// For license of this file, see <project-root-folder>/LICENSE.md.

#include "src/standardserviceroot.h"

#include "src/definitions.h"
#include "src/gui/formdiscoverfeeds.h"
#include "src/gui/formeditstandardaccount.h"
#include "src/gui/formstandardfeeddetails.h"
#include "src/gui/formstandardimportexport.h"
#include "src/parsers/atomparser.h"
#include "src/parsers/icalparser.h"
#include "src/parsers/jsonparser.h"
#include "src/parsers/rdfparser.h"
#include "src/parsers/rssparser.h"
#include "src/parsers/sitemapparser.h"
#include "src/standardcategory.h"
#include "src/standardfeed.h"
#include "src/standardfeedsimportexportmodel.h"
#include "src/standardserviceentrypoint.h"

#include <librssguard/database/databasequeries.h>
#include <librssguard/definitions/definitions.h>
#include <librssguard/exceptions/applicationexception.h>
#include <librssguard/exceptions/feedfetchexception.h>
#include <librssguard/exceptions/scriptexception.h>
#include <librssguard/gui/messagebox.h>
#include <librssguard/miscellaneous/application.h>
#include <librssguard/miscellaneous/iconfactory.h>
#include <librssguard/miscellaneous/mutex.h>
#include <librssguard/miscellaneous/settings.h>
#include <librssguard/network-web/networkfactory.h>
#include <librssguard/services/abstract/gui/formcategorydetails.h>

#if defined(NO_LITE)
#include <librssguard/gui/webviewers/webengine/webengineviewer.h>
#include <librssguard/network-web/webengine/webenginepage.h>
#endif

#if defined(ENABLE_COMPRESSED_SITEMAP)
#include "src/3rd-party/qcompressor/qcompressor.h"
#endif

#include <QAction>
#include <QSqlTableModel>
#include <QStack>
#include <QTextCodec>
#include <QThread>

StandardServiceRoot::StandardServiceRoot(RootItem* parent) : ServiceRoot(parent), m_spacingSameHostsRequests(0) {
  setIcon(StandardServiceEntryPoint().icon());
  setDescription(tr("This is the obligatory service account for standard RSS/RDF/ATOM feeds."));
}

StandardServiceRoot::~StandardServiceRoot() {
  qDeleteAll(m_feedContextMenu);
}

void StandardServiceRoot::onDatabaseCleanup() {
  for (Feed* fd : getSubTreeFeeds()) {
    qobject_cast<StandardFeed*>(fd)->setLastEtag({});
  }
}

void StandardServiceRoot::start(bool freshly_activated) {
  DatabaseQueries::loadRootFromDatabase<StandardCategory, StandardFeed>(this);

  if (freshly_activated && getSubTreeFeeds().isEmpty()) {
    // In other words, if there are no feeds or categories added.
    if (MsgBox::show(qApp->mainFormWidget(),
                     QMessageBox::Question,
                     QObject::tr("Load initial set of feeds"),
                     tr("This new account does not include any feeds. You can now add default set of feeds."),
                     tr("Do you want to load initial set of feeds?"),
                     QString(),
                     QMessageBox::Yes | QMessageBox::No) == QMessageBox::Yes) {
      QString target_opml_file = APP_INITIAL_FEEDS_PATH + QDir::separator() + FEED_INITIAL_OPML_PATTERN;
      QString current_locale = qApp->localization()->loadedLanguage();
      QString file_to_load;

      if (QFile::exists(target_opml_file.arg(current_locale))) {
        file_to_load = target_opml_file.arg(current_locale);
      }
      else if (QFile::exists(target_opml_file.arg(QSL(DEFAULT_LOCALE)))) {
        file_to_load = target_opml_file.arg(QSL(DEFAULT_LOCALE));
      }

