// Copyright 2019-2021 The Hush developers
// Released under the GPLv3
#include "connection.h"
#include "mainwindow.h"
#include "settings.h"
#include "ui_connection.h"
#include "ui_createzcashconfdialog.h"
#include "rpc.h"
#include "precompiled.h"

ConnectionLoader::ConnectionLoader(MainWindow* main, RPC* rpc) {
    this->main = main;
    this->rpc  = rpc;

    d = new QDialog(main);
    d->setWindowFlags(d->windowFlags() & ~(Qt::WindowCloseButtonHint | Qt::WindowContextHelpButtonHint));
    connD = new Ui_ConnectionDialog();
    connD->setupUi(d);
    QMovie *movie1 = new QMovie(":/img/res/silentdragon-animated-startup.gif");;
    QMovie *movie2 = new QMovie(":/img/res/silentdragon-animated-startup-dark.gif");;
    auto theme = Settings::getInstance()->get_theme_name();
    auto size  = QSize(512,512);

    if (theme == "dark" || theme == "midnight") {
        movie2->setScaledSize(size);
        connD->topIcon->setMovie(movie2);
        movie2->start();
    } else {
        movie1->setScaledSize(size);
        connD->topIcon->setMovie(movie1);
        movie1->start();
    }
    main->logger->write("set animation");
    qDebug() << "set animation";
}

ConnectionLoader::~ConnectionLoader() {
    delete d;
    delete connD;
    main->logger->write("ConnectionLoader done");
    qDebug() << "connection loader done";
}

void ConnectionLoader::loadConnection() {
    QTimer::singleShot(1, [=]() { this->doAutoConnect(); });
    if (!Settings::getInstance()->isHeadless())
        d->exec();
}

void ConnectionLoader::doAutoConnect(bool tryEzcashdStart) {
    // Priority 1: Ensure all params are present.
    if (!verifyParams()) {
        qDebug() << "Cannot find sapling params!";
        return;
    }

    // Priority 2: Try to connect to detect HUSH3.conf and connect to it.
    auto config = autoDetectZcashConf();
    main->logger->write(QObject::tr("Attempting autoconnect"));

    if (config.get() != nullptr) {
        auto connection = makeConnection(config);

        refreshZcashdState(connection, [=] () {
            // Refused connection. So try and start embedded zcashd
            if (Settings::getInstance()->useEmbedded()) {
                if (tryEzcashdStart) {
                    this->showInformation(QObject::tr("Starting embedded hushd"));
                    if (this->startEmbeddedZcashd()) {
                        // Embedded hushd started up. Wait a second and then refresh the connection
                        main->logger->write("Embedded hushd started up, trying autoconnect in 1 sec");
                        QTimer::singleShot(1000, [=]() { doAutoConnect(); } );
                    } else {
                        if (config->zcashDaemon) {
                            // hushd is configured to run as a daemon, so we must wait for a few seconds
                            // to let it start up. 
                            main->logger->write("hushd is daemon=1. Waiting for it to start up");
                            this->showInformation(QObject::tr("hushd is set to run as daemon"), QObject::tr("Waiting for hushd"));
                            QTimer::singleShot(5000, [=]() { doAutoConnect(/* don't attempt to start ehushd */ false); });
                        } else {
                            // Something is wrong. 
                            // We're going to attempt to connect to the one in the background one last time
                            // and see if that works, else throw an error
                            main->logger->write("Unknown problem while trying to start hushd!");
                            QTimer::singleShot(2000, [=]() { doAutoConnect(/* don't attempt to start ehushd */ false); });
                        }
                    }
                } else {
                    // We tried to start ehushd previously, and it didn't work. So, show the error. 
                    main->logger->write("Couldn't start embedded hushd for unknown reason");
                    QString explanation;
                    if (config->zcashDaemon) {
                        explanation = QString() % QObject::tr("You have hushd set to start as a daemon, which can cause problems "
                            "with SilentDragon\n\n."
                            "Please remove the following line from your HUSH3.conf and restart SilentDragon\n"
                            "daemon=1");
                    } else {
                        explanation = QString() % QObject::tr("Couldn't start the embedded hushd.\n\n" 
                            "Please try restarting.\n\nIf you previously started hushd with custom arguments, you might need to  reset HUSH3.conf.\n\n" 
                            "If all else fails, please run hushd manually.") %  
                            (ehushd ? QObject::tr("The process returned") + ":\n\n" % ehushd->errorString() : QString(""));
                    }
                    
