#include "sshsession.h"

#include <QEventLoop>
#include <QtConcurrent>

SshSession::SshSession(QObject *parent) : QObject(parent)
{

}

SshSession::~SshSession()
{
    if (m_isNeedSendChannelEof) {
        ssh_channel_send_eof(m_channel);
    }
    if (m_isChannelOpened) {
        ssh_channel_free(m_channel);
    }
    if (m_isSessionConnected) {
        ssh_disconnect(m_session);
    }
    ssh_free(m_session);
}

ErrorCode SshSession::connectToHost(const ServerCredentials &credentials)
{
    if (m_session == NULL) {
        return ErrorCode::InternalError;
    }

    int port = credentials.port;
    int logVerbosity = SSH_LOG_NOLOG;
    std::string hostIp = credentials.hostName.toStdString();
    std::string hostUsername = credentials.userName.toStdString() + "@" + hostIp;

    ssh_options_set(m_session, SSH_OPTIONS_HOST, hostIp.c_str());
    ssh_options_set(m_session, SSH_OPTIONS_PORT, &port);
    ssh_options_set(m_session, SSH_OPTIONS_USER, hostUsername.c_str());
    ssh_options_set(m_session, SSH_OPTIONS_LOG_VERBOSITY, &logVerbosity);

    int connectionResult = ssh_connect(m_session);

    if (connectionResult != SSH_OK) {
        qDebug() << ssh_get_error(m_session);
        return ErrorCode::SshTimeoutError;
    }

    m_isSessionConnected = true;

    std::string authUsername = credentials.userName.toStdString();

    int authResult = SSH_ERROR;
    if (credentials.password.contains("BEGIN") && credentials.password.contains("PRIVATE KEY")) {
        ssh_key privateKey;
        ssh_pki_import_privkey_base64(credentials.password.toStdString().c_str(), nullptr, nullptr, nullptr, &privateKey);
        authResult = ssh_userauth_publickey(m_session, authUsername.c_str(), privateKey);
    }
    else {
        authResult = ssh_userauth_password(m_session, authUsername.c_str(), credentials.password.toStdString().c_str());
    }

    if (authResult != SSH_OK) {
        qDebug() << ssh_get_error(m_session);
        return ErrorCode::SshAuthenticationError;
    }

    return ErrorCode::NoError;
}

ErrorCode SshSession::initChannel(const ServerCredentials &credentials)
{
    m_session = ssh_new();

    ErrorCode error = connectToHost(credentials);
    if (error) {
        return error;
    }
    m_channel = ssh_channel_new(m_session);

    if (m_channel == NULL) {
        qDebug() << ssh_get_error(m_session);
        return ErrorCode::SshAuthenticationError;
    }

    int result = ssh_channel_open_session(m_channel);

    if (result == SSH_OK && ssh_channel_is_open(m_channel)) {
        qDebug() << "SSH chanel opened";
        m_isChannelOpened = true;
    } else {
        qDebug() << ssh_get_error(m_session);
        return ErrorCode::SshAuthenticationError;
    }

    result = ssh_channel_request_pty(m_channel);
    if (result != SSH_OK) {
        qDebug() << ssh_get_error(m_session);
        return ErrorCode::SshInternalError;
    }

    result = ssh_channel_change_pty_size(m_channel, 80, 1024);
    if (result != SSH_OK) {
        qDebug() << ssh_get_error(m_session);
        return ErrorCode::SshInternalError;
    }

//    result = ssh_channel_request_shell(m_channel);
//    if (result != SSH_OK) {
//        qDebug() << ssh_get_error(m_session);
//        return ErrorCode::SshInternalError;
//    }

    return ErrorCode::NoError;
}

ErrorCode SshSession::writeToChannel(const QString &data,
                                     const std::function<void(const QString &)> &cbReadStdOut,
                                     const std::function<void(const QString &)> &cbReadStdErr)
{
    QFutureWatcher<ErrorCode> watcher;
    connect(&watcher, &QFutureWatcher<ErrorCode>::finished, this, &SshSession::writeToChannelFinished);

    QFuture<ErrorCode> future = QtConcurrent::run([this, &data, &cbReadStdOut, &cbReadStdErr]() {
        const int channelReadTimeoutMs = 10;
        const size_t bufferSize = 2048;

        int bytesRead = 0;
        int attempts = 0;
        char buffer[bufferSize];

        std::string output1;
        if (ssh_channel_is_open(m_channel) && !ssh_channel_is_eof(m_channel)) {
            bytesRead = ssh_channel_read_timeout(m_channel, buffer, sizeof(buffer), 0, channelReadTimeoutMs);
            while (bytesRead > 0)
            {
                output1.append(buffer, bytesRead);
                bytesRead = ssh_channel_read_timeout(m_channel, buffer, sizeof(buffer), 0, channelReadTimeoutMs);
            }
        }
        qDebug().noquote() << "stdOut: " << QString(output1.c_str());

        int bytesWritten = ssh_channel_write(m_channel, data.toUtf8(), (uint32_t)data.size());
        if (bytesWritten == data.size()) {
            std::string stdOut;
            std::string stdErr;

            auto readOutput = [&](bool isStdErr) {
                std::string output;
                if (ssh_channel_is_open(m_channel) && !ssh_channel_is_eof(m_channel)) {
                    bytesRead = ssh_channel_read_timeout(m_channel, buffer, sizeof(buffer), isStdErr, channelReadTimeoutMs);
                    while (bytesRead > 0)
                    {
                        output.append(buffer, bytesRead);
                        bytesRead = ssh_channel_read_timeout(m_channel, buffer, sizeof(buffer), isStdErr, channelReadTimeoutMs);
                    }
                }
                return output;
            };

            stdOut = readOutput(false);
            stdErr = readOutput(true);

            if (cbReadStdOut){
                cbReadStdOut(stdOut.c_str());
            }
            if (cbReadStdErr){
                cbReadStdErr(stdErr.c_str());
            }
            if (!stdOut.empty()) {
                qDebug().noquote() << "stdOut: " << QString(stdOut.c_str());
            }
            if (!stdErr.empty()) {
                qDebug().noquote() << "stdErr: " << QString(stdOut.c_str());
            }
        } else {
            qDebug() << ssh_get_error(m_session);
            return ErrorCode::SshInternalError;
        }
        m_isNeedSendChannelEof = true;
        return ErrorCode::NoError;
    });
    watcher.setFuture(future);

    QEventLoop wait;

    QObject::connect(this, &SshSession::writeToChannelFinished, &wait, &QEventLoop::quit);
    wait.exec();

    return watcher.result();
}