src/WeChatOcrCpp/Utilities.cpp

#include "Utilities.h"
#include "Constant.h"
#include <Windows.h>
#include <ShlObj.h>
#include <filesystem>
#include <fstream>
#include <iostream>

// 静态成员初始化
const std::string Utilities::WeChatDefaultPath = "C:\\Program Files\\Tencent\\WeChat";
const std::string Utilities::MmMojoDll = "mmmojo.dll";
const std::string Utilities::MmMojo64Dll = "mmmojo_64.dll";

std::string Utilities::GetWeChatDir(const std::string& path)
{
    std::string wechatPath = path.empty() ? WeChatDefaultPath : path;

    // 移除路径末尾的反斜杠
    if (!wechatPath.empty() && wechatPath.back() == '\\')
        wechatPath.pop_back();

    // 根据给定路径下 mmmojo.dll 的存在与否，判断是否为微信完整路径
    std::string dllPath = wechatPath + "\\" + MmMojoDll;
    if (std::filesystem::exists(dllPath))
        return wechatPath;

    // 从注册表中获取微信安装版本并根据参数path拼接微信安装目录
    HKEY hKey;
    if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, "SOFTWARE\\WOW6432Node\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\WeChat", 0, KEY_READ, &hKey) == ERROR_SUCCESS)
    {
        char displayVersion[256] = { 0 };
        DWORD bufferSize = sizeof(displayVersion);
        DWORD type = REG_SZ;

        if (RegQueryValueExA(hKey, "DisplayVersion", NULL, &type, (LPBYTE)displayVersion, &bufferSize) == ERROR_SUCCESS)
        {
            std::string versionDir = wechatPath + "\\[" + displayVersion + "]";
            RegCloseKey(hKey);

            if (std::filesystem::exists(versionDir))
                return versionDir;
        }
        RegCloseKey(hKey);
    }

    return "";
}

std::string Utilities::GetWeChatOcrExePath()
{
    char appDataPath[MAX_PATH];
    if (SUCCEEDED(SHGetFolderPathA(NULL, CSIDL_APPDATA, NULL, 0, appDataPath)))
    {
        std::string searchPath = std::string(appDataPath) + "\\Tencent\\WeChat\\XPlugin\\Plugins\\WeChatOCR";
        
        // 使用 Windows API 查找文件
        WIN32_FIND_DATAA findData;
        std::string searchPattern = searchPath + "\\*";
        HANDLE hFind = FindFirstFileA(searchPattern.c_str(), &findData);
        
        if (hFind != INVALID_HANDLE_VALUE)
        {
            do
            {
                if (findData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
                {
                    if (strcmp(findData.cFileName, ".") != 0 && strcmp(findData.cFileName, "..") != 0)
                    {
                        std::string subDir = searchPath + "\\" + findData.cFileName;
                        std::string exePath = subDir + "\\WeChatOCR.exe";
                        
                        if (std::filesystem::exists(exePath))
                        {
                            FindClose(hFind);
                            return exePath;
                        }
                    }
                }
            } while (FindNextFileA(hFind, &findData));
            
            FindClose(hFind);
        }
    }
    
    return "";
}

void Utilities::WriteBytesToFile(const std::string& filePath, const unsigned char* bytes, size_t length)
{
    std::ofstream fileStream(filePath, std::ios::binary);
    if (fileStream.is_open())
    {
        fileStream.write(reinterpret_cast<const char*>(bytes), length);
        fileStream.close();
    }
}

void Utilities::CopyMmmojoDll(const std::string& wechatFullDir)
{
    char currentDir[MAX_PATH];
    GetCurrentDirectoryA(MAX_PATH, currentDir);
    
    std::string targetPath = std::string(currentDir) + "\\" + Constant::WeChatOcrData;
    
