/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */

/*
    Rosegarden
    A MIDI and audio sequencer and musical notation editor.
 
    This program is Copyright 2000-2007
        Guillaume Laurent   <glaurent@telegraph-road.org>,
        Chris Cannam        <cannam@all-day-breakfast.com>,
        Richard Bown        <richard.bown@ferventsoftware.com>
 
    The moral rights of Guillaume Laurent, Chris Cannam, and Richard
    Bown to claim authorship of this work have been asserted.
 
    Other copyrights also apply to some parts of this work.  Please
    see the AUTHORS file and individual file headers for details.
 
    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.  See the file
    COPYING included with this distribution for more information.
*/


#include "RosegardenCanvasView.h"

#include "misc/Debug.h"
#include "gui/general/CanvasItemGC.h"
#include <qcanvas.h>
#include <qcursor.h>
#include <qpoint.h>
#include <qrect.h>
#include <qscrollbar.h>
#include <qsize.h>
#include <qsizepolicy.h>
#include <qtimer.h>
#include <qwidget.h>


namespace Rosegarden
{

RosegardenCanvasView::RosegardenCanvasView(QCanvas* canvas,
        QWidget* parent,
        const char* name, WFlags f)
        : QCanvasView(canvas, parent, name, f),
        m_bottomWidget(0),
        m_currentBottomWidgetHeight( -1),
        m_smoothScroll(true),
        m_smoothScrollTimeInterval(DefaultSmoothScrollTimeInterval),
        m_minDeltaScroll(DefaultMinDeltaScroll),
        m_autoScrollTime(InitialScrollTime),
        m_autoScrollAccel(InitialScrollAccel),
        m_autoScrollXMargin(0),
        m_autoScrollYMargin(0),
        m_currentScrollDirection(None),
        m_scrollDirectionConstraint(NoFollow),
        m_autoScrolling(false)
{
    setDragAutoScroll(true);
    connect( &m_autoScrollTimer, SIGNAL( timeout() ),
             this, SLOT( doAutoScroll() ) );
}

void RosegardenCanvasView::fitWidthToContents()
{
    QRect allItemsBoundingRect;

    QCanvasItemList items = canvas()->allItems();

    QCanvasItemList::Iterator it;

    for (it = items.begin(); it != items.end(); ++it) {
        allItemsBoundingRect |= (*it)->boundingRect();
    }

    QSize currentSize = canvas()->size();
    resizeContents(allItemsBoundingRect.width(), currentSize.height());
}

void RosegardenCanvasView::setBottomFixedWidget(QWidget* w)
{
    m_bottomWidget = w;
    if (m_bottomWidget) {
        m_bottomWidget->reparent(this, 0, QPoint(0, 0));
        m_bottomWidget->setSizePolicy(QSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed));
        setMargins(0, 0, 0, m_bottomWidget->sizeHint().height());
    }
}

void RosegardenCanvasView::slotUpdate()
{
    CanvasItemGC::gc();
    canvas()->update();
}

// Smooth scroll checks
//

const int RosegardenCanvasView::AutoscrollMargin = 16;
const int RosegardenCanvasView::InitialScrollTime = 30;
const int RosegardenCanvasView::InitialScrollAccel = 5;
const int RosegardenCanvasView::MaxScrollDelta = 100;      // max a.scroll speed
const double RosegardenCanvasView::ScrollAccelValue = 1.04;// acceleration rate

const int RosegardenCanvasView::DefaultSmoothScrollTimeInterval = 10;
const double RosegardenCanvasView::DefaultMinDeltaScroll = 1.2;

void RosegardenCanvasView::startAutoScroll()
{
    //    RG_DEBUG << "RosegardenCanvasView::startAutoScroll()\n";

    if ( !m_autoScrollTimer.isActive() ) {
        m_autoScrollTime = InitialScrollTime;
        m_autoScrollAccel = InitialScrollAccel;
        m_autoScrollTimer.start( m_autoScrollTime );
    }

    QPoint autoScrollStartPoint = viewport()->mapFromGlobal( QCursor::pos() );
    m_autoScrollYMargin = autoScrollStartPoint.y() / 10;
    m_autoScrollXMargin = autoScrollStartPoint.x() / 10;

    m_autoScrolling = true;
}

void RosegardenCanvasView::startAutoScroll(int directionConstraint)
{
    setScrollDirectionConstraint(directionConstraint);
    startAutoScroll();
}

void RosegardenCanvasView::stopAutoScroll()
{
    //    RG_DEBUG << "RosegardenCanvasView::stopAutoScroll()\n";

    m_autoScrollTimer.stop();
    m_minDeltaScroll = DefaultMinDeltaScroll;
    m_currentScrollDirection = None;

    m_autoScrolling = false;
}

void RosegardenCanvasView::doAutoScroll()
{
    //    RG_DEBUG << "RosegardenCanvasView::doAutoScroll()\n";

