/*
 * Copyright (C) 2014 Emeric Poupon
 *
 * This file is part of LMS.
 *
 * LMS 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.
 *
 * LMS 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 LMS.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <boost/random/mersenne_twister.hpp>
#include <boost/random/uniform_int_distribution.hpp>

#include <Wt/WApplication>
#include <Wt/WImage>
#include <Wt/WItemDelegate>
#include <Wt/WStandardItem>
#include <Wt/WFileResource>
#include <Wt/WTheme>

#include "logger/Logger.hpp"

#include "LmsApplication.hpp"
#include "PlayQueue.hpp"

static const int TrackInfoRole = Wt::UserRole;

namespace {

	void swapRows(Wt::WStandardItemModel *model, int row1, int row2)
	{
		// Swap data column by column
		for (int i = 0; i < model->columnCount(); ++i)
		{
			Wt::WModelIndex index1 = model->index(row1, i);
			Wt::WModelIndex index2 = model->index(row2, i);

			// swap data associated with standard roles
			{
				auto tmp = model->itemData(index1);			// 1 -> tmp
				model->setItemData(index1, model->itemData(index2));	// 2 -> 1
				model->setItemData(index2, tmp);			// tmp-> 2
			}
			// caution: swap data associated with our custom roles if any!!
		}
	}
}

namespace UserInterface {
namespace Desktop {

enum ColumnId
{
	COLUMN_ID_TRACK_ID	= 0,
	COLUMN_ID_COVER		= 1,
	COLUMN_ID_NAME		= 2,
};

static const int trackPosInvalid = -1;

class TrackSelector
{
	public:
		TrackSelector();

		void setShuffle(bool enable);
		void setLoop(bool enable) { _loop = enable; }

		int previous(void);
		int next(void);
		int getCurrent(void);

		// Set the internal pos thanks to the track pos
		void setPosByRowId(int rowId);
		void setPos(int pos)	{ _curPos = pos; }

		void setSize(std::size_t size);
		std::size_t getSize(void) const { return _size;}

	private:

		void refreshPositions();

		bool _loop;
		bool _shuffle;

		std::size_t _size;
		std::size_t _curPos;

		std::vector<int> _trackPos;
};

TrackSelector::TrackSelector()
: _loop(false),
_shuffle(false),
_size(0),
_curPos(0)
{
}

void
TrackSelector::refreshPositions()
{
	_trackPos.clear();

	if (_size == 0)
		return;

	for (std::size_t i = 0; i < _size; ++i)
		_trackPos.push_back(i);

	// Now shuffle
	// Source: http://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle
	boost::random::mt19937 rng;         // produces randomness out of thin air
	rng.seed(static_cast<unsigned int>(std::time(0)));

	for (std::size_t i = 0; i < _size; ++i)
	{
		boost::random::uniform_int_distribution<> distribution(i, _size - 1);
		int val1 = distribution(rng);
		int tmp = _trackPos[i];
		_trackPos[i] = _trackPos[val1];
		_trackPos[val1] = tmp;
	}
}

int
TrackSelector::getCurrent()
{
	return _shuffle ? _trackPos[_curPos] : _curPos;
}

void
TrackSelector::setShuffle(bool enable)
{
	_shuffle = enable;

	if (_size != 0)
	{
		// Update the current index we are playing if we switch shuffle
		if (_shuffle)
			setPosByRowId(_curPos);
		else
			setPos(_trackPos[_curPos]);
	}
}

int
TrackSelector::next()
{
	if (_size == 0)
		return trackPosInvalid;

	if (_curPos == _size - 1)
	{
		if (!_loop)
			return trackPosInvalid;
		else
			_curPos = 0;
	}
	else
		++_curPos;

	return _shuffle ? _trackPos[_curPos] : _curPos;
}

int
TrackSelector::previous()
{
	if (_size == 0)
		return trackPosInvalid;

	if (_curPos == 0)
	{
		if (!_loop)
			return trackPosInvalid;
		else
			_curPos = _size - 1;
	}
	else
		--_curPos;

