/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
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****************************************************************************/

#include "qplatformopenglcontext_qpa.h"
#include "qopenglcontext.h"
#include "qopenglcontext_p.h"
#include "qwindow.h"

#include <QtCore/QThreadStorage>
#include <QtCore/QThread>

#include <QtGui/private/qguiapplication_p.h>
#include <QtGui/QScreen>

#include <private/qopenglextensions_p.h>

#include <QDebug>

class QGuiGLThreadContext
{
public:
    ~QGuiGLThreadContext() {
        if (context)
            context->doneCurrent();
    }
    QOpenGLContext *context;
};

static QThreadStorage<QGuiGLThreadContext *> qwindow_context_storage;

void QOpenGLContextPrivate::setCurrentContext(QOpenGLContext *context)
{
    QGuiGLThreadContext *threadContext = qwindow_context_storage.localData();
    if (!threadContext) {
        if (!QThread::currentThread()) {
            qWarning("No QTLS available. currentContext wont work");
            return;
        }
        threadContext = new QGuiGLThreadContext;
        qwindow_context_storage.setLocalData(threadContext);
    }
    threadContext->context = context;
}

/*!
  Returns the last context which called makeCurrent. This function is thread aware.
*/
QOpenGLContext* QOpenGLContext::currentContext()
{
    QGuiGLThreadContext *threadContext = qwindow_context_storage.localData();
    if(threadContext) {
        return threadContext->context;
    }
    return 0;
}

bool QOpenGLContext::areSharing(QOpenGLContext *first, QOpenGLContext *second)
{
    return first->shareGroup() == second->shareGroup();
}

QPlatformOpenGLContext *QOpenGLContext::handle() const
{
    Q_D(const QOpenGLContext);
    return d->platformGLContext;
}

QPlatformOpenGLContext *QOpenGLContext::shareHandle() const
{
    Q_D(const QOpenGLContext);
    if (d->shareContext)
        return d->shareContext->handle();
    return 0;
}

/*!
  Creates a new GL context instance, you need to call create() before it can be used.
*/
QOpenGLContext::QOpenGLContext(QObject *parent)
    : QObject(*new QOpenGLContextPrivate(), parent)
{
    Q_D(QOpenGLContext);
    d->screen = QGuiApplication::primaryScreen();
}

/*!
  Sets the format the GL context should be compatible with. You need to call create() before it takes effect.
*/
void QOpenGLContext::setFormat(const QSurfaceFormat &format)
{
    Q_D(QOpenGLContext);
    d->requestedFormat = format;
}

/*!
  Sets the context to share textures, shaders, and other GL resources with. You need to call create() before it takes effect.
*/
void QOpenGLContext::setShareContext(QOpenGLContext *shareContext)
{
    Q_D(QOpenGLContext);
    d->shareContext = shareContext;
}

/*!
  Sets the screen the GL context should be valid for. You need to call create() before it takes effect.
*/
void QOpenGLContext::setScreen(QScreen *screen)
{
    Q_D(QOpenGLContext);
    d->screen = screen;
    if (!d->screen)
        d->screen = QGuiApplication::primaryScreen();
}

/*!
  Attempts to create the GL context with the desired parameters.

  Returns true if the native context was successfully created and is ready to be used.
*/
bool QOpenGLContext::create()
{
    destroy();

    Q_D(QOpenGLContext);
    d->platformGLContext = QGuiApplicationPrivate::platformIntegration()->createPlatformOpenGLContext(this);
    d->platformGLContext->setContext(this);
    d->shareGroup = d->shareContext ? d->shareContext->shareGroup() : new QOpenGLContextGroup;
    d->shareGroup->d_func()->addContext(this);
    return d->platformGLContext;
}

void QOpenGLContext::destroy()
{
    Q_D(QOpenGLContext);
    if (QOpenGLContext::currentContext() == this)
        doneCurrent();
    if (d->shareGroup)
        d->shareGroup->d_func()->removeContext(this);
    d->shareGroup = 0;
    delete d->platformGLContext;
    d->platformGLContext = 0;
    delete d->functions;
    d->functions = 0;
}

/*!
  If this is the current context for the thread, doneCurrent is called
*/
QOpenGLContext::~QOpenGLContext()
{
    destroy();
}

/*!
  Returns if this context is valid, i.e. has been successfully created.
*/
bool QOpenGLContext::isValid() const
{
    Q_D(const QOpenGLContext);
    return d->platformGLContext != 0;
}

/*!
  Get the QOpenGLFunctions instance for this context.