                    this->showError(explanation);
                }                
            } else {
                // HUSH3.conf exists, there's no connection, and the user asked us not to start hushd. Error!
                main->logger->write("Not using embedded and couldn't connect to hushd");
                QString explanation = QString() % QObject::tr("Couldn't connect to hushd configured in HUSH3.conf.\n\n" 
                                      "Not starting embedded hushd because --no-embedded was passed");
                this->showError(explanation);
            }
        });
    } else {
        if (Settings::getInstance()->useEmbedded()) {
            // HUSH3.conf was not found, so create one
            createZcashConf();
        } else {
            // Fall back to manual connect
            doManualConnect();
        }
    } 
}

QString randomPassword() {
    static const char alphanum[] =
        "0123456789"
        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
        "abcdefghijklmnopqrstuvwxyz";

    const int passwordLength = 10;
    char* s = new char[passwordLength + 1];

    for (int i = 0; i < passwordLength; ++i) {
        s[i] = alphanum[randombytes_uniform(sizeof(alphanum))];
    }

    s[passwordLength] = 0;
    return QString::fromStdString(s);
}

/**
 * This will create a new HUSH3.conf and download params if they cannot be found
 */ 
void ConnectionLoader::createZcashConf() {
    main->logger->write("createZcashConf");

    auto confLocation = zcashConfWritableLocation();
    QFileInfo fi(confLocation);

    QDialog d(main);
    Ui_createZcashConf ui;
    ui.setupUi(&d);

    QPixmap logo(":/img/res/zcashdlogo.gif");
    ui.lblTopIcon->setBasePixmap(logo.scaled(512,512, Qt::KeepAspectRatio, Qt::SmoothTransformation));
    ui.btnPickDir->setEnabled(false);

    ui.grpAdvanced->setVisible(false);
    QObject::connect(ui.btnAdvancedConfig, &QPushButton::toggled, [=](bool isVisible) {
        ui.grpAdvanced->setVisible(isVisible);
        ui.btnAdvancedConfig->setText(isVisible ? QObject::tr("Hide Advanced Config") : QObject::tr("Show Advanced Config"));
    });

    QObject::connect(ui.chkCustomDatadir, &QCheckBox::stateChanged, [=](int chked) {
        if (chked == Qt::Checked) {
            ui.btnPickDir->setEnabled(true);
        }
        else {
            ui.btnPickDir->setEnabled(false);
        }
    });

    QObject::connect(ui.btnPickDir, &QPushButton::clicked, [=]() {
        auto datadir = QFileDialog::getExistingDirectory(main, QObject::tr("Choose data directory"), ui.lblDirName->text(), QFileDialog::ShowDirsOnly);
        if (!datadir.isEmpty()) {
            ui.lblDirName->setText(QDir::toNativeSeparators(datadir));
        }
    });

    // Show the dialog
    QString datadir = "";
    bool useTor = false;
    if (d.exec() == QDialog::Accepted) {
        datadir = ui.lblDirName->text();
        useTor = ui.chkUseTor->isChecked();
    }

    main->logger->write("Creating file " + confLocation);
    QDir().mkpath(fi.dir().absolutePath());

    QFile file(confLocation);
    if (!file.open(QIODevice::ReadWrite | QIODevice::Truncate)) {
        main->logger->write("Could not create HUSH3.conf, returning");

        QString explanation = QString() % QObject::tr("Could not create HUSH3.conf.");
        this->showError(explanation);
        return;
    }

