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#ifndef __CCGEMETRY_H__
#define __CCGEMETRY_H__

#include <math.h>
#include <functional>

#include "platform/CCPlatformMacros.h"
#include "CCObject.h"
#include "ccMacros.h"

NS_CC_BEGIN

/** Clamp a value between from and to.
 @since v0.99.1
 */
inline float clampf(float value, float min_inclusive, float max_inclusive)
{
    if (min_inclusive > max_inclusive) {
        CC_SWAP(min_inclusive, max_inclusive, float);
    }
    return value < min_inclusive ? min_inclusive : value < max_inclusive? value : max_inclusive;
}

/**
 * @addtogroup data_structures
 * @{
 */

// for Point assignement operator and copy constructor
class CC_DLL Size;

class CC_DLL Point
{
public:
    float x;
    float y;

public:
    Point();
    Point(float x, float y);
    Point(const Point& other);
    explicit Point(const Size& size);
    Point& operator= (const Point& other);
    Point& operator= (const Size& size);
    Point operator+(const Point& right) const;
    Point operator-(const Point& right) const;
    Point operator-() const;
    Point operator*(float a) const;
    Point operator/(float a) const;
    void setPoint(float x, float y);
    bool equals(const Point& target) const;
    
    /** @returns if points have fuzzy equality which means equal with some degree of variance.
     @since v2.1.4
     */
    bool fuzzyEquals(const Point& target, float variance) const;

    /** Calculates distance between point an origin
     @return float
     @since v2.1.4
     */
    inline float getLength() const {
        return sqrtf(x*x + y*y);
    };

    /** Calculates the square length of a Point (not calling sqrt() )
     @return float
     @since v2.1.4
     */
    inline float getLengthSq() const {
        return dot(*this); //x*x + y*y;
    };

    /** Calculates the square distance between two points (not calling sqrt() )
     @return float
     @since v2.1.4
    */
    inline float getDistanceSq(const Point& other) const {
        return (*this - other).getLengthSq();
    };

    /** Calculates the distance between two points
     @return float
     @since v2.1.4
     */
    inline float getDistance(const Point& other) const {
        return (*this - other).getLength();
    };

    /** @returns the angle in radians between this vector and the x axis
     @since v2.1.4
    */
    inline float getAngle() const {
        return atan2f(y, x);
    };

    /** @returns the angle in radians between two vector directions
     @since v2.1.4
    */
    float getAngle(const Point& other) const;

    /** Calculates dot product of two points.
     @return float
     @since v2.1.4
     */
    inline float dot(const Point& other) const {
        return x*other.x + y*other.y;
    };

    /** Calculates cross product of two points.
     @return float
     @since v2.1.4
     */
    inline float cross(const Point& other) const {
        return x*other.y - y*other.x;
    };

    /** Calculates perpendicular of v, rotated 90 degrees counter-clockwise -- cross(v, perp(v)) >= 0
     @return Point
     @since v2.1.4
     */
    inline Point getPerp() const {
        return Point(-y, x);
    };
    
    /** Calculates midpoint between two points.
     @return Point
     @since v3.0
     */
    inline Point getMidpoint(const Point& other) const
    {
        return Point((x + other.x) / 2.0f, (y + other.y) / 2.0f);
    }
    
    /** Clamp a point between from and to.
     @since v3.0
     */
    inline Point getClampPoint(const Point& min_inclusive, const Point& max_inclusive) const
    {
        return Point(clampf(x,min_inclusive.x,max_inclusive.x), clampf(y, min_inclusive.y, max_inclusive.y));
    }
    
    /** Run a math operation function on each point component
     * absf, fllorf, ceilf, roundf
     * any function that has the signature: float func(float);
     * For example: let's try to take the floor of x,y
     * p.compOp(floorf);
     @since v3.0
     */
    inline Point compOp(std::function<float(float)> function) const
    {
        return Point(function(x), function(y));
    }

    /** Calculates perpendicular of v, rotated 90 degrees clockwise -- cross(v, rperp(v)) <= 0
     @return Point
     @since v2.1.4
     */
    inline Point getRPerp() const {
        return Point(y, -x);
    };

    /** Calculates the projection of this over other.
     @return Point
     @since v2.1.4
     */
    inline Point project(const Point& other) const {
        return other * (dot(other)/other.dot(other));
    };

    /** Complex multiplication of two points ("rotates" two points).
     @return Point vector with an angle of this.getAngle() + other.getAngle(),
     and a length of this.getLength() * other.getLength().
     @since v2.1.4
     */
    inline Point rotate(const Point& other) const {
        return Point(x*other.x - y*other.y, x*other.y + y*other.x);
    };

    /** Unrotates two points.
     @return Point vector with an angle of this.getAngle() - other.getAngle(),
     and a length of this.getLength() * other.getLength().
     @since v2.1.4
     */
    inline Point unrotate(const Point& other) const {
        return Point(x*other.x + y*other.y, y*other.x - x*other.y);
    };

