#include "StringUtility.h"
#include "BoostLog.h"
#include <cctype>
#include <codecvt>
#ifdef WIN32
#include <Windows.h>
#endif

namespace Amass {

namespace StringUtility {

std::string &replace(std::string &string, const std::string &before, const std::string &after) {
    for (size_t pos = 0; pos != std::string::npos; pos += after.length()) {
        pos = string.find(before, pos);
        if (pos != std::string::npos)
            string.replace(pos, before.length(), after);
        else
            break;
    }
    return string;
}

size_t utf8Length(const std::string &text) {
    size_t ret = 0;
    for (uint32_t i = 0; i < text.length();) {
        uint32_t byte_length = utf8CharacterByteSize(text.c_str() + i);
        ret++;
        i += byte_length;
    }
    return ret;
}

std::string_view utf8At(const std::string &text, size_t index) {
    const char *ret = text.c_str();
    for (uint32_t i = 0; i < index; i++) {
        uint32_t byte_length = utf8CharacterByteSize(ret);
        ret += byte_length;
    }
    return std::string_view(ret, utf8CharacterByteSize(ret));
}

size_t utf8CharacterByteSize(const char *character) {
    if (character == nullptr) return 0;
    uint32_t ret = 0;
    uint8_t temp = character[0];
    while (temp & 0x80) {
        ret++;
        temp <<= 1;
    }
    return ret > 0 ? ret : 1;
}

std::wstring stringToWString(const std::string &string) {
    std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> converter;
    return converter.from_bytes(string);
}

std::string wstringToString(const std::wstring &string) {
#ifdef WIN32
    int sizeNeeded = WideCharToMultiByte(CP_UTF8, 0, string.c_str(), string.size(), NULL, 0, NULL, NULL);
    std::string ret(sizeNeeded, 0);
    WideCharToMultiByte(CP_UTF8, 0, string.c_str(), string.size(), &ret[0], sizeNeeded, NULL, NULL);
#else
    std::string ret;
    assert(false && "not implement.");
#endif
    return ret;
}

bool equal(std::string_view lhs, std::string_view rhs, bool caseSensitivity) {
    auto n = lhs.size();
    if (rhs.size() != n) return false;
    auto p1 = lhs.data();
    auto p2 = rhs.data();
    char a, b;

    while (n--) { // fast loop
        a = *p1++;
        b = *p2++;
        if (a != b) {
            if (caseSensitivity) {
                return false;
            } else {
                goto slow;
            }
        }
    }
    return true;
slow:
    do {
        if (std::tolower(a) != std::tolower(b)) return false;
        a = *p1++;
        b = *p2++;
    } while (n--);
    return true;
}

std::string UTF8ToGBK(const std::string &utf8Str) {
    int wideStrLen = MultiByteToWideChar(CP_UTF8, 0, utf8Str.c_str(), -1, NULL, 0);
    if (wideStrLen == 0) {
        return "";
    }

    std::wstring wideStr(wideStrLen, 0);
    MultiByteToWideChar(CP_UTF8, 0, utf8Str.c_str(), -1, &wideStr[0], wideStrLen);

    int gbkStrLen = WideCharToMultiByte(CP_ACP, 0, wideStr.c_str(), -1, NULL, 0, NULL, NULL);
    if (gbkStrLen == 0) {
        return "";
    }

    std::string gbkStr(gbkStrLen, 0);
    WideCharToMultiByte(CP_ACP, 0, wideStr.c_str(), -1, &gbkStr[0], gbkStrLen, NULL, NULL);

    return gbkStr;
}

} // namespace StringUtility
} // namespace Amass