    QTextStream out(&file);

    out << "# Autogenerated by Hush SilentDragon https://hush.is\n";
    out << "server=1\n";
    out << "rpcuser=hush\n";
    out << "rpcpassword=" % randomPassword() << "\n";
    out << "rpcport=18031\n";
    out << "txindex=1\n";
    out << "addressindex=1\n";
    out << "spentindex=1\n";
    out << "timestampindex=1\n";
    out << "rpcworkqueue=256\n";
    out << "rpcallowip=127.0.0.1\n";

    // Consolidation is now defaulted to ON for new wallets
    out << "consolidation=1\n";

    if (!datadir.isEmpty()) {
        out << "datadir=" % datadir % "\n";
    }
    if (useTor) {
        out << "proxy=127.0.0.1:9050\n";
    }

    file.close();

    // Now that HUSH3.conf exists, try to autoconnect again
    this->doAutoConnect();
}


void ConnectionLoader::doNextDownload(std::function<void(void)> cb) {
    auto fnSaveFileName = [&] (QUrl url) {
        QString path = url.path();
        QString basename = QFileInfo(path).fileName();

        return basename;
    };

    if (downloadQueue->isEmpty()) {
        delete downloadQueue;
        client->deleteLater();

        main->logger->write("All Downloads done");
        this->showInformation(QObject::tr("All Downloads Finished Successfully!"));
        cb();
        return;
    }

    QUrl url = downloadQueue->dequeue();
    int filesRemaining = downloadQueue->size();

    QString filename = fnSaveFileName(url);
    QString paramsDir = zcashParamsDir();

    if (QFile(QDir(paramsDir).filePath(filename)).exists()) {
        main->logger->write(filename + " already exists, skipping");
        doNextDownload(cb);

        return;
    }

    // The downloaded file is written to a new name, and then renamed when the operation completes.
    currentOutput = new QFile(QDir(paramsDir).filePath(filename + ".part"));   

    if (!currentOutput->open(QIODevice::WriteOnly)) {
        main->logger->write("Couldn't open " + currentOutput->fileName() + " for writing");
        this->showError(QObject::tr("Couldn't download params. Please check the help site for more info."));
    }
    main->logger->write("Downloading to " + filename);
    qDebug() << "Downloading " << url << " to " << filename;
    
    QNetworkRequest request(url);
    request.setAttribute(QNetworkRequest::FollowRedirectsAttribute, true);
    currentDownload = client->get(request);
    downloadTime.start();
    
    // Download Progress
    QObject::connect(currentDownload, &QNetworkReply::downloadProgress, [=] (auto done, auto total) {
        // calculate the download speed
        double speed = done * 1000.0 / downloadTime.elapsed();
        QString unit;
        if (speed < 1024) {
            unit = "bytes/sec";
        } else if (speed < 1024*1024) {
            speed /= 1024;
            unit = "kB/s";
        } else {
            speed /= 1024*1024;
            unit = "MB/s";
        }

        this->showInformation(
            QObject::tr("Downloading ") % filename % (filesRemaining > 1 ? " ( +" % QString::number(filesRemaining)  % QObject::tr(" more remaining )") : QString("")),
            QString::number(done/1024/1024, 'f', 0) % QObject::tr("MB of ") % QString::number(total/1024/1024, 'f', 0) + QObject::tr("MB at ") % QString::number(speed, 'f', 2) % unit);
    });
    
    // Download Finished
    QObject::connect(currentDownload, &QNetworkReply::finished, [=] () {
        // Rename file
        main->logger->write("Finished downloading " + filename);
        currentOutput->rename(QDir(paramsDir).filePath(filename));

        currentOutput->close();
        currentDownload->deleteLater();
        currentOutput->deleteLater();

        if (currentDownload->error()) {
            main->logger->write("Downloading " + filename + " failed");
            this->showError(QObject::tr("Downloading ") + filename + QObject::tr(" failed. Please check the help site for more info"));                
        } else {
            doNextDownload(cb);
        }
    });

