/* This file is part of Clementine.

   Clementine 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.

   Clementine 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 Clementine.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "playlistview.h"
#include "playlist.h"
#include "playlistheader.h"
#include "playlistdelegates.h"
#include "playlist.h"

#include <QPainter>
#include <QHeaderView>
#include <QSettings>
#include <QtDebug>
#include <QTimer>
#include <QKeyEvent>

#include <math.h>

const char* PlaylistView::kSettingsGroup = "Playlist";
const int PlaylistView::kGlowIntensitySteps = 32;
const int PlaylistView::kAutoscrollGraceTimeout = 60; // seconds
const int PlaylistView::kDropIndicatorWidth = 2;
const int PlaylistView::kDropIndicatorGradientWidth = 5;


PlaylistView::PlaylistView(QWidget *parent)
  : QTreeView(parent),
    glow_enabled_(false),
    glow_intensity_step_(0),
    inhibit_autoscroll_timer_(new QTimer(this)),
    inhibit_autoscroll_(false),
    currently_autoscrolling_(false),
    row_height_(-1),
    currenttrack_play_(":currenttrack_play.png"),
    currenttrack_pause_(":currenttrack_pause.png"),
    drop_indicator_row_(-1)
{
  setHeader(new PlaylistHeader(Qt::Horizontal, this));
  header()->setMovable(true);

  connect(header(), SIGNAL(sectionResized(int,int,int)), SLOT(SaveGeometry()));
  connect(header(), SIGNAL(sectionMoved(int,int,int)), SLOT(SaveGeometry()));

  inhibit_autoscroll_timer_->setInterval(kAutoscrollGraceTimeout * 1000);
  inhibit_autoscroll_timer_->setSingleShot(true);
  connect(inhibit_autoscroll_timer_, SIGNAL(timeout()), SLOT(InhibitAutoscrollTimeout()));

  setAlternatingRowColors(true);
}

void PlaylistView::setItemDelegates(Library* library) {
  setItemDelegate(new PlaylistDelegateBase(this));
  setItemDelegateForColumn(Playlist::Column_Title, new TextItemDelegate(this));
  setItemDelegateForColumn(Playlist::Column_Album,
      new TagCompletionItemDelegate(this, library, Playlist::Column_Album));
  setItemDelegateForColumn(Playlist::Column_Artist,
      new TagCompletionItemDelegate(this, library, Playlist::Column_Artist));
  setItemDelegateForColumn(Playlist::Column_AlbumArtist,
      new TagCompletionItemDelegate(this, library, Playlist::Column_AlbumArtist));
  setItemDelegateForColumn(Playlist::Column_Length, new LengthItemDelegate(this));
  setItemDelegateForColumn(Playlist::Column_Filesize, new SizeItemDelegate(this));
  setItemDelegateForColumn(Playlist::Column_Filetype, new FileTypeItemDelegate(this));
  setItemDelegateForColumn(Playlist::Column_DateCreated, new DateItemDelegate(this));
  setItemDelegateForColumn(Playlist::Column_DateModified, new DateItemDelegate(this));
}

void PlaylistView::setModel(QAbstractItemModel *m) {
  if (model())
    disconnect(model(), 0, this, 0);

  QTreeView::setModel(m);
  LoadGeometry();

  Playlist* playlist = qobject_cast<Playlist*>(m);
  connect(playlist, SIGNAL(CurrentSongChanged(Song)), SLOT(MaybeAutoscroll()));
}

void PlaylistView::LoadGeometry() {
  QSettings settings;
  settings.beginGroup(kSettingsGroup);

  if (!header()->restoreState(settings.value("state").toByteArray())) {
    header()->hideSection(Playlist::Column_Disc);
    header()->hideSection(Playlist::Column_Year);
    header()->hideSection(Playlist::Column_Genre);
    header()->hideSection(Playlist::Column_BPM);
    header()->hideSection(Playlist::Column_Bitrate);
    header()->hideSection(Playlist::Column_Samplerate);
    header()->hideSection(Playlist::Column_Filename);
    header()->hideSection(Playlist::Column_BaseFilename);
    header()->hideSection(Playlist::Column_Filesize);
    header()->hideSection(Playlist::Column_Filetype);
    header()->hideSection(Playlist::Column_DateCreated);
    header()->hideSection(Playlist::Column_DateModified);
    header()->hideSection(Playlist::Column_AlbumArtist);
    header()->hideSection(Playlist::Column_Composer);
  }
}

void PlaylistView::SaveGeometry() {
  QSettings settings;
  settings.beginGroup(kSettingsGroup);
  settings.setValue("state", header()->saveState());
}

void PlaylistView::ReloadBarPixmaps() {
  currenttrack_bar_left_ = LoadBarPixmap(":currenttrack_bar_left.png");
  currenttrack_bar_mid_ = LoadBarPixmap(":currenttrack_bar_mid.png");
  currenttrack_bar_right_ = LoadBarPixmap(":currenttrack_bar_right.png");
}

