/* ORIGINAL LICENSE: Do What The F*ck You Want To Public License
 * AUTHOR: LBYPatrick
 *
 * MODIFIED BY Leroy.H.Y @lhy0403 re-licenced under GPLv3
 */

#include "common/QvHelpers.hpp"

namespace Qv2ray::components::pac
{
    // Private function
    string getRawDomain(string originLine)
    {
        size_t startPosition = 0;
        size_t endPosition = originLine.size();
        string returnBuffer;
        bool skipRule1 = originLine.find("[") != string::npos; // [Auto xxxx...
        bool skipRule2 = originLine.find("!") != string::npos; // Comments
        bool skipRule3 = originLine.find("@") != string::npos; // Non-proxy Lines
        bool skipRule4 = originLine.find("*") != string::npos;
        bool passRule1 = originLine.find("|") != string::npos; // Proxy Lines
        bool passRule2 = originLine.find(".") != string::npos; // Link-Contained Lines

        if (originLine[endPosition] == '\n') { endPosition -= 1; }

        if (originLine.find("http://") != string::npos) { startPosition += 8; }
        else if (originLine.find("https://") != string::npos)
        {
            startPosition += 9;
        }

        // Skip unrelated lines
        if (skipRule1 || skipRule2 || skipRule3 || skipRule4) { return ""; }
        else if (passRule2)
        {
            if (passRule1) { startPosition += originLine.find_last_of("|") + 1; }

            if (originLine[startPosition] == '\n') startPosition += 1;

            for (size_t i = startPosition; i < endPosition; ++i) { returnBuffer += originLine[i]; }
        }

        return returnBuffer;
    }

    QString ConvertGFWToPAC(const QString &rawContent, const QString &customProxyString)
    {
        auto rawFileContent = Base64Decode(rawContent).toStdString();
        string readBuffer = ""; // cleanup
        string writeBuffer;
        string domainListCache = "";

        for (size_t i = 0; i < rawFileContent.size(); ++i)
        {
            readBuffer += rawFileContent[i];

            if (rawFileContent[i + 1] == '\n')
            {
                writeBuffer = getRawDomain(readBuffer);

                if (writeBuffer != "") { domainListCache += writeBuffer + "\n"; }

                readBuffer = "";
                i += 1;
            }
        }

        size_t rotatorTwo = 0;
        string readDomainBuffer = "";
        bool isFirstLine = true;
        string outputContent = "";
        // Header
        outputContent += "var domains = {\n";

        // Read and process output content line by line
        while (rotatorTwo < domainListCache.size())
        {
            while (true)
            {
                // Get Domain
                readDomainBuffer += domainListCache[rotatorTwo];

                if (domainListCache[rotatorTwo + 1] == '\n')
                {
                    rotatorTwo += 2;
                    break;
                }

                rotatorTwo++;
            }

            // Format
            if (!isFirstLine) outputContent += ",\n";
            else
                isFirstLine = false;

            outputContent += "\t\"";
            outputContent += readDomainBuffer;
            outputContent += "\" : 1";
            readDomainBuffer = "";
        }

        // End Message
        outputContent += NEWLINE "};" NEWLINE "" NEWLINE "   var proxy = \"" + customProxyString.toStdString() + ";\";" +
                         NEWLINE "   var direct = 'DIRECT;';" NEWLINE "    function FindProxyForURL(url, host) {" NEWLINE
                                 "        var suffix;" NEWLINE "        var pos = host.lastIndexOf('.');" NEWLINE
                                 "        pos = host.lastIndexOf('.', pos - 1);" NEWLINE "        //" NEWLINE "        while (1) {" NEWLINE
                                 "            if (domains[host] != undefined) {" NEWLINE "                return proxy;" NEWLINE
                                 "            }" NEWLINE "            else if (pos <= 0) {" NEWLINE
                                 "                return domains['.' + host] != undefined ? proxy : direct;" NEWLINE "            }" NEWLINE
                                 "            suffix = host.substring(pos);" NEWLINE "            if (domains[suffix] != undefined) {" NEWLINE
                                 "                return proxy;" NEWLINE "            }" NEWLINE
                                 "            pos = host.lastIndexOf('.', pos - 1);" NEWLINE "        }" NEWLINE "    }";
        //
        return QString::fromStdString(outputContent);
    }
} // namespace Qv2ray::components::pac