      FeedsImportExportModel model(this);
      QString output_msg;

      try {
        model.importAsOPML20(IOFactory::readFile(file_to_load), false, false, false);
        model.checkAllItems();

        if (mergeImportExportModel(&model, this, output_msg)) {
          requestItemExpand(getSubTree(), true);
        }
      }
      catch (ApplicationException& ex) {
        MsgBox::show(qApp->mainFormWidget(),
                     QMessageBox::Critical,
                     tr("Error when loading initial feeds"),
                     ex.message());
      }
    }
    else {
      requestItemExpand({this}, true);
    }
  }
}

void StandardServiceRoot::stop() {
  qDebugNN << LOGSEC_CORE << "Stopping StandardServiceRoot instance.";
}

QString StandardServiceRoot::code() const {
  return StandardServiceEntryPoint().code();
}

bool StandardServiceRoot::canBeEdited() const {
  return true;
}

FormAccountDetails* StandardServiceRoot::accountSetupDialog() const {
  return new FormEditStandardAccount(qApp->mainFormWidget());
}

void StandardServiceRoot::editItems(const QList<RootItem*>& items) {
  auto std_feeds = boolinq::from(items)
                     .select([](RootItem* it) {
                       return qobject_cast<Feed*>(it);
                     })
                     .where([](Feed* fd) {
                       return fd != nullptr;
                     })
                     .toStdList();

  if (!std_feeds.empty()) {
    QScopedPointer<FormStandardFeedDetails> form_pointer(new FormStandardFeedDetails(this,
                                                                                     nullptr,
                                                                                     {},
                                                                                     qApp->mainFormWidget()));

    form_pointer->addEditFeed<StandardFeed>(FROM_STD_LIST(QList<Feed*>, std_feeds));
    return;
  }

  if (items.first()->kind() == RootItem::Kind::ServiceRoot) {
    QScopedPointer<FormEditStandardAccount> p(qobject_cast<FormEditStandardAccount*>(accountSetupDialog()));

    p->addEditAccount(this);
    return;
  }

  ServiceRoot::editItems(items);
}

bool StandardServiceRoot::supportsFeedAdding() const {
  return true;
}

bool StandardServiceRoot::supportsCategoryAdding() const {
  return true;
}

void StandardServiceRoot::addNewFeed(RootItem* selected_item, const QString& url) {
  if (!qApp->feedUpdateLock()->tryLock()) {
    // Lock was not obtained because
    // it is used probably by feed updater or application
    // is quitting.
    qApp->showGuiMessage(Notification::Event::GeneralEvent,
                         {tr("Cannot add item"),
                          tr("Cannot add feed because another critical operation is ongoing."),
                          QSystemTrayIcon::MessageIcon::Warning});

    return;
  }

  QScopedPointer<FormDiscoverFeeds> form_discover(new FormDiscoverFeeds(this,
                                                                        selected_item,
                                                                        url,
                                                                        qApp->mainFormWidget()));

  if (form_discover->exec() == ADVANCED_FEED_ADD_DIALOG_CODE) {
    QScopedPointer<FormStandardFeedDetails> form_pointer(new FormStandardFeedDetails(this,
                                                                                     selected_item,
                                                                                     url,
                                                                                     qApp->mainFormWidget()));

    form_pointer->addEditFeed<StandardFeed>();
  }

  qApp->feedUpdateLock()->unlock();
}

Qt::ItemFlags StandardServiceRoot::additionalFlags() const {
  return ServiceRoot::additionalFlags() | Qt::ItemFlag::ItemIsDragEnabled | Qt::ItemFlag::ItemIsDropEnabled;
}

void StandardServiceRoot::spaceHost(const QString& host, const QString& url) {
  if (m_spacingSameHostsRequests <= 0 || host.simplified().isEmpty()) {
    // Spacing not enabled or host information unavailable.
    return;
  }

  m_spacingMutex.lock();