    // Download new data available. 
    QObject::connect(currentDownload, &QNetworkReply::readyRead, [=] () {
        currentOutput->write(currentDownload->readAll());
    });    
}

bool ConnectionLoader::startEmbeddedZcashd() {
    if (!Settings::getInstance()->useEmbedded()) 
        return false;
    
    main->logger->write("Trying to start embedded hushd");

    // Static because it needs to survive even after this method returns.
    static QString processStdErrOutput;

    if (ehushd != nullptr) {
        if (ehushd->state() == QProcess::NotRunning) {
            if (!processStdErrOutput.isEmpty()) {
                QMessageBox::critical(main, QObject::tr("hushd error"), "hushd said: " + processStdErrOutput, 
                                      QMessageBox::Ok);
            }
            return false;
        } else {
            return true;
        }        
    }

    QDir appPath(QCoreApplication::applicationDirPath());

#ifdef Q_OS_WIN64
    auto hushdProgram = appPath.absoluteFilePath("komodod.exe");
#else
    auto hushdProgram = appPath.absoluteFilePath("komodod");
#endif
    
    //if (!QFile(hushdProgram).exists()) {
    if (!QFile::exists(hushdProgram)) {
        qDebug() << "Can't find hushd at " << hushdProgram;
        main->logger->write("Can't find hushd at " + hushdProgram);
        return false;
    } else {
        main->logger->write("Found hushd at " + hushdProgram);
    }

    ehushd = std::shared_ptr<QProcess>(new QProcess(main));
    QObject::connect(ehushd.get(), &QProcess::started, [=] () {
        qDebug() << "Embedded hushd started via " << hushdProgram;
    });

    QObject::connect(ehushd.get(), QOverload<int, QProcess::ExitStatus>::of(&QProcess::finished),
                        [=](int exitCode, QProcess::ExitStatus exitStatus) {
        qDebug() << "hushd finished with code " << exitCode << "," << exitStatus;
    });

    QObject::connect(ehushd.get(), &QProcess::errorOccurred, [&] (QProcess::ProcessError error) {
        qDebug() << "Couldn't start hushd at " << hushdProgram << ":" << error;
    });

    std::weak_ptr<QProcess> weak_obj(ehushd);
    auto ptr_main(main);
    QObject::connect(ehushd.get(), &QProcess::readyReadStandardError, [weak_obj, ptr_main]() {
        auto output = weak_obj.lock()->readAllStandardError();
        ptr_main->logger->write("hushd stderr:" + output);
        processStdErrOutput.append(output);
    });

    // This string should be the exact arg list seperated by single spaces
    QString params = "-ac_name=HUSH3 -ac_sapling=1 -ac_reward=0,1125000000,562500000 -ac_halving=129,340000,840000 -ac_end=128,340000,5422111 -ac_eras=3 -ac_blocktime=150 -ac_cc=2 -ac_ccenable=228,234,235,236,241 -ac_founders=1 -ac_supply=6178674 -ac_perc=11111111 -clientname=GoldenSandtrout -addnode=node1.hush.is -addnode=node2.hush.is -addnode=node3.hush.is -addnode=node4.hush.is -addnode=node5.hush.is -addnode=node6.hush.is -addnode=node7.hush.is -addnode=node8.hush.is -ac_cclib=hush3 -tls=only -ac_script=76a9145eb10cf64f2bab1b457f1f25e658526155928fac88ac";
    QStringList arguments = params.split(" ");

