/*
 * Bittorrent Client using Qt4 and libtorrent.
 * Copyright (C) 2013  Nick Tiskov
 *
 * 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 Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * In addition, as a special exception, the copyright holders give permission to
 * link this program with the OpenSSL project's "OpenSSL" library (or with
 * modified versions of it that use the same license as the "OpenSSL" library),
 * and distribute the linked executables. You must obey the GNU General Public
 * License in all respects for all of the code used other than "OpenSSL".  If you
 * modify file(s), you may extend this exception to your version of the file(s),
 * but you are not obligated to do so. If you do not wish to do so, delete this
 * exception statement from your version.
 *
 * Contact : daymansmail@gmail.com
 */

#include "transferlistsortmodel.h"

#include "torrentmodel.h"
#include "misc.h"

TransferListSortModel::TransferListSortModel(QObject *parent)
  : QSortFilterProxyModel(parent)
  , filter0(TorrentFilter::ALL)
{}

void TransferListSortModel::setStatusFilter(const TorrentFilter::TorrentFilter &filter) {
  if (filter != filter0) {
    filter0 = filter;
    invalidateFilter();
  }
}

void TransferListSortModel::setLabelFilter(QString const& label) {
  if (!labelFilterEnabled || labelFilter != label) {
    labelFilterEnabled = true;
    labelFilter = label;
    invalidateFilter();
  }
}

void TransferListSortModel::disableLabelFilter() {
  if (labelFilterEnabled) {
    labelFilterEnabled = false;
    labelFilter = QString();
    invalidateFilter();
  }
}

bool TransferListSortModel::lessThan(const QModelIndex &left, const QModelIndex &right) const {
  const int column  = sortColumn();

  if (column == TorrentModelItem::TR_NAME) {
    QVariant vL = left.data();
    QVariant vR = right.data();
    if (!(vL.isValid() && vR.isValid()))
      return QSortFilterProxyModel::lessThan(left, right);
    Q_ASSERT(vL.isValid());
    Q_ASSERT(vR.isValid());

    bool res = false;
    if (misc::naturalSort(vL.toString(), vR.toString(), res))
      return res;

    return QSortFilterProxyModel::lessThan(left, right);
  }
  else if (column == TorrentModelItem::TR_ADD_DATE || column == TorrentModelItem::TR_SEED_DATE || column == TorrentModelItem::TR_SEEN_COMPLETE_DATE) {
    QDateTime vL = left.data().toDateTime();
    QDateTime vR = right.data().toDateTime();

    //not valid dates should be sorted at the bottom.
    if (!vL.isValid()) return false;
    if (!vR.isValid()) return true;

    return vL < vR;
  }
  else if (column == TorrentModelItem::TR_PRIORITY) {
    const int vL = left.data().toInt();
    const int vR = right.data().toInt();

    // Seeding torrents should be sorted by their completed date instead.
    if (vL == -1 && vR == -1) {
      QAbstractItemModel *model = sourceModel();
      const QDateTime dateL = model->data(model->index(left.row(), TorrentModelItem::TR_SEED_DATE)).toDateTime();
      const QDateTime dateR = model->data(model->index(right.row(), TorrentModelItem::TR_SEED_DATE)).toDateTime();

      //not valid dates should be sorted at the bottom.
      if (!dateL.isValid()) return false;
      if (!dateR.isValid()) return true;

      return dateL < dateR;
    }

    // Seeding torrents should be at the bottom
    if (vL == -1) return false;
    if (vR == -1) return true;
    return vL < vR;
  }
  else if (column == TorrentModelItem::TR_PEERS || column == TorrentModelItem::TR_SEEDS) {
    int left_active = left.data().toInt();
    int left_total = left.data(Qt::UserRole).toInt();
    int right_active = right.data().toInt();
    int right_total = right.data(Qt::UserRole).toInt();

    // Active peers/seeds take precedence over total peers/seeds.
    if (left_active == right_active)
      return (left_total < right_total);
    else return (left_active < right_active);
  }
  else if (column == TorrentModelItem::TR_ETA) {
    const QAbstractItemModel *model = sourceModel();
    const int prioL = model->data(model->index(left.row(), TorrentModelItem::TR_PRIORITY)).toInt();
    const int prioR = model->data(model->index(right.row(), TorrentModelItem::TR_PRIORITY)).toInt();
    const qlonglong etaL = left.data().toLongLong();
    const qlonglong etaR = right.data().toLongLong();
    const bool ascend = (sortOrder() == Qt::AscendingOrder);
    const bool invalidL = (etaL < 0 || etaL >= MAX_ETA);
    const bool invalidR = (etaR < 0 || etaR >= MAX_ETA);
    const bool seedingL = (prioL < 0);
    const bool seedingR = (prioR < 0);
    bool activeL;
    bool activeR;