    // 创建目标目录（如果不存在）
    if (!std::filesystem::exists(targetPath))
        std::filesystem::create_directories(targetPath);
    
    std::string mmMojoFullPath = wechatFullDir + "\\" + MmMojoDll;
    std::string mmMojo64FullPath = wechatFullDir + "\\" + MmMojo64Dll;
    std::string targetMmMojoFullPath = targetPath + "\\" + MmMojoDll;
    std::string targetMmMojo64FullPath = targetPath + "\\" + MmMojo64Dll;
    
    // 复制文件（如果目标文件不存在）
    if (!std::filesystem::exists(targetMmMojoFullPath) && std::filesystem::exists(mmMojoFullPath))
        std::filesystem::copy_file(mmMojoFullPath, targetMmMojoFullPath);
    
    if (!std::filesystem::exists(targetMmMojo64FullPath) && std::filesystem::exists(mmMojo64FullPath))
        std::filesystem::copy_file(mmMojo64FullPath, targetMmMojo64FullPath);
}

bool Utilities::RemoveMmmojoDll(std::string& error)
{
    bool ret = true;
    error = "";
    
    char currentDir[MAX_PATH];
    GetCurrentDirectoryA(MAX_PATH, currentDir);
    
    std::string targetMmMojoFullPath = std::string(currentDir) + "\\" + MmMojoDll;
    std::string targetMmMojo64FullPath = std::string(currentDir) + "\\" + MmMojo64Dll;
    
    try
    {
        if (std::filesystem::exists(targetMmMojoFullPath))
            std::filesystem::remove(targetMmMojoFullPath);
        
        if (std::filesystem::exists(targetMmMojo64FullPath))
            std::filesystem::remove(targetMmMojo64FullPath);
    }
    catch (const std::exception& ex)
    {
        error = ex.what();
        ret = false;
    }
    
    return ret;
}

// Base64解码函数
std::string Utilities::Base64Decode(const std::string& encoded_string) {
    if (encoded_string.empty()) return "";

    // Base64编码表
    static const std::string base64_chars =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
        "abcdefghijklmnopqrstuvwxyz"
        "0123456789+/";

    // 解码过程
    size_t in_len = encoded_string.size();
    size_t i = 0;
    size_t j = 0;
    size_t in_ = 0;
    unsigned char char_array_4[4], char_array_3[3];
    std::string ret;

    while (in_len-- && (encoded_string[in_] != '=') &&
        (isalnum(encoded_string[in_]) || (encoded_string[in_] == '+') || (encoded_string[in_] == '/'))) {
        char_array_4[i++] = encoded_string[in_]; in_++;
        if (i == 4) {
            for (i = 0; i < 4; i++)
                char_array_4[i] = base64_chars.find(char_array_4[i]);

            char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
            char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
            char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];

            for (i = 0; i < 3; i++)
                ret += char_array_3[i];
            i = 0;
        }
    }

    if (i) {
        for (j = i; j < 4; j++)
            char_array_4[j] = 0;

        for (j = 0; j < 4; j++)
            char_array_4[j] = base64_chars.find(char_array_4[j]);

        char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
        char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
        char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];

        for (j = 0; j < i - 1; j++)
            ret += char_array_3[j];
    }

    return ret;
}

std::vector<unsigned char> Utilities::Base64Decode_Raw(const std::string& input) {

    const std::string BASE64_CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

    std::vector<int> decode_table(256, -1);
    for (int i = 0; i < 64; i++)
        decode_table[BASE64_CHARS[i]] = i; // 构建解码表[6,8](@ref)

    std::vector<unsigned char> decoded;
    int val = 0, bits = -8; // val:24位缓冲区, bits:当前有效位数
    for (unsigned char c : input) {
        if (c == '=') break;               // 遇填充符终止
        if (decode_table[c] == -1) continue; // 跳过非法字符

        val = (val << 6) + decode_table[c]; // 合并6位数据[6](@ref)
        bits += 6;
        if (bits >= 0) {                   // 每凑够8位输出1字节
            decoded.push_back((val >> bits) & 0xFF);
            bits -= 8;
        }
    }
    return decoded;
}