/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2019 KiCad Developers, see AUTHORS.txt for contributors.
 * Copyright (C) 2020 CERN
 *
 * 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, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-3.0.html
 * or you may search the http://www.gnu.org website for the version 3 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */

#ifndef DRC_RTREE_H_
#define DRC_RTREE_H_

#include <eda_rect.h>
#include <class_board_item.h>
#include <class_track.h>
#include <class_zone.h>
#include <unordered_set>
#include <set>
#include <vector>

#include <geometry/rtree.h>
#include <math/vector2d.h>

/**
 * DRC_RTREE -
 * Implements an R-tree for fast spatial and layer indexing of connectable items.
 * Non-owning.
 */
class DRC_RTREE
{

public:

    struct ITEM_WITH_SHAPE
    {
        ITEM_WITH_SHAPE( BOARD_ITEM *aParent, SHAPE* aShape, std::shared_ptr<SHAPE> aParentShape = nullptr ) :
            parent ( aParent ),
            shape ( aShape ),
            parentShape( aParentShape ) {};
        BOARD_ITEM* parent;
        SHAPE* shape;
        std::shared_ptr<SHAPE> parentShape;
    };

private:
    
    using drc_rtree = RTree<ITEM_WITH_SHAPE*, int, 2, double>;

public:

    DRC_RTREE()
    {
        for( int layer : LSET::AllLayersMask().Seq() )
            m_tree[layer] = new drc_rtree();

        m_count = 0;
    }

    ~DRC_RTREE()
    {
        for( auto tree : m_tree )
            delete tree;
    }

    /**
     * Function Insert()
     * Inserts an item into the tree. Item's bounding box is taken via its GetBoundingBox() method.
     */
    void insert( BOARD_ITEM* aItem )
    {
        std::vector<SHAPE*> subshapes;

        for( int layer : aItem->GetLayerSet().Seq() )
        {
            std::shared_ptr<SHAPE> itemShape = aItem->GetEffectiveShape( (PCB_LAYER_ID) layer );

            if( itemShape->HasIndexableSubshapes() )
            {
                itemShape->GetIndexableSubshapes( subshapes );
            }
            else
            {
                subshapes.push_back( itemShape.get() );
            }

            for( auto subshape : subshapes )
            {
                BOX2I     bbox    = subshape->BBox();
                const int mmin[2] = { bbox.GetX(), bbox.GetY() };
                const int mmax[2] = { bbox.GetRight(), bbox.GetBottom() };

                m_tree[layer]->Insert( mmin, mmax, new ITEM_WITH_SHAPE( aItem, subshape, itemShape ) );
                m_count++;
            }
        }
    }

#if 0
    /**
     * Function Remove()
     * Removes an item from the tree. Removal is done by comparing pointers, attempting
     * to remove a copy of the item will fail.
     */
    bool remove( BOARD_ITEM* aItem )
    {
        // First, attempt to remove the item using its given BBox
        const EDA_RECT& bbox    = aItem->GetBoundingBox();
        const int       mmin[2] = { bbox.GetX(), bbox.GetY() };
        const int       mmax[2] = { bbox.GetRight(), bbox.GetBottom() };
        bool            removed = false;

        for( auto layer : aItem->GetLayerSet().Seq() )
        {
            if( ZONE_CONTAINER* zone = dyn_cast<ZONE_CONTAINER*>( aItem ) )
            {
                // Continue removing the zone elements from the tree until they cannot be found
                while( !m_tree[int( layer )]->Remove( mmin, mmax, aItem ) )
                    ;

                const int mmin2[2] = { INT_MIN, INT_MIN };
                const int mmax2[2] = { INT_MAX, INT_MAX };

            // If we are not successful ( true == not found ), then we expand
            // the search to the full tree
                while( !m_tree[int( layer )]->Remove( mmin2, mmax2, aItem ) )
                    ;

                // Loop to the next layer
                continue;
            }

            // The non-zone search expects only a single element in the tree with the same
            // pointer aItem
            if( m_tree[int( layer )]->Remove( mmin, mmax, aItem ) )
            {
                // N.B. We must search the whole tree for the pointer to remove
                // because the item may have been moved before we have the chance to
                // delete it from the tree
                const int mmin2[2] = { INT_MIN, INT_MIN };
                const int mmax2[2] = { INT_MAX, INT_MAX };

                if( m_tree[int( layer )]->Remove( mmin2, mmax2, aItem ) )
                    continue;
            }

            removed = true;
        }

        m_count -= int( removed );

        return removed;
    }

#endif

    /**
     * Function RemoveAll()
     * Removes all items from the RTree
     */
    void clear()
    {
        for( auto tree : m_tree )
            tree->RemoveAll();

