/*
* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
* its licensors.
*
* For complete copyright and license terms please see the LICENSE at the root of this
* distribution (the "License"). All use of this software is governed by the License,
* or, if provided, by the license below or the license accompanying this file. Do not
* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*
*/
// Original file Copyright Crytek GMBH or its affiliates, used under license.

#ifndef CRYINCLUDE_CRYAISYSTEM_POLYGONSETOPS_POLYGON2D_H
#define CRYINCLUDE_CRYAISYSTEM_POLYGONSETOPS_POLYGON2D_H
#pragma once

#include "Utils.h"

#include "LineSeg.h"
#include "BiDirMap.h"

class BspLineSegSplitter;
class BspTree2d;

/**
 * @brief 2D polygon class with support for set operations and subsequent contour extraction.
 */
class Polygon2d
{
public:

    /**
     * Not really a stand-alone polygon edge class, vertices are only stored as
     * indices into the owning Polygon2d::m_vertices.
     */
    class Edge
    {
    public:
        Edge (int ind0 = -1, int ind1 = -1);

        bool operator< (const Edge& rhs) const;
        bool operator== (const Edge& rhs) const;

        int m_vertIndex0;
        int m_vertIndex1;
    };

    Polygon2d ();
    Polygon2d (const LineSegVec& edges);
    Polygon2d (const Polygon2d& rhs);
    ~Polygon2d ();

    Polygon2d& operator= (const Polygon2d& rhs);

    int AddVertex (const Vector2d&);
    int AddEdge (const Edge&);
    int AddEdge (const Vector2d& v0, const Vector2d& v1);

    bool GetVertex (int i, Vector2d& vertex) const;
    bool GetEdge (int i, Edge& edge) const;

    int NumVertices () const;
    int NumEdges () const;

    // calculates the contiguous pts from the edges. If removeInterior then any contours that are encircled
    // by another contour get removed. All are guaranteed to be anti-clockwise wound
    void CalculateContours (bool removeInterior);
    // returns the number of unique contours
    unsigned GetContourQuantity() const;
    // gets the ith contour - returns the number of points
    unsigned GetContour(unsigned i, const Vector2d** ppPts) const;

    /// Set inversion operator.
    Polygon2d operator~ () const;

    /// Set union operator.
    Polygon2d operator| (const Polygon2d& rhs) const;

    /// Set intersection operator.
    Polygon2d operator& (const Polygon2d& rhs) const;

    /// Symmetric difference (AKA xor) operator.
    Polygon2d operator^ (const Polygon2d& rhs) const;

    /// Complement (or set difference) operator.
    Polygon2d operator- (const Polygon2d& rhs) const;

    // this only makes sense if there's only one contour
    bool IsWoundAnticlockwise() const;

    void CollapseVertices(double tol);

private:

    /// Computes BspTree2d using this polygon's edges as dividing hyperplanes and caches it in m_bsp.
    void ComputeBspTree () const;
    /// Cuts all of this polygon's edges by edge splitter passed in the argument.
    void Cut (BspLineSegSplitter&) const;

    BidirectionalMap<int, Vector2d> m_vertices;
    BidirectionalMap<int, Edge> m_edges;

    /// Cached corresponding BSP tree, useful during set operations.
    mutable BspTree2d* m_bsp;

    std::vector <std::vector<Vector2d> > m_contours;
};

#endif // CRYINCLUDE_CRYAISYSTEM_POLYGONSETOPS_POLYGON2D_H