/***************************************************************************
 *   Copyright (C) 2004 by Albert Astals Cid <tsdgeos@terra.es>            *
 *                                                                         *
 *   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.                                   *
 ***************************************************************************/

#include <qtimer.h>
#include <klocale.h>
#include <kurl.h>
#include <kurldrag.h>
#include <kaction.h>
#include <kactioncollection.h>

#include "thumbnaillist.h"
#include "pixmapwidget.h"
#include "page.h"

ThumbnailList::ThumbnailList( QWidget *parent, KPDFDocument *document )
	: QScrollView( parent, "KPDF::Thumbnails", WNoAutoErase | WStaticContents ),
	m_document( document ), m_selected( 0 ), m_delayTimer( 0 )
{
	// set scrollbars
	setHScrollBarMode( QScrollView::AlwaysOff );
	setVScrollBarMode( QScrollView::AlwaysOn );

	// dealing with large areas so enable clipper
	enableClipper( true );

	// widget setup: can be focused by tab and mouse click (not wheel)
	viewport()->setFocusProxy( this );
	viewport()->setFocusPolicy( StrongFocus );
	viewport()->setPaletteBackgroundColor( Qt::gray );
	setResizePolicy( Manual );
	setAcceptDrops( true );
	setDragAutoScroll( false );

	// set contents background to the 'base' color
	viewport()->setPaletteBackgroundColor( palette().active().base() );

	setFrameStyle( StyledPanel | Raised );
	connect( this, SIGNAL(contentsMoving(int, int)), this, SLOT(slotRequestPixmaps(int, int)) );
}


//BEGIN KPDFDocumentObserver inherited methods 
void ThumbnailList::pageSetup( const QValueVector<KPDFPage*> & pages, bool /*documentChanged*/ )
{
	// delete all the Thumbnails
	QValueVector<ThumbnailWidget *>::iterator thumbIt = m_thumbnails.begin();
	QValueVector<ThumbnailWidget *>::iterator thumbEnd = m_thumbnails.end();
	for ( ; thumbIt != thumbEnd; ++thumbIt )
		delete *thumbIt;
	m_thumbnails.clear();
	m_selected = 0;

	if ( pages.count() < 1 )
	{
		resizeContents( 0, 0 );
		return;
	}

	//FIXME change this quick fix (lines that follows). Check if filtering:
	bool skipCheck = true;
	for ( uint i = 0; i < pages.count(); i++ )
		if ( pages[i]->isHilighted() )
			skipCheck = false;

	// generate Thumbnails for the given set of pages
	ThumbnailWidget *t;
	int width = clipper()->width(),
	    totalHeight = 0;
	QValueVector<KPDFPage*>::const_iterator pageIt = pages.begin();
	QValueVector<KPDFPage*>::const_iterator pageEnd = pages.end();
	for (; pageIt != pageEnd ; ++pageIt)
		if ( skipCheck || (*pageIt)->isHilighted() ) {
			t = new ThumbnailWidget( viewport(), *pageIt );
			t->setFocusProxy( this );
			// add to the scrollview
			addChild( t, 0, totalHeight );
			// add to the internal queue
			m_thumbnails.push_back( t );
			// update total height (asking widget its own height)
			t->setZoomFitWidth( width );
			t->resize( t->widthHint(), t->heightHint() );
			totalHeight += t->heightHint() + 4;
			t->show();
		}

	// update scrollview's contents size (sets scrollbars limits)
	resizeContents( width, totalHeight );

	// request for thumbnail generation
	requestPixmaps( 200 );
}

void ThumbnailList::pageSetCurrent( int pageNumber, const QRect & /*viewport*/ )
{
	// deselect previous thumbnail
	if ( m_selected )
		m_selected->setSelected( false );
	m_selected = 0;

	// select next page
	m_vectorIndex = 0;
	QValueVector<ThumbnailWidget *>::iterator thumbIt = m_thumbnails.begin();
	QValueVector<ThumbnailWidget *>::iterator thumbEnd = m_thumbnails.end();
	for (; thumbIt != thumbEnd; ++thumbIt)
	{
		if ( (*thumbIt)->pageNumber() == pageNumber )
		{
			m_selected = *thumbIt;
			m_selected->setSelected( true );
			ensureVisible( 0, childY( m_selected ) + m_selected->height()/2, 0, visibleHeight()/2 );
			//non-centered version: ensureVisible( 0, itemTop + itemHeight/2, 0, itemHeight/2 );
			break;
		}
		m_vectorIndex++;
	}
}

void ThumbnailList::notifyPixmapChanged( int pageNumber )
{
	QValueVector<ThumbnailWidget *>::iterator thumbIt = m_thumbnails.begin(), thumbEnd = m_thumbnails.end();
	for (; thumbIt != thumbEnd; ++thumbIt)
		if ( (*thumbIt)->pageNumber() == pageNumber )
		{
			(*thumbIt)->update();
			break;
		}
}

void ThumbnailList::dragEnterEvent( QDragEnterEvent * ev )
{
	ev->accept();
}

void ThumbnailList::dropEvent( QDropEvent * ev )
{
	KURL::List lst;
	if (  KURLDrag::decode(  ev, lst ) )
		emit urlDropped( lst.first() );
}
//END KPDFDocumentObserver inherited methods 

