/*
-----------------------------------------------------------------------------
This source file is part of OGRE
(Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2014 Torus Knot Software Ltd

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
-----------------------------------------------------------------------------
*/
#include "OgreTerrainPagedWorldSection.h"
#include "OgreTerrainGroup.h"
#include "OgreGrid2DPageStrategy.h"
#include "OgrePagedWorld.h"
#include "OgrePageManager.h"
#include "OgreRoot.h"
#include "OgreTimer.h"

namespace Ogre
{
    const uint16 TerrainPagedWorldSection::WORKQUEUE_LOAD_TERRAIN_PAGE_REQUEST = 1;

    //---------------------------------------------------------------------
    TerrainPagedWorldSection::TerrainPagedWorldSection(const String& name, PagedWorld* parent, SceneManager* sm)
        : PagedWorldSection(name, parent, sm)
        , mTerrainGroup(0)
        , mTerrainDefiner(0)
        , mHasRunningTasks(false)
        , mLoadingIntervalMs(900)
    {
        // we always use a grid strategy
        setStrategy(parent->getManager()->getStrategy("Grid2D"));

        WorkQueue* wq = Root::getSingleton().getWorkQueue();
        mWorkQueueChannel = wq->getChannel("Ogre/TerrainPagedWorldSection");
        wq->addRequestHandler(mWorkQueueChannel, this);
        wq->addResponseHandler(mWorkQueueChannel, this);

        mNextLoadingTime = Root::getSingletonPtr()->getTimer()->getMilliseconds();
    }
    //---------------------------------------------------------------------
    TerrainPagedWorldSection::~TerrainPagedWorldSection()
    {
        //remove the pending tasks, but keep the front one, as it may have been in running
        if(!mPagesInLoading.empty())
            mPagesInLoading.erase( ++mPagesInLoading.begin(), mPagesInLoading.end() );

        while(!mPagesInLoading.empty())
        {
            OGRE_THREAD_SLEEP(50);
            Root::getSingleton().getWorkQueue()->processResponses();
        }

        WorkQueue* wq = Root::getSingleton().getWorkQueue();
        wq->removeRequestHandler(mWorkQueueChannel, this);
        wq->removeResponseHandler(mWorkQueueChannel, this);

        OGRE_DELETE mTerrainGroup;
        if(mTerrainDefiner)
            OGRE_DELETE mTerrainDefiner;
    }
    //---------------------------------------------------------------------
    void TerrainPagedWorldSection::init(TerrainGroup* grp)
    {
        if (mTerrainGroup == grp)
            return;

        if (mTerrainGroup)
            OGRE_DELETE mTerrainGroup;

        mTerrainGroup = grp;
        syncSettings();

        // Unload all existing terrain pages, because we want the paging system
        // to be in charge of this
        mTerrainGroup->removeAllTerrains();
    }
    //---------------------------------------------------------------------
    void TerrainPagedWorldSection::syncSettings()
    {

        // Base grid on terrain settings
        Grid2DPageStrategyData* gridData = getGridStrategyData();
        switch (mTerrainGroup->getAlignment())
        {
        case Terrain::ALIGN_X_Y:
            gridData->setMode(G2D_X_Y);
            break;
        case Terrain::ALIGN_X_Z:
            gridData->setMode(G2D_X_Z);
            break;
        case Terrain::ALIGN_Y_Z:
            gridData->setMode(G2D_Y_Z);
            break;
        }
        gridData->setOrigin(mTerrainGroup->getOrigin());

        gridData->setCellSize(mTerrainGroup->getTerrainWorldSize());

