        // convert decimal point to '.'
        if (decimal_point != '\0' and decimal_point != '.')
        {
            const auto dec_pos = std::find(number_buffer.begin(), number_buffer.end(), decimal_point);
            if (dec_pos != number_buffer.end())
            {
                *dec_pos = '.';
            }
        }

        o.write_characters(number_buffer.data(), static_cast<std::size_t>(len));

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

        if (value_is_int_like)
        {
            o.write_characters(".0", 2);
        }
    }

    /*!
    @brief check whether a string is UTF-8 encoded

    The function checks each byte of a string whether it is UTF-8 encoded. The
    result of the check is stored in the @a state parameter. The function must
    be called initially with state 0 (accept). State 1 means the string must
    be rejected, because the current byte is not allowed. If the string is
    completely processed, but the state is non-zero, the string ended
    prematurely; that is, the last byte indicated more bytes should have
    followed.

    @param[in,out] state  the state of the decoding
    @param[in,out] codep  codepoint (valid only if resulting state is UTF8_ACCEPT)
    @param[in] byte       next byte to decode
    @return               new state

    @note The function has been edited: a std::array is used.

    @copyright Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de>
    @sa http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
    */
    static uint8_t decode(uint8_t& state, uint32_t& codep, const uint8_t byte) noexcept
    {
        static const std::array<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
            }
        };

        const uint8_t type = utf8d[byte];

        codep = (state != UTF8_ACCEPT)
                ? (byte & 0x3fu) | (codep << 6)
                : static_cast<uint32_t>(0xff >> type) & (byte);

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

  private:
    /// a (hopefully) large enough character buffer
    std::array<char, 64> number_buffer{{}};

    /// the locale
    const std::lconv* loc = nullptr;
    /// the locale's thousand separator character
    const char thousands_sep = '\0';
    /// the locale's decimal point character
    const char decimal_point = '\0';

    /// string buffer
    std::array<char, 512> string_buffer{{}};
};
}
}