/**
 * Copyright (c) 2011, The University of Southampton and the individual contributors.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 *   *  Redistributions of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 *
 *   *  Redistributions in binary form must reproduce the above copyright notice,
 *      this list of conditions and the following disclaimer in the documentation
 *      and/or other materials provided with the distribution.
 *
 *   *  Neither the name of the University of Southampton nor the names of its
 *      contributors may be used to endorse or promote products derived from this
 *      software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.openimaj.audio.util;

import org.openimaj.audio.timecode.MeasuresBeatsTicksTimecode;
import org.openimaj.time.TimeKeeper;

/**
 *      A timekeeper that generates {@link MeasuresBeatsTicksTimecode}s that allow
 *      the position within a music score to be tracked.
 *
 *      @author David Dupplaw (dpd@ecs.soton.ac.uk)
 *  @created 12 Feb 2013
 *      @version $Author$, $Revision$, $Date$
 */
public class BasicMusicTimekeeper implements TimeKeeper<MeasuresBeatsTicksTimecode>
{
        /** The time the timekeeper is started */
        private long lastStarted;
        
        /** The time to offset if the timekeeper is paused and restarted */
        private long timeOffset;
        
        /** The time the timekeeper was paused */
        private long pausedAt;

        /** Whether the timekeeper is running or not */
        private boolean isRunning;

        /** The last calculated timestamp - with offsets */
        private long currentTime;

        /** The timecode */
        private MeasuresBeatsTicksTimecode timecode = 
                        new MeasuresBeatsTicksTimecode( 120, 0, 0, 0, 4 );
        
        /**
         *      Set the tempo of the timekeeper
         *      @param bpm The new beats per minute.
         */
        public void setBPM( final float bpm )
        {
                this.timecode = new MeasuresBeatsTicksTimecode( bpm, 
                                this.timecode.getMeasures(), this.timecode.getBeats(), 
                                this.timecode.getTicks(), this.timecode.beatsPerMeasure );
        }
        
        /**
         *      Returns the number of BPMs this timekeeper is running at.
         *      @return The BPMs
         */
        public double getBPM()
        {
                return this.timecode.bpm;
        }
        
        /**
         *      {@inheritDoc}
         *      @see org.openimaj.time.TimeKeeper#run()
         */
        @Override
        public void run()
        {
                if( this.lastStarted == 0 )
                        this.lastStarted = System.currentTimeMillis();
                else
                        if( this.supportsPause() )
                                this.timeOffset += System.currentTimeMillis() - this.pausedAt;
                
                this.isRunning = true;
        }

        /**
         *      {@inheritDoc}
         *      @see org.openimaj.time.TimeKeeper#pause()
         */
        @Override
        public void pause()
        {
                if( this.supportsPause() )
                {
                        this.isRunning = false;
                        this.pausedAt = System.currentTimeMillis();
                }
        }

        /**
         *      {@inheritDoc}
         *      @see org.openimaj.time.TimeKeeper#stop()
         */
        @Override
        public void stop()
        {
                this.isRunning = false;
                this.currentTime = 0;
        }

        /**
         *      {@inheritDoc}
         *      @see org.openimaj.time.TimeKeeper#getTime()
         */
        @Override
        public MeasuresBeatsTicksTimecode getTime()
        {
                if( this.isRunning )
                {
                        // Update the current time.
                        this.currentTime = (System.currentTimeMillis() -
                                        this.lastStarted - this.timeOffset);
                        this.timecode.setTimecodeInMilliseconds( this.currentTime );
                }

                return this.timecode;
        }

        /**
         *      {@inheritDoc}
         *      @see org.openimaj.time.TimeKeeper#seek(long)
         */
        @Override
        public void seek( final long timestamp )
        {
                // Doesn't support seek
        }

        /**
         *      {@inheritDoc}
         *      @see org.openimaj.time.TimeKeeper#reset()
         */
        @Override
        public void reset()
        {
                this.lastStarted = 0;
                this.pausedAt = -1;
                this.run();
        }

        /**
         *      {@inheritDoc}
         *      @see org.openimaj.time.TimeKeeper#supportsPause()
         */
        @Override
        public boolean supportsPause()
        {
                return true;
        }

        /**
         *      {@inheritDoc}
         *      @see org.openimaj.time.TimeKeeper#supportsSeek()
         */
        @Override
        public boolean supportsSeek()
        {
                return false;
        }

        /**
         *      Returns the number of ticks per beat
         *      @return the number of ticks per beat
         */
        public int getTicksPerBeat()
        {
                return this.timecode.ticksPerBeat;
        }
}