    // Finally, actually start the full node
#ifdef Q_OS_LINUX
    qDebug() << "Starting on Linux: " + hushdProgram + " " + params;
    ehushd->start(hushdProgram, arguments);
#elif defined(Q_OS_DARWIN)
    qDebug() << "Starting on Darwin: " + hushdProgram + " " + params;
    ehushd->start(hushdProgram, arguments);
#elif defined(Q_OS_WIN64)
    qDebug() << "Starting on Win64: " + hushdProgram + " " + params;
    ehushd->setWorkingDirectory(appPath.absolutePath());
    ehushd->start(hushdProgram, arguments);
#else
    qDebug() << "Starting on Unknown OS(!): " + hushdProgram + " " + params;
    ehushd->setWorkingDirectory(appPath.absolutePath());
    ehushd->start(hushdProgram, arguments);
#endif // Q_OS_LINUX

    main->logger->write("Started via " + hushdProgram + " " + params);
    return true;
}

void ConnectionLoader::doManualConnect() {
    auto config = loadFromSettings();

    if (!config) {
        // Nothing configured, show an error
        QString explanation = QString()
                % QObject::tr("A manual connection was requested, but the settings are not configured.\n\n"
                "Please set the host/port and user/password in the Edit->Settings menu.");

        showError(explanation);
        doRPCSetConnection(nullptr);

        return;
    }

    auto connection = makeConnection(config);
    refreshZcashdState(connection, [=] () {
        QString explanation = QString()
                % QObject::tr("Could not connect to hushd configured in settings.\n\n" 
                "Please set the host/port and user/password in the Edit->Settings menu.");

        showError(explanation);
        doRPCSetConnection(nullptr);

        return;
    });
}

void ConnectionLoader::doRPCSetConnection(Connection* conn) {
    rpc->setEZcashd(ehushd);
    rpc->setConnection(conn);
    
    d->accept();

    delete this;
}

Connection* ConnectionLoader::makeConnection(std::shared_ptr<ConnectionConfig> config) {
    QNetworkAccessManager* client = new QNetworkAccessManager(main);
         
    QUrl myurl;
    myurl.setScheme("http");
    myurl.setHost(config.get()->host);
    myurl.setPort(config.get()->port.toInt());

    QNetworkRequest* request = new QNetworkRequest();
    request->setUrl(myurl);
    request->setHeader(QNetworkRequest::ContentTypeHeader, "text/plain");
    
    QString userpass = config.get()->rpcuser % ":" % config.get()->rpcpassword;
    QString headerData = "Basic " + userpass.toLocal8Bit().toBase64();
    request->setRawHeader("Authorization", headerData.toLocal8Bit());    

    return new Connection(main, client, request, config);
}

void ConnectionLoader::refreshZcashdState(Connection* connection, std::function<void(void)> refused) {
    main->logger->write("refreshing state");

    QJsonObject payload = {
        {"jsonrpc", "1.0"},
        {"id", "someid"},
        {"method", "getinfo"}
    };
    connection->doRPC(payload,
        [=] (auto) {
            // Success
            main->logger->write("hushd is online!");
            // Delay 1 second to ensure loading (splash) is seen at least 1 second.
            QTimer::singleShot(1000, [=]() { this->doRPCSetConnection(connection); });
        },
        [=] (QNetworkReply* reply, const QJsonValue &res) {
            // Failed, see what it is. 
            auto err = reply->error();
            //qDebug() << err << res;

            if (err == QNetworkReply::NetworkError::ConnectionRefusedError) {   
                refused();
            } else if (err == QNetworkReply::NetworkError::AuthenticationRequiredError) {
                main->logger->write("Authentication failed");
                QString explanation = QString() % 
                        QObject::tr("Authentication failed. The username / password you specified was "
                        "not accepted by hushd. Try changing it in the Edit->Settings menu");

                this->showError(explanation);
            } else if (err == QNetworkReply::NetworkError::InternalServerError && 
                    !res.isNull()) {
                // The server is loading, so just poll until it succeeds
                QString status      = res["error"].toObject()["message"].toString();
                {
                    static int dots = 0;
                    status = status.left(status.length() - 3) + QString(".").repeated(dots);
                    dots++;
                    if (dots > 3)
                        dots = 0;
                }
                this->showInformation(QObject::tr("Your hushd is starting up. Please wait."), status);
                main->logger->write("Waiting for hushd to come online.");
                // Refresh after one second
                QTimer::singleShot(1000, [=]() { this->refreshZcashdState(connection, refused); });
            }
        }
    );
}