    QPoint p = viewport()->mapFromGlobal( QCursor::pos() );
    QPoint dp = p - m_previousP;
    m_previousP = p;

    m_autoScrollTimer.start( m_autoScrollTime );
    ScrollDirection scrollDirection = None;

    int dx = 0, dy = 0;
    if (m_scrollDirectionConstraint & FollowVertical) {
        if ( p.y() < m_autoScrollYMargin ) {
            dy = -(int(m_minDeltaScroll));
            scrollDirection = Top;
        } else if ( p.y() > visibleHeight() - m_autoScrollYMargin ) {
            dy = + (int(m_minDeltaScroll));
            scrollDirection = Bottom;
        }
    }
    bool startDecelerating = false;
    if (m_scrollDirectionConstraint & FollowHorizontal) {

        //        RG_DEBUG << "p.x() : " << p.x() << " - visibleWidth : " << visibleWidth() << " - autoScrollXMargin : " << m_autoScrollXMargin << endl;

        if ( p.x() < m_autoScrollXMargin ) {
            if ( dp.x() > 0 ) {
                startDecelerating = true;
                m_minDeltaScroll /= ScrollAccelValue;
            }
            dx = -(int(m_minDeltaScroll));
            scrollDirection = Left;
        } else if ( p.x() > visibleWidth() - m_autoScrollXMargin ) {
            if ( dp.x() < 0 ) {
                startDecelerating = true;
                m_minDeltaScroll /= ScrollAccelValue;
            }
            dx = + (int(m_minDeltaScroll));
            scrollDirection = Right;
        }
    }

    //     RG_DEBUG << "dx: " << dx << ", dy: " << dy << endl;

    if ( (dx || dy) &&
            ((scrollDirection == m_currentScrollDirection) || (m_currentScrollDirection == None)) ) {
        scrollBy(dx, dy);
        if ( startDecelerating )
            m_minDeltaScroll /= ScrollAccelValue;
        else
            m_minDeltaScroll *= ScrollAccelValue;
        if (m_minDeltaScroll > MaxScrollDelta )
            m_minDeltaScroll = MaxScrollDelta;
        m_currentScrollDirection = scrollDirection;

    } else {
        // Don't automatically stopAutoScroll() here, the mouse button
        // is presumably still pressed.
        m_minDeltaScroll = DefaultMinDeltaScroll;
        m_currentScrollDirection = None;
    }

}

bool RosegardenCanvasView::isTimeForSmoothScroll()
{
    if (m_smoothScroll) {
        int ta = m_scrollAccelerationTimer.elapsed();
        int t = m_scrollTimer.elapsed();

        //	RG_DEBUG << "t = " << t << ", ta = " << ta << ", int " << m_smoothScrollTimeInterval << ", delta " << m_minDeltaScroll << endl;

        if (t < m_smoothScrollTimeInterval) {

            return false;

        } else {

            if (ta > 300) {
                // reset smoothScrollTimeInterval
                m_smoothScrollTimeInterval = DefaultSmoothScrollTimeInterval;
                m_minDeltaScroll = DefaultMinDeltaScroll;
                m_scrollAccelerationTimer.restart();
            } else if (ta > 50) {
                //                 m_smoothScrollTimeInterval /= 2;
                m_minDeltaScroll *= 1.08;
                m_scrollAccelerationTimer.restart();
            }

            m_scrollTimer.restart();
            return true;
        }
    }

    return true;
}

void RosegardenCanvasView::slotScrollHoriz(int hpos)
{
    QScrollBar* hbar = getMainHorizontalScrollBar();
    int currentContentYPos = contentsY();

    /* Lots of performance hitting debug
    RG_DEBUG << "RosegardenCanvasView::slotScrollHoriz: hpos is " << hpos
      << ", contentsX is " << contentsX() << ", visibleWidth is "
      << visibleWidth() << endl;
             */

    if (hpos == 0) {

        // returning to zero
        //         hbar->setValue(0);
        setContentsPos(0, currentContentYPos);

    } else if (hpos > (contentsX() +
                       visibleWidth() * 1.6) ||
               hpos < (contentsX() -
                       visibleWidth() * 0.7)) {

        // miles off one side or the other
        // 	hbar->setValue(hpos - int(visibleWidth() * 0.4));
        setContentsPos(hpos - int(visibleWidth() * 0.4), currentContentYPos);

    } else if (hpos > (contentsX() +
                       visibleWidth() * 0.9)) {

        // moving off the right hand side of the view
        // 	hbar->setValue(hbar->value() + int(visibleWidth() * 0.6));
        setContentsPos(hbar->value() + int(visibleWidth() * 0.6), currentContentYPos);