    switch (model->data(model->index(left.row(), TorrentModelItem::TR_STATUS)).toInt()) {
    case TorrentModelItem::STATE_DOWNLOADING:
    case TorrentModelItem::STATE_DOWNLOADING_META:
    case TorrentModelItem::STATE_STALLED_DL:
    case TorrentModelItem::STATE_SEEDING:
    case TorrentModelItem::STATE_STALLED_UP:
      activeL = true;
      break;
    default:
      activeL = false;
    }

    switch (model->data(model->index(right.row(), TorrentModelItem::TR_STATUS)).toInt()) {
    case TorrentModelItem::STATE_DOWNLOADING:
    case TorrentModelItem::STATE_DOWNLOADING_META:
    case TorrentModelItem::STATE_STALLED_DL:
    case TorrentModelItem::STATE_SEEDING:
    case TorrentModelItem::STATE_STALLED_UP:
      activeR = true;
      break;
    default:
      activeR = false;
    }

    // Sorting rules prioritized.
    // 1. Active torrents at the top
    // 2. Seeding torrents at the bottom
    // 3. Torrents with invalid ETAs at the bottom

    if (activeL != activeR) return activeL;
    if (seedingL != seedingR) {
      if (seedingL) return !ascend;
      else return ascend;
    }

    if (invalidL && invalidR) {

      if (seedingL) { //Both seeding
        QDateTime dateL = model->data(model->index(left.row(), TorrentModelItem::TR_SEED_DATE)).toDateTime();
        QDateTime dateR = model->data(model->index(right.row(), TorrentModelItem::TR_SEED_DATE)).toDateTime();

        //not valid dates should be sorted at the bottom.
        if (!dateL.isValid()) return false;
        if (!dateR.isValid()) return true;

        return dateL < dateR;
      }
      else
        return prioL < prioR;
    }
    else if ((invalidL == false) && (invalidR == false))
      return QSortFilterProxyModel::lessThan(left, right);
    else
      return !invalidL;
  }

  return QSortFilterProxyModel::lessThan(left, right);
}

bool TransferListSortModel::filterAcceptsRow(int sourceRow, const QModelIndex &sourceParent) const {
  return matchStatusFilter(sourceRow, sourceParent)
      && matchLabelFilter(sourceRow, sourceParent)
      && QSortFilterProxyModel::filterAcceptsRow(sourceRow, sourceParent);
}

bool TransferListSortModel::matchStatusFilter(int sourceRow, const QModelIndex &sourceParent) const {
  if (filter0 == TorrentFilter::ALL)
    return true;
  QAbstractItemModel *model = sourceModel();
  if (!model) return false;
  QModelIndex index = model->index(sourceRow, TorrentModelItem::TR_STATUS, sourceParent);
  TorrentModelItem::State state = (TorrentModelItem::State)index.data().toInt();

  switch (filter0) {
  case TorrentFilter::DOWNLOADING:
    return (state == TorrentModelItem::STATE_DOWNLOADING || state == TorrentModelItem::STATE_STALLED_DL
            || state == TorrentModelItem::STATE_PAUSED_DL || state == TorrentModelItem::STATE_CHECKING_DL
            || state == TorrentModelItem::STATE_QUEUED_DL || state == TorrentModelItem::STATE_DOWNLOADING_META);

  case TorrentFilter::COMPLETED:
    return (state == TorrentModelItem::STATE_SEEDING || state == TorrentModelItem::STATE_STALLED_UP
            || state == TorrentModelItem::STATE_PAUSED_UP || state == TorrentModelItem::STATE_CHECKING_UP
            || state == TorrentModelItem::STATE_QUEUED_UP);

  case TorrentFilter::PAUSED:
    return (state == TorrentModelItem::STATE_PAUSED_UP || state == TorrentModelItem::STATE_PAUSED_DL);

  case TorrentFilter::ACTIVE:
    if (state == TorrentModelItem::STATE_STALLED_DL) {
      const qulonglong up_speed = model->index(sourceRow, TorrentModelItem::TR_UPSPEED, sourceParent).data().toULongLong();
      return (up_speed > 0);
    }

    return (state == TorrentModelItem::STATE_DOWNLOADING || state == TorrentModelItem::STATE_SEEDING);

  case TorrentFilter::INACTIVE:
    if (state == TorrentModelItem::STATE_STALLED_DL) {
      const qulonglong up_speed = model->index(sourceRow, TorrentModelItem::TR_UPSPEED, sourceParent).data().toULongLong();
      return !(up_speed > 0);
    }

    return (state != TorrentModelItem::STATE_DOWNLOADING && state != TorrentModelItem::STATE_SEEDING);

  default:
    return false;
  }
}

bool TransferListSortModel::matchLabelFilter(int sourceRow, const QModelIndex &sourceParent) const {
  if (!labelFilterEnabled)
    return true;

  QAbstractItemModel *model = sourceModel();
  if (!model)
    return false;

  return model->index(sourceRow, TorrentModelItem::TR_LABEL, sourceParent).data().toString() == labelFilter;
}