	return _shuffle ? _trackPos[_curPos] : _curPos;
}

void
TrackSelector::setPosByRowId(int rowId)
{
	if (_shuffle)
	{
		for (std::size_t i = 0; i < _trackPos.size(); ++i)
		{
			if (rowId == _trackPos[i])
			{
				_curPos = i;
				break;
			}
		}
	}
	else
		_curPos = rowId;
}

void
TrackSelector::setSize(std::size_t size)
{
	_size = size;
	_curPos = 0;
	refreshPositions();
}

struct TrackInfo
{
	Wt::WString track;
	Wt::WString artist;
	Wt::WString release;
};

class PlayQueueItemDelegate : public Wt::WItemDelegate
{
	public:
		PlayQueueItemDelegate(Wt::WObject *parent = 0) : Wt::WItemDelegate(parent) {}

		Wt::WWidget* update(Wt::WWidget *widget, const Wt::WModelIndex &index, Wt::WFlags< Wt::ViewItemRenderFlag > flags)
		{
			Wt::WWidget* res;

			if (!index.data(TrackInfoRole).empty())
			{
				TrackInfo trackInfo = boost::any_cast<TrackInfo>(index.data(TrackInfoRole));

				Wt::WContainerWidget *container = new Wt::WContainerWidget();
				Wt::WText* track = new Wt::WText(trackInfo.track, Wt::PlainText, container);
				Wt::WText* artist = new Wt::WText(trackInfo.artist + " - " + trackInfo.release, Wt::PlainText, container);

				artist->setInline(false);
				track->setInline(false);

				artist->setStyleClass("playqueue-artist");
				track->setStyleClass("playqueue-track");

				// Apply style if any
				Wt::WString styleClass = Wt::asString(index.data(Wt::StyleClassRole));

				// Apply selection style if any
				if (flags & Wt::RenderSelected)
					styleClass += " " + Wt::WApplication::instance()->theme()->activeClass();

				container->setStyleClass(styleClass);

				res = container;
			}
			else
				res = Wt::WItemDelegate::update(widget, index, flags);

			return res;
		}

	private:

};


PlayQueue::PlayQueue(Wt::WContainerWidget* parent)
: Wt::WTableView(parent),
_curPlayedTrackPos(trackPosInvalid),
_trackSelector(new TrackSelector())
{
	_model = new Wt::WStandardItemModel(0, 3, this);

	// 0 Column is hidden (track id)

	this->setHeaderHeight(0);
	this->setModel(_model);
	this->setSelectionMode(Wt::ExtendedSelection);
	this->setSortingEnabled(false);
	this->setAlternatingRowColors(true);
	this->setRowHeight(64);
	this->setColumnWidth(COLUMN_ID_COVER, 64);
	this->setColumnWidth(COLUMN_ID_NAME, 240);

	this->setLayoutSizeAware(true);
#if WT_VERSION >= 0X03030400
	this->setOverflow(Wt::WContainerWidget::OverflowHidden, Wt::Horizontal);
	this->setOverflow(Wt::WContainerWidget::OverflowScroll, Wt::Vertical);
#endif
	this->setColumnHidden(COLUMN_ID_TRACK_ID, true);

	_itemDelegate = new PlayQueueItemDelegate();
	this->setItemDelegate(_itemDelegate);

	this->doubleClicked().connect( std::bind([=] (Wt::WModelIndex idx, Wt::WMouseEvent evt)
	{
		if (!idx.isValid())
			return;

		// Update selection
		Wt::WModelIndexSet indexSet;
		indexSet.insert(idx);

		this->setSelectedIndexes( indexSet );

		// Read the requested track
		play(idx.row());

	}, std::placeholders::_1, std::placeholders::_2));

}

void
PlayQueue::layoutSizeChanged (int width, int height)
{
	std::size_t coverColumnSize = this->columnWidth(COLUMN_ID_COVER).toPixels();
	// Set the remaining size for the name column
	this->setColumnWidth(COLUMN_ID_NAME, width - coverColumnSize - (7 * 2) - 2);
}

void
PlayQueue::setShuffle(bool enable)
{
	_trackSelector->setShuffle(enable);
}

void
PlayQueue::setLoop(bool enable)
{
	_trackSelector->setLoop(enable);
}

void
PlayQueue::play()
{
	_trackSelector->setPos(0);

	readTrack(_trackSelector->getCurrent());
}

void
PlayQueue::play(int rowId)
{
	// Update the track selector to use the requested track as current position
	_trackSelector->setPosByRowId(rowId);

	readTrack(_trackSelector->getCurrent());
}

void
PlayQueue::select(int rowId)
{
	// Update the track selector to use the requested track as current position
	_trackSelector->setPosByRowId(rowId);

