/*==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"


#include "plPipeline.h"
#include "pnSceneObject/plSceneObject.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);
}

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

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);
        }
    }
}