/*
 * Copyright (C) 2010 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  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.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") 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 APPLE AND ITS 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 APPLE OR ITS 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.
 */

#include "config.h"

#if ENABLE(WEB_AUDIO)

#include "AudioContext.h"

#include "AudioBuffer.h"
#include "AudioBufferSourceNode.h"
#include "AudioChannelMerger.h"
#include "AudioChannelSplitter.h"
#include "AudioGainNode.h"
#include "AudioListener.h"
#include "AudioPannerNode.h"
#include "CachedAudio.h"
#include "ConvolverNode.h"
#include "DelayNode.h"
#include "Document.h"
#include "HRTFDatabaseLoader.h"
#include "HRTFPanner.h"
#include "HTMLNames.h"
#include "HighPass2FilterNode.h"
#include "JavaScriptAudioNode.h"
#include "LowPass2FilterNode.h"
#include "PlatformString.h"
#include "RealtimeAnalyserNode.h"

#include <wtf/OwnPtr.h>
#include <wtf/PassOwnPtr.h>
#include <wtf/RefCounted.h>

// FIXME: check the proper way to reference an undefined thread ID
const int UndefinedThreadIdentifier = 0xffffffff;
 
namespace WebCore {

PassRefPtr<CachedAudio> AudioContext::createAudioRequest(const String &url, bool mixToMono)
{
    lazyInitialize();

    // Convert relative URL to absolute
    KURL completedURL = document()->completeURL(url);
    String completedURLString = completedURL.string();

    RefPtr<CachedAudio> cachedAudio = CachedAudio::create(completedURLString, this, document(), sampleRate(), mixToMono);
    CachedAudio* c = cachedAudio.get();

    m_cachedAudioReferences.append(c);

    return cachedAudio;
}

PassRefPtr<AudioContext> AudioContext::create(Document* document)
{
    return adoptRef(new AudioContext(document));
}

AudioContext::AudioContext(Document* document)
    : ActiveDOMObject(document, this)
    , m_isInitialized(false)
    , m_isAudioThreadFinished(false)
    , m_document(document)
    , m_destinationNode(0)
    , m_connectionCount(0)
    , m_audioThread(0)
    , m_graphOwnerThread(UndefinedThreadIdentifier)
{
    // Note: because adoptRef() won't be called until we leave this constructor, but code in this constructor needs to reference this context,
    // relax the check.
    relaxAdoptionRequirement();
    
    m_destinationNode = AudioDestinationNode::create(this);
    m_listener = AudioListener::create();
    m_temporaryMonoBus = adoptPtr(new AudioBus(1, AudioNode::ProcessingSizeInFrames));
    m_temporaryStereoBus = adoptPtr(new AudioBus(2, AudioNode::ProcessingSizeInFrames));

    // This sets in motion an asynchronous loading mechanism on another thread.
    // We can check hrtfDatabaseLoader()->isLoaded() to find out whether or not it has been fully loaded.
    // It's not that useful to have a callback function for this since the audio thread automatically starts rendering on the graph
    // when this has finished (see AudioDestinationNode).
    hrtfDatabaseLoader()->loadAsynchronously(sampleRate());
}

AudioContext::~AudioContext()
{
#if DEBUG_AUDIONODE_REFERENCES
    printf("%p: AudioContext::~AudioContext()\n", this);
#endif    
    // AudioNodes keep a reference to their context, so there should be no way to be in the destructor if there are still AudioNodes around.
    ASSERT(!m_nodesToDelete.size());
    ASSERT(!m_referencedNodes.size());
    ASSERT(!m_finishedNodes.size());
}

void AudioContext::lazyInitialize()
{
    if (!m_isInitialized) {
        // Don't allow the context to initialize a second time after it's already been explicitly uninitialized.
        ASSERT(!m_isAudioThreadFinished);
        if (!m_isAudioThreadFinished) {
            if (m_destinationNode.get()) {
                // This starts the audio thread.  The destination node's provideInput() method will now be called repeatedly to render audio.
                // Each time provideInput() is called, a portion of the audio stream is rendered.  Let's call this time period a "render quantum".
                m_destinationNode->initialize();
            }
            m_isInitialized = true;
        }
    }
}

void AudioContext::uninitialize()
{
    if (m_isInitialized) {    
        // This stops the audio thread and all audio rendering.
        m_destinationNode->uninitialize();

        // Don't allow the context to initialize a second time after it's already been explicitly uninitialized.
        m_isAudioThreadFinished = true;

        // We have to release our reference to the destination node before the context will ever be deleted since the destination node holds a reference to the context.
        m_destinationNode.clear();
        
        // Get rid of the sources which may still be playing.
        derefUnfinishedSourceNodes();
        
