/*
 * This file Copyright (C) 2009-2015 Mnemosyne LLC
 *
 * It may be used under the GNU GPL versions 2 or 3
 * or any future license endorsed by Mnemosyne LLC.
 *
 * $Id$
 */

#include <algorithm>
#include <cassert>

#include <QHeaderView>
#include <QMenu>
#include <QQueue>
#include <QResizeEvent>
#include <QSortFilterProxyModel>

#include <libtransmission/transmission.h> // priorities

#include "FileTreeDelegate.h"
#include "FileTreeItem.h"
#include "FileTreeModel.h"
#include "FileTreeView.h"
#include "Formatter.h"
#include "Utils.h"

#define PRIORITY_KEY "priority"

FileTreeView::FileTreeView (QWidget * parent, bool isEditable):
  QTreeView (parent),
  myModel (new FileTreeModel (this, isEditable)),
  myProxy (new QSortFilterProxyModel (this)),
  myDelegate (new FileTreeDelegate (this))
{
  myProxy->setSourceModel (myModel);
  myProxy->setSortRole (FileTreeModel::SortRole);
  myProxy->setSortCaseSensitivity (Qt::CaseInsensitive);

  setModel (myProxy);
  setItemDelegate (myDelegate);
  sortByColumn (FileTreeModel::COL_NAME, Qt::AscendingOrder);

  connect (this, SIGNAL(clicked(QModelIndex)),
           this, SLOT(onClicked(QModelIndex)));

  connect (myModel, SIGNAL(priorityChanged(QSet<int>, int)),
           this,    SIGNAL(priorityChanged(QSet<int>, int)));

  connect (myModel, SIGNAL(wantedChanged(QSet<int>, bool)),
           this,    SIGNAL(wantedChanged(QSet<int>, bool)));

  connect (myModel, SIGNAL(pathEdited(QString, QString)),
           this,    SIGNAL(pathEdited(QString, QString)));

  connect (myModel, SIGNAL (openRequested (QString)),
           this,    SIGNAL (openRequested (QString)));
}

void
FileTreeView::onClicked (const QModelIndex& proxyIndex)
{
  const QModelIndex modelIndex = myProxy->mapToSource (proxyIndex);
  if (modelIndex.column () == FileTreeModel::COL_WANTED)
    myModel->twiddleWanted (QModelIndexList () << modelIndex);
  else if (modelIndex.column () == FileTreeModel::COL_PRIORITY)
    myModel->twiddlePriority (QModelIndexList () << modelIndex);
}

void
FileTreeView::resizeEvent (QResizeEvent * event)
{
  QTreeView::resizeEvent (event);

  // this is kind of a hack to get the last four columns be the
  // right size, and to have the filename column use whatever
  // space is left over...

  int left = event->size ().width () - 1;
  for (int column = 0; column < FileTreeModel::NUM_COLUMNS; ++column)
    {
      if (column == FileTreeModel::COL_NAME)
        continue;

      int minWidth = 0;

      QStringList itemTexts;
      switch (column)
        {
          case FileTreeModel::COL_SIZE:
            for (int s = Formatter::B; s <= Formatter::TB; ++s)
              itemTexts << QLatin1String ("999.9 ") +
                           Formatter::unitStr (Formatter::MEM, static_cast<Formatter::Size> (s));
            break;

          case FileTreeModel::COL_PROGRESS:
            itemTexts << QLatin1String ("  100%  ");
            break;

          case FileTreeModel::COL_WANTED:
            minWidth = 20;
            break;

          case FileTreeModel::COL_PRIORITY:
            itemTexts << FileTreeItem::tr ("Low") << FileTreeItem::tr ("Normal") <<
                         FileTreeItem::tr ("High") << FileTreeItem::tr ("Mixed");
            break;
        }

      int itemWidth = 0;
      for (const QString& itemText: itemTexts)
        itemWidth = std::max (itemWidth, Utils::measureViewItem (this, itemText));

      const QString headerText = myModel->headerData (column, Qt::Horizontal).toString ();
      int headerWidth = Utils::measureHeaderItem (this->header (), headerText);

      const int width = std::max (minWidth, std::max (itemWidth, headerWidth));
      setColumnWidth (column, width);

      left -= width;
    }

  setColumnWidth (FileTreeModel::COL_NAME, std::max (left, 0));
}

void
FileTreeView::keyPressEvent (QKeyEvent * event)
{
  if (state () != EditingState)
    {
      if (event->key () == Qt::Key_Space)
        {
          // handle using the keyboard to toggle the
          // wanted/unwanted state or the file priority

          const Qt::KeyboardModifiers modifiers = event->modifiers ();

          if (modifiers == Qt::NoModifier)
            {
              myModel->twiddleWanted (selectedSourceRows ());
              return;
            }

          if (modifiers == Qt::ShiftModifier)
            {
              myModel->twiddlePriority (selectedSourceRows ());
              return;
            }
        }
    }

