#include <stdinc.hpp>
#include "loader/component_loader.hpp"

#include "game/structs.hpp"
#include "game/game.hpp"

#include "gsc.hpp"

#include <utils/io.hpp>
#include <uchar.h>

// lua/lstrlib.c
#define MAX_FORMAT	32
#define L_FMTFLAGSF	"-+#0 "
#define L_FMTFLAGSX	"-#0"
#define L_FMTFLAGSI	"-+0 "
#define L_FMTFLAGSU	"-0"
#define L_FMTFLAGSC	"-"

namespace string
{
    namespace
    {
        // lua/lstrlib.c
        const char* getformat(const char* strfrmt, char* form) 
        {
            const auto len = std::strspn(strfrmt, L_FMTFLAGSF "123456789.") + 1;
            if (len >= MAX_FORMAT - 10)
            {
                throw std::runtime_error("invalid format (too long)");
            }

            *(form++) = '%';
            std::memcpy(form, strfrmt, len * sizeof(char));
            *(form + len) = '\0';
            return strfrmt + len - 1;
        }

        // lua/lstrlib.c
        const char* get_2_digits(const char* s) 
        {
            if (isdigit(static_cast<unsigned char>(*s))) 
            {
                s++;
                if (isdigit(static_cast<unsigned char>(*s)))
                {
                    s++;
                }
            }

            return s;
        }

        // lua/lstrlib.c
        void check_format(const char* form, const char* flags, int precision) 
        {
            const char* spec = form + 1;
            spec += std::strspn(spec, flags);
            if (*spec != '0') 
            {
                spec = get_2_digits(spec);
                if (*spec == '.' && precision) 
                {
                    spec++;
                    spec = get_2_digits(spec);
                }
            }
            if (!std::isalpha(static_cast<unsigned char>(*spec)))
            {
                throw std::runtime_error(utils::string::va("invalid conversion specification: '%s'", form));
            }
        }

        // partially lua/lstrlib.c
        std::string format_string(const std::string& fmt, const scripting::variadic_args& va)
        {
            std::string buffer{};
            size_t va_index{};
            const char* strfrmt = fmt.data();
            const char* strfrmt_end = strfrmt + fmt.size();

            while (strfrmt < strfrmt_end)
            {
                if (*strfrmt != '%')
                {
                    buffer.push_back(*strfrmt++);
                }
                else if (*++strfrmt == '%')
                {
                    buffer.push_back(*strfrmt++);
                }
                else
                {
                    char form[MAX_FORMAT]{};
                    const char* flags = "";
                    strfrmt = getformat(strfrmt, form);

                    switch (*strfrmt++)
                    {
                    case 'd':
                    case 'i':
                        flags = L_FMTFLAGSI;
                        goto intcase;
                    case 'u':
                    case 'p':
                        flags = L_FMTFLAGSU;
                        goto intcase;
                    case 'o':
                    case 'x':
                    case 'X':
                        flags = L_FMTFLAGSX;
                    intcase:
                    {
                        check_format(form, flags, 1);
                        const auto value = va[va_index].as<int>();
                        buffer.append(utils::string::va(form, value));
                        va_index++;
                        break;
                    }
                    case 'f':
                    case 'F':
                    case 'e':
                    case 'E':
                    case 'g':
                    case 'G':
                    {
                        check_format(form, L_FMTFLAGSF, 1);
                        const auto value = va[va_index].as<float>();
                        buffer.append(utils::string::va(form, value));
                        va_index++;
                        break;
                    }
                    case 'c':
                    {
                        const auto value = va[va_index].as<int>();
                        check_format(form, L_FMTFLAGSC, 0);
                        buffer.append(utils::string::va(form, static_cast<char>(value)));
                        va_index++;
                        break;
                    }
                    case 's':
                    {
                        const auto str = va[va_index].as<std::string>();
                        buffer.append(str);
                        va_index++;
                        break;
                    }
                    default:
                    {
                        throw std::runtime_error(utils::string::va("invalid conversion '%s' to 'format'", form));
                    }
                    }
                }
            }

            return buffer;
        }
    }

    class component final : public component_interface
    {
    public:
        void post_unpack() override
        {
            gsc::function::add_multiple(format_string, "va", "string::va", 
                "formatstring", "string::format", "sprintf");

            gsc::function::add("printf", [](const std::string& fmt, const scripting::variadic_args& va)
            {
                printf("%s", format_string(fmt, va).data());
            });

            gsc::function::add("print", [](const scripting::variadic_args& va)
            {
                for (const auto& arg : va)
                {
                    printf("%s\t", arg.to_string().data());
                }
                printf("\n");
            });

            gsc::function::add_multiple(utils::string::to_upper, "toupper", "string::to_upper");
            gsc::function::add_multiple(utils::string::to_lower, "tolower", "string::to_lower");

            gsc::function::add("string::is_numeric", utils::string::is_numeric);
            gsc::function::add("string::start_swith", utils::string::starts_with);
            gsc::function::add("string::ends_with", utils::string::ends_with);
            gsc::function::add("string::replace", utils::string::replace);

            gsc::function::add("string::regex_replace", [](const std::string& str, const std::regex& expr, 
                const std::string& with)
            {
                return std::regex_replace(str, expr, with);
            });

            gsc::function::add("string::regex_match", [](const std::string& str, const std::regex& expr)
            {
                scripting::array array_match{};
                std::smatch match{};

                if (std::regex_match(str, match, std::regex(expr)))
                {
                    for (const auto& s : match)
                    {
                        array_match.push((s.str()));
                    }
                }

                return array_match;
            });

            gsc::function::add("string::regex_search", [](const std::string& str, const std::regex& expr)
            {
                return std::regex_search(str, expr);
            });
        }
    };
}

REGISTER_COMPONENT(string::component)