/*
 * Copyright (C) 2008-2020 The QXmpp developers
 *
 * Author:
 *  Linus Jahn
 *  Germán Márquez Mejía
 *
 * Source:
 *  https://github.com/qxmpp-project/qxmpp
 *
 * This file is a part of QXmpp library.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 */

#include "QXmppPubSubManager.h"

#include <QDomElement>
#include <QFutureInterface>

#include "QXmppClient.h"
#include "QXmppConstants_p.h"
#include "QXmppPubSubItem.h"
#include "QXmppPubSubEventManager.h"
#include "QXmppPubSubSubscription.h"
#include "QXmppPubSubAffiliation.h"
#include "QXmppPubSubSubscribeOptions.h"
#include "QXmppStanza.h"
#include "QXmppUtils.h"

using namespace QXmpp::Private;

///
/// \class QXmppPubSubManager
///
/// \brief The QXmppPubSubManager aims to provide publish-subscribe
/// functionality as specified in \xep{0060, Publish-Subscribe} (PubSub).
///
/// However, it currently only supports a few PubSub use cases but all of the
/// \xep{0060, Personal Eventing Protocol} (PEP) ones. PEP allows
/// a standard XMPP user account to function as a virtual PubSub service.
///
/// To make use of this manager, you need to instantiate it and load it into
/// the QXmppClient instance as follows:
///
/// \code
/// QXmppPubSubManager *manager = new QXmppPubSubManager;
/// client->addExtension(manager);
/// \endcode
///
/// \note To subscribe to PEP event notifications use the
/// QXmppClientExtension::discoveryFeatures method of your client extension
/// according to section 9.2 of \xep{0060}. For example:
/// \code
/// QStringList YourExtension::discoveryFeatures() const
/// {
///    return { "http://jabber.org/protocol/tune+notify" };
/// }
/// \endcode
///
/// \todo
///  - Item pagination:
///    Requesting a continuation
///  - Requesting most recent items (max_items=x):
///    https://xmpp.org/extensions/xep-0060.html#subscriber-retrieve-requestrecent
///  - (Manually) subscribing to a node
///
/// \ingroup Managers
///
/// \since QXmpp 1.5
///

///
/// \struct QXmppPubSubManager::Items<T>
///
/// Struct containing a list of items and a continuation if the results were
/// incomplete.
///

///
/// \typedef QXmppPubSubManager::Result
///
/// Result of a generic request without a return value. Contains Success in case
/// everything went well. If the returned IQ contained an error a
/// QXmppStanza::Error is reported.
///

///
/// \typedef QXmppPubSubManager::NodesResult
///
/// Type containing a list of node names or the returned IQ error
/// (QXmppStanza::Error).
///

///
/// \typedef QXmppPubSubManager::InstantNodeResult
///
/// Contains the name of the new node (QString) or the returned IQ error
/// (QXmppStanza::Error).
///

///
/// \typedef QXmppPubSubManager::ItemResult
///
/// Contains the item if it has been found (std::optional<T>) or the returned IQ
/// error (QXmppStanza::Error).
///

///
/// \typedef QXmppPubSubManager::ItemsResult
///
/// Contains all items that have been found (QVector<T>) or the returned IQ
/// error (QXmppStanza::Error).
///

///
/// \typedef QXmppPubSubManager::PublishItemResult
///
/// Contains the ID of the item, if no ID was set in the request (QString) or
/// the returned IQ error (QXmppStanza::Error).
///

///
/// \typedef QXmppPubSubManager::PublishItemsResult
///
/// Contains the IDs of the items, if no IDs were set in the request
/// (QVector<QString>) or the returned IQ error (QXmppStanza::Error).
///

///
/// \typedef QXmppPubSubManager::SubscriptionsResult
///
/// Contains a list of active subscriptions (QVector<QXmppPubSubSubscription>)
/// or the returned IQ error (QXmppStanza::Error).
///

///
/// \typedef QXmppPubSubManager::AffiliationsResult
///
/// Contains the list of affiliations with the node(s)
/// (QVector<QXmppPubSubAffiliation>) or the returned IQ error
/// (QXmppStanza::Error).
///

///
/// \typedef QXmppPubSubManager::OptionsResult
///
/// Contains the current subscribe options (QXmppPubSubSubscribeOptions) or the
/// returned IQ error (QXmppStanza::Error).
///