QList<QPixmap> PlaylistView::LoadBarPixmap(const QString& filename) {
  QImage image(filename);
  image = image.scaledToHeight(row_height_, Qt::SmoothTransformation);

  // Colour the bar with the palette colour
  QPainter p(&image);
  p.setCompositionMode(QPainter::CompositionMode_SourceAtop);
  p.setOpacity(0.7);
  p.fillRect(image.rect(), QApplication::palette().color(QPalette::Highlight));
  p.end();

  // Animation steps
  QList<QPixmap> ret;
  for(int i=0 ; i<kGlowIntensitySteps ; ++i) {
    QImage step(image.copy());
    p.begin(&step);
    p.setCompositionMode(QPainter::CompositionMode_SourceAtop);
    p.setOpacity(0.4 - 0.6 * sin(float(i)/kGlowIntensitySteps * (M_PI/2)));
    p.fillRect(step.rect(), Qt::white);
    p.end();
    ret << QPixmap::fromImage(step);
  }

  return ret;
}

void PlaylistView::drawRow(QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& index) const {
  QStyleOptionViewItemV4 opt(option);

  bool is_current = index.data(Playlist::Role_IsCurrent).toBool();
  bool is_paused = index.data(Playlist::Role_IsPaused).toBool();

  if (is_current) {
    const_cast<PlaylistView*>(this)->last_current_item_ = index;
    const_cast<PlaylistView*>(this)->last_glow_rect_ = opt.rect;

    int step = glow_intensity_step_;
    if (step >= kGlowIntensitySteps)
      step = 2*(kGlowIntensitySteps-1) - step + 1;

    int row_height = opt.rect.height();
    if (row_height != row_height_) {
      // Recreate the pixmaps if the height changed since last time
      const_cast<PlaylistView*>(this)->row_height_ = row_height;
      const_cast<PlaylistView*>(this)->ReloadBarPixmaps();
    }

    QRect middle(opt.rect);
    middle.setLeft(middle.left() + currenttrack_bar_left_[0].width());
    middle.setRight(middle.right() - currenttrack_bar_right_[0].width());

    // Selection
    if (selectionModel()->isSelected(index))
      painter->fillRect(opt.rect, opt.palette.color(QPalette::Highlight));

    // Draw the bar
    painter->drawPixmap(opt.rect.topLeft(), currenttrack_bar_left_[step]);
    painter->drawPixmap(opt.rect.topRight() - currenttrack_bar_right_[0].rect().topRight(), currenttrack_bar_right_[step]);
    painter->drawPixmap(middle, currenttrack_bar_mid_[step]);

    // Draw the play icon
    QPoint play_pos(currenttrack_bar_left_[0].width() / 3 * 2,
                    (row_height - currenttrack_play_.height()) / 2);
    painter->drawPixmap(opt.rect.topLeft() + play_pos,
                        is_paused ? currenttrack_pause_ : currenttrack_play_);

    // Set the font
    opt.palette.setColor(QPalette::Text, Qt::white);
    opt.palette.setColor(QPalette::HighlightedText, Qt::white);
    opt.palette.setColor(QPalette::Highlight, Qt::transparent);
    opt.palette.setColor(QPalette::AlternateBase, Qt::transparent);
    opt.font.setItalic(true);
    opt.decorationSize = QSize(20,20);
  }

