#include "OgreItemBufferQueryManager.h"
#include <OgreLogManager.h>
#include <OgreStringConverter.h>
#include <vector>


namespace Ogre {
//----------------------------------------------------------------------- 
ItemBufferQueryManager::ItemBufferQueryManager(PlatformHierarchyInterface *hierarchyInterface, Viewport *vp):
PlatformQueryManager(hierarchyInterface, vp)
{
}
//-----------------------------------------------------------------------
bool ItemBufferQueryManager::ShootRay(const Ray &ray, std::vector<Mesh *> *visibleMeshes, bool isGlobalLine)
{
    // run OGRE ray shooting query
    return false;
}
//-----------------------------------------------------------------------
void ItemBufferQueryManager::ComputeCameraVisibility(const Camera &camera,
			    InfoContainer<GtpVisibility::NodeInfo> *visibleNodes,
			    InfoContainer<GtpVisibility::MeshInfo> *visibleGeometry,
			    bool relativeVisibility)
{
	// initialise item buffer (if not already initialised)
	InitItemBuffer(visibleNodes, visibleGeometry);

	// we need access to the scene manager and the rendersystem
	PlatformHierarchyInterface *pfHierarchyInterface = 
		dynamic_cast<PlatformHierarchyInterface *>(mHierarchyInterface);

	SceneManager *sm = pfHierarchyInterface->GetSceneManager();

	// ---- Render scene with item buffer (i.e., objects with their id as color codes)

	// const_cast allowed because camera is not changed in renderScene
	Camera *pCam = const_cast<Camera *>(&camera); 

	// disable overlays, reset them later
	bool overlayEnabled = mViewport->getOverlaysEnabled();
	mViewport->setOverlaysEnabled(false);

	// set item buffer (must be provided by scene manager)
	bool useItemBuffer = true;
	sm->setOption("UseItemBuffer", &useItemBuffer);
	
	// clear background with black (i.e., not a valid item id)
	ColourValue bg = mViewport->getBackgroundColour();
	mViewport->setBackgroundColour(ColourValue(0, 0, 0, 0));


	// --- render item buffer
	pfHierarchyInterface->GetSceneManager()->_renderScene(pCam, mViewport, false);


	//---- collect results
	int dimx = 0;
	int dimy = 0;

	// get frame buffer
	uchar *buf = mViewport->getTarget()->getBufferContents(dimx, dimy);

	
	// loop through frame buffer & collect visible pixels
	for (int idx = 0; idx < dimy * dimx * 3; idx += 3)
	{
		// -- decode color code to receive id
		int id = buf[idx] << 16;
		id += buf[idx + 1] << 8;
		id += buf[idx + 2];

		// if valid id <= add visibility (id values start at 1
		if ((id > 0) && (id < (int)visibleGeometry->size()))
		{
			((*visibleGeometry)[id]).AddVisibility(1, 1);
		}
	}

	//-- reset options

	// don't need item buffer anymore
	useItemBuffer = false;
	sm->setOption("UseItemBuffer", &useItemBuffer);
	// reset initialised - flag
	mWasInitialised = false;
	// reset old overlay status
	mViewport->setOverlaysEnabled(overlayEnabled);
	// reset background color
	mViewport->setBackgroundColour(bg);

	// delete array storing the frame buffer
	delete [] buf;
}
//-----------------------------------------------------------------------
void ItemBufferQueryManager::InitItemBuffer(InfoContainer<GtpVisibility::NodeInfo> *visibleNodes,
			    InfoContainer<GtpVisibility::MeshInfo> *visibleGeometry)
{
	if (mWasInitialised)
		return;

	mWasInitialised = true;

	SceneManager *sm = 
		dynamic_cast<PlatformHierarchyInterface *>(mHierarchyInterface)->GetSceneManager();

	SceneManager::EntityIterator it = sm->getEntityIterator();

	// TODO: make this more efficient
	visibleGeometry->clear();
	visibleNodes->clear();

	while (it.hasMoreElements())
	{
		visibleGeometry->push_back(GtpVisibility::MeshInfo(it.getNext(), 0, 0));
	}
}

} // namespace Ogre