    /** Returns point multiplied to a length of 1.
     * If the point is 0, it returns (1, 0)
     @return Point
     @since v2.1.4
     */
    inline Point normalize() const {
        float length = getLength();
        if(length == 0.) return Point(1.f, 0);
        return *this / getLength();
    };

    /** Linear Interpolation between two points a and b
     @returns
        alpha == 0 ? a
        alpha == 1 ? b
        otherwise a value between a..b
     @since v2.1.4
     */
    inline Point lerp(const Point& other, float alpha) const {
        return *this * (1.f - alpha) + other * alpha;
    };

    /** Rotates a point counter clockwise by the angle around a pivot
     @param pivot is the pivot, naturally
     @param angle is the angle of rotation ccw in radians
     @returns the rotated point
     @since v2.1.4
     */
    Point rotateByAngle(const Point& pivot, float angle) const;

    static inline Point forAngle(const float a)
    {
    	return Point(cosf(a), sinf(a));
    }
    
    /** A general line-line intersection test
     @param A   the startpoint for the first line L1 = (A - B)
     @param B   the endpoint for the first line L1 = (A - B)
     @param C   the startpoint for the second line L2 = (C - D)
     @param D   the endpoint for the second line L2 = (C - D)
     @param S   the range for a hitpoint in L1 (p = A + S*(B - A))
     @param T   the range for a hitpoint in L2 (p = C + T*(D - C))
     @returns   whether these two lines interects.

     Note that to truly test intersection for segments we have to make
     sure that S & T lie within [0..1] and for rays, make sure S & T > 0
     the hit point is        C + T * (D - C);
     the hit point also is   A + S * (B - A);
     @since 3.0
     */
    static bool isLineIntersect(const Point& A, const Point& B,
                                 const Point& C, const Point& D,
                                 float *S = nullptr, float *T = nullptr);
    
    /*
     returns true if Line A-B overlap with segment C-D
     @since v3.0
     */
    static bool isLineOverlap(const Point& A, const Point& B,
                                const Point& C, const Point& D);
    
    /*
     returns true if Line A-B parallel with segment C-D
     @since v3.0
     */
    static bool isLineParallel(const Point& A, const Point& B,
                   const Point& C, const Point& D);
    
    /*
     returns true if Segment A-B overlap with segment C-D
     @since v3.0
     */
    static bool isSegmentOverlap(const Point& A, const Point& B,
                                 const Point& C, const Point& D,
                                 Point* S = nullptr, Point* E = nullptr);
    
    /*
     returns true if Segment A-B intersects with segment C-D
     @since v3.0
     */
    static bool isSegmentIntersect(const Point& A, const Point& B, const Point& C, const Point& D);
    
    /*
     returns the intersection point of line A-B, C-D
     @since v3.0
     */
    static Point getIntersectPoint(const Point& A, const Point& B, const Point& C, const Point& D);
    
    static const Point ZERO;
    
private:
    // returns true if segment A-B intersects with segment C-D. S->E is the ovderlap part
    static bool isOneDemensionSegmentOverlap(float A, float B, float C, float D, float *S, float * E);
    
    // cross procuct of 2 vector. A->B X C->D
    static float crossProduct2Vector(const Point& A, const Point& B, const Point& C, const Point& D) { return (D.y - C.y) * (B.x - A.x) - (D.x - C.x) * (B.y - A.y); }
};

class CC_DLL Size
{
public:
    float width;
    float height;

public:
    Size();
    Size(float width, float height);
    Size(const Size& other);
    explicit Size(const Point& point);
    Size& operator= (const Size& other);
    Size& operator= (const Point& point);
    Size operator+(const Size& right) const;
    Size operator-(const Size& right) const;
    Size operator*(float a) const;
    Size operator/(float a) const;
    void setSize(float width, float height);
    bool equals(const Size& target) const;
    
    static const Size ZERO;
};

class CC_DLL Rect
{
public:
    Point origin;
    Size  size;

public:
    Rect();
    Rect(float x, float y, float width, float height);
    Rect(const Rect& other);
    Rect& operator= (const Rect& other);
    void setRect(float x, float y, float width, float height);
    float getMinX() const; /// return the leftmost x-value of current rect
    float getMidX() const; /// return the midpoint x-value of current rect
    float getMaxX() const; /// return the rightmost x-value of current rect
    float getMinY() const; /// return the bottommost y-value of current rect
    float getMidY() const; /// return the midpoint y-value of current rect
    float getMaxY() const; /// return the topmost y-value of current rect
    bool equals(const Rect& rect) const;   
    bool containsPoint(const Point& point) const;
    bool intersectsRect(const Rect& rect) const;
    Rect unionWithRect(const Rect & rect) const;
    
    static const Rect ZERO;
};

// end of data_structure group
/// @}

NS_CC_END

#endif // __CCGEMETRY_H__