  QDateTime host_last_fetched = m_spacingHosts.value(host);
  QDateTime now = QDateTime::currentDateTimeUtc();
  int secs_to_wait = 0;

  if (host_last_fetched.isValid()) {
    // No last fetch time saved yet.
    QDateTime last = host_last_fetched.addSecs(m_spacingSameHostsRequests);

    if (last < now) {
      // This host was last fetched sometimes in the past and not within the critical spacing window.
      // We can therefore fetch now.
      secs_to_wait = 0;
    }
    else {
      secs_to_wait = now.secsTo(last);
    }
  }

  resetHostSpacing(host, now.addSecs(secs_to_wait));

  m_spacingMutex.unlock();

  if (secs_to_wait > 0) {
    qDebugNN << LOGSEC_CORE << "Freezing feed with URL" << QUOTE_W_SPACE(url) << "for" << NONQUOTE_W_SPACE(secs_to_wait)
             << "seconds, because its host was used for fetching another feed during the spacing period.";
    QThread::sleep(ulong(secs_to_wait));
    qDebugNN << LOGSEC_CORE << "Freezing feed with URL" << QUOTE_W_SPACE(url) << "is done.";
  }
}

void StandardServiceRoot::resetHostSpacing(const QString& host, const QDateTime& next_dt) {
  m_spacingHosts.insert(host, next_dt);
  qDebugNN << LOGSEC_CORE << "Setting spacing for" << QUOTE_W_SPACE(host) << "to" << QUOTE_W_SPACE_DOT(next_dt);
}

QList<Message> StandardServiceRoot::obtainNewMessages(Feed* feed,
                                                      const QHash<ServiceRoot::BagOfMessages, QStringList>&
                                                        stated_messages,
                                                      const QHash<QString, QStringList>& tagged_messages) {
  Q_UNUSED(stated_messages)
  Q_UNUSED(tagged_messages)

  StandardFeed* f = static_cast<StandardFeed*>(feed);
  QString host = QUrl(f->source()).host();
  QByteArray feed_contents;
  QString formatted_feed_contents;
  int download_timeout = qApp->settings()->value(GROUP(Feeds), SETTING(Feeds::UpdateTimeout)).toInt();

  if (f->sourceType() == StandardFeed::SourceType::Url) {
    spaceHost(host, f->source());

    qDebugNN << LOGSEC_CORE << "Downloading URL" << QUOTE_W_SPACE(feed->source()) << "to obtain feed data.";

    QList<QPair<QByteArray, QByteArray>> headers = StandardFeed::httpHeadersToList(f->httpHeaders());

    headers << NetworkFactory::generateBasicAuthHeader(f->protection(), f->username(), f->password());

    if (!f->lastEtag().isEmpty()) {
      headers.append({QSL("If-None-Match").toLocal8Bit(), f->lastEtag().toLocal8Bit()});

      qDebugNN << "Using ETag value:" << QUOTE_W_SPACE_DOT(f->lastEtag());
    }

    auto network_result = NetworkFactory::performNetworkOperation(f->source(),
                                                                  download_timeout,
                                                                  {},
                                                                  feed_contents,
                                                                  QNetworkAccessManager::Operation::GetOperation,
                                                                  headers,
                                                                  false,
                                                                  {},
                                                                  {},
                                                                  networkProxy(),
                                                                  f->http2Status());

    // Update last datetime this host was used.
    // resetHostSpacing(host);

    if (network_result.m_networkError != QNetworkReply::NetworkError::NoError) {
      qWarningNN << LOGSEC_CORE << "Error" << QUOTE_W_SPACE(network_result.m_networkError)
                 << "during fetching of new messages for feed" << QUOTE_W_SPACE_DOT(feed->source());
      throw FeedFetchException(Feed::Status::NetworkError,
                               NetworkFactory::networkErrorText(network_result.m_networkError),
                               QVariant::fromValue(network_result));
    }
    else {
      f->setLastEtag(network_result.m_headers.value(QSL("etag")));