// Update the UI with the status
void ConnectionLoader::showInformation(QString info, QString detail) {
    static int rescanCount = 0;
    if (detail.toLower().startsWith("rescan")) {
        rescanCount++;
    }
    
    if (rescanCount > 10) {
        detail = detail + "\n" + QObject::tr("This may take several hours, grab some popcorn");
    }

    connD->status->setText(info);
    connD->statusDetail->setText(detail);

    if (rescanCount < 10)
        main->logger->write(info + ":" + detail);
}

/**
 * Show error will close the loading dialog and show an error. 
*/
void ConnectionLoader::showError(QString explanation) {    
    rpc->setEZcashd(nullptr);
    rpc->noConnection();

    QMessageBox::critical(main, QObject::tr("Connection Error"), explanation, QMessageBox::Ok);
    d->close();
}

QString ConnectionLoader::locateZcashConfFile() {
#ifdef Q_OS_LINUX
    auto confLocation = QStandardPaths::locate(QStandardPaths::HomeLocation, ".komodo/HUSH3/HUSH3.conf");
#elif defined(Q_OS_DARWIN)
    auto confLocation = QStandardPaths::locate(QStandardPaths::HomeLocation, "Library/Application Support/Komodo/HUSH3/HUSH3.conf");
#else
    auto confLocation = QStandardPaths::locate(QStandardPaths::AppDataLocation, "../../Komodo/HUSH3/HUSH3.conf");
#endif

    main->logger->write("Found HUSH3.conf at " + QDir::cleanPath(confLocation));
    return QDir::cleanPath(confLocation);
}

QString ConnectionLoader::zcashConfWritableLocation() {
#ifdef Q_OS_LINUX
    auto confLocation = QDir(QStandardPaths::writableLocation(QStandardPaths::HomeLocation)).filePath(".komodo/HUSH3/HUSH3.conf");
#elif defined(Q_OS_DARWIN)
    auto confLocation = QDir(QStandardPaths::writableLocation(QStandardPaths::HomeLocation)).filePath("Library/Application Support/Komodo/HUSH3/HUSH3.conf");
#else
    auto confLocation = QDir(QStandardPaths::writableLocation(QStandardPaths::AppDataLocation)).filePath("../../Komodo/HUSH3/HUSH3.conf");
#endif

    main->logger->write("Found HUSH3.conf at " + QDir::cleanPath(confLocation));
    return QDir::cleanPath(confLocation);
}

QString ConnectionLoader::zcashParamsDir() {
#ifdef Q_OS_LINUX
    //TODO: If /usr/share/hush exists, use that. It should not be assumed writeable
    auto paramsLocation = QDir(QDir(QStandardPaths::writableLocation(QStandardPaths::HomeLocation)).filePath(".zcash-params"));
    // Debian packages do not install into per-user dirs
    if (!paramsLocation.exists()) {
        paramsLocation = QDir(QDir("/").filePath("usr/share/hush"));
    }
#elif defined(Q_OS_DARWIN)
    auto paramsLocation = QDir(QDir(QStandardPaths::writableLocation(QStandardPaths::HomeLocation)).filePath("Library/Application Support/ZcashParams"));
#else
    auto paramsLocation = QDir(QDir(QStandardPaths::writableLocation(QStandardPaths::AppDataLocation)).filePath("../../ZcashParams"));
#endif

    if (!paramsLocation.exists()) {
        main->logger->write("Creating params location at " + paramsLocation.absolutePath());
        QDir().mkpath(paramsLocation.absolutePath());
    }

    main->logger->write("Found Hush params directory at " + paramsLocation.absolutePath());
    return paramsLocation.absolutePath();
}

bool ConnectionLoader::verifyParams() {
    QDir paramsDir(zcashParamsDir());

    // TODO: better error reporting if only 1 file exists or is missing
    qDebug() << "Verifying sapling param files exist";


