/*
   Copyright (C) 2001-2006, William Joseph.
   All Rights Reserved.

   This file is part of GtkRadiant.

   GtkRadiant is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   GtkRadiant is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with GtkRadiant; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#pragma once

#include <cstddef>

#include "generic/vector.h"
#include "scenelib.h"
#include "generic/callbackfwd.h"

class SelectionIntersection
{
	float m_depth;
	float m_distance;
	float m_depth2;
	bool m_indirect;
public:
	SelectionIntersection() : m_depth( 1 ), m_distance( 2 ), m_depth2( -1 ), m_indirect( true ){
	}
	SelectionIntersection( float depth, float distance ) : m_depth( depth ), m_distance( distance ), m_depth2( -1 ), m_indirect( distance != 0.f ){
	}
	SelectionIntersection( float depth, float distance, float depth2 ) : m_depth( depth ), m_distance( distance ), m_depth2( depth2 ), m_indirect( distance != 0.f ){
	}
	bool operator<( const SelectionIntersection& other ) const {
		if( m_indirect != other.m_indirect ){
			return other.m_indirect; //m_distance < other.m_distance;
		}
		else if( m_indirect && other.m_indirect ){
			if( fabs( m_distance - other.m_distance ) > 1e-3f /*0.00002f*/ ){
				return m_distance < other.m_distance;
			}
			else if( fabs( m_depth - other.m_depth ) > 1e-6f ){
				return m_depth < other.m_depth;
			}
			else{
				return m_depth2 > other.m_depth2;
			}
		}
		else if( m_depth != other.m_depth ){
			return m_depth < other.m_depth;
		}
		return false;
	}
	bool equalEpsilon( const SelectionIntersection& other, float distanceEpsilon, float depthEpsilon ) const {
		if( m_indirect != other.m_indirect ){
			return false;
		}
		else if( m_indirect && other.m_indirect ){
#if 1
			return float_equal_epsilon( m_distance, other.m_distance, distanceEpsilon )
			    && float_equal_epsilon( m_depth, other.m_depth, depthEpsilon )
			    && float_equal_epsilon( m_depth2, other.m_depth2, 3e-7f );
#else
			return ( m_distance == other.m_distance )
			    && ( m_depth == other.m_depth )
			    && ( m_depth2 == other.m_depth2 );
#endif
		}
		return float_equal_epsilon( m_distance, other.m_distance, distanceEpsilon )
		    && float_equal_epsilon( m_depth, other.m_depth, depthEpsilon )
		    && float_equal_epsilon( m_depth2, other.m_depth2, depthEpsilon );
	}
	float depth() const {
		return m_depth;
	}
	float distance() const {
		return m_distance;
	}
	bool valid() const {
		return depth() < 1;
	}
};

// returns true if self is closer than other
inline bool SelectionIntersection_closer( const SelectionIntersection& self, const SelectionIntersection& other ){
	return self < other;
}

// assigns other to best if other is closer than best
inline void assign_if_closer( SelectionIntersection& best, const SelectionIntersection& other ){
	if ( SelectionIntersection_closer( other, best ) ) {
		best = other;
	}
}




class VertexPointer
{
	typedef const unsigned char* byte_pointer;
public:
	typedef float elem_type;
	typedef const elem_type* pointer;
	typedef const elem_type& reference;

	class iterator
	{
	public:
		iterator() {}
		iterator( byte_pointer vertices, std::size_t stride )
			: m_iter( vertices ), m_stride( stride ) {}

		bool operator==( const iterator& other ) const {
			return m_iter == other.m_iter;
		}
		bool operator!=( const iterator& other ) const {
			return !operator==( other );
		}

		iterator operator+( std::size_t i ){
			return iterator( m_iter + i * m_stride, m_stride );
		}
		iterator operator+=( std::size_t i ){
			m_iter += i * m_stride;
			return *this;
		}
		iterator& operator++(){
			m_iter += m_stride;
			return *this;
		}
		iterator operator++( int ){
			iterator tmp = *this;
			m_iter += m_stride;
			return tmp;
		}
		reference operator*() const {
			return *reinterpret_cast<pointer>( m_iter );
		}
	private:
		byte_pointer m_iter;
		std::size_t m_stride;
	};

