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

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

   The code included in this file is provided under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license. Permission
   To use, copy, modify, and/or distribute this software for any purpose with or
   without fee is hereby granted provided that the above copyright notice and
   this permission notice appear in all copies.

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

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

/*******************************************************************************
 The block below describes the properties of this PIP. A PIP is a short snippet
 of code that can be read by the Projucer and used to generate a JUCE project.

 BEGIN_JUCE_PIP_METADATA

 name:             LoopingAudioSampleBufferAdvancedTutorial
 version:          2.0.0
 vendor:           JUCE
 website:          http://juce.com
 description:      Explores advanced audio sample buffer looping.

 dependencies:     juce_audio_basics, juce_audio_devices, juce_audio_formats,
                   juce_audio_processors, juce_audio_utils, juce_core,
                   juce_data_structures, juce_events, juce_graphics,
                   juce_gui_basics, juce_gui_extra
 exporters:        xcode_mac, vs2019, linux_make

 type:             Component
 mainClass:        MainContentComponent

 useLocalCopy:     1

 END_JUCE_PIP_METADATA

*******************************************************************************/


#pragma once
using namespace std;
//==============================================================================
class MainContentComponent   : public juce::AudioAppComponent,
                               private juce::Thread
{
public:
    class ReferenceCountedBuffer  : public juce::ReferenceCountedObject
    {
    public:
        typedef juce::ReferenceCountedObjectPtr<ReferenceCountedBuffer> Ptr;

        ReferenceCountedBuffer (const juce::String& nameToUse,
                                int numChannels,
                                int numSamples)
            : name (nameToUse),
              buffer (numChannels, numSamples)
        {
            DBG (juce::String ("Buffer named '") + name + "' constructed. numChannels = " + juce::String (numChannels) + ", numSamples = " + juce::String (numSamples));
        }

        ~ReferenceCountedBuffer()
        {
            DBG (juce::String ("Buffer named '") + name + "' destroyed");
        }

        juce::AudioSampleBuffer* getAudioSampleBuffer()
        {
            return &buffer;
        }

        int position = 0;

    private:
        juce::String name;
        juce::AudioSampleBuffer buffer;

        JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ReferenceCountedBuffer)
    };

    MainContentComponent()
        : Thread ("Background Thread")
    {
        addAndMakeVisible (openButton);
        openButton.setButtonText ("Open...");
        openButton.onClick = [this] { openButtonClicked(); };

        addAndMakeVisible (clearButton);
        clearButton.setButtonText ("Clear");
        clearButton.onClick = [this] { clearButtonClicked(); };

        setSize (300, 200);

        formatManager.registerBasicFormats();
        setAudioChannels (0, 2);

        startThread();
    }

    ~MainContentComponent() override
    {
        stopThread (4000);
        shutdownAudio();
    }

    void prepareToPlay (int, double) override {}

    void getNextAudioBlock (const juce::AudioSourceChannelInfo& bufferToFill) override
    {
        auto retainedCurrentBuffer = [&]() -> ReferenceCountedBuffer::Ptr
        {
            const juce::SpinLock::ScopedTryLockType spinlock (mutex);

            if (spinlock.isLocked())
                return currentBuffer;

            return nullptr;
        }();

        if (retainedCurrentBuffer == nullptr)
        {
            bufferToFill.clearActiveBufferRegion();
            return;
        }

        auto* currentAudioSampleBuffer = retainedCurrentBuffer->getAudioSampleBuffer();
        auto position = retainedCurrentBuffer->position;

        auto numInputChannels = currentAudioSampleBuffer->getNumChannels();
        auto numOutputChannels = bufferToFill.buffer->getNumChannels();

        auto outputSamplesRemaining = bufferToFill.numSamples;
        auto outputSamplesOffset = 0;

        while (outputSamplesRemaining > 0)
        {
            auto bufferSamplesRemaining = currentAudioSampleBuffer->getNumSamples() - position;
            auto samplesThisTime = juce::jmin (outputSamplesRemaining, bufferSamplesRemaining);