      if (network_result.m_httpCode == HTTP_CODE_NOT_MODIFIED && feed_contents.trimmed().isEmpty()) {
        // We very likely used "eTag" before and server reports that
        // content was not modified since.
        qWarningNN << LOGSEC_CORE << QUOTE_W_SPACE(feed->source())
                   << "reported HTTP/304, meaning that the remote file did not change since last time we checked it.";
        return {};
      }
    }
  }
  else if (f->sourceType() == StandardFeed::SourceType::EmbeddedBrowser) {
#if defined(NO_LITE)
    feed_contents = WebEngineViewer::getJsEnabledHtml(f->source(), true);
#else
    throw ApplicationException(tr("this source type cannot be used on 'lite' %1 build").arg(QSL(APP_NAME)));
#endif
  }
  else if (f->sourceType() == StandardFeed::SourceType::LocalFile) {
    feed_contents = IOFactory::readFile(feed->source());
  }
  else {
    qDebugNN << LOGSEC_CORE << "Running custom script" << QUOTE_W_SPACE(feed->source()) << "to obtain feed data.";

    // Use script to generate feed file.
    try {
      feed_contents = StandardFeed::generateFeedFileWithScript(feed->source(), download_timeout);
    }
    catch (const ScriptException& ex) {
      qCriticalNN << LOGSEC_CORE << "Custom script for generating feed file failed:" << QUOTE_W_SPACE_DOT(ex.message());

      throw FeedFetchException(Feed::Status::OtherError, ex.message());
    }
  }

  // Sitemap parser supports gzip-encoded data too.
  // We need to decode it here before encoding
  // stuff kicks in.
  if (SitemapParser::isGzip(feed_contents)) {
#if defined(ENABLE_COMPRESSED_SITEMAP)
    qWarningNN << LOGSEC_CORE << "Decompressing gzipped feed data.";

    QByteArray uncompressed_feed_contents;

    if (!QCompressor::gzipDecompress(feed_contents, uncompressed_feed_contents)) {
      throw ApplicationException("gzip decompression failed");
    }

    feed_contents = uncompressed_feed_contents;
#else
    qWarningNN << LOGSEC_CORE << "This feed is gzipped.";
#endif
  }

  if (!f->postProcessScript().simplified().isEmpty()) {
    qDebugNN << LOGSEC_CORE << "We will process feed data with post-process script"
             << QUOTE_W_SPACE_DOT(f->postProcessScript());

    try {
      feed_contents =
        StandardFeed::postProcessFeedFileWithScript(f->postProcessScript(), feed_contents, download_timeout);
    }
    catch (const ScriptException& ex) {
      qCriticalNN << LOGSEC_CORE << "Post-processing script for feed file failed:" << QUOTE_W_SPACE_DOT(ex.message());

      throw FeedFetchException(Feed::Status::OtherError, ex.message());
    }
  }

  // Encode obtained data for further parsing.
  QTextCodec* codec = QTextCodec::codecForName(f->encoding().toLocal8Bit());

  if (codec == nullptr) {
    // No suitable codec for this encoding was found.
    // Use UTF-8.
    formatted_feed_contents = QString::fromUtf8(feed_contents);
  }
  else {
    formatted_feed_contents = codec->toUnicode(feed_contents);
  }

  // Feed data are downloaded and encoded.
  // Parse data and obtain messages.
  QList<Message> messages;
  FeedParser* parser;
  QElapsedTimer tmr;

  tmr.start();

  switch (f->type()) {
    case StandardFeed::Type::Rss0X:
    case StandardFeed::Type::Rss2X:
      parser = new RssParser(formatted_feed_contents);
      break;

    case StandardFeed::Type::Rdf:
      parser = new RdfParser(formatted_feed_contents);
      break;

    case StandardFeed::Type::Atom10:
      parser = new AtomParser(formatted_feed_contents);
      break;

    case StandardFeed::Type::Json:
      parser = new JsonParser(formatted_feed_contents);
      break;

    case StandardFeed::Type::iCalendar:
      parser = new IcalParser(formatted_feed_contents);
      break;

    case StandardFeed::Type::Sitemap:
      parser = new SitemapParser(formatted_feed_contents);
      break;

    default:
      break;
  }

  if (!f->dateTimeFormat().isEmpty()) {
    parser->setDateTimeFormat(f->dateTimeFormat());
  }

  parser->setDontUseRawXmlSaving(f->dontUseRawXmlSaving());
  messages = parser->messages();

