/*==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/>.

Additional permissions under GNU GPL version 3 section 7

If you modify this Program, or any covered work, by linking or
combining it with any of RAD Game Tools Bink SDK, Autodesk 3ds Max SDK,
NVIDIA PhysX SDK, Microsoft DirectX SDK, OpenSSL library, Independent
JPEG Group JPEG library, Microsoft Windows Media SDK, or Apple QuickTime SDK
(or a modified version of those libraries),
containing parts covered by the terms of the Bink SDK EULA, 3ds Max EULA,
PhysX SDK EULA, DirectX SDK EULA, OpenSSL and SSLeay licenses, IJG
JPEG Library README, Windows Media SDK EULA, or QuickTime SDK EULA, the
licensors of this Program grant you additional
permission to convey the resulting work. Corresponding Source for a
non-source form of such a combination shall include the source code for
the parts of OpenSSL and IJG JPEG Library used as well as that of the covered
work.

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 "HeadSpin.h"

#include "MaxMain/MaxAPI.h"

#include "plDistTree.h"

plDistTree::plDistTree()
:   fRoot(-1)
{
}

plDistTree::~plDistTree()
{
}

void plDistTree::Reset()
{
    fRoot = -1;
    fNodes.clear();
}

void plDistTree::AddBoxIData(const Box3& box, const Box3& fade, uintptr_t iData)
{
    fRoot = IAddNodeRecur(fRoot, box, fade, iData);
}

BOOL plDistTree::BoxClear(const Box3& box, const Box3& fade) const
{
    return IBoxClearRecur(fRoot, box, fade);
}

BOOL plDistTree::PointClear(const Point3& pt, const Box3& fade) const
{
    return IPointClearRecur(fRoot, pt, fade);
}

BOOL plDistTree::IFadesClear(const Box3& fade0, const Box3& fade1) const
{
    // Only two ways fade can come out non-overlapping.
    // Either fade0 fades out before fade1 fades in, or v.v.

    // First case, does fade0 fade out?
    if( fade0.Max()[2] > 0 )
    {
        // does fade1 fade in?
        if( fade1.Min()[2] < 0 )
        {
            // Okay they do, does fade0 fade out before fade1 fades in?
            if( fade0.Max()[0] <= fade1.Min()[0] )
                return true;
        }
    }
    // Second case, same thing but reversed order
    if( fade1.Max()[2] > 0 )
    {
        // does fade0 fade in?
        if( fade0.Min()[2] < 0 )
        {
            // Okay they do, does fade1 fade out before fade0 fades in?
            if( fade1.Max()[0] <= fade0.Min()[0] )
                return true;
        }
    }
    return false;
}

BOOL plDistTree::IBox0ContainsBox1(const Box3& box0, const Box3& box1, const Box3& fade0, const Box3& fade1) const
{
#ifdef MAX_CONTAINS_WORKS
    if( !box0.Contains(box1) )
        return false;
#else MAX_CONTAINS_WORKS
    if( (box0.Min()[0] > box1.Min()[0])
        ||(box0.Min()[1] > box1.Min()[1])
        ||(box0.Min()[2] > box1.Min()[2])
        ||(box0.Max()[0] < box1.Max()[0])
        ||(box0.Max()[1] < box1.Max()[1])
        ||(box0.Max()[2] < box1.Max()[2]) )
        return false;
#endif // MAX_CONTAINS_WORKS

    if( IFadesClear(fade0, fade1) )
        return false;

    return true;
}

BOOL plDistTree::IBoxesClear(const Box3& box0, const Box3& box1) const
{
    return (box0.Min()[0] > box1.Max()[0])
        ||(box0.Max()[0] < box1.Min()[0])

        ||(box0.Min()[1] > box1.Max()[1])
        ||(box0.Max()[1] < box1.Min()[1])

        ||(box0.Min()[2] > box1.Max()[2])
        ||(box0.Max()[2] < box1.Min()[2]);
}

BOOL plDistTree::IBoxClearRecur(int32_t iNode, const Box3& box, const Box3& fade) const
{
    if( iNode < 0 )
        return true;

    if( IBoxesClear(fNodes[iNode].fBox, box) )
        return true;

    if( IFadesClear(fNodes[iNode].fFade, fade) )
        return true;

    if( fNodes[iNode].IsLeaf() )
        return false;

    int i;
    for( i = 0; i < 8; i++ )
    {
        if( !IBoxClearRecur(fNodes[iNode].fChildren[i], box, fade) )
            return false;
    }
    return true;
}