            for (auto channel = 0; channel < numOutputChannels; ++channel)
            {
                bufferToFill.buffer->copyFrom (channel,
                                               bufferToFill.startSample + outputSamplesOffset,
                                               *currentAudioSampleBuffer,
                                               channel % numInputChannels,
                                               position,
                                               samplesThisTime);
            }

            outputSamplesRemaining -= samplesThisTime;
            outputSamplesOffset += samplesThisTime;
            position += samplesThisTime;

            if (position == currentAudioSampleBuffer->getNumSamples())
                position = 0;
        }

        retainedCurrentBuffer->position = position;
    }

    void releaseResources() override
    {
        const juce::SpinLock::ScopedLockType lock (mutex);
        currentBuffer = nullptr;
    }

    void resized() override
    {
        openButton .setBounds (10, 10, getWidth() - 20, 20);
        clearButton.setBounds (10, 40, getWidth() - 20, 20);
    }

private:
    void run() override
    {
        while (! threadShouldExit())
        {
            checkForPathToOpen();
            checkForBuffersToFree();
            wait (500);
        }
    }

    void checkForBuffersToFree()
    {
        for (auto i = buffers.size(); --i >= 0;)
        {
            ReferenceCountedBuffer::Ptr buffer (buffers.getUnchecked (i));

            if (buffer->getReferenceCount() == 2)
                buffers.remove (i);
        }
    }

    void checkForPathToOpen()
    {
        juce::String pathToOpen;

        {
            const juce::ScopedLock lock (pathMutex);
            pathToOpen.swapWith (chosenPath);
        }

        if (pathToOpen.isNotEmpty())
        {
            juce::File file (pathToOpen);
            std::unique_ptr<juce::AudioFormatReader> reader (formatManager.createReaderFor (file));

            if (reader.get() != nullptr)
            {
                auto duration = (float) reader->lengthInSamples / reader->sampleRate;

                if (duration < 2)
                {
                    ReferenceCountedBuffer::Ptr newBuffer = new ReferenceCountedBuffer (file.getFileName(),
                                                                                        (int) reader->numChannels,
                                                                                        (int) reader->lengthInSamples);

                    reader->read (newBuffer->getAudioSampleBuffer(), 0, (int) reader->lengthInSamples, 0, true, true);

                    {
                        const juce::SpinLock::ScopedLockType lock (mutex);
                        currentBuffer = newBuffer;
                    }

                    buffers.add (newBuffer);
                }
                else
                {
                    // handle the error that the file is 2 seconds or longer..
                }
            }
        }
    }

    void openButtonClicked()
    {
        chooser = std::make_unique<juce::FileChooser> ("Select a Wave file shorter than 2 seconds to play...",
                                                       juce::File{},
                                                       "*.wav");
        auto chooserFlags = juce::FileBrowserComponent::openMode
                          | juce::FileBrowserComponent::canSelectFiles;

        chooser->launchAsync (chooserFlags, [this] (const juce::FileChooser& fc)
        {
            auto file = fc.getResult();

            if (file == juce::File{})
                return;

            auto path = file.getFullPathName();


            {
                const juce::ScopedLock lock (pathMutex);
                chosenPath.swapWith (path);
            }

            notify();
        });
    }

    void clearButtonClicked()
    {
        const juce::SpinLock::ScopedLockType lock (mutex);
        currentBuffer = nullptr;
    }

    //==========================================================================
    juce::TextButton openButton;
    juce::TextButton clearButton;

    std::unique_ptr<juce::FileChooser> chooser;

    juce::AudioFormatManager formatManager;
    juce::ReferenceCountedArray<ReferenceCountedBuffer> buffers;

    juce::SpinLock mutex;
    ReferenceCountedBuffer::Ptr currentBuffer;
    juce::CriticalSection pathMutex;
    juce::String chosenPath;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (MainContentComponent)
};