/*
 * This file is part of Remote Support Desktop
 * https://gitlab.das-netzwerkteam.de/RemoteWebApp/rwa.support.desktopapp
 * Copyright 2021 Daniel Teichmann <daniel.teichmann@das-netzwerkteam.de>
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the
 * Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include "DBusAPI.h"

/*!
 * \class DBusAPI
 * \brief The DBusAPI class provides all necessary D-Bus methods and distributes the response via signals.
 */
DBusAPI::DBusAPI() {
    _initDBus();
}

/*!
 * \brief Initializes private _dbus_rwa object.
 */
void DBusAPI::_initDBus() {
    if (!QDBusConnection::sessionBus().isConnected()) {
        qCritical() << "Cannot connect to the D-Bus session bus.";
    }

    // Create DBus object
    _dbus_rwa = new OrgArcticaProjectRWASupportSessionServiceInterface("org.ArcticaProject.RWASupportSessionService",
                                                                       "/RWASupportSessionService",
                                                                       QDBusConnection::sessionBus(),
                                                                       this->parent());

    qDebug("Initialized DBus object!");
}

/*!
 * \brief Ask the session service to start a session.
 *
 * \a host RWAHost object which includes all necessary information about a RWA host.
 */
void DBusAPI::start_request(RWAHost *host) {
    Q_ASSERT(host != nullptr);

    qDebug() << "Requesting D-Bus service to start a new session on host:" << host->alias();

    // Make an asynchrous 'start' call (Response will be sent to 'start_reply')
    QDBusPendingCall async = _dbus_rwa->asyncCall("start", host->uuid());
    QDBusPendingCallWatcher *watcher = new QDBusPendingCallWatcher(async, this);

    QObject::connect(watcher, SIGNAL(finished(QDBusPendingCallWatcher*)),
                     this, SLOT(start_reply(QDBusPendingCallWatcher*)));
}

/*!
 * \brief Method gets called when a D-Bus response is ready.
 *
 * \a call contains the D-Bus response (session service or for example maybe just a error message).
 *
 * TODO: Example of json input
 */
void DBusAPI::start_reply(QDBusPendingCallWatcher *call) {
    QString result = "";
    QDBusPendingReply<QString> reply = *call;
    if (reply.isError()) {
        qCritical() << "D-Bus 'start' request failed, this was the reply:";
        qCritical() << reply.error();

        if (QDBusError::ServiceUnknown == reply.error().type()) {
            qCritical() << "The session service was probably just not started!";
        }

        emit serviceStartResponse(nullptr);

        return;
    } else {
        result = reply.argumentAt<0>();
    }
    call->deleteLater();

    qDebug() << "Raw JSON from starting session is:" << result.toUtf8().replace('"', "");
    QJsonDocument doc = QJsonDocument::fromJson(result.toUtf8());

    emit serviceStartResponse(&doc);
}

/*!
 * \brief Ask the session service to stop session #<session_id>.
 *
 * \a host RWAHost object which includes all necessary information about a RWA host.
 *
 * \a session_id Unique identifier for a session in a specific host.
 */
void DBusAPI::stop_request(RWAHost *host, QString session_id) {
    Q_ASSERT(host != nullptr);
    Q_ASSERT(session_id != "");

    bool ok;
    long long session_id_number = session_id.toLongLong(&ok);

    // Sanity Check
    if(ok == false){
        qWarning() << QString("Unable to parse '%0' as long long!").arg(session_id);
        return;
    }

    qDebug().noquote() << QString("Requesting D-Bus service to stop "
                                  "session #'%0' on host '%1'")
                          .arg(session_id)
                          .arg(host->alias());

    // Make an asynchrous 'start' call (Response will be sent to 'stop_reply')
    QDBusPendingCall async = _dbus_rwa->asyncCall("stop", host->uuid(), session_id_number);
    QDBusPendingCallWatcher *watcher = new QDBusPendingCallWatcher(async, this);

    QObject::connect(watcher, SIGNAL(finished(QDBusPendingCallWatcher*)),
                     this, SLOT(stop_reply(QDBusPendingCallWatcher*)));
}

/*!
 * \brief Method gets called when a D-Bus response is ready.
 *
 * \a call contains the D-Bus response (session service or for example maybe just a error message).
 *
 * TODO: Example of json input
 */
void DBusAPI::stop_reply(QDBusPendingCallWatcher *call) {
    QString result = "";

