/****************************************************************************
Copyright (c) 2008-2010 Ricardo Quesada
Copyright (c) 2010-2012 cocos2d-x.org
Copyright (c) 2011      Zynga Inc.
Copyright (c) 2013-2016 Chukong Technologies Inc.
Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.

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#ifndef COCOS_2D_CCAUTOPOLYGON_H__
#define COCOS_2D_CCAUTOPOLYGON_H__

#include <string>
#include <vector>
#include "platform/CCImage.h"
#include "renderer/CCTrianglesCommand.h"

NS_CC_BEGIN

/**
 * @addtogroup _2d
 * @{
 */

/**
 * PolygonInfo is an object holding the required data to display Sprites.
 * It can be a simple as a triangle, or as complex as a whole 3D mesh
 */
class CC_DLL PolygonInfo
{
public:
    /// @name Creators
    /// @{
    /**
     * Creates an empty Polygon info
     * @memberof PolygonInfo
     * @return PolygonInfo object
     */
    PolygonInfo();

    /**
     * Create an polygoninfo from the data of another Polygoninfo
     * @param other     another PolygonInfo to be copied
     * @return duplicate of the other PolygonInfo
     */
    PolygonInfo(const PolygonInfo& other);
    //  end of creators group
    /// @}

    /**
     * Copy the member of the other PolygonInfo
     * @param other     another PolygonInfo to be copied
     */
    PolygonInfo& operator=(const PolygonInfo& other);
    ~PolygonInfo();

    /**
     * set the data to be a pointer to a quad
     * the member verts will not be released when this PolygonInfo destructs
     * as the verts memory are managed by other objects
     * @param quad  a pointer to the V3F_C4B_T2F_Quad object
     */
    void setQuad(V3F_C4B_T2F_Quad* quad);

    /**
     * set the data to be a pointer to a number of Quads
     * the member verts will not be released when this PolygonInfo destructs
     * as the verts memory are managed by other objects
     * @param quad  a pointer to the V3F_C4B_T2F_Quad quads
     */
    void setQuads(V3F_C4B_T2F_Quad* quads, int numberOfQuads);

    /**
     * set the data to be a pointer to a triangles
     * the member verts will not be released when this PolygonInfo destructs
     * as the verts memory are managed by other objects
     * @param triangles  a pointer to the TrianglesCommand::Triangles object
     */
    void setTriangles(const TrianglesCommand::Triangles& triangles);

    /**
     * get vertex count
     * @return number of vertices
     */
    unsigned int getVertCount() const;

    /**
     * get triangles count
     * @return number of triangles
     */
    unsigned int getTrianglesCount() const;

    /**
     * get sum of all triangle area size
     * @return sum of all triangle area size
     */
    float getArea() const;

    const Rect& getRect() const { return _rect; }
    void setRect(const Rect& rect) { _rect = rect; }
    const std::string& getFilename() const { return _filename; }
    void setFilename(const std::string& filename) { _filename = filename; }

    // FIXME: this should be a property, not a public ivar
    TrianglesCommand::Triangles triangles;

protected:
    bool _isVertsOwner;
    Rect _rect;
    std::string _filename;

private:
    void releaseVertsAndIndices();
};

/**
 * AutoPolygon is a helper Object
 * AutoPolygon's purpose is to process an image into 2d polygon mesh in runtime
 * It has functions for each step in the process, from tracing all the points, to triangulation
 * the result can be then passed to Sprite::create() to create a Polygon Sprite
 */
class CC_DLL AutoPolygon
{
public:
    /**
     * create an AutoPolygon and initialize it with an image file
     * the image must be a 32bit PNG for current version 3.7
     * @param   filename    a path to image file, e.g., "scene1/monster.png".
     * @return  an AutoPolygon object;
     */
    AutoPolygon(const std::string& filename);

    /**
     * Destructor of AutoPolygon.
     */
    ~AutoPolygon();

    /**
     * trace all the points along the outline of the image,
     * @warning must create AutoPolygon with filename to use this function
     * @param   rect    a texture rect for specify an area of the image
     * @param   threshold   the value when alpha is greater than this value will be counted as opaque, default to 0.0
     * @return  a vector of vec2 of all the points found in clockwise order
     * @code
     * auto ap = AutoPolygon("grossini.png");
     * auto rect = Rect(100, 100, 200, 200);
     * std::vector<Vec2> points = ap.trace(rect);//default threshold is 0.0
     * @endcode
     */
    std::vector<Vec2> trace(const cocos2d::Rect& rect, float threshold = 0.0f);

    /**
     * reduce the amount of points so its faster for GPU to process and draw
     * based on Ramer-Douglas-Peucker algorithm
     * @param   points  a vector of Vec2 points as input
     * @param   rect    a texture rect for specify an area of the image to avoid over reduction
     * @param   epsilon the perpendicular distance where points smaller than this value will be discarded
     * @return  a vector of Vec2 of the remaining points in clockwise order
     * @code
     * auto ap = AutoPolygon();
     * std::vector<Vec2> reduced = ap.reduce(inputPoints, rect);//default epsilon is 2
     * @endcode
     */
    std::vector<Vec2> reduce(const std::vector<Vec2>& points, const Rect& rect, float epsilon = 2.0f);