	Wt::WTableView::select(_model->index(_trackSelector->getCurrent(), 0));

	this->scrollTo( _model->index(_trackSelector->getCurrent(), 0));
}

void
PlayQueue::addTracks(const std::vector<Database::Track::id_type>& trackIds)
{
	using namespace Database;

	LMS_LOG(UI, DEBUG) << "Adding " << trackIds.size() << " tracks to play queue";

	// Add tracks to model
	for (Track::id_type trackId : trackIds)
	{
		Wt::Dbo::Transaction transaction(DboSession());

		Track::pointer track (Track::getById(DboSession(), trackId));

		if (track)
		{
			int dataRow = _model->rowCount();

			_model->insertRows(dataRow, 1);

			_model->setData(dataRow, COLUMN_ID_TRACK_ID, track.id(), Wt::UserRole);

			std::string coverUrl;
			coverUrl = SessionImageResource()->getTrackUrl(track.id(), 64);

			_model->setData(dataRow, COLUMN_ID_COVER, coverUrl, Wt::DecorationRole);
			_model->setData(dataRow, COLUMN_ID_COVER, std::string("playqueue-cover"), Wt::StyleClassRole);

			TrackInfo trackInfo;
			trackInfo.track = Wt::WString::fromUTF8(track->getName());
			trackInfo.artist = Wt::WString::fromUTF8(track->getArtist()->getName());
			trackInfo.release = Wt::WString::fromUTF8(track->getRelease()->getName());
			_model->setData(dataRow, COLUMN_ID_NAME, trackInfo, TrackInfoRole);
		}
	}

	_trackSelector->setSize( _model->rowCount() );

	_sigTracksUpdated.emit();
}

void
PlayQueue::clear(void)
{
	_model->removeRows(0, _model->rowCount());

	// Reset play id
	_curPlayedTrackPos = trackPosInvalid;
	_trackSelector->setSize( 0 );

	_sigTracksUpdated.emit();
}

void
PlayQueue::handlePlaybackComplete(void)
{
	playNext();
}

void
PlayQueue::playNext(void)
{
	std::size_t nbTries = _trackSelector->getSize();

	while (nbTries > 0)
	{
		int pos = _trackSelector->next();
		if (pos == trackPosInvalid)
			break;

		readTrack(pos);

		break;
	}
}

void
PlayQueue::playPrevious(void)
{
	std::size_t nbTries = _trackSelector->getSize();

	while (nbTries > 0)
	{
		int pos = _trackSelector->previous();
		if (pos == trackPosInvalid)
			break;

		readTrack(pos);
		break;

	}
}

void
PlayQueue::readTrack(int rowPos)
{
	LMS_LOG(UI, DEBUG) << "Reading track at pos " << rowPos << ", row count = " << _model->rowCount();

	if (rowPos < _model->rowCount())
	{
		Database::Track::id_type trackId = boost::any_cast<Database::Track::id_type>(_model->data(rowPos, COLUMN_ID_TRACK_ID, Wt::UserRole));

		setPlayingTrackPos(rowPos);

		_sigTrackPlay.emit(trackId, rowPos);

		this->scrollTo( _model->index(_trackSelector->getCurrent(), 0));
	}
}

void
PlayQueue::setPlayingTrackPos(int newRowPos)
{
	int oldRowPos = _curPlayedTrackPos;
	_curPlayedTrackPos = newRowPos;