    // This list of locations to look must be kept in sync with the list in hushd
    if( QFile( QDir(".").filePath("sapling-output.params") ).exists() && QFile( QDir(".").filePath("sapling-spend.params") ).exists() ) {
        qDebug() << "Found params in .";
        return true;
    }

    if( QFile( QDir("..").filePath("sapling-output.params") ).exists() && QFile( QDir("..").filePath("sapling-spend.params") ).exists() ) {
        qDebug() << "Found params in ..";
        return true;
    }

    if( QFile( QDir("..").filePath("hush3/sapling-output.params") ).exists() && QFile( QDir("..").filePath("hush3/sapling-spend.params") ).exists() ) {
        qDebug() << "Found params in ../hush3";
        return true;
    }

    // this is to support SD on mac in /Applications1
    if( QFile( QDir("/Applications").filePath("silentdragon.app/Contents/MacOS/sapling-output.params") ).exists() && QFile( QDir("/Applications").filePath("./silentdragon.app/Contents/MacOS/sapling-spend.params") ).exists() ) {
        qDebug() << "Found params in /Applications/silentdragon.app/Contents/MacOS";
        return true;
    }

    // this is to support SD on mac inside a DMG
    if( QFile( QDir("./").filePath("silentdragon.app/Contents/MacOS/sapling-output.params") ).exists() && QFile( QDir("./").filePath("./silentdragon.app/Contents/MacOS/sapling-spend.params") ).exists() ) {
        qDebug() << "Found params in ./silentdragon.app/Contents/MacOS";
        return true;
    }

    if (QFile(paramsDir.filePath("sapling-output.params")).exists() && QFile(paramsDir.filePath("sapling-spend.params")).exists()) {
        qDebug() << "Found params in " << paramsDir;
        return true;
    }

    qDebug() << "Did not find Sapling params!";
    return false;
}

/**
 * Try to automatically detect a HUSH3/HUSH3.conf file in the correct location and load parameters
 */ 
std::shared_ptr<ConnectionConfig> ConnectionLoader::autoDetectZcashConf() {    
    auto confLocation = locateZcashConfFile();

    if (confLocation.isNull()) {
        // No Zcash file, just return with nothing
        return nullptr;
    }

    QFile file(confLocation);
    if (!file.open(QIODevice::ReadOnly)) {
        qDebug() << file.errorString();
        return nullptr;
    }

    QTextStream in(&file);

    auto zcashconf = new ConnectionConfig();
    zcashconf->host     = "127.0.0.1";
    zcashconf->connType = ConnectionType::DetectedConfExternalHushD;
    zcashconf->usingZcashConf = true;
    zcashconf->zcashDir = QFileInfo(confLocation).absoluteDir().absolutePath();
    zcashconf->zcashDaemon = false;
   
    Settings::getInstance()->setUsingZcashConf(confLocation);

    while (!in.atEnd()) {
        QString line = in.readLine();
        auto s = line.indexOf("=");
        QString name  = line.left(s).trimmed().toLower();
        QString value = line.right(line.length() - s - 1).trimmed();

        if (name == "rpcuser") {
            zcashconf->rpcuser = value;
        }
        if (name == "rpcpassword") {
            zcashconf->rpcpassword = value;
        }
        if (name == "rpcport") {
            zcashconf->port = value;
        }
        if (name == "daemon" && value == "1") {
            zcashconf->zcashDaemon = true;
        }
        if (name == "proxy") {
            zcashconf->proxy = value;
        }
         if (name == "consolidation") {
            zcashconf->consolidation = value;
        }
          if (name == "deletetx") {
            zcashconf->deletetx = value;
        }
          if (name == "zindex") {
            zcashconf->zindex = value;
        }
        if (name == "testnet" &&
            value == "1"  &&
            zcashconf->port.isEmpty()) {
                zcashconf->port = "18232";
        }
    }