        m_count = 0;
    }

#if 0
    /**
     * Determine if a given item exists in the tree.  Note that this does not search the full tree
     * so if the item has been moved, this will return false when it should be true.
     *
     * @param aItem Item that may potentially exist in the tree
     * @param aRobust If true, search the whole tree, not just the bounding box
     * @return true if the item definitely exists, false if it does not exist within bbox
     */
    bool contains( BOARD_ITEM* aItem, bool aRobust = false )
    {
        const EDA_RECT& bbox    = aItem->GetBoundingBox();
        const int       mmin[2] = { bbox.GetX(), bbox.GetY() };
        const int       mmax[2] = { bbox.GetRight(), bbox.GetBottom() };
        bool            found   = false;

        auto search = [&found, &aItem]( const ITEM_WITH_SHAPE* aSearchItem ) {
            if( aSearchItem->parent == aItem )
            {
                found = true;
                return false;
            }

            return true;
        };

        for( int layer : aItem->GetLayerSet().Seq() )
        {
            m_tree[layer]->Search( mmin, mmax, search );

            if( found )
                break;
        }

        if( !found && aRobust )
        {
            for( int layer : LSET::AllCuMask().Seq() )
            {
                // N.B. We must search the whole tree for the pointer to remove
                // because the item may have been moved.  We do not expand the item
                // layer search as this should not change.

                const int mmin2[2] = { INT_MIN, INT_MIN };
                const int mmax2[2] = { INT_MAX, INT_MAX };

                m_tree[layer]->Search( mmin2, mmax2, search );

                if( found )
                    break;
            }
        }

        return found;
    }

#endif

    bool CheckColliding( SHAPE* aRefShape,
                         PCB_LAYER_ID aTargetLayer,
                         int aClearance = 0,
                         std::function<bool( BOARD_ITEM*)> aFilter = nullptr )
    {
        BOX2I box = aRefShape->BBox();
        box.Inflate( aClearance );

        int min[2] = { box.GetX(),         box.GetY() };
        int max[2] = { box.GetRight(),     box.GetBottom() };

        int count = 0;

        auto visit = [&] ( ITEM_WITH_SHAPE* aItem ) -> bool
        {
            int actual;

            // keep searching
            if( aFilter && ! aFilter( aItem->parent ) )
                return true;

            bool colliding = aRefShape->Collide( aItem->shape, aClearance, &actual );

            if( colliding )
            {
                count++;
                return false;
            }

            return true;
        };

        this->m_tree[aTargetLayer]->Search( min, max, visit );
        return count > 0;
    }

    int QueryColliding( BOARD_ITEM* aRefItem,
                        PCB_LAYER_ID aRefLayer,
                        PCB_LAYER_ID aTargetLayer,
                        std::function<bool( BOARD_ITEM*)> aFilter = nullptr,
                        std::function<bool( BOARD_ITEM*, int)> aVisitor = nullptr,
                        int aClearance = 0
                        )
    {
        // keep track of BOARD_ITEMs that have been already found to collide (some items
        // might be build of COMPOUND/triangulated shapes and a single subshape collision
        // means we have a hit)
        std::unordered_set<BOARD_ITEM*> collidingCompounds;

        EDA_RECT box = aRefItem->GetBoundingBox();
        box.Inflate( aClearance );

        int min[2] = { box.GetX(),         box.GetY() };
        int max[2] = { box.GetRight(),     box.GetBottom() };

        std::shared_ptr<SHAPE> refShape = aRefItem->GetEffectiveShape( aRefLayer );

        int count = 0;

        auto visit = [&] ( ITEM_WITH_SHAPE* aItem ) -> bool
        {
            if( collidingCompounds.find( aItem->parent ) != collidingCompounds.end() )
                return true;

            if( aFilter && !aFilter( aItem->parent ) )
                return true;

            int actual;

            bool colliding = refShape->Collide( aItem->shape, aClearance, &actual );

            if( colliding )
            {
                collidingCompounds.insert( aItem->parent );
                count++;
                if( aVisitor )
                {
                    return aVisitor( aItem->parent, actual );
                }
                else
                {
                    return true;
                }
            }


            return true;
        };

        this->m_tree[aTargetLayer]->Search( min, max, visit );
        return count;
    }

    typedef std::pair<PCB_LAYER_ID, PCB_LAYER_ID> LAYER_PAIR;

    int QueryCollidingPairs( DRC_RTREE* aRefTree,
                             std::vector<LAYER_PAIR> aLayers,
                             std::function<bool( const LAYER_PAIR&,
                                                 ITEM_WITH_SHAPE*, ITEM_WITH_SHAPE*,
                                                 bool* aCollision )> aVisitor,
                             int aMaxClearance )
    {
        // keep track of BOARD_ITEMs pairs that have been already found to collide (some items
        // might be build of COMPOUND/triangulated shapes and a single subshape collision
        // means we have a hit)
        std::set< std::pair<BOARD_ITEM*, BOARD_ITEM*>> collidingCompounds;

        for( auto refLayerIter : aLayers )
        {
            const PCB_LAYER_ID refLayer = refLayerIter.first;
            const PCB_LAYER_ID targetLayer = refLayerIter.second;

            for( auto refItem : aRefTree->OnLayer( refLayer ) )
            {
                BOX2I box = refItem->shape->BBox();
                box.Inflate( aMaxClearance );

                int min[2] = { box.GetX(),         box.GetY() };
                int max[2] = { box.GetRight(),     box.GetBottom() };

                auto visit =
                        [&]( ITEM_WITH_SHAPE* aItemToTest ) -> bool
                        {
                            const std::pair<BOARD_ITEM*, BOARD_ITEM*>
                                    chkCompoundPair( refItem->parent, aItemToTest->parent );

