/**************************************************************
 * 
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 * 
 *************************************************************/



#include "precompiled_sd.hxx"

#include "ChangeRequestQueueProcessor.hxx"
#include "ConfigurationTracer.hxx"

#include "framework/ConfigurationController.hxx"
#include "ConfigurationUpdater.hxx"

#include <vcl/svapp.hxx>
#include <com/sun/star/container/XNamed.hpp>
#include <com/sun/star/drawing/framework/XConfiguration.hpp>
#include <com/sun/star/drawing/framework/ConfigurationChangeEvent.hpp>

using namespace ::com::sun::star;
using namespace ::com::sun::star::uno;
using namespace ::com::sun::star::drawing::framework;

#undef VERBOSE
//#define VERBOSE 1

namespace {

#ifdef VERBOSE

void TraceRequest (const Reference<XConfigurationChangeRequest>& rxRequest)
{
    Reference<container::XNamed> xNamed (rxRequest, UNO_QUERY);
    if (xNamed.is())
        OSL_TRACE("    %s\n",
            ::rtl::OUStringToOString(xNamed->getName(), RTL_TEXTENCODING_UTF8).getStr());
}

#endif

} // end of anonymous namespace


namespace sd { namespace framework {

ChangeRequestQueueProcessor::ChangeRequestQueueProcessor (
    const ::rtl::Reference<ConfigurationController>& rpConfigurationController,
    const ::boost::shared_ptr<ConfigurationUpdater>& rpConfigurationUpdater)
    : maMutex(),
      maQueue(),
      mnUserEventId(0),
      mxConfiguration(),
      mpConfigurationController(rpConfigurationController),
      mpConfigurationUpdater(rpConfigurationUpdater)
{
}




ChangeRequestQueueProcessor::~ChangeRequestQueueProcessor (void)
{
    if (mnUserEventId != 0)
        Application::RemoveUserEvent(mnUserEventId);
}




void ChangeRequestQueueProcessor::SetConfiguration (
    const Reference<XConfiguration>& rxConfiguration)
{
    ::osl::MutexGuard aGuard (maMutex);

    mxConfiguration = rxConfiguration;
    StartProcessing();
}




void ChangeRequestQueueProcessor::AddRequest (
    const Reference<XConfigurationChangeRequest>& rxRequest)
{
    ::osl::MutexGuard aGuard (maMutex);

#ifdef VERBOSE
    if (maQueue.empty())
    {
        OSL_TRACE("Adding requests to empty queue\n");
        ConfigurationTracer::TraceConfiguration(
            mxConfiguration, "current configuration of queue processor");
    }
    OSL_TRACE("Adding request\n");
    TraceRequest(rxRequest);
#endif
    
    maQueue.push_back(rxRequest);
    StartProcessing();
}




void ChangeRequestQueueProcessor::StartProcessing (void)
{
    ::osl::MutexGuard aGuard (maMutex);

    if (mnUserEventId == 0
        && mxConfiguration.is()
        && ! maQueue.empty())
    {
#ifdef VERBOSE
        OSL_TRACE("ChangeRequestQueueProcessor scheduling processing\n");
#endif
        mnUserEventId = Application::PostUserEvent(
            LINK(this,ChangeRequestQueueProcessor,ProcessEvent));
    }
}




IMPL_LINK(ChangeRequestQueueProcessor, ProcessEvent, void*, pUnused)
{
    (void)pUnused;

    ::osl::MutexGuard aGuard (maMutex);

    mnUserEventId = 0;

    ProcessOneEvent();

    if ( ! maQueue.empty())
    {
        // Schedule the processing of the next event.
        StartProcessing();
    }

    return 0;
}




void ChangeRequestQueueProcessor::ProcessOneEvent (void)
{
    ::osl::MutexGuard aGuard (maMutex);

#ifdef VERBOSE
    OSL_TRACE("ProcessOneEvent\n");
#endif

    if (mxConfiguration.is()
        && ! maQueue.empty())
    {
        // Get and remove the first entry from the queue.
        Reference<XConfigurationChangeRequest> xRequest (maQueue.front());
        maQueue.pop_front();

        // Execute the change request.
        if (xRequest.is())
        {
#ifdef VERBOSE
            TraceRequest(xRequest);
#endif
            xRequest->execute(mxConfiguration);
        }

        if (maQueue.empty())
        {
#ifdef VERBOSE
            OSL_TRACE("All requests are processed\n");
#endif
            // The queue is empty so tell the ConfigurationManager to update
            // its state.
            if (mpConfigurationUpdater.get() != NULL)
            {
#ifdef VERBOSE
                ConfigurationTracer::TraceConfiguration (
                    mxConfiguration, "updating to configuration");
#endif
                mpConfigurationUpdater->RequestUpdate(mxConfiguration);
            }
        }
    }
}




bool ChangeRequestQueueProcessor::IsEmpty (void) const
{
    return maQueue.empty();
}




void ChangeRequestQueueProcessor::ProcessUntilEmpty (void)
{
    while ( ! IsEmpty())
        ProcessOneEvent();
}




void ChangeRequestQueueProcessor::Clear (void)
{
    ::osl::MutexGuard aGuard (maMutex);
    maQueue.clear();
}


} } // end of namespace sd::framework::configuration