        // Because the AudioBuffers are garbage collected, we can't delete them here.
        // Instead, at least release the potentially large amount of allocated memory for the audio data.
        // Note that we do this *after* the context is uninitialized and stops processing audio.
        for (unsigned i = 0; i < m_allocatedBuffers.size(); ++i)
            m_allocatedBuffers[i]->releaseMemory();
        m_allocatedBuffers.clear();
    
        m_isInitialized = false;
    }
}

bool AudioContext::isInitialized() const
{
    return m_isInitialized;
}

bool AudioContext::isRunnable() const
{
    if (!isInitialized())
        return false;
    
    // Check with the HRTF spatialization system to see if it's finished loading.
    return hrtfDatabaseLoader()->isLoaded();
}

void AudioContext::stop()
{
    m_document = 0; // document is going away
    uninitialize();
}

Document* AudioContext::document()
{
    ASSERT(m_document);
    return m_document;
}

bool AudioContext::hasDocument()
{
    return m_document;
}

void AudioContext::refBuffer(PassRefPtr<AudioBuffer> buffer)
{
    m_allocatedBuffers.append(buffer);
}

PassRefPtr<AudioBuffer> AudioContext::createBuffer(unsigned numberOfChannels, size_t numberOfFrames, double sampleRate)
{
    return AudioBuffer::create(numberOfChannels, numberOfFrames, sampleRate);
}

PassRefPtr<AudioBufferSourceNode> AudioContext::createBufferSource()
{
    ASSERT(isMainThread());
    lazyInitialize();
    RefPtr<AudioBufferSourceNode> node = AudioBufferSourceNode::create(this, m_destinationNode->sampleRate());

    refNode(node.get()); // context keeps reference until source has finished playing
    return node;
}

PassRefPtr<JavaScriptAudioNode> AudioContext::createJavaScriptNode(size_t bufferSize)
{
    ASSERT(isMainThread());
    lazyInitialize();
    RefPtr<JavaScriptAudioNode> node = JavaScriptAudioNode::create(this, m_destinationNode->sampleRate(), bufferSize);

    refNode(node.get()); // context keeps reference until we stop making javascript rendering callbacks
    return node;
}

PassRefPtr<LowPass2FilterNode> AudioContext::createLowPass2Filter()
{
    ASSERT(isMainThread());
    lazyInitialize();
    return LowPass2FilterNode::create(this, m_destinationNode->sampleRate());
}

PassRefPtr<HighPass2FilterNode> AudioContext::createHighPass2Filter()
{
    ASSERT(isMainThread());
    lazyInitialize();
    return HighPass2FilterNode::create(this, m_destinationNode->sampleRate());
}

PassRefPtr<AudioPannerNode> AudioContext::createPanner()
{
    ASSERT(isMainThread());
    lazyInitialize();
    return AudioPannerNode::create(this, m_destinationNode->sampleRate());
}

PassRefPtr<ConvolverNode> AudioContext::createConvolver()
{
    ASSERT(isMainThread());
    lazyInitialize();
    return ConvolverNode::create(this, m_destinationNode->sampleRate());
}

PassRefPtr<RealtimeAnalyserNode> AudioContext::createAnalyser()
{
    ASSERT(isMainThread());
    lazyInitialize();
    return RealtimeAnalyserNode::create(this, m_destinationNode->sampleRate());
}

PassRefPtr<AudioGainNode> AudioContext::createGainNode()
{
    ASSERT(isMainThread());
    lazyInitialize();
    return AudioGainNode::create(this, m_destinationNode->sampleRate());
}

PassRefPtr<DelayNode> AudioContext::createDelayNode()
{
    ASSERT(isMainThread());
    lazyInitialize();
    return DelayNode::create(this, m_destinationNode->sampleRate());
}

PassRefPtr<AudioChannelSplitter> AudioContext::createChannelSplitter()
{
    ASSERT(isMainThread());
    lazyInitialize();
    return AudioChannelSplitter::create(this, m_destinationNode->sampleRate());
}

PassRefPtr<AudioChannelMerger> AudioContext::createChannelMerger()
{
    ASSERT(isMainThread());
    lazyInitialize();
    return AudioChannelMerger::create(this, m_destinationNode->sampleRate());
}

void AudioContext::notifyNodeFinishedProcessing(AudioNode* node)
{
    ASSERT(isAudioThread());
    m_finishedNodes.append(node);
}

void AudioContext::derefFinishedSourceNodes()
{
    ASSERT(isGraphOwner());
    ASSERT(isAudioThread() || isAudioThreadFinished());
    for (unsigned i = 0; i < m_finishedNodes.size(); i++)
        derefNode(m_finishedNodes[i]);

    m_finishedNodes.clear();
}

void AudioContext::refNode(AudioNode* node)
{
    ASSERT(isMainThread());
    AutoLocker locker(this);
    
