/*
 * *****************************************************************************
 * Copyright (C) 2014-2023 Dennis Sheirer
 *
 * 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 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>
 * ****************************************************************************
 */
package io.github.dsheirer.buffer;

import java.util.Arrays;

/**
 * Circular sample buffer - allocates a buffer and stores samples in a circular fashion, overwriting older samples with
 * newly arrived samples.  Initially fills buffer with 0-valued (default) samples or with a specified value.
 */
public class FloatCircularBuffer
{
    private float[] mBuffer;
    private int mBufferPointer = 0;

    /**
     * Creates a circular double buffer of the specified size and all entries filled with the specified initial value.
     * @param size of the buffer
     * @param initialFillValue to fill the buffer entries
     */
    public FloatCircularBuffer(int size, float initialFillValue)
    {
        mBuffer = new float[size];
        Arrays.fill(mBuffer, initialFillValue);
    }

    /**
     * Creates a circular double buffer of the specified size and all entries filled with an initial value of zero.
     * @param size of the buffer
     */
    public FloatCircularBuffer(int size)
    {
        this(size, 0.0f);
    }

    /**
     * Resets the delay buffer to an all zeros state
     */
    public void reset(float fillValue)
    {
        Arrays.fill(mBuffer, fillValue);
    }

    /**
     * Puts the new value into the buffer and returns the oldest buffer value that it replaced
     *
     * @param newValue to add to the buffer
     * @return oldest value that was overwritten by the new value
     */
    public float get(float newValue)
    {
        float oldestSample = mBuffer[mBufferPointer];

        mBuffer[mBufferPointer] = newValue;

        mBufferPointer++;

        if(mBufferPointer >= mBuffer.length)
        {
            mBufferPointer = 0;
        }

        return oldestSample;
    }

    public float[] getAll()
    {
        int valuePointer = 0;
        float[] values = new float[mBuffer.length];
        int bufferPointer = mBufferPointer;

        while(valuePointer < values.length)
        {
            values[valuePointer++] = mBuffer[bufferPointer++];

            if(bufferPointer >= mBuffer.length)
            {
                bufferPointer = 0;
            }
        }

        return values;
    }

    /**
     * Places the new value into the buffer, overwriting the oldest value
     * @param newValue to add to the buffer
     */
    public void put(float newValue)
    {
        mBuffer[mBufferPointer] = newValue;

        mBufferPointer++;

        if(mBufferPointer >= mBuffer.length)
        {
            mBufferPointer = 0;
        }
    }

    /**
     * Returns the maximum from the values currently in the buffer
     */
    public float max(float referenceValue)
    {
        float max = referenceValue;

        for(int x = 0; x < mBuffer.length; x++)
        {
            if(mBuffer[x] > max)
            {
                max = mBuffer[x];
            }
        }

//        System.out.println("Max [" + max + "] from " + Arrays.toString(mBuffer));

        return max;
    }

    /**
     * Returns the minimum from the values currently in the buffer
     */
    public float min()
    {
        float min = 0.0f;

        for(int x = 0; x < mBuffer.length; x++)
        {
            if(mBuffer[x] < min)
            {
                min = mBuffer[x];
            }
        }

        return min;
    }

    /**
     * Calculates the average/mean of the values contained in this buffer
     */
    public float mean()
    {
        double accumulator = 0.0;

        for(float value: mBuffer)
        {
            accumulator += value;
        }

        return (float)(accumulator / mBuffer.length);
    }
}