//BEGIN widget events 
void ThumbnailList::keyPressEvent( QKeyEvent * keyEvent )
{
	if ( m_thumbnails.count() < 1 )
		return keyEvent->ignore();

	int nextPage = -1;
	if ( keyEvent->key() == Key_Up )
	{
		if ( !m_selected )
			nextPage = 0;
		else if ( m_vectorIndex > 0 )
			nextPage = m_thumbnails[ m_vectorIndex - 1 ]->pageNumber();
	}
	else if ( keyEvent->key() == Key_Down )
	{
		if ( !m_selected )
			nextPage = 0;
		else if ( m_vectorIndex < (int)m_thumbnails.count() - 1 )
			nextPage = m_thumbnails[ m_vectorIndex + 1 ]->pageNumber();
	}
	else if ( keyEvent->key() == Key_Home )
		nextPage = m_thumbnails[ 0 ]->pageNumber();
	else if ( keyEvent->key() == Key_End )
		nextPage = m_thumbnails[ m_thumbnails.count() - 1 ]->pageNumber();

	if ( nextPage == -1 )
		return keyEvent->ignore();

	keyEvent->accept();
	if ( m_selected )
		m_selected->setSelected( false );
	m_selected = 0;
	m_document->slotSetCurrentPage( nextPage );
}

void ThumbnailList::contentsMousePressEvent( QMouseEvent * e )
{
	if ( e->button() != Qt::LeftButton )
		return;
	int clickY = e->y();
	QValueVector<ThumbnailWidget *>::iterator thumbIt = m_thumbnails.begin();
	QValueVector<ThumbnailWidget *>::iterator thumbEnd = m_thumbnails.end();
	for ( ; thumbIt != thumbEnd; ++thumbIt )
	{
		ThumbnailWidget * t = *thumbIt;
		int childTop = childY(t);
		if ( clickY > childTop && clickY < (childTop + t->height()) )
		{
			m_document->slotSetCurrentPage( t->pageNumber() );
			break;
		}
	}
}

void ThumbnailList::viewportResizeEvent( QResizeEvent * e )
{
	if ( m_thumbnails.count() < 1 || width() < 1 )
		return;
	// if width changed resize all the Thumbnails, reposition them to the
	// right place and recalculate the contents area
	if ( e->size().width() != e->oldSize().width() )
	{
		// runs the timer avoiding a thumbnail regeneration by 'contentsMoving'
		requestPixmaps( 2000 );

		// resize and reposition items
		int totalHeight = 0,
		    newWidth = e->size().width();
		QValueVector<ThumbnailWidget *>::iterator thumbIt = m_thumbnails.begin();
		QValueVector<ThumbnailWidget *>::iterator thumbEnd = m_thumbnails.end();
		for ( ; thumbIt != thumbEnd; ++thumbIt )
		{
			ThumbnailWidget *t = *thumbIt;
			moveChild( t, 0, totalHeight );
			t->setZoomFitWidth( newWidth );
			t->resize( t->widthHint(), t->heightHint() );
			totalHeight += t->heightHint() + 4;
		}

		// update scrollview's contents size (sets scrollbars limits)
		resizeContents( newWidth, totalHeight );

		// ensure selected item remains visible
		if ( m_selected )
			ensureVisible( 0, childY( m_selected ) + m_selected->height()/2, 0, visibleHeight()/2 );
	}
	else if ( e->size().height() <= e->oldSize().height() )
		return;
	// update Thumbnails since width has changed or height has increased
	requestPixmaps( 500 );
}
//END widget events

//BEGIN internal SLOTS 
void ThumbnailList::slotRequestPixmaps( int /*newContentsX*/, int newContentsY )
{
	// if an update is already scheduled or the widget is hidden, don't proceed
	if ( (m_delayTimer && m_delayTimer->isActive()) || !isShown() )
		return;

	int vHeight = visibleHeight(),
	    vOffset = newContentsY == -1 ? contentsY() : newContentsY;

	// scroll from the top to the last visible thumbnail
	QValueVector<ThumbnailWidget *>::iterator thumbIt = m_thumbnails.begin();
	QValueVector<ThumbnailWidget *>::iterator thumbEnd = m_thumbnails.end();
	for ( ; thumbIt != thumbEnd; ++thumbIt )
	{
		ThumbnailWidget * t = *thumbIt;
		int top = childY( t ) - vOffset;
		if ( top > vHeight )
			break;
		else if ( top + t->height() > 0 )
			m_document->requestPixmap( THUMBNAILS_ID, t->pageNumber(), t->pixmapWidth(), t->pixmapHeight(), true );
	}
}
//END internal SLOTS

void ThumbnailList::requestPixmaps( int delayMs )
{
	if ( !m_delayTimer )
	{
		m_delayTimer = new QTimer( this );
		connect( m_delayTimer, SIGNAL( timeout() ), this, SLOT( slotRequestPixmaps() ) );
	}
	m_delayTimer->start( delayMs, true );
}

#include "thumbnaillist.moc"