	// Hack re-set the data in order to trigger the rerending of the widget
	// calling the update method of our custom item delegate gives bad results
	if (oldRowPos >= 0)
	{
		_model->setData(oldRowPos, COLUMN_ID_NAME, boost::any(), Wt::StyleClassRole);
	}

	if (newRowPos >= 0)
	{
		_model->setData(newRowPos, COLUMN_ID_NAME, std::string("playqueue-playing"), Wt::StyleClassRole);
	}
}

void
PlayQueue::delSelected(void)
{
	int minId = _model->rowCount();
	Wt::WModelIndexSet indexSet = this->selectedIndexes();

	// Make sure to delete entries in the reverse order
	std::vector<int> rowIds;
	for (Wt::WModelIndex index : indexSet)
		rowIds.push_back(index.row());

	std::sort(rowIds.begin(), rowIds.end(), std::greater<int>());
	if (!rowIds.empty())
		minId = rowIds.back();

	for (int rowId : rowIds)
		_model->removeRow(rowId);

	// If the current played track is removed, make sure to unselect it
	_trackSelector->setSize(_model->rowCount());

	renumber(minId, _model->rowCount() - 1);
	_sigTracksUpdated.emit();
}

void
PlayQueue::delAll(void)
{
	_model->removeRows(0, _model->rowCount());
	_trackSelector->setSize(0);
	_sigTracksUpdated.emit();
}

void
PlayQueue::moveSelectedUp(void)
{
	int minId = _model->rowCount();
	int maxId = 0;

	Wt::WModelIndexSet indexSet = this->selectedIndexes();
	Wt::WModelIndexSet newIndexSet;

	// ordered from up to down
	for (Wt::WModelIndex index : indexSet)
	{
		// Do nothing if the first selected index is on the top
		if (index.row() == 0)
			return;

		// TODO optimize for blocks
		swapRows(_model, index.row() - 1, index.row());

		if (index.row() - 1 < minId)
			minId = index.row() - 1;

		if (index.row() > maxId)
			maxId = index.row();

		// Update playing status
		if (_curPlayedTrackPos == index.row())
			setPlayingTrackPos(_curPlayedTrackPos - 1);
		else if (_curPlayedTrackPos == index.row() - 1)
			setPlayingTrackPos(_curPlayedTrackPos + 1);

		newIndexSet.insert( _model->index(index.row() - 1, 0));
	}

	_trackSelector->setPosByRowId(_curPlayedTrackPos);
	this->setSelectedIndexes( newIndexSet );

	renumber(minId, maxId);

	_sigTracksUpdated.emit();
}


void
PlayQueue::moveSelectedDown(void)
{
	int minId = _model->rowCount();
	int maxId = 0;

	Wt::WModelIndexSet indexSet = this->selectedIndexes();
	Wt::WModelIndexSet newIndexSet;

	// ordered from up to down
	for (Wt::WModelIndex index : indexSet)
	{
		// Do nothing if the last selected index is the last one
		if (index.row() == _model->rowCount() - 1)
			return;

		// TODO optimize for blocks
		swapRows(_model, index.row(), index.row() + 1);

		if (index.row() < minId)
			minId = index.row();

		if (index.row() + 1 > maxId)
			maxId = index.row() + 1;

		// Update playing status
		if (_curPlayedTrackPos == index.row())
			setPlayingTrackPos(_curPlayedTrackPos + 1);
		else if (_curPlayedTrackPos == index.row() + 1)
			setPlayingTrackPos(_curPlayedTrackPos - 1);

		newIndexSet.insert( _model->index(index.row() + 1, 0));
	}

	_trackSelector->setPosByRowId(_curPlayedTrackPos);
	this->setSelectedIndexes( newIndexSet );

	renumber(minId, maxId);

	_sigTracksUpdated.emit();
}

void
PlayQueue::renumber(int firstId, int lastId)
{
	for (int i = firstId; i <= lastId; ++i)
		_model->setData( i, 1, i + 1);
}

void
PlayQueue::getTracks(std::vector<Database::Track::id_type>& trackIds) const
{
	// Now add each entry in the playlist
	for (int i = 0; i < _model->rowCount(); ++i)
	{
		Database::Track::id_type trackId = boost::any_cast<Database::Track::id_type>(_model->data(i, COLUMN_ID_TRACK_ID, Wt::UserRole));
		trackIds.push_back(trackId);
	}
}

} // namespace Desktop
} // namespace UserInterface