11 template enum Log constexpr string_view logGetColor return template

// c++11
template<enum Log>
constexpr string_view logGetColor() {
    return "\e[m";
}

template<>
constexpr string_view logGetColor<Log::General>() {
    return "\e[m";
}

template<>
constexpr string_view logGetColor<Log::Warning>() {
    return "\e[33m";
}

template<>
constexpr string_view logGetColor<Log::Error>() {
    return "\e[31m";
}

template<>
constexpr string_view logGetColor<Log::Alert>() {
    return "\e[41m";
}

template<>
constexpr string_view logGetColor<Log::Debug>() {
    return "\e[2m";
}

constexpr std::size_t strlen_iter(const char *filename, size_t size) {
    return filename[size] == '\0'? size : strlen_iter(filename, size + 1);
}

constexpr std::size_t strlen(const char *filename) {
    return strlen_iter(filename, 0);
}

constexpr std::size_t trimFilePath_loop(const char *filename, std::size_t size) {
    return ((size > 0) && (filename[size] != '/')) ?
                trimFilePath_loop(filename, size - 1) 
            : size;
}

constexpr string_view trimFilePath2(const char *filename, size_t length) {
    return (!length)? filename + length : 
            filename + length + 1;
}

constexpr string_view trimFilePath1(const char *filename, size_t length) {
    return (!length)? 
            filename + length                      
            : filename[length - 1] == '.'? 
                filename + length + 1
                : trimFilePath2(filename, trimFilePath_loop(filename, length - 1));
}

constexpr string_view trimFilePath(const char *filename, size_t length) {
    return trimFilePath1(filename, trimFilePath_loop(filename, length)); 
}

constexpr string_view trimFilePath(const char *filename) {
    return trimFilePath(filename, strlen(filename)); 
}

#define DETAIL_WRITE_LOG_SUM3(a, b, out, COUNTER) static constexpr auto A##COUNTER = (a); static constexpr auto B##COUNTER = (b); static constexpr auto out = A##COUNTER + B##COUNTER;
#define DETAIL_WRITE_LOG_SUM2(a, b, out, COUNTER) DETAIL_WRITE_LOG_SUM3(a, b, out, COUNTER)
#define DETAIL_WRITE_LOG_SUM(a, b, out) DETAIL_WRITE_LOG_SUM2(a, b, out, __COUNTER__)
#define DETAIL_WRITE_LOG(_filename, _line, _type, s_type, _fmt, ...) do {\
    static constexpr string_view view_filename = detail::trimFilePath(_filename);\
    static constexpr auto view_size = view_filename.size(); \
    static constexpr auto color = logGetColor<_type>(); \
    static constexpr auto color_size = color.size(); \
    DETAIL_WRITE_LOG_SUM(make_constexpr_string<color_size>(color.data()), make_constexpr_string("%s "), part1); \
    DETAIL_WRITE_LOG_SUM(part1, make_constexpr_string(s_type), part2); \
    DETAIL_WRITE_LOG_SUM(part2, make_constexpr_string(": "), part3); \
    DETAIL_WRITE_LOG_SUM(part3, make_constexpr_string<view_size>(view_filename.data()), part4); \
    DETAIL_WRITE_LOG_SUM(part4, make_constexpr_string(": "), part5); \
    DETAIL_WRITE_LOG_SUM(part5, make_constexpr_string(_line), part6); \
    DETAIL_WRITE_LOG_SUM(part6, make_constexpr_string(": "), part7); \
    DETAIL_WRITE_LOG_SUM(part7, make_constexpr_string(_fmt), part8); \
    DETAIL_WRITE_LOG_SUM(part8, make_constexpr_string("\e[m\n"), part9); \
    static constexpr auto fmt_ = part9; \
    time_t t;\
    tm now;\
    char time_str[40];\
    std::time(&t);\
    localtime_r(&t, &now);\
    std::strftime(time_str, sizeof(time_str), "%Y-%m-%dT%H:%M:%S", &now);\
    printf(fmt_.data(), time_str,##__VA_ARGS__); \
} while(0)

//c++14

namespace detail {  
constexpr string_view logGetColor(Log type) {
    switch (type) {
        case Log::General: return "\e[m";
        case Log::Warning: return "\e[33m";
        case Log::Error: return "\e[31m";
        case Log::Alert: return "\e[41m";
        case Log::Debug: return "\e[2m";
    }
    return "\e[m";
}

constexpr string_view trimFilePath(const char *filename) {
        size_t length = 0;
        for (; *filename; ++length, ++filename) {}
        
        for (; length > 0 && *filename != '/'; --length, --filename) {}
        
        if (!length) {
            return filename;
        }
        
        if (*(filename-1) == '.') {
            return filename + 1;
        }
        
        for (--filename, --length; length > 0 && *filename != '/'; --length, --filename) {}
        return (!length)? filename : filename + 1;
    }
}

#define DETAIL_WRITE_LOG(_filename, _line, _type, s_type, _fmt, ...) do {\
    static constexpr string_view view_filename = detail::trimFilePath(_filename);\
    static constexpr auto color = detail::logGetColor(_type); \
    static constexpr auto color_size = color.size(); \
    static constexpr auto fmt_ = make_constexpr_string<color_size>(color.data()) + "HOST: %s " + make_constexpr_string(s_type) + ": " + make_constexpr_string<view_filename.size()>(view_filename.data()) + ":" + _line + ": " + _fmt + "\e[m" "\n"; \
    time_t t;\
    tm now;\
    char time_str[256];\
    std::time(&t);\
    localtime_r(&t, &now);\
    std::strftime(time_str, sizeof(time_str), "%Y-%m-%dT%H:%M:%S", &now);\
    printf(fmt_.data(), time_str ,##__VA_ARGS__); \
} while(0)