/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2013 CERN
 * @author Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
 *
 * This program 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.
 *
 * This program 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 this program; if not, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */

#include <math/vector2d.h>

#include <geometry/shape.h>
#include <geometry/shape_line_chain.h>
#include <geometry/shape_circle.h>
#include <geometry/shape_rect.h>

typedef VECTOR2I::extended_type ecoord;

static inline bool Collide( const SHAPE_CIRCLE& aA, const SHAPE_CIRCLE& aB, int aClearance,
                            bool aNeedMTV, VECTOR2I& aMTV )
{
	ecoord min_dist = aClearance + aA.GetRadius() + aB.GetRadius();
	ecoord min_dist_sq = min_dist * min_dist;
		
	const VECTOR2I delta = aB.GetCenter() - aA.GetCenter();

	ecoord dist_sq = delta.SquaredEuclideanNorm();

	if ( dist_sq >= min_dist_sq )
		return false;
	
	if ( aNeedMTV )
		aMTV = delta.Resize( sqrt ( abs( min_dist_sq - dist_sq ) ) + 1 );

	return true;
}

static inline  bool Collide( const SHAPE_RECT& aA, const SHAPE_CIRCLE& aB, int aClearance,
                             bool aNeedMTV, VECTOR2I& aMTV )
{
	const VECTOR2I c = aB.GetCenter();
	const VECTOR2I p0 = aA.GetPosition();
	const VECTOR2I size = aA.GetSize();
	const ecoord r = aB.GetRadius();
	const ecoord min_dist = aClearance + r;
	const ecoord min_dist_sq = min_dist * min_dist;

	if ( aA.BBox( 0 ).Contains( c ) )
		return true;
			
	const VECTOR2I vts[] = { 
						VECTOR2I(p0.x, 			p0.y),
						VECTOR2I(p0.x,			p0.y + size.y),
						VECTOR2I(p0.x + size.x, p0.y + size.y),
						VECTOR2I(p0.x + size.x, p0.y),
						VECTOR2I(p0.x, 			p0.y) };

	ecoord nearest_seg_dist_sq = VECTOR2I::ECOORD_MAX;
	VECTOR2I nearest;

	bool inside =  c.x >= p0.x && c.x <= ( p0.x + size.x )
				&& c.y >= p0.y && c.y <= ( p0.y + size.y );

	if( !inside )
	{

		for( int i = 0; i < 4; i++ )
		{
			const SEG seg( vts[i], vts[i+1] );
			ecoord dist_sq = seg.SquaredDistance( c );
		
			if( dist_sq < min_dist_sq )
			{
				if( !aNeedMTV )
					return true;
				else
				{
					nearest = seg.NearestPoint( c );
					nearest_seg_dist_sq = dist_sq;
				}
			}
		}
	}

	if( nearest_seg_dist_sq >= min_dist_sq && !inside )
		return false;

	VECTOR2I delta = c - nearest;

	if( !aNeedMTV )
		return true;

	if( inside )
		aMTV = -delta.Resize( sqrt( abs( r * r + nearest_seg_dist_sq ) + 1 ) );
	else
		aMTV = delta.Resize( sqrt( abs( r * r - nearest_seg_dist_sq ) + 1 ) );

	return true;
}


static inline bool Collide( const SHAPE_CIRCLE& aA, const SHAPE_LINE_CHAIN& aB, int aClearance,
                            bool aNeedMTV, VECTOR2I& aMTV )
{
	for( int s = 0; s < aB.SegmentCount(); s++ )
	{
		if ( aA.Collide( aB.CSegment( s ), aClearance ) )
			return true;
	}
	
	return false;	
}


static inline bool Collide( const SHAPE_LINE_CHAIN& aA, const SHAPE_LINE_CHAIN& aB, int aClearance,
                            bool aNeedMTV, VECTOR2I& aMTV )
{
	for( int i = 0; i < aB.SegmentCount(); i++ )
		if( aA.Collide( aB.CSegment(i), aClearance ) )
			return true;
	return false;
}


static inline bool Collide( const SHAPE_RECT& aA, const SHAPE_LINE_CHAIN& aB, int aClearance,
                            bool aNeedMTV, VECTOR2I& aMTV )
{
	for( int s = 0; s < aB.SegmentCount(); s++ )
	{
		SEG seg = aB.CSegment( s );
			if( aA.Collide( seg, aClearance ) )
				return true;
	}

	return false;
}


bool CollideShapes( const SHAPE* aA, const SHAPE* aB, int aClearance, bool aNeedMTV, VECTOR2I& aMTV )
{
	switch( aA->Type() )
	{
		case SH_RECT:
			switch( aB->Type() )
			{
				case SH_CIRCLE:
					return Collide( *static_cast<const SHAPE_RECT*>( aA ),
					        *static_cast<const SHAPE_CIRCLE*>( aB ), aClearance, aNeedMTV, aMTV );

				case SH_LINE_CHAIN:
					return Collide( *static_cast<const SHAPE_RECT*>( aA ),
					        *static_cast<const SHAPE_LINE_CHAIN*>( aB ), aClearance, aNeedMTV, aMTV );

				default:
					break;
			}

		case SH_CIRCLE:
			switch( aB->Type() )
			{
				case SH_RECT:
					return Collide( *static_cast<const SHAPE_RECT*>( aB ),
					        *static_cast<const SHAPE_CIRCLE*>( aA ), aClearance, aNeedMTV, aMTV );

				case SH_CIRCLE:
					return Collide( *static_cast<const SHAPE_CIRCLE*>( aA ),
					        *static_cast<const SHAPE_CIRCLE*>( aB ), aClearance, aNeedMTV, aMTV );

				case SH_LINE_CHAIN:
					return Collide( *static_cast<const SHAPE_CIRCLE*>( aA ),
					        *static_cast<const SHAPE_LINE_CHAIN *>( aB ), aClearance, aNeedMTV, aMTV );

				default:
					break;
			}

		case SH_LINE_CHAIN:
			switch( aB->Type() )
			{
				case SH_RECT:
					return Collide( *static_cast<const SHAPE_RECT*>( aB ),
					        *static_cast<const SHAPE_LINE_CHAIN*>( aA ), aClearance, aNeedMTV, aMTV );

				case SH_CIRCLE:
					return Collide( *static_cast<const SHAPE_CIRCLE*>( aB ),
					        *static_cast<const SHAPE_LINE_CHAIN*>( aA ), aClearance, aNeedMTV, aMTV );

				case SH_LINE_CHAIN:
					return Collide( *static_cast<const SHAPE_LINE_CHAIN*>( aA ),
					        *static_cast<const SHAPE_LINE_CHAIN*>( aB ), aClearance, aNeedMTV, aMTV );

				default:
					break;
			}

		default:
			break;
	}

	bool unsupported_collision = true;

	assert( unsupported_collision == false );

	return false;
}


bool SHAPE::Collide( const SHAPE* aShape, int aClerance, VECTOR2I& aMTV ) const
{
	return CollideShapes( this, aShape, aClerance, true, aMTV);
}


bool SHAPE::Collide ( const SHAPE* aShape, int aClerance ) const
{
	VECTOR2I dummy;
	return CollideShapes( this, aShape, aClerance, false, dummy );
}