    /**
     * expand the points along their edge, useful after you reduce the points that cuts into the sprite
     * using ClipperLib
     * @param   points  a vector of Vec2 points as input
     * @param   rect    a texture rect for specify an area of the image, the expanded points will be clamped in this
     * rect, ultimately resulting in a quad if the expansion is too great
     * @param   epsilon the distance which the edges will expand
     * @return  a vector of Vec2 as the result of the expansion
     * @code
     * auto ap = AutoPolygon();
     * std::vector<Vec2> expanded = ap.expand(inputPoints, rect, 2.0);
     * @endcode
     */
    std::vector<Vec2> expand(const std::vector<Vec2>& points, const Rect& rect, float epsilon);

    /**
     * Triangulate the input points into triangles for rendering
     * using poly2tri
     * @warning points must be closed loop, cannot have 2 points sharing the same position and cannot intersect itself
     * @param   points  a vector of vec2 points as input
     * @return  a Triangles object with points and indices
     * @code
     * auto ap = AutoPolygon();
     * TrianglesCommand::Triangles myPolygons = ap.triangulate(myPoints);
     * @endcode
     */
    TrianglesCommand::Triangles triangulate(const std::vector<Vec2>& points);

    /**
     * calculate the UV coordinates for each points based on a texture rect
     * @warning This method requires the AutoPolygon object to know the texture file dimension
     * @param   rect    a texture rect to specify where to map the UV
     * @param   verts   a pointer to the verts array, served both as input and output verts
     * @param   count   the count for the verts array
     * @code
     * auto ap = AutoPolygon("grossini.png");
     * TrianglesCommand::Triangles myPolygons = ap.triangulate(myPoints);
     * ap.calculateUV(rect, myPolygons.verts, 20);
     * @endcode
     */
    void calculateUV(const Rect& rect, V3F_C4B_T2F* verts, ssize_t count);

    /**
     * a helper function, packing trace, reduce, expand, triangulate and calculate uv in one function
     * @param   rect    texture rect, use Rect::ZERO for the size of the texture, default is Rect::ZERO
     * @param   epsilon the value used to reduce and expand, default to 2.0
     * @param   threshold   the value where bigger than the threshold will be counted as opaque, used in trace
     * @return  a PolygonInfo, to use with sprite
     * @code
     * auto ap = AutoPolygon("grossini.png");
     * PolygonInfo myInfo = ap.generateTriangles();//use all default values
     * auto sp1 = Sprite::create(myInfo);
     * polygonInfo myInfo2 = ap.generateTriangles(Rect::ZERO, 5.0, 0.1);//ap can be reused to generate another set of
     * PolygonInfo with different settings auto sp2 = Sprite::create(myInfo2);
     * @endcode
     */
    PolygonInfo generateTriangles(const Rect& rect = Rect::ZERO, float epsilon = 2.0f, float threshold = 0.05f);

    /**
     * a helper function, packing autoPolygon creation, trace, reduce, expand, triangulate and calculate uv in one
     * function
     * @warning if you want to repetitively generate polygons, consider create an AutoPolygon object, and use
     * generateTriangles function, as it only reads the file once
     * @param   filename     A path to image file, e.g., "scene1/monster.png".
     * @param   rect    texture rect, use Rect::ZERO for the size of the texture, default is Rect::ZERO
     * @param   epsilon the value used to reduce and expand, default to 2.0
     * @param   threshold   the value where bigger than the threshold will be counted as opaque, used in trace
     * @return  a PolygonInfo, to use with sprite
     * @code
     * auto sp = Sprite::create(AutoPolygon::generatePolygon("grossini.png"));
     * @endcode
     */
    static PolygonInfo generatePolygon(const std::string& filename,
                                       const Rect& rect = Rect::ZERO,
                                       float epsilon    = 2.0f,
                                       float threshold  = 0.05f);

protected:
    Vec2 findFirstNoneTransparentPixel(const Rect& rect, float threshold);
    std::vector<cocos2d::Vec2> marchSquare(const Rect& rect, const Vec2& first, float threshold);
    unsigned int getSquareValue(unsigned int x, unsigned int y, const Rect& rect, float threshold);

    unsigned char getAlphaByIndex(unsigned int i);
    unsigned char getAlphaByPos(const Vec2& pos);

    int getIndexFromPos(unsigned int x, unsigned int y) { return y * _width + x; }
    cocos2d::Vec2 getPosFromIndex(unsigned int i)
    {
        return cocos2d::Vec2(static_cast<float>(i % _width), static_cast<float>(i / _width));
    }

    std::vector<cocos2d::Vec2> rdp(const std::vector<cocos2d::Vec2>& v, float optimization);
    float perpendicularDistance(const cocos2d::Vec2& i, const cocos2d::Vec2& start, const cocos2d::Vec2& end);

    // real rect is the size that is in scale with the texture file
    Rect getRealRect(const Rect& rect);

    Image* _image;
    unsigned char* _data;
    std::string _filename;
    unsigned int _width;
    unsigned int _height;
    float _scaleFactor;
    unsigned int _threshold;
};

NS_CC_END

#endif  // #ifndef COCOS_2D_CCAUTOPOLYGON_H__