    node->ref(AudioNode::RefTypeConnection);
    m_referencedNodes.append(node);
}

void AudioContext::derefNode(AudioNode* node)
{
    ASSERT(isGraphOwner());
    
    node->deref(AudioNode::RefTypeConnection);

    for (unsigned i = 0; i < m_referencedNodes.size(); ++i) {
        if (node == m_referencedNodes[i]) {
            m_referencedNodes.remove(i);
            break;
        }
    }
}

void AudioContext::derefUnfinishedSourceNodes()
{
    ASSERT(isMainThread() && isAudioThreadFinished());
    for (unsigned i = 0; i < m_referencedNodes.size(); ++i)
        m_referencedNodes[i]->deref(AudioNode::RefTypeConnection);

    m_referencedNodes.clear();
}

void AudioContext::lock(bool& mustReleaseLock)
{
    // Don't allow regular lock in real-time audio thread.
    ASSERT(isMainThread());

    ThreadIdentifier thisThread = currentThread();

    if (thisThread == m_graphOwnerThread) {
        // We already have the lock.
        mustReleaseLock = false;
    } else {
        // Acquire the lock.
        m_contextGraphMutex.lock();
        mustReleaseLock = true;
    }

    m_graphOwnerThread = thisThread;
}

bool AudioContext::tryLock(bool& mustReleaseLock)
{
    ThreadIdentifier thisThread = currentThread();
    bool isAudioThread = thisThread == audioThread();

    // Try to catch cases of using try lock on main thread - it should use regular lock.
    ASSERT(isAudioThread || isAudioThreadFinished());
    
    if (!isAudioThread) {
        // In release build treat tryLock() as lock() (since above ASSERT(isAudioThread) never fires) - this is the best we can do.
        lock(mustReleaseLock);
        return true;
    }
    
    bool hasLock;
    
    if (thisThread == m_graphOwnerThread) {
        // Thread already has the lock.
        hasLock = true;
        mustReleaseLock = false;
    } else {
        // Don't already have the lock - try to acquire it.
        hasLock = m_contextGraphMutex.tryLock();
        
        if (hasLock)
            m_graphOwnerThread = thisThread;

        mustReleaseLock = hasLock;
    }
    
    return hasLock;
}

void AudioContext::unlock()
{
    ASSERT(currentThread() == m_graphOwnerThread);

    m_graphOwnerThread = UndefinedThreadIdentifier;
    m_contextGraphMutex.unlock();
}

bool AudioContext::isAudioThread()
{
    return currentThread() == m_audioThread;
}

bool AudioContext::isGraphOwner()
{
    return currentThread() == m_graphOwnerThread;
}

void AudioContext::addDeferredFinishDeref(AudioNode* node, AudioNode::RefType refType)
{
    ASSERT(isAudioThread());
    m_deferredFinishDerefList.append(AudioContext::RefInfo(node, refType));
}

void AudioContext::handlePostRenderTasks()
{
    ASSERT(isAudioThread());
    
    // Must use a tryLock() here too.  Don't worry, the lock will very rarely be contended and this method is called frequently.
    // The worst that can happen is that there will be some nodes which will take slightly longer than usual to be deleted or removed
    // from the render graph (in which case they'll render silence).
    bool mustReleaseLock;
    if (tryLock(mustReleaseLock)) {
        // Take care of finishing any derefs where the tryLock() failed previously.
        handleDeferredFinishDerefs();

        // Dynamically clean up nodes which are no longer needed.
        derefFinishedSourceNodes();

        // Finally actually delete.
        deleteMarkedNodes();

        if (mustReleaseLock)
            unlock();
    }
}

void AudioContext::handleDeferredFinishDerefs()
{
    ASSERT(isAudioThread());
    for (unsigned i = 0; i < m_deferredFinishDerefList.size(); ++i) {
        AudioNode* node = m_deferredFinishDerefList[i].m_node;
        AudioNode::RefType refType = m_deferredFinishDerefList[i].m_refType;
        node->finishDeref(refType);
    }
    
    m_deferredFinishDerefList.clear();
}

void AudioContext::markForDeletion(AudioNode* node)
{
    ASSERT(isGraphOwner());
    m_nodesToDelete.append(node);
}

void AudioContext::deleteMarkedNodes()
{
    ASSERT(isGraphOwner() || isAudioThreadFinished());

    // Note: deleting an AudioNode can cause m_nodesToDelete to grow.
    while (size_t n = m_nodesToDelete.size()) {
        AudioNode* node = m_nodesToDelete[n - 1];
        m_nodesToDelete.removeLast();
        delete node;
    }
}

} // namespace WebCore

#endif // ENABLE(WEB_AUDIO)