	VertexPointer( pointer vertices, std::size_t stride )
		: m_vertices( reinterpret_cast<byte_pointer>( vertices ) ), m_stride( stride ) {}

	iterator begin() const {
		return iterator( m_vertices, m_stride );
	}

	reference operator[]( std::size_t i ) const {
		return *reinterpret_cast<pointer>( m_vertices + m_stride * i );
	}

private:
	byte_pointer m_vertices;
	std::size_t m_stride;
};

class IndexPointer
{
public:
	typedef unsigned int index_type;
	typedef const index_type* pointer;

	class iterator
	{
	public:
		iterator( pointer iter ) : m_iter( iter ) {}

		bool operator==( const iterator& other ) const {
			return m_iter == other.m_iter;
		}
		bool operator!=( const iterator& other ) const {
			return !operator==( other );
		}

		iterator operator+( std::size_t i ){
			return m_iter + i;
		}
		iterator operator+=( std::size_t i ){
			return m_iter += i;
		}
		iterator operator++(){
			return ++m_iter;
		}
		iterator operator++( int ){
			return m_iter++;
		}
		const index_type& operator*() const {
			return *m_iter;
		}
	private:
		void increment(){
			++m_iter;
		}
		pointer m_iter;
	};

	IndexPointer( pointer indices, std::size_t count )
		: m_indices( indices ), m_finish( indices + count ) {}

	iterator begin() const {
		return m_indices;
	}
	iterator end() const {
		return m_finish;
	}

private:
	pointer m_indices;
	pointer m_finish;
};

class Matrix4;
class VolumeTest;

class SelectionTest
{
public:
	virtual void BeginMesh( const Matrix4& localToWorld, bool twoSided = false ) = 0;
	virtual const VolumeTest& getVolume() const = 0;
//	virtual const Vector3& getNear() const = 0;
//	virtual const Vector3& getFar() const = 0;
	virtual const Matrix4& getScreen2world() const = 0;
	virtual void TestPoint( const Vector3& point, SelectionIntersection& best ) = 0;
	virtual void TestPolygon( const VertexPointer& vertices, std::size_t count, SelectionIntersection& best, const DoubleVector3 planepoints[3] ) = 0;
	virtual void TestLineLoop( const VertexPointer& vertices, std::size_t count, SelectionIntersection& best ) = 0;
	virtual void TestLineStrip( const VertexPointer& vertices, std::size_t count, SelectionIntersection& best ) = 0;
	virtual void TestLines( const VertexPointer& vertices, std::size_t count, SelectionIntersection& best ) = 0;
	virtual void TestTriangles( const VertexPointer& vertices, const IndexPointer& indices, SelectionIntersection& best ) = 0;
	virtual void TestQuads( const VertexPointer& vertices, const IndexPointer& indices, SelectionIntersection& best ) = 0;
	virtual void TestQuadStrip( const VertexPointer& vertices, const IndexPointer& indices, SelectionIntersection& best ) = 0;
};

class Selectable;

class Selector
{
public:
	virtual void pushSelectable( Selectable& selectable ) = 0;
	virtual void popSelectable() = 0;
	virtual void addIntersection( const SelectionIntersection& intersection ) = 0;
};

inline void Selector_add( Selector& selector, Selectable& selectable ){
	selector.pushSelectable( selectable );
	selector.addIntersection( SelectionIntersection( 0, 0 ) );
	selector.popSelectable();
}

inline void Selector_add( Selector& selector, Selectable& selectable, const SelectionIntersection& intersection ){
	selector.pushSelectable( selectable );
	selector.addIntersection( intersection );
	selector.popSelectable();
}


class VolumeTest;
class SelectionTestable
{
public:
	STRING_CONSTANT( Name, "SelectionTestable" );

	virtual void testSelect( Selector& selector, SelectionTest& test ) = 0;
};

inline SelectionTestable* Instance_getSelectionTestable( scene::Instance& instance ){
	return InstanceTypeCast<SelectionTestable>::cast( instance );
}


template<typename T> class Plane3___;
typedef Plane3___<double> Plane3;
typedef Callback1<const Plane3&> PlaneCallback;

class SelectedPlanes
{
public:
	virtual bool contains( const Plane3& plane ) const = 0;
};

/// \todo Support localToWorld.
class PlaneSelectable
{
public:
	STRING_CONSTANT( Name, "PlaneSelectable" );

	virtual void selectPlanes( Selector& selector, SelectionTest& test, const PlaneCallback& selectedPlaneCallback ) = 0;
	virtual void selectReversedPlanes( Selector& selector, const SelectedPlanes& selectedPlanes ) = 0;

	virtual void bestPlaneDirect( SelectionTest& test, Plane3& plane, SelectionIntersection& intersection ) const = 0;
	virtual void bestPlaneIndirect( SelectionTest& test, Plane3& plane, Vector3& intersection, float& dist ) const = 0;
	virtual void selectByPlane( const Plane3& plane ) = 0;
	virtual void gatherPolygonsByPlane( const Plane3& plane, std::vector<std::vector<Vector3>>& polygons ) const = 0;
};