  QTreeView::drawRow(painter, opt, index);
}

void PlaylistView::timerEvent(QTimerEvent* event) {
  QTreeView::timerEvent(event);
  if (event->timerId() == glow_timer_.timerId())
    GlowIntensityChanged();
}

void PlaylistView::GlowIntensityChanged() {
  glow_intensity_step_ = (glow_intensity_step_ + 1) % (kGlowIntensitySteps * 2);

  viewport()->update(last_glow_rect_);
}

void PlaylistView::StopGlowing() {
  glow_enabled_ = false;
  glow_timer_.stop();
  glow_intensity_step_ = kGlowIntensitySteps;
}

void PlaylistView::StartGlowing() {
  glow_enabled_ = true;
  if (isVisible())
    glow_timer_.start(1500 / kGlowIntensitySteps, this);
}

void PlaylistView::hideEvent(QHideEvent*) {
  glow_timer_.stop();
}

void PlaylistView::showEvent(QShowEvent*) {
  if (glow_enabled_)
    glow_timer_.start(1500 / kGlowIntensitySteps, this);
  MaybeAutoscroll();
}

bool CompareSelectionRanges(const QItemSelectionRange& a, const QItemSelectionRange& b) {
  return b.bottom() < a.bottom();
}

void PlaylistView::keyPressEvent(QKeyEvent* event) {
  if (!model()) {
    QTreeView::keyPressEvent(event);
  } else if (state() == QAbstractItemView::EditingState) {
    QTreeView::keyPressEvent(event);
  } else if (event->matches(QKeySequence::Delete) ||
      event->key() == Qt::Key_Backspace) {
    RemoveSelected();
    event->accept();
  } else if (event->key() == Qt::Key_Enter ||
             event->key() == Qt::Key_Return ||
             event->key() == Qt::Key_Space) {
    if (currentIndex().isValid())
      emit PlayPauseItem(currentIndex());
    event->accept();
  } else {
    QTreeView::keyPressEvent(event);
  }
}

void PlaylistView::contextMenuEvent(QContextMenuEvent* e) {
  emit RightClicked(e->globalPos(), indexAt(e->pos()));
  e->accept();
}

void PlaylistView::RemoveSelected() {
  QItemSelection selection(selectionModel()->selection());

  // Sort the selection so we remove the items at the *bottom* first, ensuring
  // we don't have to mess around with changing row numbers
  qSort(selection.begin(), selection.end(), CompareSelectionRanges);

  foreach (const QItemSelectionRange& range, selection) {
    model()->removeRows(range.top(), range.height(), range.parent());
  }

  // Select the new current item
  if (currentIndex().isValid())
    selectionModel()->select(
        QItemSelection(currentIndex().sibling(currentIndex().row(), 0),
                       currentIndex().sibling(currentIndex().row(), model()->columnCount()-1)),
        QItemSelectionModel::Select);
}

QList<int> PlaylistView::GetEditableColumns() {
  QList<int> columns;
  QHeaderView* h = header();
  for (int col=0; col<h->count(); col++) {
    if (h->isSectionHidden(col))
      continue;
    QModelIndex index = model()->index(0, col);
    if (index.flags() & Qt::ItemIsEditable)
      columns << h->visualIndex(col);
  }
  qSort(columns);
  return columns;
}

QModelIndex PlaylistView::NextEditableIndex(const QModelIndex& current) {
  QList<int> columns = GetEditableColumns();
  QHeaderView* h = header();
  int index = columns.indexOf(h->visualIndex(current.column()));

  if(index+1 >= columns.size())
    return model()->index(current.row()+1, h->logicalIndex(columns.first()));

  return model()->index(current.row(), h->logicalIndex(columns[index+1]));
}

QModelIndex PlaylistView::PrevEditableIndex(const QModelIndex& current) {
  QList<int> columns = GetEditableColumns();
  QHeaderView* h = header();
  int index = columns.indexOf(h->visualIndex(current.column()));

  if(index-1 < 0)
    return model()->index(current.row()-1, h->logicalIndex(columns.last()));

  return model()->index(current.row(), h->logicalIndex(columns[index-1]));
}

void PlaylistView::closeEditor(QWidget* editor, QAbstractItemDelegate::EndEditHint hint) {
  if (hint == QAbstractItemDelegate::NoHint) {
    QTreeView::closeEditor(editor, QAbstractItemDelegate::SubmitModelCache);
  } else if (hint == QAbstractItemDelegate::EditNextItem ||
             hint == QAbstractItemDelegate::EditPreviousItem) {