  qDebugNN << LOGSEC_CORE << "XML parsing for feed" << QUOTE_W_SPACE(f->title()) << "took"
           << NONQUOTE_W_SPACE(tmr.elapsed()) << "ms.";

  if (!parser->dateTimeFormat().isEmpty()) {
    f->setDateTimeFormat(parser->dateTimeFormat());
  }

  delete parser;

  for (Message& mess : messages) {
    mess.m_feedId = feed->customId();
  }

  return messages;
}

QList<QAction*> StandardServiceRoot::getContextMenuForFeed(StandardFeed* feed) {
  if (m_feedContextMenu.isEmpty()) {
    // Initialize.
    auto* action_metadata =
      new QAction(qApp->icons()->fromTheme(QSL("download"), QSL("emblem-downloads")), tr("Fetch metadata"), this);

    m_feedContextMenu.append(action_metadata);

    connect(action_metadata, &QAction::triggered, this, [this]() {
      m_feedForMetadata->fetchMetadataForItself();
    });
  }

  m_feedForMetadata = feed;

  return m_feedContextMenu;
}

QVariantHash StandardServiceRoot::customDatabaseData() const {
  QVariantHash data = ServiceRoot::customDatabaseData();

  data[QSL("title")] = title();
  data[QSL("icon")] = IconFactory::toByteArray(icon());
  data[QSL("requests_spacing")] = spacingSameHostsRequests();

  return data;
}

void StandardServiceRoot::setCustomDatabaseData(const QVariantHash& data) {
  ServiceRoot::setCustomDatabaseData(data);

  setTitle(data.value(QSL("title"), defaultTitle()).toString());

  QByteArray icon_data = data.value(QSL("icon")).toByteArray();

  if (!icon_data.isEmpty()) {
    setIcon(IconFactory::fromByteArray(icon_data));
  }

  setSpacingSameHostsRequests(data.value(QSL("requests_spacing")).toInt());
}

QString StandardServiceRoot::defaultTitle() {
  return qApp->system()->loggedInUser() + QSL(" (RSS/ATOM/JSON)");
}

bool StandardServiceRoot::mergeImportExportModel(FeedsImportExportModel* model,
                                                 RootItem* target_root_node,
                                                 QString& output_message) {
  QStack<RootItem*> original_parents;

  original_parents.push(target_root_node);
  QStack<RootItem*> new_parents;

  new_parents.push(model->sourceModel()->rootItem());
  bool some_feed_category_error = false;

  QSqlDatabase database = qApp->database()->driver()->connection(metaObject()->className());

  // Iterate all new items we would like to merge into current model.
  while (!new_parents.isEmpty()) {
    RootItem* target_parent = original_parents.pop();
    RootItem* source_parent = new_parents.pop();
    auto sour_chi = source_parent->childItems();

    for (RootItem* source_item : std::as_const(sour_chi)) {
      if (!model->sourceModel()->isItemChecked(source_item)) {
        // We can skip this item, because it is not checked and should not be imported.
        // NOTE: All descendants are thus skipped too.
        continue;
      }

      if (source_item->kind() == RootItem::Kind::Category) {
        auto* source_category = qobject_cast<StandardCategory*>(source_item);
        auto* new_category = new StandardCategory(*source_category);
        QString new_category_title = new_category->title();

        // Add category to model.
        new_category->clearChildren();

        try {
          DatabaseQueries::createOverwriteCategory(database,
                                                   new_category,
                                                   target_root_node->getParentServiceRoot()->accountId(),
                                                   target_parent->id());
          requestItemReassignment(new_category, target_parent);

          original_parents.push(new_category);
          new_parents.push(source_category);
        }
        catch (ApplicationException& ex) {
          // Add category failed, but this can mean that the same category (with same title)
          // already exists. If such a category exists in current parent, then find it and
          // add descendants to it.
          RootItem* existing_category = nullptr;
          auto tar_chi = target_parent->childItems();

          for (RootItem* child : std::as_const(tar_chi)) {
            if (child->kind() == RootItem::Kind::Category && child->title() == new_category_title) {
              existing_category = child;
            }
          }

