/*==LICENSE==*

CyanWorlds.com Engine - MMOG client, server and tools
Copyright (C) 2011  Cyan Worlds, Inc.

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 3 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, see <http://www.gnu.org/licenses/>.

You can contact Cyan Worlds, Inc. by email legal@cyan.com
 or by snail mail at:
      Cyan Worlds, Inc.
      14617 N Newport Hwy
      Mead, WA   99021

*==LICENSE==*/

#include "hsTypes.h"
#include "hsBounds.h"
#include "hsFastMath.h"

#include "plVisLOSMgr.h"

#include "plSpaceTree.h"
#include "plDrawableSpans.h"
#include "plAccessGeometry.h"
#include "plAccessSpan.h"

#include "plSurface/hsGMaterial.h"
#include "plSurface/plLayerInterface.h"

#include "plScene/plSceneNode.h"
#include "plScene/plPageTreeMgr.h"

// Stuff for cursor los
#include "plInputCore/plInputDevice.h"
#include "plPipeline.h"


#include "plTweak.h"

#include <algorithm>
#include <functional>

plVisLOSMgr* plVisLOSMgr::Instance()
{
	static plVisLOSMgr inst;
	return &inst;
}

hsBool plVisLOSMgr::ICheckSpaceTreeRecur(plSpaceTree* space, int which, hsTArray<plSpaceHit>& hits)
{
	const plSpaceTreeNode& node = space->GetNode(which);

	if( node.fFlags & plSpaceTreeNode::kDisabled )
		return false;

	hsScalar closest;
	// If it's a hit
	if( ICheckBound(node.fWorldBounds, closest) )
	{
		// If it's a leaf, 
		if( node.IsLeaf() )
		{
			// add it to the list with the closest intersection point,
			plSpaceHit* hit = hits.Push();
			hit->fIdx = which;
			hit->fClosest = closest;

			return true;
		}
		// else recurse on its children
		else
		{
			hsBool retVal = false;
			if( ICheckSpaceTreeRecur(space, node.GetChild(0), hits) )
				retVal = true;

			if( ICheckSpaceTreeRecur(space, node.GetChild(1), hits) )
				retVal = true;

			return retVal;
		}
	}
	return false;
}

struct plCompSpaceHit : public std::binary_function<plSpaceHit, plSpaceHit, bool>
{
	bool operator()( const plSpaceHit& lhs, const plSpaceHit& rhs) const
	{
		return lhs.fClosest < rhs.fClosest;
	}
};


hsBool plVisLOSMgr::ICheckSpaceTree(plSpaceTree* space, hsTArray<plSpaceHit>& hits)
{
	hits.SetCount(0);

	if( space->IsEmpty() )
		return false;

	// Hierarchical search down the tree for bounds intersecting the current ray.
	hsBool retVal = ICheckSpaceTreeRecur(space, space->GetRoot(), hits);

	// Now sort them front to back.
	plSpaceHit* begin = hits.AcquireArray();
	plSpaceHit* end = begin + hits.GetCount();

	std::sort(begin, end, plCompSpaceHit());

	return retVal;
}

hsBool plVisLOSMgr::ISetup(const hsPoint3& pStart, const hsPoint3& pEnd)
{
	fCurrFrom = pStart;
	fCurrTarg = pEnd;

	fMaxDist = hsVector3(&fCurrTarg, &fCurrFrom).Magnitude();

	const hsScalar kMinMaxDist(0);
	return fMaxDist > kMinMaxDist;
}

hsBool plVisLOSMgr::Check(const hsPoint3& pStart, const hsPoint3& pEnd, plVisHit& hit)
{
	if( !fPageMgr )
		return false;

	// Setup any internals, like fMaxDist
	if( !ISetup(pStart, pEnd) )
		return false;

	// Go through the nodes in the PageMgr and find the closest
	// point of intersection for each scene node. If none are before
	// pEnd, return false.
	// Node come out sorted by closest point, front to back
	static hsTArray<plSpaceHit> hits;
	if( !ICheckSpaceTree(fPageMgr->GetSpaceTree(), hits) )
		return false;

	// In front to back order, check inside each node.
	// Our max distance can be changing as we do this, because a
	// face hit will limit how far we need to look. When we hit the
	// first node with a closest distance < fMaxDist, we're done.
	hsBool retVal = false;

	int i;
	for( i = 0; i < hits.GetCount(); i++ )
	{
		if( hits[i].fClosest > fMaxDist )
			break;

		if( ICheckSceneNode(fPageMgr->GetNodes()[hits[i].fIdx], hit)  )
			retVal = true;
	}

	return retVal;
}

hsBool plVisLOSMgr::ICheckSceneNode(plSceneNode* node, plVisHit& hit)
{
	static hsTArray<plSpaceHit> hits;
	if( !ICheckSpaceTree(node->GetSpaceTree(), hits) )
		return false;