///
/// Default constructor.
///
QXmppPubSubManager::QXmppPubSubManager()
{
}

///
/// Default destructor.
///
QXmppPubSubManager::~QXmppPubSubManager()
{
}

///
/// Requests all listed nodes of a pubsub service via service discovery.
///
/// This uses a \xep{0030, Service Discovery} items request to get a list of
/// nodes.
///
/// \param jid Jabber ID of the entity hosting the pubsub service
/// \return
///
QFuture<QXmppPubSubManager::NodesResult> QXmppPubSubManager::fetchNodes(const QString &jid)
{
    QXmppDiscoveryIq request;
    request.setType(QXmppIq::Get);
    request.setQueryType(QXmppDiscoveryIq::ItemsQuery);
    request.setTo(jid);

    return chainIq(client()->sendIq(std::move(request)), this, [](QXmppDiscoveryIq &&iq) -> NodesResult {
        const auto items = iq.items();
        QVector<QString> nodes;
        for (const auto &item : items) {
            // only accept non-empty nodes
            if (const auto node = item.node(); !node.isEmpty()) {
                nodes << node;
            }
        }
        // make unique
        std::sort(nodes.begin(), nodes.end());
        nodes.erase(std::unique(nodes.begin(), nodes.end()), nodes.end());
        return nodes;
    });
}

///
/// Creates an empty pubsub node with the default configuration.
///
/// Calling this before QXmppPubSubManager::publishItems is usually not
/// necessary when publishing to a node for the first time if the service
/// suppports the auto-create feature (Section 7.1.4 of \xep{0060}).
///
/// \param jid Jabber ID of the entity hosting the pubsub service
/// \param nodeName the name of the node to be created
/// \return
///
auto QXmppPubSubManager::createNode(const QString &jid, const QString &nodeName) -> QFuture<Result>
{
    QXmppPubSubIq request;
    request.setType(QXmppIq::Set);
    request.setQueryType(QXmppPubSubIq<>::Create);
    request.setQueryNode(nodeName);
    request.setTo(jid);

    return client()->sendGenericIq(std::move(request));
}

///
/// Creates an instant pubsub node with the default configuration.
///
/// The pubsub service automatically generates a random node name. On success
/// it is returned via the QFuture.
///
/// \param jid Jabber ID of the entity hosting the pubsub service
/// \return
///
QFuture<QXmppPubSubManager::InstantNodeResult> QXmppPubSubManager::createInstantNode(const QString &jid)
{
    QXmppPubSubIq request;
    request.setType(QXmppIq::Set);
    request.setQueryType(QXmppPubSubIq<>::Create);
    request.setTo(jid);

    return chainIq(client()->sendIq(std::move(request)), this,
                   [](const QXmppPubSubIq<> &iq) -> InstantNodeResult {
        return iq.queryNode();
    });
}

///
/// Deletes a pubsub node.
///
/// \param jid Jabber ID of the entity hosting the pubsub service
/// \param nodeName the name of the node to delete along with all of its items
/// \return
///
auto QXmppPubSubManager::deleteNode(const QString &jid, const QString &nodeName) -> QFuture<Result>
{
    QXmppPubSubIq request;
    request.setType(QXmppIq::Set);
    request.setQueryType(QXmppPubSubIq<>::Delete);
    request.setQueryNode(nodeName);
    request.setTo(jid);

    return client()->sendGenericIq(std::move(request));
}

///
/// Deletes an item from a pubsub node.
///
/// \param jid Jabber ID of the entity hosting the pubsub service
/// \param nodeName the name of the node to delete the item from
/// \param itemId the ID of the item to delete
/// \return
///
auto QXmppPubSubManager::retractItem(const QString &jid, const QString &nodeName, const QString &itemId) -> QFuture<Result>
{
    QXmppPubSubIq request;
    request.setType(QXmppIq::Set);
    request.setQueryType(QXmppPubSubIq<>::Retract);
    request.setQueryNode(nodeName);
    request.setItems({QXmppPubSubItem(itemId)});
    request.setTo(jid);

    return client()->sendGenericIq(std::move(request));
}

///
/// Purges all items from a node.
///
/// \param jid Jabber ID of the entity hosting the pubsub service
/// \param nodeName the name of the PEP node to delete along with all of its
/// items
/// \return
///
auto QXmppPubSubManager::purgeItems(const QString &jid, const QString &nodeName) -> QFuture<Result>
{
    QXmppPubSubIq request;
    request.setType(QXmppIq::Set);
    request.setQueryType(QXmppPubSubIq<>::Purge);
    request.setQueryNode(nodeName);
    request.setTo(jid);

    return client()->sendGenericIq(std::move(request));
}

///
/// Requests all subscriptions with a PubSub service.
///
/// \param jid JID of the pubsub service
/// \return
///
QFuture<QXmppPubSubManager::SubscriptionsResult> QXmppPubSubManager::requestSubscriptions(const QString &jid)
{
    return requestSubscriptions(jid, {});
}