    // If rpcport is not in the file, and it was not set by the testnet=1 flag, then go to default
    if (zcashconf->port.isEmpty()) zcashconf->port = "18031";
    file.close();

    // In addition to the HUSH3/HUSH3.conf file, also double check the params. 

    return std::shared_ptr<ConnectionConfig>(zcashconf);
}

/**
 * Load connection settings from the UI, which indicates an unknown, external zcashd
 */ 
std::shared_ptr<ConnectionConfig> ConnectionLoader::loadFromSettings() {
    // Load from the QT Settings. 
    QSettings s;
    
    auto host        = s.value("connection/host").toString();
    auto port        = s.value("connection/port").toString();
    auto username    = s.value("connection/rpcuser").toString();
    auto password    = s.value("connection/rpcpassword").toString();
  
    if (username.isEmpty() || password.isEmpty())
        return nullptr;

    auto uiConfig = new ConnectionConfig{ host, port, username, password, false, false,"","", "", "","", ConnectionType::UISettingsZCashD};

    return std::shared_ptr<ConnectionConfig>(uiConfig);
}





/***********************************************************************************
 *  Connection Class
 ************************************************************************************/ 
Connection::Connection(MainWindow* m, QNetworkAccessManager* c, QNetworkRequest* r, 
                        std::shared_ptr<ConnectionConfig> conf) {
    this->restclient  = c;
    this->request     = r;
    this->config      = conf;
    this->main        = m;
}

Connection::~Connection() {
    delete restclient;
    delete request;
}

void Connection::doRPC(const QJsonValue& payload, const std::function<void(QJsonValue)>& cb,
                       const std::function<void(QNetworkReply*, const QJsonValue&)>& ne) {
    if (shutdownInProgress) {
        // Ignoring RPC because shutdown in progress
        return;
    }

    qDebug() << "RPC:" << payload["method"].toString() << payload;

    QJsonDocument jd_rpc_call(payload.toObject());
    QByteArray ba_rpc_call = jd_rpc_call.toJson();

    QNetworkReply *reply = restclient->post(*request, ba_rpc_call);

    QObject::connect(reply, &QNetworkReply::finished, [=] {
        reply->deleteLater();
        if (shutdownInProgress) {
            // Ignoring callback because shutdown in progress
            return;
        }
        
        QJsonDocument jd_reply = QJsonDocument::fromJson(reply->readAll());
        QJsonValue parsed;

        if (jd_reply.isObject())
            parsed = jd_reply.object();
        else
            parsed = jd_reply.array();

        if (reply->error() != QNetworkReply::NoError) {
            ne(reply, parsed);
            return;
        } 
        
        if (parsed.isNull()) {
            ne(reply, "Unknown error");
        }
        
        cb(parsed["result"]);        
    });
}

void Connection::doRPCWithDefaultErrorHandling(const QJsonValue& payload, const std::function<void(QJsonValue)>& cb) {
    doRPC(payload, cb, [=] (QNetworkReply* reply, const QJsonValue &parsed) {
        if (!parsed.isUndefined() && !parsed["error"].toObject()["message"].isNull()) {
            this->showTxError(parsed["error"].toObject()["message"].toString());
        } else {
            this->showTxError(reply->errorString());
        }
    });
}

void Connection::doRPCIgnoreError(const QJsonValue& payload, const std::function<void(QJsonValue)>& cb) {
    doRPC(payload, cb, [=] (auto, auto) {
        // Ignored error handling
    });
}

void Connection::showTxError(const QString& error) {
    if (error.isNull()) return;

    // Prevent multiple dialog boxes from showing, because they're all called async
    static bool shown = false;
    if (shown)
        return;

    shown = true;
    QMessageBox::critical(main, QObject::tr("Transaction Error"), QObject::tr("There was an error! : ") + "\n\n"
        + error, QMessageBox::StandardButton::Ok);
    shown = false;
}

/**
 * Prevent all future calls from going through
 */ 
void Connection::shutdown() {
    shutdownInProgress = true;
}