	hsBool retVal = false;
	int i;
	for( i = 0; i < hits.GetCount(); i++ )
	{
		if( hits[i].fClosest > fMaxDist )
			break;

		if( (node->GetDrawPool()[hits[i].fIdx]->GetRenderLevel().Level() > 0)
			&& !node->GetDrawPool()[hits[i].fIdx]->GetNativeProperty(plDrawable::kPropHasVisLOS) )
			continue;

		if( ICheckDrawable(node->GetDrawPool()[hits[i].fIdx], hit) )
			retVal = true;
	}

	return retVal;
}


hsBool plVisLOSMgr::ICheckDrawable(plDrawable* d, plVisHit& hit)
{
	plDrawableSpans* ds = plDrawableSpans::ConvertNoRef(d);
	if( !ds )
		return false;

	static hsTArray<plSpaceHit> hits;
	if( !ICheckSpaceTree(ds->GetSpaceTree(), hits) )
		return false;

	const hsBool isOpaque = !ds->GetRenderLevel().Level();

	const hsTArray<plSpan *> spans = ds->GetSpanArray();

	hsBool retVal = false;
	int i;
	for( i = 0; i < hits.GetCount(); i++ )
	{
		if( hits[i].fClosest > fMaxDist )
			break;

		if( isOpaque || (spans[hits[i].fIdx]->fProps & plSpan::kVisLOS) )
		{
			if( ICheckSpan(ds, hits[i].fIdx, hit) )
				retVal = true;
		}
	}

	return retVal;
}

hsBool plVisLOSMgr::ICheckSpan(plDrawableSpans* dr, UInt32 spanIdx, plVisHit& hit)
{
	if( !(dr->GetSpan(spanIdx)->fTypeMask & plSpan::kIcicleSpan) )
		return false;

	plAccessSpan src;
	plAccessGeometry::Instance()->OpenRO(dr, spanIdx, src);

	const hsBool twoSided = !!(src.GetMaterial()->GetLayer(0)->GetMiscFlags() & hsGMatState::kMiscTwoSided);

	hsBool retVal = false;

	// We move into local space, look for hits, and convert the closest we find 
	// (if any) back into world space at the end.
	hsPoint3 currFrom = src.GetWorldToLocal() * fCurrFrom;
	hsPoint3 currTarg = src.GetWorldToLocal() * fCurrTarg;

	hsVector3 currDir(&currTarg, &currFrom);
	hsScalar maxDist = currDir.Magnitude();

	currDir /= maxDist;

	plAccTriIterator tri(&src.AccessTri());
	for( tri.Begin(); tri.More(); tri.Advance() )
	{
		// Project the current ray onto the tri plane
		hsVector3 norm = hsVector3(&tri.Position(1), &tri.Position(0)) % hsVector3(&tri.Position(2), &tri.Position(0));
		hsScalar dotNorm = norm.InnerProduct(currDir);

		const hsScalar kMinDotNorm = 1.e-3f;
		if( dotNorm >= -kMinDotNorm )
		{
			if( !twoSided )
				continue;
			if( dotNorm <= kMinDotNorm )
				continue;
		}
		hsScalar dist = hsVector3(&tri.Position(0), &currFrom).InnerProduct(norm);
		if( dist > 0 )
			continue;
		dist /= dotNorm;
		hsPoint3 projPt = currFrom;
		projPt += currDir * dist;

		// If the distance from source point to projected point is too long, skip
		if( dist > maxDist )
			continue;

		// Find the 3 cross products (v[i+1]-v[i]) X (proj - v[i]) dotted with current ray
		hsVector3 cross0 = hsVector3(&tri.Position(1), &tri.Position(0)) % hsVector3(&projPt, &tri.Position(0));
		hsScalar dot0 = cross0.InnerProduct(currDir);

		hsVector3 cross1 = hsVector3(&tri.Position(2), &tri.Position(1)) % hsVector3(&projPt, &tri.Position(1));
		hsScalar dot1 = cross1.InnerProduct(currDir);

		hsVector3 cross2 = hsVector3(&tri.Position(0), &tri.Position(2)) % hsVector3(&projPt, &tri.Position(2));
		hsScalar dot2 = cross2.InnerProduct(currDir);

