//
// Created by robin on 8/8/15.
//

#include <iostream>
#include <fstream>
#include <sysexits.h>
#include <jsoncpp/json/json.h>
#include <cstring>
#include "CommandLineParser.h"
#include "MainClass.h"

MainClass* MainClass::_instance = nullptr;

MainClass *MainClass::getInstance()
{
    return _instance;
}

sfsistat mlfi_header(SMFICTX *ctx)
{
    return MainClass::getInstance()->mlfiHeader(ctx);
}

MainClass::MainClass(int argc, char *argv[])
    : _argc(argc)
    , _argv(argv)
{
    _instance = this;
    _cryptoBusiness = std::make_shared<CryptoBusiness>();
}

MainClass::~MainClass()
{
}

int MainClass::main()
{
    CommandLineParser commandLineParser(_argc, _argv);
    CommandLineOption configOption("config", 'c', "Use FILE as configuration file.", "FILE", "/etc/milter-sasl/milter-sasl.json");
    commandLineParser.addOption(&configOption);
    CommandLineOption decryptOption("decrypt", 'd', "Decrypt DATA and exit. Can be specified multiple times. Use - to read from stdin.", "DATA");
    commandLineParser.addOption(&decryptOption);
    CommandLineOption helpOption("help", 'h', "Show this help.");
    commandLineParser.addOption(&helpOption);

    if (!commandLineParser.parse())
    {
        return commandLineParser.showHelp(EX_USAGE, true);
    }

    if (helpOption.isSet())
    {
        return commandLineParser.showHelp(0, false);
    }

    auto configFile = configOption.getValue();
    auto configResult = loadConfig(configFile);
    if (configResult != 0)
    {
        std::cerr << "Failed to read configuration file: " << strerror(configResult) << std::endl;
        return EX_NOINPUT;
    }
    else if (decryptOption.isSet())
    {
        return launchDecrypt(decryptOption.getValues());
    }
    else
    {
        return launchMilter(_defaultSocket);
    }
}

sfsistat MainClass::mlfiHeader(SMFICTX *ctx)
{
    Json::Value root;
    auto auth_authen = smfi_getsymval(ctx, (char*)"{auth_authen}");
    if (auth_authen)
    {
        root["auth_authen"] = randomizeString(auth_authen);
    }
    auto auth_author = smfi_getsymval(ctx, (char*)"{auth_author}");
    if (auth_author)
    {
        root["auth_author"] = randomizeString(auth_author);
    }
    auto auth_type = smfi_getsymval(ctx, (char*)"{auth_type}");
    if (auth_type)
    {
        root["auth_type"] = randomizeString(auth_type);
    }

    Json::StyledWriter w;
    auto json = w.write(root);
    auto encrypted = _cryptoBusiness->encryptToHex(json);

    smfi_addheader(ctx, (char*)"X-Sasl-User", (char*)encrypted.c_str());

    return SMFIS_CONTINUE;
}

int MainClass::loadConfig(const std::string& filePath)
{
    std::ifstream stream(filePath, std::ifstream::in);
    if (stream)
    {
        Json::Reader reader;
        Json::Value root;
        reader.parse(stream, root);
        _cryptoBusiness->setKey(root["key"].asString());
        _defaultSocket = root["socket"].asString();
    }
    return errno;
}

int MainClass::launchMilter(const std::string &socket)
{
    srand(time(nullptr));
    struct smfiDesc smfilter =
            {
                    (char*)"milter-sasl",	/* filter name */
                    SMFI_VERSION,	/* version code -- do not change */
                    SMFIF_ADDHDRS,	/* flags */
                    NULL,		/* connection info filter */
                    NULL,		/* SMTP HELO command filter */
                    NULL,	/* envelope sender filter */
                    NULL,		/* envelope recipient filter */
                    NULL,	/* header filter */
                    NULL,	/* end of header */
                    NULL,	/* body block filter */
                    mlfi_header,	/* end of message */
                    NULL,	/* message aborted */
                    NULL,	/* connection cleanup */
                    NULL,	/* unknown/unimplemented SMTP commands */
                    NULL,	/* DATA command filter */
                    NULL	/* option negotiation at connection startup */
            };

    if (smfi_setconn((char*)socket.c_str()) == MI_FAILURE)
    {
        std::cerr << "smfi_setconn failed" << std::endl;
        return EX_UNAVAILABLE;
    }

    if (smfi_register(smfilter) == MI_FAILURE)
    {
        std::cerr << "smfi_register failed" << std::endl;
        return EX_UNAVAILABLE;
    }

    return smfi_main();
}

int MainClass::launchDecrypt(const std::vector<std::string> values)
{
    for (auto value : values)
    {
        if (value == "-")
        {
            std::cin >> value;
        }
        std::cout << _cryptoBusiness->decryptFromHex(value) << std::endl;
    }
    return 0;
}

std::string MainClass::randomizeString(const std::string &str)
{
    int cc = 2;
    std::string out;
    for (int i = 0; i < cc; ++i)
    {
        auto c = 'a' + (rand() % 26);
        out.push_back((char)c);
    }
    out += "|" + str + "|";
    for (int i = 0; i < cc; ++i)
    {
        auto c = 'a' + (rand() % 26);
        out.push_back((char)c);
    }
    return out;
}