/*
  ==============================================================================

   This file is part of the JUCE 6 technical preview.
   Copyright (c) 2020 - Raw Material Software Limited

   You may use this code under the terms of the GPL v3
   (see www.gnu.org/licenses).

   For this technical preview, this file is not subject to commercial licensing.

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

struct AudioVisualiserComponent::ChannelInfo
{
    ChannelInfo (AudioVisualiserComponent& o, int bufferSize) : owner (o)
    {
        setBufferSize (bufferSize);
        clear();
    }

    void clear() noexcept
    {
        levels.fill ({});
        value = {};
        subSample = 0;
    }

    void pushSamples (const float* inputSamples, int num) noexcept
    {
        for (int i = 0; i < num; ++i)
            pushSample (inputSamples[i]);
    }

    void pushSample (float newSample) noexcept
    {
        if (--subSample <= 0)
        {
            if (++nextSample == levels.size())
                nextSample = 0;

            levels.getReference (nextSample) = value;
            subSample = owner.getSamplesPerBlock();
            value = Range<float> (newSample, newSample);
        }
        else
        {
            value = value.getUnionWith (newSample);
        }
    }

    void setBufferSize (int newSize)
    {
        levels.removeRange (newSize, levels.size());
        levels.insertMultiple (-1, {}, newSize - levels.size());

        if (nextSample >= newSize)
            nextSample = 0;
    }

    AudioVisualiserComponent& owner;
    Array<Range<float>> levels;
    Range<float> value;
    std::atomic<int> nextSample { 0 }, subSample { 0 };

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ChannelInfo)
};

//==============================================================================
AudioVisualiserComponent::AudioVisualiserComponent (int initialNumChannels)
  : numSamples (1024),
    inputSamplesPerBlock (256),
    backgroundColour (Colours::black),
    waveformColour (Colours::white)
{
    setOpaque (true);
    setNumChannels (initialNumChannels);
    setRepaintRate (60);
}

AudioVisualiserComponent::~AudioVisualiserComponent()
{
}

void AudioVisualiserComponent::setNumChannels (int numChannels)
{
    channels.clear();

    for (int i = 0; i < numChannels; ++i)
        channels.add (new ChannelInfo (*this, numSamples));
}

void AudioVisualiserComponent::setBufferSize (int newNumSamples)
{
    numSamples = newNumSamples;

    for (auto* c : channels)
        c->setBufferSize (newNumSamples);
}

void AudioVisualiserComponent::clear()
{
    for (auto* c : channels)
        c->clear();
}

void AudioVisualiserComponent::pushBuffer (const float** d, int numChannels, int num)
{
    numChannels = jmin (numChannels, channels.size());

    for (int i = 0; i < numChannels; ++i)
        channels.getUnchecked(i)->pushSamples (d[i], num);
}

void AudioVisualiserComponent::pushBuffer (const AudioBuffer<float>& buffer)
{
    pushBuffer (buffer.getArrayOfReadPointers(),
                buffer.getNumChannels(),
                buffer.getNumSamples());
}

void AudioVisualiserComponent::pushBuffer (const AudioSourceChannelInfo& buffer)
{
    auto numChannels = jmin (buffer.buffer->getNumChannels(), channels.size());

    for (int i = 0; i < numChannels; ++i)
        channels.getUnchecked(i)->pushSamples (buffer.buffer->getReadPointer (i, buffer.startSample),
                                               buffer.numSamples);
}

void AudioVisualiserComponent::pushSample (const float* d, int numChannels)
{
    numChannels = jmin (numChannels, channels.size());

    for (int i = 0; i < numChannels; ++i)
        channels.getUnchecked(i)->pushSample (d[i]);
}

void AudioVisualiserComponent::setSamplesPerBlock (int newSamplesPerPixel) noexcept
{
    inputSamplesPerBlock = newSamplesPerPixel;
}

void AudioVisualiserComponent::setRepaintRate (int frequencyInHz)
{
    startTimerHz (frequencyInHz);
}

void AudioVisualiserComponent::timerCallback()
{
    repaint();
}

void AudioVisualiserComponent::setColours (Colour bk, Colour fg) noexcept
{
    backgroundColour = bk;
    waveformColour = fg;
    repaint();
}

void AudioVisualiserComponent::paint (Graphics& g)
{
    g.fillAll (backgroundColour);

    auto r = getLocalBounds().toFloat();
    auto channelHeight = r.getHeight() / channels.size();

    g.setColour (waveformColour);

    for (auto* c : channels)
        paintChannel (g, r.removeFromTop (channelHeight),
                      c->levels.begin(), c->levels.size(), c->nextSample);
}

void AudioVisualiserComponent::getChannelAsPath (Path& path, const Range<float>* levels,
                                                 int numLevels, int nextSample)
{
    path.preallocateSpace (4 * numLevels + 8);

    for (int i = 0; i < numLevels; ++i)
    {
        auto level = -(levels[(nextSample + i) % numLevels].getEnd());

        if (i == 0)
            path.startNewSubPath (0.0f, level);
        else
            path.lineTo ((float) i, level);
    }

    for (int i = numLevels; --i >= 0;)
        path.lineTo ((float) i, -(levels[(nextSample + i) % numLevels].getStart()));

    path.closeSubPath();
}

void AudioVisualiserComponent::paintChannel (Graphics& g, Rectangle<float> area,
                                             const Range<float>* levels, int numLevels, int nextSample)
{
    Path p;
    getChannelAsPath (p, levels, numLevels, nextSample);

    g.fillPath (p, AffineTransform::fromTargetPoints (0.0f, -1.0f,               area.getX(), area.getY(),
                                                      0.0f, 1.0f,                area.getX(), area.getBottom(),
                                                      (float) numLevels, -1.0f,  area.getRight(), area.getY()));
}

} // namespace juce