		// If all 3 are negative, projPt is a hit
		// If all 3 are positive and we're two sided, projPt is a hit
		// We've already checked for back facing (when we checked for edge on in projection),
		// so we'll accept either case here.
		if( ((dot0 <= 0) && (dot1 <= 0) && (dot2 <= 0))
			||((dot0 >= 0) && (dot1 >= 0) && (dot2 >= 0)) )
		{
			if( dist < maxDist )
			{
				maxDist = dist;
				hit.fPos = projPt;
				retVal = true;
			}
		}
	}
	plAccessGeometry::Instance()->Close(src);

	if( retVal )
	{
		hit.fPos = src.GetLocalToWorld() * hit.fPos;
		fCurrTarg = hit.fPos;
		fMaxDist = hsVector3(&fCurrTarg, &fCurrFrom).Magnitude();
	}

	return retVal;
}

hsBool plVisLOSMgr::ICheckBound(const hsBounds3Ext& bnd, hsScalar& closest)
{
	if( bnd.GetType() != kBoundsNormal )
		return false;

	if( bnd.IsInside(&fCurrFrom) || bnd.IsInside(&fCurrTarg) )
	{
		closest = 0;
		return true;
	}

	const int face[6][4] =
	{
		{0,1,3,2},
		{1,5,7,3},
		{2,3,7,6},
		{5,4,6,7},
		{0,4,5,1},
		{0,2,6,4}
	};

	hsPoint3 corn[8];
	bnd.GetCorners(corn);

	hsBool retVal = false;

	const hsPoint3& currFrom = fCurrFrom;
	const hsPoint3& currTarg = fCurrTarg;

	hsVector3 currDir(&currTarg, &currFrom);
	const hsScalar maxDistSq = currDir.MagnitudeSquared();

	currDir *= hsFastMath::InvSqrt(maxDistSq);

	int i;
	for( i = 0; i < 6; i++ )
	{
		const hsPoint3& p0 = corn[face[i][0]];
		const hsPoint3& p1 = corn[face[i][1]];
		const hsPoint3& p2 = corn[face[i][2]];
		const hsPoint3& p3 = corn[face[i][3]];

		// Project the current ray onto the tri plane
		hsVector3 norm = hsVector3(&p1, &p0) % hsVector3(&p2, &p0);
		hsScalar dotNorm = norm.InnerProduct(currDir);

		const hsScalar kMinDotNorm = 1.e-3f;
		if( dotNorm >= -kMinDotNorm )
		{
			continue;
		}
		hsScalar dist = hsVector3(&p0, &currFrom).InnerProduct(norm);
		if( dist >= 0 )
			continue;
		dist /= dotNorm;

		// If the distance from source point to projected point is too long, skip
		if( dist > fMaxDist )
			continue;

		hsPoint3 projPt = currFrom;
		projPt += currDir * dist;

		// Find the 3 cross products (v[i+1]-v[i]) X (proj - v[i]) dotted with current ray
		hsVector3 cross0 = hsVector3(&p1, &p0) % hsVector3(&projPt, &p0);
		hsScalar dot0 = cross0.InnerProduct(currDir);

		hsVector3 cross1 = hsVector3(&p2, &p1) % hsVector3(&projPt, &p1);
		hsScalar dot1 = cross1.InnerProduct(currDir);

		hsVector3 cross2 = hsVector3(&p3, &p2) % hsVector3(&projPt, &p2);
		hsScalar dot2 = cross2.InnerProduct(currDir);

		hsVector3 cross3 = hsVector3(&p0, &p3) % hsVector3(&projPt, &p3);
		hsScalar dot3 = cross3.InnerProduct(currDir);

		// If all 4 are negative, projPt is a hit
		if( (dot0 <= 0) && (dot1 <= 0) && (dot2 <= 0) && (dot3 <= 0) )
		{
			closest = dist;
			return true;
		}
	}
	return false;
}

hsBool plVisLOSMgr::CursorCheck(plVisHit& hit)
{
	Int32 sx= Int32(plMouseDevice::Instance()->GetCursorX() * fPipe->Width());
	Int32 sy= Int32(plMouseDevice::Instance()->GetCursorY() * fPipe->Height());

	hsPoint3 from = fPipe->GetViewPositionWorld();
	plConst(hsScalar) dist(1.e5f);

	hsPoint3 targ;
	fPipe->ScreenToWorldPoint(1, 0, &sx, &sy, dist, 0, &targ);
	return Check(from, targ, hit);
}

/////////////////////////////////////////////////////////////////

#include "plPipeline.h"
#include "../pnSceneObject/plSceneObject.h"

static plSceneObject* marker = nil;
static plPipeline* pipe = nil;


void VisLOSHackBegin(plPipeline* p, plSceneObject* m)
{
	marker = m;
	pipe = p;
}

void VisLOSHackPulse()
{
	if( !pipe )
		return;

	plVisHit hit;
	if( plVisLOSMgr::Instance()->CursorCheck(hit) )
	{
		if( marker )
		{
			hsMatrix44 l2w = marker->GetLocalToWorld();
			l2w.fMap[0][3] = hit.fPos.fX;
			l2w.fMap[1][3] = hit.fPos.fY;
			l2w.fMap[2][3] = hit.fPos.fZ;
			l2w.NotIdentity();
			hsMatrix44 w2l;
			l2w.GetInverse(&w2l);
			marker->SetTransform(l2w, w2l);
		}
	}
}