  QTreeView::keyPressEvent (event);
}

void
FileTreeView::mouseDoubleClickEvent (QMouseEvent * event)
{
  const QModelIndex index = currentIndex ();
  if (!index.isValid () || index.column () == FileTreeModel::COL_WANTED || index.column () == FileTreeModel::COL_PRIORITY)
    return;

  if (openSelectedItem ())
    return;

  QTreeView::mouseDoubleClickEvent (event);
}

void
FileTreeView::contextMenuEvent (QContextMenuEvent * event)
{
  const QModelIndex rootIndex = myModel->index (0, 0);
  if (!rootIndex.isValid ())
    return;

  if (myContextMenu == nullptr)
    initContextMenu ();
  myContextMenu->popup (event->globalPos ());
}

void
FileTreeView::update (const FileList& files, bool updateFields)
{
  const bool modelWasEmpty = myProxy->rowCount () == 0;

  for (const TorrentFile& file: files)
    myModel->addFile (file.index, file.filename, file.wanted, file.priority, file.size, file.have, updateFields);

  if (modelWasEmpty)
    {
      // expand up until the item with more than one expandable child
      for (QModelIndex index = myProxy->index (0, 0); index.isValid ();)
        {
          const QModelIndex oldIndex = index;

          expand (oldIndex);

          index = QModelIndex ();
          for (int i = 0, count = myProxy->rowCount (oldIndex); i < count; ++i)
            {
              const QModelIndex newIndex = myProxy->index (i, 0, oldIndex);
              if (myProxy->rowCount (newIndex) == 0)
                continue;
              if (index.isValid ())
                {
                  index = QModelIndex ();
                  break;
                }
              index = newIndex;
            }
        }
    }

  myProxy->sort (header ()->sortIndicatorSection (), header ()->sortIndicatorOrder ());
}

void
FileTreeView::clear ()
{
  myModel->clear();
}

void
FileTreeView::setEditable (bool editable)
{
  myModel->setEditable (editable);
}

bool
FileTreeView::edit (const QModelIndex& index, EditTrigger trigger, QEvent * event)
{
  if (selectionModel ()->selectedRows ().size () != 1)
    return false;

  const QModelIndex nameIndex = index.sibling (index.row (), FileTreeModel::COL_NAME);
  if (editTriggers ().testFlag (trigger))
    selectionModel ()->setCurrentIndex (nameIndex, QItemSelectionModel::NoUpdate);

  return QTreeView::edit (nameIndex, trigger, event);
}

void
FileTreeView::checkSelectedItems ()
{
  myModel->setWanted (selectedSourceRows (), true);
}

void
FileTreeView::uncheckSelectedItems ()
{
  myModel->setWanted (selectedSourceRows (), false);
}

void
FileTreeView::onlyCheckSelectedItems ()
{
  const QModelIndex rootIndex = myModel->index (0, 0);
  if (!rootIndex.isValid ())
    return;

  QModelIndexList wantedIndices = selectedSourceRows ();
  myModel->setWanted (wantedIndices, true);

  qSort (wantedIndices);

  QSet<QModelIndex> wantedIndicesParents;
  for (const QModelIndex& i: wantedIndices)
    {
      for (QModelIndex p = i.parent (); p.isValid (); p = p.parent ())
        wantedIndicesParents.insert (p);
    }

  QQueue<QModelIndex> parentsQueue;
  parentsQueue.enqueue (rootIndex);
  QModelIndexList unwantedIndices;
  while (!parentsQueue.isEmpty ())
    {
      const QModelIndex parentIndex = parentsQueue.dequeue ();
      if (qBinaryFind (wantedIndices, parentIndex) != wantedIndices.end ())
        continue;

      for (int i = 0, count = myModel->rowCount (parentIndex); i < count; ++i)
        {
          const QModelIndex childIndex = parentIndex.child (i, 0);
          const int childCheckState = childIndex.data (FileTreeModel::WantedRole).toInt ();
          if (childCheckState == Qt::Unchecked || qBinaryFind (wantedIndices, childIndex) != wantedIndices.end ())
            continue;

          if (childCheckState == Qt::Checked && childIndex.data (FileTreeModel::FileIndexRole).toInt () >= 0)
            {
              unwantedIndices << childIndex;
            }
          else
            {
              if (!wantedIndicesParents.contains (childIndex))
                unwantedIndices << childIndex;
              else
                parentsQueue.enqueue (childIndex);
            }
        }
    }