                            // don't report multiple collisions for compound or triangulated shapes
                            if( alg::contains( collidingCompounds, chkCompoundPair ) )
                                return true;

                            // don't collide items against themselves
                            if( refLayer == targetLayer && aItemToTest->parent == refItem->parent )
                                return true;

                            bool collisionDetected = false;
                            bool continueSearch = aVisitor( refLayerIter, refItem, aItemToTest,
                                                            &collisionDetected );

                            if( collisionDetected )
                                collidingCompounds.insert( chkCompoundPair );

                            return continueSearch;
                        };

                this->m_tree[targetLayer]->Search( min, max, visit );
            };
        }
        return 0;
    }

#if 0
    std::vector<std::pair<int, BOARD_ITEM*>> GetNearest( const wxPoint &aPoint,
                                                                   PCB_LAYER_ID aLayer,
                                                                   int aLimit )
    {

        const int point[2] = { aPoint.x, aPoint.y };
        auto result = m_tree[int( aLayer )]->NearestNeighbors( point,
                [aLimit]( std::size_t a_count, int a_maxDist ) -> bool
                {
                    return a_count >= aLimit;
                },
                []( BOARD_ITEM* aElement) -> bool
                {
                    // Don't remove any elements from the list
                    return false;
                },
                [aLayer]( const int* a_point, BOARD_ITEM* a_data ) -> int
                {
                    switch( a_data->Type() )
                    {
                    case PCB_TRACE_T:
                    {
                        TRACK* track = static_cast<TRACK*>( a_data );
                        SEG seg( track->GetStart(), track->GetEnd() );
                        return seg.Distance( VECTOR2I( a_point[0], a_point[1] ) ) -
                                           ( track->GetWidth() + 1 ) / 2;
                    }
                    case PCB_VIA_T:
                    {
                        VIA* via = static_cast<VIA*>( a_data );
                        return ( VECTOR2I( via->GetPosition() ) -
                                 VECTOR2I( a_point[0], a_point[1] ) ).EuclideanNorm() -
                               ( via->GetWidth() + 1 ) / 2;

                    }
                    default:
                    {
                        VECTOR2I point( a_point[0], a_point[1] );
                        int      dist = 0;
                        auto     shape = a_data->GetEffectiveShape( aLayer );

                        // Here we use a hack to get the distance by colliding with a large area
                        // However, we can't use just MAX_INT because we will overflow the collision calculations
                        shape->Collide( point, std::numeric_limits<int>::max() / 2, &dist);
                        return dist;
                    }
                    }
                    return 0;
                });

        return result;
    }
#endif

    /**
     * Returns the number of items in the tree
     * @return number of elements in the tree;
     */
    size_t size()
    {
        return m_count;
    }

    bool empty()
    {
        return m_count == 0;
    }

    using iterator = typename drc_rtree::Iterator;

    /**
     * The DRC_LAYER struct provides a layer-specific auto-range iterator to the RTree.  Using
     * this struct, one can write lines like:
     *
     * for( auto item : rtree.OnLayer( In1_Cu ) )
     *
     * and iterate over only the RTree items that are on In1
     */
    struct DRC_LAYER
    {
        DRC_LAYER( drc_rtree* aTree ) : layer_tree( aTree )
        {
            m_rect = { { INT_MIN, INT_MIN }, { INT_MAX, INT_MAX } };
        };

        DRC_LAYER( drc_rtree* aTree, const EDA_RECT aRect ) : layer_tree( aTree )
        {
            m_rect = { { aRect.GetX(), aRect.GetY() },
                       { aRect.GetRight(), aRect.GetBottom() } };
        };

        drc_rtree::Rect m_rect;
        drc_rtree*      layer_tree;

        iterator begin()
        {
            return layer_tree->begin( m_rect );
        }

        iterator end()
        {
            return layer_tree->end( m_rect );
        }
    };

    DRC_LAYER OnLayer( PCB_LAYER_ID aLayer )
    {
        return DRC_LAYER( m_tree[int( aLayer )] );
    }

    DRC_LAYER Overlapping( PCB_LAYER_ID aLayer, const wxPoint& aPoint, int aAccuracy = 0 )
    {
        EDA_RECT rect( aPoint, wxSize( 0, 0 ) );
        rect.Inflate( aAccuracy );
        return DRC_LAYER( m_tree[int( aLayer )], rect );
    }

    DRC_LAYER Overlapping( PCB_LAYER_ID aLayer, const EDA_RECT& aRect )
    {
        return DRC_LAYER( m_tree[int( aLayer )], aRect );
    }


private:
    drc_rtree*  m_tree[PCB_LAYER_ID_COUNT];
    size_t      m_count;
};


#endif /* DRC_RTREE_H_ */