    } else if (hpos < (contentsX() +
                       visibleWidth() * 0.1)) {

        // moving off the left
        // 	hbar->setValue(hbar->value() - int(visibleWidth() * 0.6));
        setContentsPos(hbar->value() - int(visibleWidth() * 0.6), currentContentYPos);
    }
}

void RosegardenCanvasView::slotScrollHorizSmallSteps(int hpos)
{
    QScrollBar* hbar = getMainHorizontalScrollBar();
    int currentContentYPos = contentsY();

    int diff = 0;

    if (hpos == 0) {

        // returning to zero
        //         hbar->setValue(0);
        setContentsPos(0, currentContentYPos);

    } else if ((diff = int(hpos - (contentsX() +
                                   visibleWidth() * 0.90))) > 0) {

        // moving off the right hand side of the view

        int delta = diff / 6;
        int diff10 = std::min(diff, (int)m_minDeltaScroll);
        delta = std::max(delta, diff10);

        // 	hbar->setValue(hbar->value() + delta);
        setContentsPos(hbar->value() + delta, currentContentYPos);

    } else if ((diff = int(hpos - (contentsX() +
                                   visibleWidth() * 0.10))) < 0) {
        // moving off the left

        int delta = -diff / 6;
        int diff10 = std::min( -diff, (int)m_minDeltaScroll);
        delta = std::max(delta, diff10);

        // 	hbar->setValue(hbar->value() - delta);
        setContentsPos(hbar->value() - delta, currentContentYPos);

    }
}

void RosegardenCanvasView::slotScrollVertSmallSteps(int vpos)
{
    QScrollBar* vbar = verticalScrollBar();

    //    RG_DEBUG << "RosegardenCanvasView::slotScrollVertSmallSteps: vpos is " << vpos << ", contentsY is " << contentsY() << ", visibleHeight is " << visibleHeight() << endl;

    // As a special case (or hack), ignore any request made before we've
    // actually been rendered and sized
    if (visibleHeight() <= 1)
        return ;

    int diff = 0;

    if (vpos == 0) {

        // returning to zero
        vbar->setValue(0);

    } else if ((diff = int(vpos - (contentsY() +
                                   visibleHeight() * 0.90))) > 0) {

        // moving off up

        int delta = diff / 6;
        int diff10 = std::min(diff, (int)m_minDeltaScroll);
        delta = std::max(delta, diff10);

        vbar->setValue(vbar->value() + diff);

    } else if ((diff = int(vpos - (contentsY() +
                                   visibleHeight() * 0.10))) < 0) {

        // moving off down

        int delta = -diff / 6;
        int diff10 = std::min( -diff, (int)m_minDeltaScroll);
        delta = std::max(delta, diff10);

        vbar->setValue(vbar->value() - delta);

    }
}

void RosegardenCanvasView::slotScrollVertToTop(int vpos)
{
    QScrollBar* vbar = verticalScrollBar();
    if (vpos < visibleHeight() / 3)
        vbar->setValue(0);
    else
        vbar->setValue(vpos - visibleHeight() / 5);
}

void RosegardenCanvasView::slotSetScrollPos(const QPoint &pos)
{
    getMainHorizontalScrollBar()->setValue(pos.x());
    verticalScrollBar()->setValue(pos.y());
}

void RosegardenCanvasView::resizeEvent(QResizeEvent* e)
{
    QCanvasView::resizeEvent(e);
    if (!horizontalScrollBar()->isVisible())
        updateBottomWidgetGeometry();

}

void RosegardenCanvasView::setHBarGeometry(QScrollBar &hbar, int x, int y, int w, int h)
{
    QCanvasView::setHBarGeometry(hbar, x, y, w, h);
    updateBottomWidgetGeometry();
}

void RosegardenCanvasView::updateBottomWidgetGeometry()
{
    if (!m_bottomWidget)
        return ;

    int bottomWidgetHeight = m_bottomWidget->sizeHint().height();

    setMargins(0, 0, 0, bottomWidgetHeight);
    QRect r = frameRect();
    int hScrollBarHeight = 0;
    if (horizontalScrollBar()->isVisible())
        hScrollBarHeight = horizontalScrollBar()->height() + 2; // + 2 offset needed to preserve border shadow

    int vScrollBarWidth = 0;
    if (verticalScrollBar()->isVisible())
        vScrollBarWidth = verticalScrollBar()->width();

    m_bottomWidget->setGeometry(r.x(),
                                r.y() + r.height() - bottomWidgetHeight - hScrollBarHeight,
                                r.width() - vScrollBarWidth,
                                bottomWidgetHeight);

    if (bottomWidgetHeight != m_currentBottomWidgetHeight) {
        emit bottomWidgetHeightChanged(bottomWidgetHeight);
        m_currentBottomWidgetHeight = bottomWidgetHeight;
    }
}

void RosegardenCanvasView::wheelEvent(QWheelEvent *e)
{
    if (e->state() & ControlButton) {
        if (e->delta() > 0)
            emit zoomIn();
        else if (e->delta() < 0)
            emit zoomOut();
        return ;
    }
    QCanvasView::wheelEvent(e);
}

}
#include "RosegardenCanvasView.moc"
