MalachScript/extern/format.hpp

#pragma once

#include <algorithm>
#include <iomanip>
#include <iostream>
#include <sstream>
#include <stdlib.h>
#include <string>
#include <vector>

namespace util {
    class ArgBase {
    public:
        ArgBase() {}
        virtual ~ArgBase() {}
        virtual void Format(std::ostringstream& ss, const std::string& fmt) = 0;
    };

    template <class T> class Arg : public ArgBase {
    public:
        Arg(T arg) : m_arg(arg) {}
        virtual ~Arg() {}
        virtual void Format(std::ostringstream& ss, const std::string&) { ss << m_arg; }

    private:
        T m_arg;
    };

    class ArgArray : public std::vector<ArgBase*> {
    public:
        ArgArray() {}
        ~ArgArray() {
            std::for_each(begin(), end(), [](ArgBase* p) { delete p; });
        }
    };

    static void FormatItem(std::ostringstream& ss, const std::string& item, const ArgArray& args) {
        int index = 0;
        int alignment = 0;
        std::string fmt;

        char* endptr = nullptr;
        index = strtol(&item[0], &endptr, 10);
        if (index >= (int)args.size()) {
            return;
        }
        if (index < 0) {
            index = args.size() + index;
        }

        if (*endptr == ',') {
            alignment = strtol(endptr + 1, &endptr, 10);
            if (alignment > 0) {
                ss << std::right << std::setw(alignment);
            } else if (alignment < 0) {
                ss << std::left << std::setw(-alignment);
            }
        }

        if (*endptr == ':') {
            fmt = endptr + 1;
        }
        if (*endptr == '.' && *(endptr + 1) == '.') {
            auto endIndex = strtol(endptr + 2, &endptr, 10);
            if (endIndex < 0) {
                endIndex = args.size() + endIndex + 1;
            }

            for (; index < endIndex; index++) {
                args[index]->Format(ss, fmt);
                if (index != endIndex - 1) {
                    ss << ", ";
                }
            }
        } else {
            args[index]->Format(ss, fmt);
        }

        return;
    }

    template <class T> static void Transfer(ArgArray& argArray, T t) { argArray.push_back(new Arg<T>(t)); }

    template <class T, typename... Args> static void Transfer(ArgArray& argArray, T t, Args&&... args) {
        Transfer(argArray, t);
        Transfer(argArray, args...);
    }

    template <typename... Args> std::string Format(const std::string& format, Args&&... args) {
        if (sizeof...(args) == 0) {
            return format;
        }

        ArgArray argArray;
        Transfer(argArray, args...);
        size_t start = 0;
        size_t pos = 0;
        std::ostringstream ss;
        while (true) {
            pos = format.find('{', start);
            if (pos == std::string::npos) {
                ss << format.substr(start);
                break;
            }

            ss << format.substr(start, pos - start);
            if (format[pos + 1] == '{') {
                ss << '{';
                start = pos + 2;
                continue;
            }

            start = pos + 1;
            pos = format.find('}', start);
            if (pos == std::string::npos) {
                ss << format.substr(start - 1);
                break;
            }

            FormatItem(ss, format.substr(start, pos - start), argArray);
            start = pos + 1;
        }

        return ss.str();
    }

    std::string Format(const std::string& format, const std::vector<std::string>& args) {
        if (args.size() == 0) {
            return format;
        }

        ArgArray argArray;
        for (const auto& arg : args) {
            Transfer(argArray, arg);
        }
        size_t start = 0;
        size_t pos = 0;
        std::ostringstream ss;
        while (true) {
            pos = format.find('{', start);
            if (pos == std::string::npos) {
                ss << format.substr(start);
                break;
            }

            ss << format.substr(start, pos - start);
            if (format[pos + 1] == '{') {
                ss << '{';
                start = pos + 2;
                continue;
            }

            start = pos + 1;
            pos = format.find('}', start);
            if (pos == std::string::npos) {
                ss << format.substr(start - 1);
                break;
            }

            FormatItem(ss, format.substr(start, pos - start), argArray);
            start = pos + 1;
        }

        return ss.str();
    }

}