BOOL plDistTree::IPointClearRecur(int32_t iNode, const Point3& pt, const Box3& fade) const
{
    if( iNode < 0 )
        return true;

    if( !fNodes[iNode].fBox.Contains(pt) )
        return true;

    if( IFadesClear(fNodes[iNode].fFade, fade) )
        return true;

    if( fNodes[iNode].IsLeaf() )
        return false;

    int i;
    for( i = 0; i < 8; i++ )
    {
        if( !IPointClearRecur(fNodes[iNode].fChildren[i], pt, fade) )
            return false;
    }
    return true;
}


int32_t plDistTree::IAddNodeRecur(int32_t iNode, const Box3& box, const Box3& fade, uintptr_t iData)
{
    // if iNode < 0, make a node for box and return that.
    if( iNode < 0 )
    {
        return INextNode(box, fade, iData);
    }

    // if the box is contained
    //      if this node is a leaf, pitch the box
    //
    //      else
    //          recur on one of 8 children, based on
    //          box's center relative to node center.

    // if the box doesn't intercect this node,
    //      replace this node with a node of combined boxes.
    //      this node becomes sibling of box.

    // if the box does intercect, but isn't contained
    //      same thing.


#if 0
    if( IBox0ContainsBox1(fNodes[iNode].fBox, box, fNodes[iNode].fFade, fade) )
    {
        if( !fNodes[iNode].IsLeaf() )
#else
    if( !fNodes[iNode].IsLeaf() && IBox0ContainsBox1(fNodes[iNode].fBox, box, fNodes[iNode].fFade, fade) )
    {
#endif
        {
            int32_t iChild = IGetChild(fNodes[iNode].fBox, box);
        
            int32_t iChildNode = IAddNodeRecur(fNodes[iNode].fChildren[iChild], box, fade, iData);
            fNodes[iNode].fChildren[iChild] = iChildNode;

            fNodes[iNode].fBox += fNodes[fNodes[iNode].fChildren[iChild]].fBox;
        }
        return iNode;
    }
    else
    {
        return IMergeNodes(iNode, box, fade, iData);
    }
}

int32_t plDistTree::IMergeNodes(int32_t iNode, const Box3& box, const Box3& fade, uintptr_t iData)
{
    Box3 parBox = box;
    parBox += fNodes[iNode].fBox;

    int32_t pNode = INextNode(parBox, NonFade(), uintptr_t(-1));
    int32_t iChild = IGetChild(parBox, box);

    int32_t cNode = INextNode(box, fade, iData);

    fNodes[pNode].fChildren[iChild] = cNode;

    // Put the original node in the opposite quadrant from the child.
    // This handles the case where one of the bounds completely contains
    // the other. The octant structure of the tree isn't relied on, it
    // only helps balance the tree. So being wrong here won't hurt anything.
    iChild = iChild ^ 0x7;

    fNodes[pNode].fChildren[iChild] = iNode;

    fNodes[pNode].SetIsLeaf(false);

    return pNode;
}

int32_t plDistTree::IGetChild(const Box3& parent, const Box3& child) const
{
    Point3 parCenter = parent.Center();
    Point3 chiCenter = child.Center();

    int32_t idx = ((parCenter[0] < chiCenter[0]) << 0)
        | ((parCenter[1] < chiCenter[1]) << 1)
        | ((parCenter[2] < chiCenter[2]) << 2);
    return idx;
}

int32_t plDistTree::INextNode(const Box3& box, const Box3& fade, uintptr_t iData)
{
    int32_t iNode = (int32_t)fNodes.size();

    fNodes.emplace_back();

    fNodes[iNode].fFlags = plDistNode::kIsLeaf;
    fNodes[iNode].fBox = box;
    fNodes[iNode].fFade = fade;
    fNodes[iNode].fIData = iData;
    fNodes[iNode].fChildren[0]
        = fNodes[iNode].fChildren[1]
        = fNodes[iNode].fChildren[2]
        = fNodes[iNode].fChildren[3]
        = fNodes[iNode].fChildren[4]
        = fNodes[iNode].fChildren[5]
        = fNodes[iNode].fChildren[6]
        = fNodes[iNode].fChildren[7] = -1;

    return iNode;
}

void plDistTree::HarvestBox(const Box3& box, Tab<int32_t>& out) const
{
    IHarvestBoxRecur(fRoot, box, out);
}

void plDistTree::IHarvestBoxRecur(int32_t iNode, const Box3& box, Tab<int32_t>& out) const
{
    if( iNode < 0 )
        return;

    if( IBoxesClear(fNodes[iNode].fBox, box) )
        return;

    if( fNodes[iNode].IsLeaf() )
    {
        out.Append(1, &iNode);
    }
    else
    {
        int i;
        for( i = 0; i < 8; i++ )
            IHarvestBoxRecur(fNodes[iNode].fChildren[i], box, out);
    }
}