    QModelIndex index;
    if (hint == QAbstractItemDelegate::EditNextItem)
      index = NextEditableIndex(currentIndex());
    else
      index = PrevEditableIndex(currentIndex());

    if (!index.isValid()) {
      QTreeView::closeEditor(editor, QAbstractItemDelegate::SubmitModelCache);
    } else {
      QTreeView::closeEditor(editor, QAbstractItemDelegate::NoHint);
      setCurrentIndex(index);
      edit(index);
    }
  } else {
    QTreeView::closeEditor(editor, hint);
  }
}

void PlaylistView::mousePressEvent(QMouseEvent *event) {
  QTreeView::mousePressEvent(event);
  inhibit_autoscroll_ = true;
  inhibit_autoscroll_timer_->start();
}

void PlaylistView::scrollContentsBy(int dx, int dy) {
  QTreeView::scrollContentsBy(dx, dy);

  if (!currently_autoscrolling_) {
    // We only want to do this if the scroll was initiated by the user
    inhibit_autoscroll_ = true;
    inhibit_autoscroll_timer_->start();
  }
}

void PlaylistView::InhibitAutoscrollTimeout() {
  // For 1 minute after the user clicks on or scrolls the playlist we promise
  // not to automatically scroll the view to keep up with a track change.
  inhibit_autoscroll_ = false;
}

void PlaylistView::MaybeAutoscroll() {
  Playlist* playlist = qobject_cast<Playlist*>(model());
  Q_ASSERT(playlist);

  if (inhibit_autoscroll_)
    return;

  if (playlist->current_index() == -1)
    return;

  QModelIndex current = playlist->index(playlist->current_index(), 0);
  currently_autoscrolling_ = true;
  scrollTo(current, QAbstractItemView::PositionAtCenter);
  currently_autoscrolling_ = false;
}

void PlaylistView::paintEvent(QPaintEvent* event) {
  // Reimplemented to draw the drop indicator
  QPainter p(viewport());
  drawTree(&p, event->region());

  if (drop_indicator_row_ == -1)
    return;

  // Find the y position of the drop indicator
  QModelIndex drop_index = model()->index(drop_indicator_row_, 0);
  int drop_pos = -1;
  switch (dropIndicatorPosition()) {
    case QAbstractItemView::OnItem:
      return; // Don't draw anything

    case QAbstractItemView::AboveItem:
      drop_pos = visualRect(drop_index).top();
      break;

    case QAbstractItemView::BelowItem:
      drop_pos = visualRect(drop_index).bottom() + 1;
      break;

    case QAbstractItemView::OnViewport:
      if (model()->rowCount() == 0)
        drop_pos = 1;
      else
        drop_pos = visualRect(model()->index(model()->rowCount() - 1, 0)).bottom() + 1;
      break;
  }

  // Draw a nice gradient first
  QColor line_color(QApplication::palette().color(QPalette::Highlight));
  QColor shadow_color(line_color.lighter(140));
  QColor shadow_fadeout_color(shadow_color);
  shadow_color.setAlpha(255);
  shadow_fadeout_color.setAlpha(0);

  QLinearGradient gradient(QPoint(0, drop_pos - kDropIndicatorGradientWidth),
                           QPoint(0, drop_pos + kDropIndicatorGradientWidth));
  gradient.setColorAt(0.0, shadow_fadeout_color);
  gradient.setColorAt(0.5, shadow_color);
  gradient.setColorAt(1.0, shadow_fadeout_color);
  QPen gradient_pen(QBrush(gradient), kDropIndicatorGradientWidth * 2);
  p.setPen(gradient_pen);
  p.drawLine(QPoint(0, drop_pos),
             QPoint(width(), drop_pos));

  // Now draw the line on top
  QPen line_pen(line_color, kDropIndicatorWidth);
  p.setPen(line_pen);
  p.drawLine(QPoint(0, drop_pos),
             QPoint(width(), drop_pos));
}

void PlaylistView::dragMoveEvent(QDragMoveEvent *event) {
  QTreeView::dragMoveEvent(event);

  QModelIndex index(indexAt(event->pos()));
  drop_indicator_row_ = index.isValid() ? index.row() : 0;
}

void PlaylistView::dragLeaveEvent(QDragLeaveEvent *event) {
  QTreeView::dragLeaveEvent(event);
  drop_indicator_row_ = -1;
}

void PlaylistView::dropEvent(QDropEvent *event) {
  QTreeView::dropEvent(event);
  drop_indicator_row_ = -1;
}