  The context or a sharing context must be current.
*/

QOpenGLFunctions *QOpenGLContext::functions() const
{
    Q_D(const QOpenGLContext);
    if (!d->functions)
        const_cast<QOpenGLFunctions *&>(d->functions) = new QOpenGLExtensions(QOpenGLContext::currentContext());
    return d->functions;
}

/*!
  If surface is 0 this is equivalent to calling doneCurrent().
*/
bool QOpenGLContext::makeCurrent(QSurface *surface)
{
    Q_D(QOpenGLContext);
    if (!d->platformGLContext)
        return false;

    if (!surface) {
        doneCurrent();
        return true;
    }

    if (!surface->surfaceHandle())
        return false;

    if (d->platformGLContext->makeCurrent(surface->surfaceHandle())) {
        QOpenGLContextPrivate::setCurrentContext(this);
        d->surface = surface;

        d->shareGroup->d_func()->deletePendingResources(this);

        return true;
    }

    return false;
}

/*!
    Convenience function for calling makeCurrent with a 0 surface.
*/
void QOpenGLContext::doneCurrent()
{
    Q_D(QOpenGLContext);
    if (!d->platformGLContext)
        return;

    if (QOpenGLContext::currentContext() == this)
        d->shareGroup->d_func()->deletePendingResources(this);

    d->platformGLContext->doneCurrent();
    QOpenGLContextPrivate::setCurrentContext(0);

    d->surface = 0;
}

/*!
    Returns the surface the context is current for.
*/
QSurface *QOpenGLContext::surface() const
{
    Q_D(const QOpenGLContext);
    return d->surface;
}


void QOpenGLContext::swapBuffers(QSurface *surface)
{
    Q_D(QOpenGLContext);
    if (!d->platformGLContext)
        return;

    if (!surface) {
        qWarning() << "QOpenGLContext::swapBuffers() called with null argument";
        return;
    }

    d->platformGLContext->swapBuffers(surface->surfaceHandle());
}

void (*QOpenGLContext::getProcAddress(const QByteArray &procName)) ()
{
    Q_D(QOpenGLContext);
    if (!d->platformGLContext)
        return 0;
    return d->platformGLContext->getProcAddress(procName);
}

QSurfaceFormat QOpenGLContext::format() const
{
    Q_D(const QOpenGLContext);
    if (!d->platformGLContext)
        return d->requestedFormat;
    return d->platformGLContext->format();
}

QOpenGLContextGroup *QOpenGLContext::shareGroup() const
{
    Q_D(const QOpenGLContext);
    return d->shareGroup;
}

QOpenGLContext *QOpenGLContext::shareContext() const
{
    Q_D(const QOpenGLContext);
    return d->shareContext;
}

QScreen *QOpenGLContext::screen() const
{
    Q_D(const QOpenGLContext);
    return d->screen;
}

/*
  internal: Needs to have a pointer to qGLContext. But since this is in QtGui we cant
  have any type information.
*/
void *QOpenGLContext::qGLContextHandle() const
{
    Q_D(const QOpenGLContext);
    return d->qGLContextHandle;
}

void QOpenGLContext::setQGLContextHandle(void *handle,void (*qGLContextDeleteFunction)(void *))
{
    Q_D(QOpenGLContext);
    d->qGLContextHandle = handle;
    d->qGLContextDeleteFunction = qGLContextDeleteFunction;
}

void QOpenGLContext::deleteQGLContext()
{
    Q_D(QOpenGLContext);
    if (d->qGLContextDeleteFunction && d->qGLContextHandle) {
        d->qGLContextDeleteFunction(d->qGLContextHandle);
        d->qGLContextDeleteFunction = 0;
        d->qGLContextHandle = 0;
    }
}

QOpenGLContextGroup::QOpenGLContextGroup()
    : QObject(*new QOpenGLContextGroupPrivate())
{
}

QOpenGLContextGroup::~QOpenGLContextGroup()
{
    Q_D(QOpenGLContextGroup);

    QList<QOpenGLSharedResource *>::iterator it = d->m_sharedResources.begin();
    QList<QOpenGLSharedResource *>::iterator end = d->m_sharedResources.end();

    while (it != end) {
        (*it)->invalidateResource();
        (*it)->m_group = 0;
        ++it;
    }

    qDeleteAll(d->m_pendingDeletion.begin(), d->m_pendingDeletion.end());
}

QList<QOpenGLContext *> QOpenGLContextGroup::shares() const
{
    Q_D(const QOpenGLContextGroup);
    return d->m_shares;
}

QOpenGLContextGroup *QOpenGLContextGroup::currentContextGroup()
{
    QOpenGLContext *current = QOpenGLContext::currentContext();
    return current ? current->shareGroup() : 0;
}

void QOpenGLContextGroupPrivate::addContext(QOpenGLContext *ctx)
{
    QMutexLocker locker(&m_mutex);
    m_refs.ref();
    m_shares << ctx;
}

void QOpenGLContextGroupPrivate::removeContext(QOpenGLContext *ctx)
{
    Q_Q(QOpenGLContextGroup);