    QDBusPendingReply<QString> reply = *call;
    if (reply.isError()) {
        qCritical() << "D-Bus 'stop' request failed, this was the reply:";
        qCritical() << reply.error();

        if (QDBusError::ServiceUnknown == reply.error().type()) {
            qCritical() << "The session service was probably just not started!";
        }

        emit serviceStopResponse(nullptr);

        return;
    } else {
        result = reply.argumentAt<0>();
    }
    call->deleteLater();

    qDebug() << "Raw JSON from stopping a session is:" << result.toUtf8().replace('"', "");
    QJsonDocument doc = QJsonDocument::fromJson(result.toUtf8());

    emit serviceStopResponse(&doc);
}

/*!
 * \brief Ask the session service for status of <session_id>.
 *
 * \a host RWAHost object which includes all necessary information about a RWA host.
 *
 * \a session_id Unique identifier for a session in a specific host.
 */
void DBusAPI::status_request(RWAHost *host, QString session_id) {
    Q_ASSERT(host != nullptr);
    Q_ASSERT(session_id != "");

    bool ok;
    long long session_id_number = session_id.toLongLong(&ok);

    // Sanity Check
    if(ok == false){
        qWarning() << QString("Unable to parse '%0' as long long!").arg(session_id);
        return;
    }

    qDebug().noquote() << QString("Requesting D-Bus service for status of session "
                                  "#'%0' on host '%1'").arg(session_id).arg(host->alias());

    // Make an asynchrous 'start' call (Response will be sent to 'status_reply')
    QDBusPendingCall async = _dbus_rwa->asyncCall("status", host->uuid(), session_id_number);
    QDBusPendingCallWatcher *watcher = new QDBusPendingCallWatcher(async, this);

    QObject::connect(watcher, SIGNAL(finished(QDBusPendingCallWatcher*)),
                     this, SLOT(status_reply(QDBusPendingCallWatcher*)));
}

/*!
 * \brief Forces the session service to refresh it's status of <session_id> and tell us about it then.
 *
 * \a host RWAHost object which includes all necessary information about a RWA host.
 *
 * \a session_id Unique identifier for a session in a specific host.
 */
void DBusAPI::refresh_status_request(RWAHost *host, QString session_id) {
    Q_ASSERT(host != nullptr);
    Q_ASSERT(session_id != "");

    bool ok;
    long long session_id_number = session_id.toLongLong(&ok);

    // Sanity Check
    if(ok == false){
        qWarning() << QString("Unable to parse '%0' as long long!").arg(session_id);
        return;
    }

    qDebug().noquote() << QString("Requesting D-Bus service for refresh_status of session "
                                  "#'%0' on host '%1'").arg(session_id).arg(host->alias());

    // Make an asynchrous 'start' call (Response will be sent to 'status_reply')
    QDBusPendingCall async = _dbus_rwa->asyncCall("refresh_status", host->uuid(), session_id_number);
    QDBusPendingCallWatcher *watcher = new QDBusPendingCallWatcher(async, this);

    QObject::connect(watcher, SIGNAL(finished(QDBusPendingCallWatcher*)),
                     this, SLOT(status_reply(QDBusPendingCallWatcher*)));
}

/*!
 * \brief Method gets called when a D-Bus response is ready.
 *
 * \a call contains the D-Bus response (session service or for example maybe just a error message).
 *
 * TODO: Example of json input
 */
void DBusAPI::status_reply(QDBusPendingCallWatcher *call){
    QString result = "";

    QDBusPendingReply<QString> reply = *call;
    if (reply.isError()) {
        qCritical() << "D-Bus '(refresh_)status' request failed, this was the reply:";
        qCritical() << reply.error();

        if (QDBusError::ServiceUnknown == reply.error().type()) {
            qCritical() << "The session service was probably just not started!";
        }

        emit serviceStatusResponse(nullptr);

        return;
    } else {
        result = reply.argumentAt<0>();
    }
    call->deleteLater();

    // Get the QJsonObject
    qDebug() << "Raw JSON from a status request for a session is:" << result.toUtf8().replace('"', "");
    QJsonDocument doc = QJsonDocument::fromJson(result.toUtf8());

    emit serviceStatusResponse(&doc);
}

/*!
 * \brief This method requests the session service to list all RWAHosts.
 */
void DBusAPI::get_web_app_hosts_request() {
    qDebug().noquote() << QString("Requesting D-Bus service to list "
                                  "all remote web app hosts");

    // Make an asynchrous 'get_web_app_hosts' call
    // Response will be sent to 'get_web_app_hosts_reply'
    QDBusPendingCall async = _dbus_rwa->asyncCall("get_web_app_hosts");
    QDBusPendingCallWatcher *watcher = new QDBusPendingCallWatcher(async, this);

    QObject::connect(watcher, SIGNAL(finished(QDBusPendingCallWatcher*)),
                     this, SLOT(get_web_app_hosts_reply(QDBusPendingCallWatcher*)));
}

/*!
 * \brief This method requests the session service to add a RWAHost to its configuration files.
 *
 * \a host_url is the remote web app adress which will be used by the session service to coordinate
 * sessions, connections, settings and such.
 */
void DBusAPI::add_web_app_host_request(QString host_url, QString host_alias) {
    Q_ASSERT(host_url != "");
    Q_ASSERT(host_alias != "");

    qDebug().noquote() << QString("Requesting D-Bus service to register new "
                                  "remote web app host '%0' with url '%1'").arg(host_alias).arg(host_url);

