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

/*
    Rosegarden
    A sequencer and musical notation editor.
    Copyright 2000-2023 the Rosegarden development team.
    See the AUTHORS file for more 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 "SnapGrid.h"
#include "Composition.h"

namespace Rosegarden {


//////////////////////////////////////////////////////////////////////
// SnapGrid
//////////////////////////////////////////////////////////////////////


const timeT SnapGrid::NoSnap     = -1;
const timeT SnapGrid::SnapToBar  = -2;
const timeT SnapGrid::SnapToBeat = -3;
const timeT SnapGrid::SnapToUnit = -4;

SnapGrid::SnapGrid(const RulerScale *rulerScale, int ysnap) :
    m_rulerScale(rulerScale),
    m_snapTime(SnapToBeat),
    m_ysnap(ysnap)
{
    // nothing else 
}

void
SnapGrid::setSnapTime(timeT snap)
{
    Q_ASSERT(snap > 0 ||
             snap == NoSnap ||
             snap == SnapToBar ||
             snap == SnapToBeat ||
             snap == SnapToUnit);
    m_snapTime = snap;
}

timeT
SnapGrid::getSnapSetting() const
{
    return m_snapTime;
}

timeT
SnapGrid::getSnapTime(double x) const
{
    timeT time = m_rulerScale->getTimeForX(x);
    return getSnapTime(time);
}

timeT
SnapGrid::getSnapTime(timeT time) const
{
    if (m_snapTime == NoSnap) return 0;

    Rosegarden::Composition *composition = m_rulerScale->getComposition();
    int barNo = composition->getBarNumber(time);
    std::pair<timeT, timeT> barRange = composition->getBarRange(barNo);

    timeT snapTime = barRange.second - barRange.first;

    if (m_snapTime == SnapToBeat) {
        snapTime = composition->getTimeSignatureAt(time).getBeatDuration();
    } else if (m_snapTime == SnapToUnit) {
        snapTime = composition->getTimeSignatureAt(time).getUnitDuration();
    } else if (m_snapTime != SnapToBar && m_snapTime < snapTime) {
        snapTime = m_snapTime;
    }

    return snapTime;
}

timeT
SnapGrid::snapX(double x, SnapDirection direction) const
{
    return snapTime(m_rulerScale->getTimeForX(x), direction);
}

timeT
SnapGrid::snapTime(timeT time, SnapDirection direction) const
{
    if (m_snapTime == NoSnap) return time;

    Rosegarden::Composition *composition = m_rulerScale->getComposition();
    int barNo = composition->getBarNumber(time);
    std::pair<timeT, timeT> barRange = composition->getBarRange(barNo);

    timeT snapTime = barRange.second - barRange.first;

    if (m_snapTime == SnapToBeat) {
        snapTime = composition->getTimeSignatureAt(time).getBeatDuration();
    } else if (m_snapTime == SnapToUnit) {
        snapTime = composition->getTimeSignatureAt(time).getUnitDuration();
    } else if (m_snapTime != SnapToBar && m_snapTime < snapTime) {
        snapTime = m_snapTime;
    }

    timeT offset = (time - barRange.first);
    timeT rounded = (offset / snapTime) * snapTime;

    timeT left  = rounded + barRange.first;
    timeT right = left + snapTime;

    if (direction == SnapLeft) return left;
    else if (direction == SnapRight) return right;
    else if ((offset - rounded) > (rounded + snapTime - offset)) return right;
    else return left;
}

int
SnapGrid::getYBin(int y) const
{
    if (m_ysnap == 0) return y;

    int cy = 0;

    std::map<int, int>::const_iterator i = m_ymultiple.begin();

    int nextbin = -1;
    if (i != m_ymultiple.end()) nextbin = i->first;

    for (int b = 0; ; ++b) {

        if (nextbin == b) {

            cy += i->second * m_ysnap;
            ++i;
            if (i == m_ymultiple.end()) nextbin = -1;
            else nextbin = i->first;

        } else {

            cy += m_ysnap;
        }

        if (cy > y) {
            return b;
        }
    }
}

int
SnapGrid::getYBinCoordinate(int requestedBin) const
{
    // A "bin" is a track position.

    if (m_ysnap == 0)
        return requestedBin;

    int y = 0;

    typedef std::map<int /* trackPos */, int /* height */> SegmentHeightMap;

    SegmentHeightMap::const_iterator oSegmentHeightIter =
            m_ymultiple.begin();

    // Next bin that has an entry in the Segment height map.
    int nextBin = -1;
    if (oSegmentHeightIter != m_ymultiple.end())
        nextBin = oSegmentHeightIter->first;

    // For each bin from 0 to the requested bin
    for (int bin = 0; bin < requestedBin; ++bin) {

        // If this bin is in the Segment height map
        if (nextBin == bin) {

            // Use the height in the Segment height map.
            y += oSegmentHeightIter->second * m_ysnap;

            ++oSegmentHeightIter;
            if (oSegmentHeightIter == m_ymultiple.end())
                nextBin = -1;
            else
                nextBin = oSegmentHeightIter->first;

        } else {

            // Go with the height of a single track.
            y += m_ysnap;
        }
    }

    return y;
}


}