    QMutexLocker locker(&m_mutex);
    m_shares.removeOne(ctx);

    if (ctx == m_context && !m_shares.isEmpty())
        m_context = m_shares.first();

    if (!m_refs.deref())
        q->deleteLater();
}

void QOpenGLContextGroupPrivate::deletePendingResources(QOpenGLContext *ctx)
{
    QMutexLocker locker(&m_mutex);

    QList<QOpenGLSharedResource *> pending = m_pendingDeletion;
    m_pendingDeletion.clear();

    QList<QOpenGLSharedResource *>::iterator it = pending.begin();
    QList<QOpenGLSharedResource *>::iterator end = pending.end();
    while (it != end) {
        (*it)->freeResource(ctx);
        delete *it;
        ++it;
    }
}

QOpenGLSharedResource::QOpenGLSharedResource(QOpenGLContextGroup *group)
    : m_group(group)
{
    QMutexLocker locker(&m_group->d_func()->m_mutex);
    m_group->d_func()->m_sharedResources << this;
}

QOpenGLSharedResource::~QOpenGLSharedResource()
{
}

// schedule the resource for deletion at an appropriate time
void QOpenGLSharedResource::free()
{
    if (!m_group) {
        delete this;
        return;
    }

    QMutexLocker locker(&m_group->d_func()->m_mutex);
    m_group->d_func()->m_sharedResources.removeOne(this);
    m_group->d_func()->m_pendingDeletion << this;

    // can we delete right away?
    QOpenGLContext *current = QOpenGLContext::currentContext();
    if (current && current->shareGroup() == m_group) {
        m_group->d_func()->deletePendingResources(current);
    }
}

void QOpenGLSharedResourceGuard::freeResource(QOpenGLContext *context)
{
    if (m_id) {
        QOpenGLFunctions functions(context);
        m_func(&functions, m_id);
        m_id = 0;
    }
}

QOpenGLMultiGroupSharedResource::QOpenGLMultiGroupSharedResource()
    : active(0)
{
#ifdef QT_GL_CONTEXT_RESOURCE_DEBUG
    qDebug("Creating context group resource object %p.", this);
#endif
}

QOpenGLMultiGroupSharedResource::~QOpenGLMultiGroupSharedResource()
{
#ifdef QT_GL_CONTEXT_RESOURCE_DEBUG
    qDebug("Deleting context group resource %p. Group size: %d.", this, m_groups.size());
#endif
    for (int i = 0; i < m_groups.size(); ++i) {
        if (!m_groups.at(i)->shares().isEmpty()) {
            QOpenGLContext *context = m_groups.at(i)->shares().first();
            QOpenGLSharedResource *resource = value(context);
            if (resource)
                resource->free();
        }
        m_groups.at(i)->d_func()->m_resources.remove(this);
        active.deref();
    }
#ifndef QT_NO_DEBUG
    if (active != 0) {
        qWarning("QtGui: Resources are still available at program shutdown.\n"
                 "          This is possibly caused by a leaked QOpenGLWidget, \n"
                 "          QOpenGLFramebufferObject or QOpenGLPixelBuffer.");
    }
#endif
}

void QOpenGLMultiGroupSharedResource::insert(QOpenGLContext *context, QOpenGLSharedResource *value)
{
#ifdef QT_GL_CONTEXT_RESOURCE_DEBUG
    qDebug("Inserting context group resource %p for context %p, managed by %p.", value, context, this);
#endif
    QOpenGLContextGroup *group = context->shareGroup();
    Q_ASSERT(!group->d_func()->m_resources.contains(this));
    group->d_func()->m_resources.insert(this, value);
    m_groups.append(group);
    active.ref();
}

QOpenGLSharedResource *QOpenGLMultiGroupSharedResource::value(QOpenGLContext *context)
{
    QOpenGLContextGroup *group = context->shareGroup();
    return group->d_func()->m_resources.value(this, 0);
}

void QOpenGLMultiGroupSharedResource::cleanup(QOpenGLContext *ctx)
{
    QOpenGLSharedResource *resource = value(ctx);

    if (resource != 0) {
        resource->free();

        QOpenGLContextGroup *group = ctx->shareGroup();
        group->d_func()->m_resources.remove(this);
        m_groups.removeOne(group);
        active.deref();
    }
}

void QOpenGLMultiGroupSharedResource::cleanup(QOpenGLContext *ctx, QOpenGLSharedResource *value)
{
#ifdef QT_GL_CONTEXT_RESOURCE_DEBUG
    qDebug("Cleaning up context group resource %p, for context %p in thread %p.", this, ctx, QThread::currentThread());
#endif
    value->free();
    active.deref();

    QOpenGLContextGroup *group = ctx->shareGroup();
    m_groups.removeOne(group);
}