    }
    //---------------------------------------------------------------------
    void TerrainPagedWorldSection::setLoadRadius(Real sz)
    {
        getGridStrategyData()->setLoadRadius(sz);
    }
    //---------------------------------------------------------------------
    Real TerrainPagedWorldSection::getLoadRadius() const
    {
        return getGridStrategyData()->getLoadRadius();
    }
    //---------------------------------------------------------------------
    void TerrainPagedWorldSection::setHoldRadius(Real sz)
    {
        getGridStrategyData()->setHoldRadius(sz);
    }
    //---------------------------------------------------------------------
    Real TerrainPagedWorldSection::getHoldRadius()
    {
        return getGridStrategyData()->getHoldRadius();
    }
    //---------------------------------------------------------------------
    void TerrainPagedWorldSection::setPageRange(int32 minX, int32 minY, int32 maxX, int32 maxY)
    {
        getGridStrategyData()->setCellRange(minX, minY, maxX, maxY);
    }
    //---------------------------------------------------------------------
    void TerrainPagedWorldSection::setPageRangeMinX(int32 minX)
    {
        getGridStrategyData()->setCellRangeMinX(minX);
    }
    //---------------------------------------------------------------------
    void TerrainPagedWorldSection::setPageRangeMinY(int32 minY)
    {
        getGridStrategyData()->setCellRangeMinY(minY);
    }
    //---------------------------------------------------------------------
    void TerrainPagedWorldSection::setPageRangeMaxX(int32 maxX)
    {
        getGridStrategyData()->setCellRangeMaxX(maxX);
    }
    //---------------------------------------------------------------------
    void TerrainPagedWorldSection::setPageRangeMaxY(int32 maxY)
    {
        getGridStrategyData()->setCellRangeMaxY(maxY);
    }
    //---------------------------------------------------------------------
    int32 TerrainPagedWorldSection::getPageRangeMinX() const
    {
        return getGridStrategyData()->getCellRangeMinX();
    }
    //---------------------------------------------------------------------
    int32 TerrainPagedWorldSection::getPageRangeMinY() const
    {
        return getGridStrategyData()->getCellRangeMinY();
    }
    //---------------------------------------------------------------------
    int32 TerrainPagedWorldSection::getPageRangeMaxX() const
    {
        return getGridStrategyData()->getCellRangeMaxX();
    }
    //---------------------------------------------------------------------
    int32 TerrainPagedWorldSection::getPageRangeMaxY() const
    {
        return getGridStrategyData()->getCellRangeMaxY();
    }
    //---------------------------------------------------------------------
    Grid2DPageStrategy* TerrainPagedWorldSection::getGridStrategy() const
    {
        return static_cast<Grid2DPageStrategy*>(this->getStrategy());
    }
    //---------------------------------------------------------------------
    Grid2DPageStrategyData* TerrainPagedWorldSection::getGridStrategyData() const
    {
        return static_cast<Grid2DPageStrategyData*>(mStrategyData);
    }
    //---------------------------------------------------------------------
    void TerrainPagedWorldSection::setLoadingIntervalMs(uint32 loadingIntervalMs)
    {
        mLoadingIntervalMs = loadingIntervalMs;
    }
    //---------------------------------------------------------------------
    uint32 TerrainPagedWorldSection::getLoadingIntervalMs() const
    {
        return mLoadingIntervalMs;
    }

    //---------------------------------------------------------------------
    void TerrainPagedWorldSection::loadSubtypeData(StreamSerialiser& ser)
    {
        // we load the TerrainGroup information from here
        if (!mTerrainGroup)
            mTerrainGroup = OGRE_NEW TerrainGroup(getSceneManager());

        mTerrainGroup->loadGroupDefinition(ser);

        // params that are in the Grid2DStrategyData will have already been loaded
        // as part of the main load() routine

        syncSettings();
    }
    //---------------------------------------------------------------------
    void TerrainPagedWorldSection::saveSubtypeData(StreamSerialiser& ser)
    {
        mTerrainGroup->saveGroupDefinition(ser);

        // params that are in the Grid2DStrategyData will have already been saved
        // as part of the main save() routine