///
/// Requests the subscription(s) with a specific PubSub node.
///
/// \param jid JID of the pubsub service
/// \param nodeName Name of the node on the pubsub service
/// \return
///
QFuture<QXmppPubSubManager::SubscriptionsResult> QXmppPubSubManager::requestSubscriptions(const QString &jid, const QString &nodeName)
{
    QXmppPubSubIq request;
    request.setType(QXmppIq::Get);
    request.setTo(jid);
    request.setQueryType(QXmppPubSubIq<>::Subscriptions);
    request.setQueryNode(nodeName);

    return chainIq(client()->sendIq(std::move(request)), this,
                   [](const QXmppPubSubIq<> &iq) -> SubscriptionsResult {
        return iq.subscriptions();
    });
}

///
/// Requests the affiliations of all users on a PubSub node.
///
/// This can be used to view and manage affiliations of other users with a node.
/// Owner privileges are required.
///
/// \param jid JID of the pubsub service
/// \param nodeName Name of the pubsub node on the service.
/// \return
///
QFuture<QXmppPubSubManager::AffiliationsResult> QXmppPubSubManager::requestNodeAffiliations(const QString &jid, const QString &nodeName)
{
    QXmppPubSubIq request;
    request.setType(QXmppIq::Get);
    request.setTo(jid);
    request.setQueryType(QXmppPubSubIq<>::OwnerAffiliations);
    request.setQueryNode(nodeName);

    return chainIq(client()->sendIq(std::move(request)), this,
                   [](const QXmppPubSubIq<> &iq) -> AffiliationsResult {
        return iq.affiliations();
    });
}

///
/// Requests the user's affiliations with all PubSub nodes on a PubSub service.
///
/// \param jid JID of the pubsub service
/// \return
///
QFuture<QXmppPubSubManager::AffiliationsResult> QXmppPubSubManager::requestAffiliations(const QString &jid)
{
    return requestAffiliations(jid, {});
}

///
/// Requests the user's affiliations with a PubSub node.
///
/// \param jid JID of the pubsub service
/// \param nodeName Name of the pubsub node on the service.
/// \return
///
QFuture<QXmppPubSubManager::AffiliationsResult> QXmppPubSubManager::requestAffiliations(const QString &jid, const QString &nodeName)
{
    QXmppPubSubIq request;
    request.setType(QXmppIq::Get);
    request.setTo(jid);
    request.setQueryType(QXmppPubSubIq<>::Affiliations);
    request.setQueryNode(nodeName);

    return chainIq(client()->sendIq(std::move(request)), this,
                   [](const QXmppPubSubIq<> &iq) -> AffiliationsResult {
        return iq.affiliations();
    });
}

///
/// Requests the subscribe options form of the own subscription to a node.
///
/// \param service JID of the pubsub service
/// \param nodeName Name of the pubsub node on the service.
/// \return
///
QFuture<QXmppPubSubManager::OptionsResult> QXmppPubSubManager::requestSubscribeOptions(const QString &service, const QString &nodeName)
{
    return requestSubscribeOptions(service, nodeName, client()->configuration().jidBare());
}

///
/// Requests the subscribe options form of a user's subscription to a node.
///
/// \param service JID of the pubsub service
/// \param nodeName Name of the pubsub node on the service
/// \param subscriberJid JID of the user to request the options for
/// \return
///
QFuture<QXmppPubSubManager::OptionsResult> QXmppPubSubManager::requestSubscribeOptions(const QString &service, const QString &nodeName, const QString &subscriberJid)
{
    QXmppPubSubIq request;
    request.setType(QXmppIq::Get);
    request.setTo(service);
    request.setQueryType(QXmppPubSubIq<>::Options);
    request.setQueryNode(nodeName);
    request.setQueryJid(subscriberJid);

    return chainIq(client()->sendIq(std::move(request)), this,
                   [](const QXmppPubSubIq<> &iq) -> OptionsResult {
        if (const auto form = iq.dataForm()) {
            if (const auto options = QXmppPubSubSubscribeOptions::fromDataForm(*form)) {
                return *options;
            }
        }

        // "real" stanza errors are already handled
        using Error = QXmppStanza::Error;
        return Error(Error::Cancel,
                     Error::Condition::InternalServerError,
                     QStringLiteral("Server returned invalid data form."));
    });
}

///
/// Sets the subscription options for our own account.
///
/// \param service JID of the pubsub service
/// \param nodeName Name of the pubsub node on the service
/// \param options The new options to be set
/// \return
///
QFuture<QXmppPubSubManager::Result> QXmppPubSubManager::setSubscribeOptions(const QString &service, const QString &nodeName, const QXmppPubSubSubscribeOptions &options)
{
    return setSubscribeOptions(service, nodeName, options, client()->configuration().jidBare());
}

