/*******************************************************************************

 Copyright (c) 2009, Charles McGarvey
 All rights reserved.
 
 Redistribution   and   use  in  source  and  binary  forms,  with  or  without
 modification, are permitted provided that the following conditions are met:
 
   * Redistributions  of  source  code  must retain the above copyright notice,
     this list of conditions and the following disclaimer.
   * 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.
 
 THIS  SOFTWARE  IS  PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT HOLDER OR 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.

*******************************************************************************/

#ifndef _MOOF_OCTREE_HH_
#define _MOOF_OCTREE_HH_

#include <algorithm>
#include <list>

#include <boost/shared_ptr.hpp>

#include <stlplus/ntree.hpp>

#include <Moof/Aabb.hh>
#include <Moof/Drawable.hh>
#include <Moof/Entity.hh>
#include <Moof/Frustum.hh>
#include <Moof/Log.hh>
#include <Moof/Math.hh>
#include <Moof/Sphere.hh>
	

namespace Mf {


//class Octree;
//typedef boost::shared_ptr<Octree> OctreeP;

//class Octree::Node;
//typedef stlplus::ntree<Octree::Node>::iterator OctreeNodeP;


struct OctreeInsertable
{
	virtual ~OctreeInsertable() {}

	virtual bool isInsideAabb(const Aabb& aabb) const = 0;
	virtual int getOctant(const Aabb& aabb) const = 0;
};


template <class T>
class Octree : public Entity
{
	typedef boost::shared_ptr<T> InsertableP;

	struct Node : public Entity
	{
		std::list<InsertableP> objects;

		Aabb aabb;
		Sphere sphere;

		Node(const Aabb& box) :
			aabb(box)
		{
			sphere.point = aabb.getCenter();
			sphere.radius = (aabb.min - sphere.point).length();
		}

		void draw(Scalar alpha) const
		{
			typename std::list<InsertableP>::const_iterator it;

			for (it = objects.begin(); it != objects.end(); ++it)
			{
				(*it)->draw(alpha);
			}

			if (!objects.empty())
				aabb.draw(); // temporary
		}

		void drawIfVisible(Scalar alpha, const Frustum& frustum) const
		{
			typename std::list<InsertableP>::const_iterator it;

			for (it = objects.begin(); it != objects.end(); ++it)
			{
				(*it)->drawIfVisible(alpha, frustum);
			}

			if (!objects.empty())
			{
				//aabb.draw();
				//sphere.draw();
			}
		}


		bool isVisible(const Frustum& frustum) const
		{
			if (sphere.isVisible(frustum))
			{
				return aabb.isVisible(frustum);
			}

			return false;
		}
	};


public:

	typedef boost::shared_ptr<Octree> Ptr;
	typedef typename stlplus::ntree<Node>::iterator NodeP;
	
private:


	NodeP insert(InsertableP entity, NodeP node)
	{
		ASSERT(node.valid() && "invalid node passed");
		ASSERT(entity && "null entity passed");

		if (entity->isInsideAabb(node->aabb))
		{
			return insert_recurse(entity, node);
		}
		else
		{
			node->objects.push_back(entity);
			return node;
		}
	}

	NodeP insert_recurse(InsertableP entity, NodeP node)
	{
		ASSERT(node.valid() && "invalid node passed");
		ASSERT(entity && "null entity passed");

		int octantNum = entity->getOctant(node->aabb);
		if (octantNum == -1)
		{
			node->objects.push_back(entity);
			return node;
		}
		else
		{
			if ((int)tree_.children(node) <= octantNum)
			{
				addChild(node, octantNum);
			}

			NodeP child = tree_.child(node, octantNum);
			ASSERT(child.valid() && "expected valid child node");

			return insert(entity, child);
		}
	}

	void addChild(NodeP node, int index)
	{
		ASSERT(node.valid() && "invalid node passed");

		Aabb octant;

		for (int i = tree_.children(node); i <= index; ++i)
		{
			node->aabb.getOctant(octant, i);
			tree_.append(node, octant);
		}
	}


	void draw(Scalar alpha, NodeP node) const
	{
		ASSERT(node.valid() && "invalid node passed");

		node->draw(alpha);

		for (unsigned i = 0; i < tree_.children(node); ++i)
		{
			NodeP child = tree_.child(node, i);
			ASSERT(child.valid() && "expected valid child node");

			draw(alpha, child);
		}
	}

	void drawIfVisible(Scalar alpha, const Frustum& frustum, NodeP node) const
	{
		ASSERT(node.valid() && "invalid node passed");

		// try to cull by sphere
		Frustum::Collision collision = frustum.contains(node->sphere);
		if (collision == Frustum::OUTSIDE) return;

		// try to cull by aabb
		collision = frustum.contains(node->aabb);
		if (collision == Frustum::OUTSIDE) return;


		if (collision == Frustum::INSIDE)
		{
			node->draw(alpha);
		}
		else // collision == Frustum::INTERSECT
		{
			node->drawIfVisible(alpha, frustum);
		}

		if (tree_.children(node) > 0)
		{
			if (collision == Frustum::INSIDE)
			{
				for (unsigned i = 0; i < tree_.children(node); ++i)
				{
					NodeP child = tree_.child(node, i);
					ASSERT(child.valid() && "expected valid child node");

					draw(alpha, child);
				}
			}
			else // collision == Frustum::INTERSECT
			{
				for (unsigned i = 0; i < tree_.children(node); ++i)
				{
					NodeP child = tree_.child(node, i);
					ASSERT(child.valid() && "expected valid child node");

					drawIfVisible(alpha, frustum, child);
				}
			}
		}
	}

	mutable stlplus::ntree<Node> tree_;


public:

	void print(NodeP node)
	{
		//logDebug("-----");
		//logDebug("depth to node: %d", tree_.depth(node));
		//logDebug("size of node: %d", tree_.size(node));
	}

	static Ptr alloc(const Node& rootNode)
	{
		return Ptr(new Octree(rootNode));
	}

	explicit Octree(const Node& rootNode)
	{
		tree_.insert(rootNode);
	}

	NodeP insert(InsertableP entity)
	{
		return insert(entity, tree_.root());
	}

	NodeP reinsert(InsertableP entity, NodeP node)
	{
		ASSERT(entity && "null entity passed");
		ASSERT(node.valid() && "invalid node passed");

		typename std::list<InsertableP>::iterator it;
		it = std::find(node->objects.begin(), node->objects.end(), entity);

		if (it != node->objects.end())
		{
			node->objects.erase(it);
		}

		return insert(entity);
	}

	void draw(Scalar alpha) const
	{
		draw(alpha, tree_.root());
	}

	void drawIfVisible(Scalar alpha, const Frustum& frustum) const
	{
		drawIfVisible(alpha, frustum, tree_.root());
	}
};


} // namespace Mf

#endif // _MOOF_OCTREE_HH_

/** vim: set ts=4 sw=4 tw=80: *************************************************/