// This file is part of RSS Guard.
//
// Copyright (C) 2011-2015 by Martin Rotter <rotter.martinos@gmail.com>
//
// RSS Guard 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 3 of the License, or
// (at your option) any later version.
//
// RSS Guard 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 RSS Guard. If not, see <http://www.gnu.org/licenses/>.

#include "services/standard/standardserviceroot.h"

#include "definitions/definitions.h"
#include "miscellaneous/application.h"
#include "miscellaneous/settings.h"
#include "services/standard/standardserviceentrypoint.h"
#include "services/standard/standardrecyclebin.h"
#include "services/standard/standardfeed.h"
#include "services/standard/standardcategory.h"

#include <QSqlQuery>
#include <QSqlError>


StandardServiceRoot::StandardServiceRoot(RootItem *parent)
  : ServiceRoot(parent), m_recycleBin(new StandardRecycleBin(this)) {
  m_title = qApp->system()->getUsername() + "@" + APP_LOW_NAME;
  m_icon = StandardServiceEntryPoint().icon();

  loadFromDatabase();
}

StandardServiceRoot::~StandardServiceRoot() {
}

bool StandardServiceRoot::canBeEdited() {
  return false;
}

bool StandardServiceRoot::canBeDeleted() {
  return false;
}

QVariant StandardServiceRoot::data(int column, int role) const {
  switch (role) {
    case Qt::DisplayRole:
      if (column == FDS_MODEL_TITLE_INDEX) {
        return m_title;
      }
      else if (column == FDS_MODEL_COUNTS_INDEX) {
        return qApp->settings()->value(GROUP(Feeds), SETTING(Feeds::CountFormat)).toString()
            .replace(PLACEHOLDER_UNREAD_COUNTS, QString::number(countOfUnreadMessages()))
            .replace(PLACEHOLDER_ALL_COUNTS, QString::number(countOfAllMessages()));
      }
      else {
        return QVariant();
      }

    case Qt::EditRole:
      if (column == FDS_MODEL_TITLE_INDEX) {
        return m_title;
      }
      else if (column == FDS_MODEL_COUNTS_INDEX) {
        return countOfUnreadMessages();
      }
      else {
        return QVariant();
      }

    case Qt::DecorationRole:
      if (column == FDS_MODEL_TITLE_INDEX) {
        return m_icon;
      }
      else {
        return QVariant();
      }

    case Qt::ToolTipRole:
      if (column == FDS_MODEL_TITLE_INDEX) {
        return
            m_title + "\n" +
            tr("This is service account for standard RSS/RDF/ATOM feeds.");
      }
      else if (column == FDS_MODEL_COUNTS_INDEX) {
        //: Tooltip for "unread" column of feed list.
        return tr("%n unread message(s).", 0, countOfUnreadMessages());
      }
      else {
        return QVariant();
      }

    case Qt::TextAlignmentRole:
      if (column == FDS_MODEL_COUNTS_INDEX) {
        return Qt::AlignCenter;
      }
      else {
        return QVariant();
      }

    case Qt::FontRole:
      return countOfUnreadMessages() > 0 ? m_boldFont : m_normalFont;

    default:
      return QVariant();
  }
}

void StandardServiceRoot::loadFromDatabase(){
  // TODO: todo
  QSqlDatabase database = qApp->database()->connection("StandardServiceRoot", DatabaseFactory::FromSettings);
  CategoryAssignment categories;
  FeedAssignment feeds;

  // Obtain data for categories from the database.
  QSqlQuery query_categories(database);
  query_categories.setForwardOnly(true);

  if (!query_categories.exec(QSL("SELECT * FROM Categories;")) || query_categories.lastError().isValid()) {
    qFatal("Query for obtaining categories failed. Error message: '%s'.",
           qPrintable(query_categories.lastError().text()));
  }

  while (query_categories.next()) {
    CategoryAssignmentItem pair;
    pair.first = query_categories.value(CAT_DB_PARENT_ID_INDEX).toInt();
    pair.second = new StandardCategory(query_categories.record());

    categories << pair;
  }

  // All categories are now loaded.
  QSqlQuery query_feeds(database);
  query_feeds.setForwardOnly(true);

  if (!query_feeds.exec(QSL("SELECT * FROM Feeds;")) || query_feeds.lastError().isValid()) {
    qFatal("Query for obtaining feeds failed. Error message: '%s'.",
           qPrintable(query_feeds.lastError().text()));
  }

  while (query_feeds.next()) {
    // Process this feed.
    StandardFeed::Type type = static_cast<StandardFeed::Type>(query_feeds.value(FDS_DB_TYPE_INDEX).toInt());

    switch (type) {
      case StandardFeed::Atom10:
      case StandardFeed::Rdf:
      case StandardFeed::Rss0X:
      case StandardFeed::Rss2X: {
        FeedAssignmentItem pair;
        pair.first = query_feeds.value(FDS_DB_CATEGORY_INDEX).toInt();
        pair.second = new StandardFeed(query_feeds.record());
        pair.second->setType(type);

        feeds << pair;
        break;
      }

      default:
        break;
    }
  }

  // All data are now obtained, lets create the hierarchy.
  assembleCategories(categories);
  assembleFeeds(feeds);

  // As the last item, add recycle bin, which is needed.
  appendChild(m_recycleBin);
}

QHash<int, StandardCategory*> StandardServiceRoot::categoriesForItem(RootItem *root) {
  QHash<int, StandardCategory*> categories;
  QList<RootItem*> parents;

  parents.append(root->childItems());

  while (!parents.isEmpty()) {
    RootItem *item = parents.takeFirst();

    if (item->kind() == RootItem::Cattegory) {
      // This item is category, add it to the output list and
      // scan its children.
      int category_id = item->id();
      StandardCategory *category = item->toCategory();

      if (!categories.contains(category_id)) {
        categories.insert(category_id, category);
      }

      parents.append(category->childItems());
    }
  }

  return categories;
}

void StandardServiceRoot::assembleFeeds(FeedAssignment feeds) {
  QHash<int, StandardCategory*> categories = categoriesForItem(this);

  foreach (const FeedAssignmentItem &feed, feeds) {
    if (feed.first == NO_PARENT_CATEGORY) {
      // This is top-level feed, add it to the root item.
      appendChild(feed.second);
    }
    else if (categories.contains(feed.first)) {
      // This feed belongs to this category.
      categories.value(feed.first)->appendChild(feed.second);
    }
    else {
      qWarning("Feed '%s' is loose, skipping it.", qPrintable(feed.second->title()));
    }
  }
}

StandardRecycleBin *StandardServiceRoot::recycleBin() const {
  return m_recycleBin;
}

void StandardServiceRoot::assembleCategories(CategoryAssignment categories) {
  QHash<int, RootItem*> assignments;
  assignments.insert(NO_PARENT_CATEGORY, this);

  // Add top-level categories.
  while (!categories.isEmpty()) {
    for (int i = 0; i < categories.size(); i++) {
      if (assignments.contains(categories.at(i).first)) {
        // Parent category of this category is already added.
        assignments.value(categories.at(i).first)->appendChild(categories.at(i).second);

        // Now, added category can be parent for another categories, add it.
        assignments.insert(categories.at(i).second->id(),
                           categories.at(i).second);

        // Remove the category from the list, because it was
        // added to the final collection.
        categories.removeAt(i);
        i--;
      }
    }
  }
}