/*
 Copyright © 2017 Hasan Yavuz Özderya

 This file is part of serialplot.

 serialplot 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.

 serialplot 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 serialplot. If not, see <http://www.gnu.org/licenses/>.
*/

#include "framebuffer.h"

FrameBuffer::FrameBuffer(size_t size)
{
 _size = size;
 data = new double[_size]();
 headIndex = 0;

 brInvalid = false;
 _brCache.setCoords(0, 0, size, 0);
}

FrameBuffer::~FrameBuffer()
{
 delete[] data;
}

void FrameBuffer::resize(size_t size)
{
 int offset = size - _size;
 if (offset == 0) return;

 double* newData = new double[size];

 // move data to new array
 int fill_start = offset > 0 ? offset : 0;

 for (int i = fill_start; i < int(size); i++)
 {
 newData[i] = sample(i - offset);
 }

 // fill the beginning of the new data
 if (fill_start > 0)
 {
 for (int i = 0; i < fill_start; i++)
 {
 newData[i] = 0;
 }
 }

 // data is ready, clean and re-point
 delete data;
 data = newData;
 headIndex = 0;
 _size = size;

 // invalidate bounding rectangle
 brInvalid = true;
}

void FrameBuffer::addSamples(double* samples, size_t size)
{
 unsigned shift = size;
 if (shift < _size)
 {
 unsigned x = _size - headIndex; // distance of `head` to end

 if (shift <= x) // there is enough room at the end of array
 {
 for (size_t i = 0; i < shift; i++)
 {
 data[i+headIndex] = samples[i];
 }

 if (shift == x) // we used all the room at the end
 {
 headIndex = 0;
 }
 else
 {
 headIndex += shift;
 }
 }
 else // there isn't enough room
 {
 for (size_t i = 0; i < x; i++) // fill the end part
 {
 data[i+headIndex] = samples[i];
 }
 for (size_t i = 0; i < (shift-x); i++) // continue from the beginning
 {
 data[i] = samples[i+x];
 }
 headIndex = shift-x;
 }
 }
 else // number of new samples equal or bigger than current size
 {
 int x = shift - _size;
 for (size_t i = 0; i < _size; i++)
 {
 data[i] = samples[i+x];
 }
 headIndex = 0;
 }

 // invalidate cache
 brInvalid = true;
}

void FrameBuffer::clear()
{
 for (size_t i=0; i < _size; i++) data[i] = 0.;

 _brCache.setCoords(0, 0, _size, 0);
}

size_t FrameBuffer::size() const
{
 return _size;
}

QRectF FrameBuffer::boundingRect() const
{
 if (brInvalid) updateBoundingRect();
 return _brCache;
}

void FrameBuffer::updateBoundingRect() const
{
 double minValue = data[0];
 double maxValue = data[0];
 for (size_t i = 0; i < _size; i++)
 {
 if (data[i] > maxValue)
 {
 maxValue = data[i];
 }
 else if (data[i] < minValue)
 {
 minValue = data[i];
 }
 }
 _brCache.setTop(minValue);
 _brCache.setBottom(maxValue);

 brInvalid = false;
}

double FrameBuffer::sample(size_t i) const
{
 size_t index = headIndex + i;
 if (index >= _size) index -= _size;
 return data[index];
}