///
/// Sets the subscription options for another users's account.
///
/// \param service JID of the pubsub service
/// \param nodeName Name of the pubsub node on the service
/// \param options The new options to be set
/// \param subscriberJid The JID of the user
/// \return
///
QFuture<QXmppPubSubManager::Result> QXmppPubSubManager::setSubscribeOptions(const QString &service, const QString &nodeName, const QXmppPubSubSubscribeOptions &options, const QString &subscriberJid)
{
    QXmppPubSubIq request;
    request.setType(QXmppIq::Set);
    request.setTo(service);
    request.setQueryType(QXmppPubSubIq<>::Options);
    request.setDataForm(options);
    request.setQueryNode(nodeName);
    request.setQueryJid(subscriberJid);
    return client()->sendGenericIq(std::move(request));
}

///
/// \fn QXmppPubSubManager::createPepNode
///
/// Creates an empty PEP node with the default configuration.
///
/// This is a convenience method equivalent to calling
/// QXmppPubSubManager::createNode on the current account's bare JID.
///
/// Calling this before QXmppPubSubManager::publishPepItems is usually not
/// necessary when publishing to a node for the first time if the service
/// suppports the auto-create feature (Section 7.1.4 of \xep{0060}).
///
/// \param nodeName the name of the PEP node to be created
/// \return
///

///
/// \fn QXmppPubSubManager::deletePepNode
///
/// Deletes a PEP node.
///
/// This is a convenience method equivalent to calling
/// QXmppPubSubManager::deleteNode on the current account's bare JID.
///
/// \param nodeName the name of the PEP node to delete along with all of its
/// items
/// \return
///

///
/// \fn QXmppPubSubManager::retractPepItem
///
/// Deletes an item from a PEP node.
///
/// This is a convenience method equivalent to calling
/// QXmppPubSubManager::retractItem on the current account's bare JID.
///
/// \param nodeName the name of the PEP node to delete the item from
/// \param itemId the ID of the item to delete
/// \return
///

///
/// \fn QXmppPubSubManager::purgePepItems
///
/// Purges all items from a PEP node.
///
/// This is a convenience method equivalent to calling
/// QXmppPubSubManager::purgeItems on the current account's bare JID.
///
/// \param nodeName the name of the PEP node to delete along with all of its
/// items
/// \return
///

/// \cond
QStringList QXmppPubSubManager::discoveryFeatures() const
{
    return {
        ns_pubsub_rsm
    };
}

bool QXmppPubSubManager::handleStanza(const QDomElement &element)
{
    if (element.tagName() != "message") {
        return false;
    }
    for (auto event = element.firstChildElement("event");
         !event.isNull();
         event = event.nextSiblingElement("event")) {
        if (event.namespaceURI() == ns_pubsub_event) {
            const auto service = element.attribute("from");
            const auto node = event.firstChildElement().attribute("node");

            const auto extensions = client()->extensions();
            for (auto *extension : extensions) {
                if (auto *eventManager = qobject_cast<QXmppPubSubEventManager*>(extension)) {
                    if (eventManager->handlePubSubEvent(element, service, node)) {
                        return true;
                    }
                }
            }
        }
    }
    return false;
}

QXmppPubSubIq<> QXmppPubSubManager::requestItemsIq(const QString &jid, const QString &nodeName, const QStringList &itemIds)
{
    QXmppPubSubIq request;
    request.setTo(jid);
    request.setType(QXmppIq::Get);
    request.setQueryType(QXmppPubSubIqBase::Items);
    request.setQueryNode(nodeName);

    if (!itemIds.isEmpty()) {
        QVector<QXmppPubSubItem> items;
        items.reserve(itemIds.size());
        for (const auto &id : itemIds) {
            items << QXmppPubSubItem(id);
        }
        request.setItems(items);
    }
    return request;
}

auto QXmppPubSubManager::publishItem(QXmppPubSubIqBase &&request) -> QFuture<PublishItemResult>
{
    request.setType(QXmppIq::Set);
    request.setQueryType(QXmppPubSubIqBase::Publish);

    return chainIq(client()->sendIq(std::move(request)), this,
                   [](const QXmppPubSubIq<> &iq) -> PublishItemResult {
        if (!iq.items().isEmpty()) {
            return iq.items().constFirst().id();
        } else {
            return QString();
        }
    });
}

auto QXmppPubSubManager::publishItems(QXmppPubSubIqBase &&request) -> QFuture<PublishItemsResult>
{
    request.setType(QXmppIq::Set);
    request.setQueryType(QXmppPubSubIqBase::Publish);

    return chainIq(client()->sendIq(std::move(request)), this,
                   [](const QXmppPubSubIq<> &iq) -> PublishItemsResult {
        const auto itemToId = [](const QXmppPubSubItem &item) {
            return item.id();
        };

        const auto items = iq.items();
        QVector<QString> ids(items.size());
        std::transform(items.begin(), items.end(), ids.begin(), itemToId);
        return ids;
    });
}
/// \endcond