    }
    //---------------------------------------------------------------------
    void TerrainPagedWorldSection::loadPage(PageID pageID, bool forceSynchronous)
    {
        if (!mParent->getManager()->getPagingOperationsEnabled())
            return;

        PageMap::iterator i = mPages.find(pageID);
        if (i == mPages.end())
        {
            std::list<PageID>::iterator it = find( mPagesInLoading.begin(), mPagesInLoading.end(), pageID);
            if(it==mPagesInLoading.end())
            {
                mPagesInLoading.push_back(pageID);
                mHasRunningTasks = true;
            }
            
            // no running tasks, start the new one
            if(mPagesInLoading.size()==1)
            {
                Root::getSingleton().getWorkQueue()->addRequest(
                    mWorkQueueChannel, WORKQUEUE_LOAD_TERRAIN_PAGE_REQUEST, 
                    Any(), 0, forceSynchronous);
            }
        }

        PagedWorldSection::loadPage(pageID, forceSynchronous);
    }
    //---------------------------------------------------------------------
    void TerrainPagedWorldSection::unloadPage(PageID pageID, bool forceSynchronous)
    {
        if (!mParent->getManager()->getPagingOperationsEnabled())
            return;

        PagedWorldSection::unloadPage(pageID, forceSynchronous);

        std::list<PageID>::iterator it = find( mPagesInLoading.begin(), mPagesInLoading.end(), pageID);
        // hasn't been loaded, just remove from the queue
        if(it!=mPagesInLoading.end())
        {
            mPagesInLoading.erase(it);
        }
        else
        {
            // trigger terrain unload
            long x, y;
            // pageID is the same as a packed index
            mTerrainGroup->unpackIndex(pageID, &x, &y);
            mTerrainGroup->unloadTerrain(x, y);
        }
    }
    //---------------------------------------------------------------------
    WorkQueue::Response* TerrainPagedWorldSection::handleRequest(const WorkQueue::Request* req, const WorkQueue* srcQ)
    {
        if(mPagesInLoading.empty())
        {
            mHasRunningTasks = false;
            req->abortRequest();
            return OGRE_NEW WorkQueue::Response(req, true, Any());
        }

        unsigned long currentTime = Root::getSingletonPtr()->getTimer()->getMilliseconds();
        if(currentTime < mNextLoadingTime)
        {
            // Wait until the next page is to be loaded -> we are in background thread here
            OGRE_THREAD_SLEEP(mNextLoadingTime - currentTime);
        }

        PageID pageID = mPagesInLoading.front();

        // call the TerrainDefiner from the background thread
        long x, y;
        // pageID is the same as a packed index
        mTerrainGroup->unpackIndex(pageID, &x, &y);

        if(!mTerrainDefiner)
            mTerrainDefiner = OGRE_NEW TerrainDefiner();
        mTerrainDefiner->define(mTerrainGroup, x, y);

        // continue loading in main thread
        return OGRE_NEW WorkQueue::Response(req, true, Any());
    }

    //---------------------------------------------------------------------
    void TerrainPagedWorldSection::handleResponse(const WorkQueue::Response* res, const WorkQueue* srcQ)
    {
        if(!mPagesInLoading.empty())
        {
            PageID pageID = mPagesInLoading.front();

            // trigger terrain load
            long x, y;
            // pageID is the same as a packed index
            mTerrainGroup->unpackIndex(pageID, &x, &y);
            mTerrainGroup->loadTerrain(x, y, false);
            mPagesInLoading.pop_front();

            unsigned long currentTime = Root::getSingletonPtr()->getTimer()->getMilliseconds();
            mNextLoadingTime = currentTime + mLoadingIntervalMs;

            // Continue loading other pages
            Root::getSingleton().getWorkQueue()->addRequest(
                    mWorkQueueChannel, WORKQUEUE_LOAD_TERRAIN_PAGE_REQUEST, 
                    Any(), 0, false);
        }
        else
            mHasRunningTasks = false;
    }
}