  myModel->setWanted (unwantedIndices, false);
}

void
FileTreeView::setSelectedItemsPriority ()
{
  QAction * action = qobject_cast<QAction *> (sender ());
  assert (action != nullptr);
  myModel->setPriority (selectedSourceRows (), action->property (PRIORITY_KEY).toInt ());
}

bool
FileTreeView::openSelectedItem ()
{
  return myModel->openFile (myProxy->mapToSource (currentIndex ()));
}

void
FileTreeView::renameSelectedItem ()
{
  QTreeView::edit (currentIndex ());
}

void
FileTreeView::refreshContextMenuActionsSensitivity ()
{
  assert (myContextMenu != nullptr);

  const QModelIndexList selectedRows = selectionModel ()->selectedRows ();
  const Qt::CheckState checkState = getCumulativeCheckState (selectedRows);

  const bool haveSelection = !selectedRows.isEmpty ();
  const bool haveSingleSelection = selectedRows.size() == 1;
  const bool haveUnchecked = checkState == Qt::Unchecked || checkState == Qt::PartiallyChecked;
  const bool haveChecked = checkState == Qt::Checked || checkState == Qt::PartiallyChecked;

  myCheckSelectedAction->setEnabled (haveUnchecked);
  myUncheckSelectedAction->setEnabled (haveChecked);
  myOnlyCheckSelectedAction->setEnabled (haveSelection);
  myPriorityMenu->setEnabled (haveSelection);
  myOpenAction->setEnabled (haveSingleSelection &&
    selectedRows.first ().data (FileTreeModel::FileIndexRole).toInt () >= 0 &&
    selectedRows.first ().data (FileTreeModel::CompleteRole).toBool ());
  myRenameAction->setEnabled (haveSingleSelection);
}

void
FileTreeView::initContextMenu ()
{
  myContextMenu = new QMenu (this);

  myCheckSelectedAction = myContextMenu->addAction (tr ("Check Selected"), this, SLOT (checkSelectedItems ()));
  myUncheckSelectedAction = myContextMenu->addAction (tr ("Uncheck Selected"), this, SLOT (uncheckSelectedItems ()));
  myOnlyCheckSelectedAction = myContextMenu->addAction (tr ("Only Check Selected"), this, SLOT (onlyCheckSelectedItems ()));

  myContextMenu->addSeparator ();

  myPriorityMenu = myContextMenu->addMenu (tr ("Priority"));
  myHighPriorityAction = myPriorityMenu->addAction (FileTreeItem::tr ("High"), this, SLOT (setSelectedItemsPriority ()));
  myNormalPriorityAction = myPriorityMenu->addAction (FileTreeItem::tr ("Normal"), this, SLOT (setSelectedItemsPriority ()));
  myLowPriorityAction = myPriorityMenu->addAction (FileTreeItem::tr ("Low"), this, SLOT (setSelectedItemsPriority ()));

  myHighPriorityAction->setProperty (PRIORITY_KEY, TR_PRI_HIGH);
  myNormalPriorityAction->setProperty (PRIORITY_KEY, TR_PRI_NORMAL);
  myLowPriorityAction->setProperty (PRIORITY_KEY, TR_PRI_LOW);

  myContextMenu->addSeparator ();

  myOpenAction = myContextMenu->addAction (tr ("Open"), this, SLOT (openSelectedItem ()));
  myRenameAction = myContextMenu->addAction (tr ("Rename..."), this, SLOT (renameSelectedItem ()));

  connect (myContextMenu, SIGNAL (aboutToShow ()), SLOT (refreshContextMenuActionsSensitivity ()));
}

QModelIndexList
FileTreeView::selectedSourceRows (int column) const
{
  QModelIndexList indices;
  for (const QModelIndex& i: selectionModel ()->selectedRows (column))
    indices << myProxy->mapToSource (i);
  return indices;
}

Qt::CheckState
FileTreeView::getCumulativeCheckState (const QModelIndexList& indices)
{
  bool haveChecked = false, haveUnchecked = false;

  for (const QModelIndex& i: indices)
    {
      switch (i.data (FileTreeModel::WantedRole).toInt ())
        {
          case Qt::Checked:
            haveChecked = true;
            break;
          case Qt::Unchecked:
            haveUnchecked = true;
            break;
          case Qt::PartiallyChecked:
            return Qt::PartiallyChecked;
        }

      if (haveChecked && haveUnchecked)
        return Qt::PartiallyChecked;
    }

  return haveChecked ? Qt::Checked : Qt::Unchecked;
}