          if (existing_category != nullptr) {
            original_parents.push(existing_category);
            new_parents.push(source_category);
          }
          else {
            some_feed_category_error = true;

            qCriticalNN << LOGSEC_CORE << "Cannot import category:" << QUOTE_W_SPACE_DOT(ex.message());
          }
        }
      }
      else if (source_item->kind() == RootItem::Kind::Feed) {
        auto* source_feed = qobject_cast<StandardFeed*>(source_item);
        const auto* feed_with_same_url = target_root_node->getItemFromSubTree([source_feed](const RootItem* it) {
          return it->kind() == RootItem::Kind::Feed &&
                 it->toFeed()->source().toLower() == source_feed->source().toLower();
        });

        if (feed_with_same_url != nullptr) {
          continue;
        }

        auto* new_feed = new StandardFeed(*source_feed);

        try {
          DatabaseQueries::createOverwriteFeed(database,
                                               new_feed,
                                               target_root_node->getParentServiceRoot()->accountId(),
                                               target_parent->id());
          requestItemReassignment(new_feed, target_parent);
        }
        catch (const ApplicationException& ex) {
          qCriticalNN << LOGSEC_CORE << "Cannot import feed:" << QUOTE_W_SPACE_DOT(ex.message());
          some_feed_category_error = true;
        }
      }
    }
  }

  if (some_feed_category_error) {
    output_message = tr("Some feeds/categories were not imported due to error, check debug log for more details.");
  }
  else {
    output_message = tr("Import was completely successful.");
  }

  return !some_feed_category_error;
}

int StandardServiceRoot::spacingSameHostsRequests() const {
  return m_spacingSameHostsRequests;
}

void StandardServiceRoot::setSpacingSameHostsRequests(int spacing) {
  m_spacingSameHostsRequests = spacing;
}

void StandardServiceRoot::addNewCategory(RootItem* selected_item) {
  if (!qApp->feedUpdateLock()->tryLock()) {
    // Lock was not obtained because
    // it is used probably by feed updater or application
    // is quitting.
    qApp->showGuiMessage(Notification::Event::GeneralEvent,
                         {tr("Cannot add category"),
                          tr("Cannot add category because another critical operation is ongoing."),
                          QSystemTrayIcon::MessageIcon::Warning});

    // Thus, cannot delete and quit the method.
    return;
  }

  QScopedPointer<FormCategoryDetails> form_pointer(new FormCategoryDetails(this,
                                                                           selected_item,
                                                                           qApp->mainFormWidget()));

  form_pointer->addEditCategory<StandardCategory>();
  qApp->feedUpdateLock()->unlock();
}

void StandardServiceRoot::importFeeds() {
  QScopedPointer<FormStandardImportExport> form(new FormStandardImportExport(this, qApp->mainFormWidget()));

  form.data()->setMode(FeedsImportExportModel::Mode::Import);
  form.data()->exec();
}

void StandardServiceRoot::exportFeeds() {
  QScopedPointer<FormStandardImportExport> form(new FormStandardImportExport(this, qApp->mainFormWidget()));

  form.data()->setMode(FeedsImportExportModel::Mode::Export);
  form.data()->exec();
}

QList<QAction*> StandardServiceRoot::serviceMenu() {
  if (m_serviceMenu.isEmpty()) {
    ServiceRoot::serviceMenu();

    auto* action_export_feeds = new QAction(qApp->icons()->fromTheme(QSL("document-export")), tr("Export feeds"), this);
    auto* action_import_feeds = new QAction(qApp->icons()->fromTheme(QSL("document-import")), tr("Import feeds"), this);

    connect(action_export_feeds, &QAction::triggered, this, &StandardServiceRoot::exportFeeds);
    connect(action_import_feeds, &QAction::triggered, this, &StandardServiceRoot::importFeeds);

    m_serviceMenu.append(action_export_feeds);
    m_serviceMenu.append(action_import_feeds);
  }

  return m_serviceMenu;
}
