/*
 * Copyright (c) 2016-present The ZLMediaKit project authors. All Rights Reserved.
 *
 * This file is part of ZLMediaKit(https://github.com/ZLMediaKit/ZLMediaKit).
 *
 * Use of this source code is governed by MIT-like license that can be found in the
 * LICENSE file in the root of the source tree. All contributing project authors
 * may be found in the AUTHORS file in the root of the source tree.
 */

#include <string.h>
#include "strCoding.h"

#if defined(_WIN32)
#include <windows.h> 
#endif//defined(_WIN32)

using namespace std;

namespace mediakit {

//////////////////////////通用///////////////////////
void UTF8ToUnicode(wchar_t *pOut, const char *pText) {
    char *uchar = (char *) pOut;
    uchar[1] = ((pText[0] & 0x0F) << 4) + ((pText[1] >> 2) & 0x0F);
    uchar[0] = ((pText[1] & 0x03) << 6) + (pText[2] & 0x3F);
    return;
}

void UnicodeToUTF8(char *pOut, const wchar_t *pText) {
    // 注意 WCHAR高低字的顺序,低字节在前，高字节在后 
    const char *pchar = (const char *) pText;
    pOut[0] = (0xE0 | ((pchar[1] & 0xF0) >> 4));
    pOut[1] = (0x80 | ((pchar[1] & 0x0F) << 2)) + ((pchar[0] & 0xC0) >> 6);
    pOut[2] = (0x80 | (pchar[0] & 0x3F));
    return;
}

char HexCharToBin(char ch) {
    if (ch >= '0' && ch <= '9') return (char)(ch - '0');
    if (ch >= 'a' && ch <= 'f') return (char)(ch - 'a' + 10);
    if (ch >= 'A' && ch <= 'F') return (char)(ch - 'A' + 10);
    return -1;
}

char HexStrToBin(const char *str) {
    auto high = HexCharToBin(str[0]);
    auto low = HexCharToBin(str[1]);
    if (high == -1 || low == -1) {
        // 无法把16进制字符串转换为二进制
        return -1;
    }
    return (high << 4) | low;
}

string strCoding::UrlEncodePath(const string &str) {
    const char *dont_escape = "!#&'*+:=?@/._-$,;~()";
    string out;
    size_t len = str.size();
    for (size_t i = 0; i < len; ++i) {
        char ch = str[i];
        if (isalnum((uint8_t) ch) || strchr(dont_escape, (uint8_t) ch) != NULL) {
            out.push_back(ch);
        } else {
            char buf[4];
            snprintf(buf, 4, "%%%X%X", (uint8_t) ch >> 4, (uint8_t) ch & 0x0F);
            out.append(buf);
        }
    }
    return out;
}

string strCoding::UrlEncodeComponent(const string &str) {
    const char *dont_escape = "!'()*-._~";
    string out;
    size_t len = str.size();
    for (size_t i = 0; i < len; ++i) {
        char ch = str[i];
        if (isalnum((uint8_t) ch) || strchr(dont_escape, (uint8_t) ch) != NULL) {
            out.push_back(ch);
        } else {
            char buf[4];
            snprintf(buf, 4, "%%%X%X", (uint8_t) ch >> 4, (uint8_t) ch & 0x0F);
            out.append(buf);
        }
    }
    return out;
}

string strCoding::UrlDecodePath(const string &str) {
    const char *dont_unescape = "#$&+,/:;=?@";
    string output;
    size_t i = 0, len = str.length();
    while (i < len) {
        if (str[i] == '%') {
            if (i + 3 > len) {
                // %后面必须还有两个字节才会反转义
                output.append(str, i, len - i);
                break;
            }
            char ch = HexStrToBin(&(str[i + 1]));
            if (ch == -1 || strchr(dont_unescape, (unsigned char)ch) != NULL) {
                // %后面两个字节不是16进制字符串，转义失败；或者转义出来可能会造成url包含非path部分，比如#?，说明提交的是非法拼接的url；直接拼接3个原始字符
                output.append(str, i, 3);
            } else {
                output += ch;
            }
            i += 3;
        } else {
            output += str[i];
            ++i;
        }
    }
    return output;
}

std::string strCoding::UrlDecodeComponent(const std::string &str) {
    string output;
    size_t i = 0, len = str.length();
    while (i < len) {
        if (str[i] == '%') {
            if (i + 3 > len) {
                // %后面必须还有两个字节才会反转义
                output.append(str, i, len - i);
                break;
            }
            char ch = HexStrToBin(&(str[i + 1]));
            if (ch == -1) {
                // %后面两个字节不是16进制字符串，转义失败；直接拼接3个原始字符
                output.append(str, i, 3);
            } else {
                output += ch;
            }
            i += 3;
        } else if (str[i] == '+') {
            output += ' ';
            ++i;
        } else {
            output += str[i];
            ++i;
        }
    }
    return output;
}

///////////////////////////////windows专用///////////////////////////////////
#if defined(_WIN32)
void UnicodeToGB2312(char* pOut, wchar_t uData)
{
    WideCharToMultiByte(CP_ACP, NULL, &uData, 1, pOut, sizeof(wchar_t), NULL, NULL);
}
void Gb2312ToUnicode(wchar_t* pOut, const char *gbBuffer)
{
    MultiByteToWideChar(CP_ACP, MB_PRECOMPOSED, gbBuffer, 2, pOut, 1);
}

string strCoding::UTF8ToGB2312(const string &str) {
    auto len = str.size();
    auto pText = str.data();
    char Ctemp[4] = {0};
    char *pOut = new char[len + 1];
    memset(pOut, 0, len + 1);

    int i = 0, j = 0;
    while (i < len)
    {
        if (pText[i] >= 0)
        {
            pOut[j++] = pText[i++];
        }
        else
        {
            wchar_t Wtemp;
            UTF8ToUnicode(&Wtemp, pText + i);
            UnicodeToGB2312(Ctemp, Wtemp);
            pOut[j] = Ctemp[0];
            pOut[j + 1] = Ctemp[1];
            i += 3;
            j += 2;
        }
    }
    string ret = pOut;
    delete[] pOut;
    return ret;
}

string strCoding::GB2312ToUTF8(const string &str) {
    auto len = str.size();
    auto pText = str.data();
    char buf[4] = { 0 };
    auto nLength = len * 3;
    char* pOut = new char[nLength];
    memset(pOut, 0, nLength);
    size_t i = 0, j = 0;
    while (i < len)
    {
        //如果是英文直接复制就可以   
        if (*(pText + i) >= 0)
        {
            pOut[j++] = pText[i++];
        }
        else
        {
            wchar_t pbuffer;
            Gb2312ToUnicode(&pbuffer, pText + i);
            UnicodeToUTF8(buf, &pbuffer);
            pOut[j] = buf[0];
            pOut[j + 1] = buf[1];
            pOut[j + 2] = buf[2];
            j += 3;
            i += 2;
        }
    }   
    string ret = pOut;
    delete[] pOut;
    return ret;
}
#endif//defined(_WIN32)

} /* namespace mediakit */