    // Make an asynchrous 'add_web_app_host' call
    // Response will be sent to 'add_web_app_host_reply'
    QDBusPendingCall async = _dbus_rwa->asyncCall("add_web_app_host", host_url, host_alias);
    QDBusPendingCallWatcher *watcher = new QDBusPendingCallWatcher(async, this);

    QObject::connect(watcher, SIGNAL(finished(QDBusPendingCallWatcher*)),
                     this, SLOT(add_web_app_host_reply(QDBusPendingCallWatcher*)));
}

/*!
 * \brief This method requests the session service to remove a RWAHost from its configuration files.
 *
 * \a host_uuid Unique identifier which all hosts have.
 */
void DBusAPI::remove_web_app_host_request(QString host_uuid) {
    Q_ASSERT(host_uuid != "");

    qDebug().noquote() << QString("Requesting D-Bus service to list "
                                  "all remote web app hosts");

    // Make an asynchrous 'remove_web_app_host' call
    // Response will be sent to 'remove_web_app_host_reply'
    QDBusPendingCall async = _dbus_rwa->asyncCall("remove_web_app_host", host_uuid);
    QDBusPendingCallWatcher *watcher = new QDBusPendingCallWatcher(async, this);

    QObject::connect(watcher, SIGNAL(finished(QDBusPendingCallWatcher*)),
                     this, SLOT(remove_web_app_host_reply(QDBusPendingCallWatcher*)));
}

/*!
 * \brief Method gets called when a D-Bus response is ready.
 *
 * \a call contains the D-Bus response (session service or for example maybe just a error message).
 *
 * TODO: Example of json input
 */
void DBusAPI::get_web_app_hosts_reply(QDBusPendingCallWatcher *call){
    QString result = "";

    QDBusPendingReply<QString> reply = *call;
    if (reply.isError()) {
        qCritical() << "D-Bus 'get_web_app_hosts' request failed, this was the reply:";
        qCritical() << reply.error();

        if (QDBusError::ServiceUnknown == reply.error().type()) {
            qCritical() << "The session service was probably just not started!";
        }

        emit serviceGetWebAppHostsResponse(nullptr);

        return;
    } else {
        result = reply.argumentAt<0>();
    }
    call->deleteLater();

    // Get the QJsonObject
    qDebug() << "Raw JSON from the remote web app host listing request:" << result.toUtf8().replace('"', "");
    QJsonDocument doc = QJsonDocument::fromJson(result.toUtf8());

    emit serviceGetWebAppHostsResponse(&doc);
}

/*!
 * \brief Method gets called when a D-Bus response is ready.
 *
 * \a call contains the D-Bus response (session service or for example maybe just a error message).
 *
 * TODO: Example of json input
 */
void DBusAPI::add_web_app_host_reply(QDBusPendingCallWatcher *call){
    QString result = "";

    QDBusPendingReply<QString> reply = *call;
    if (reply.isError()) {
        qCritical() << "D-Bus 'add_web_app_host' request failed, this was the reply:";
        qCritical() << reply.error();

        if (QDBusError::ServiceUnknown == reply.error().type()) {
            qCritical() << "The session service was probably just not started!";
        }

        emit serviceAddWebAppHostResponse(nullptr);

        return;
    } else {
        result = reply.argumentAt<0>();
    }
    call->deleteLater();

    // Get the QJsonObject
    qDebug() << "Raw JSON from the remote web app host register request:" << result.toUtf8().replace('"', "");
    QJsonDocument doc = QJsonDocument::fromJson(result.toUtf8());

    emit serviceAddWebAppHostResponse(&doc);
}

/*!
 * \brief Method gets called when a D-Bus response is ready.
 *
 * \a call contains the D-Bus response (session service or for example maybe just a error message).
 *
 * TODO: Example of json input
 */
void DBusAPI::remove_web_app_host_reply(QDBusPendingCallWatcher *call){
    QString result = "";

    QDBusPendingReply<QString> reply = *call;
    if (reply.isError()) {
        qCritical() << "D-Bus 'remove_web_app_host' request failed, this was the reply:";
        qCritical() << reply.error();

        if (QDBusError::ServiceUnknown == reply.error().type()) {
            qCritical() << "The session service was probably just not started!";
        }

        emit serviceRemoveWebAppHostResponse(nullptr);

        return;
    } else {
        result = reply.argumentAt<0>();
    }
    call->deleteLater();

    // Get the QJsonObject
    qDebug() << "Raw JSON from the remote web app host deletion request:" << result.toUtf8().replace('"', "");
    QJsonDocument doc = QJsonDocument::fromJson(result.toUtf8());

    emit serviceRemoveWebAppHostResponse(&doc);
}