/*
*
*   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 2 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, write to the Free Software Foundation,
*   Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*
*   In addition, as a special exception, the author gives permission to
*   link the code of this program with the Half-Life Game Engine ("HL
*   Engine") and Modified Game Libraries ("MODs") developed by Valve,
*   L.L.C ("Valve").  You must obey the GNU General Public License in all
*   respects for all of the code used other than the HL Engine and MODs
*   from Valve.  If you modify this file, you may extend this exception
*   to your version of the file, but you are not obligated to do so.  If
*   you do not wish to do so, delete this exception statement from your
*   version.
*
*/
#pragma once

// 2DVector - used for many pathfinding and many other 
// operations that are treated as planar rather than 3d.
class Vector2D {
public:
	inline Vector2D() : x(0.0), y(0.0) {}
	inline Vector2D(float X, float Y) : x(0.0), y(0.0) { x = X; y = Y; }
	inline Vector2D operator+(const Vector2D &v) const { return Vector2D(x + v.x, y + v.y); }
	inline Vector2D operator-(const Vector2D &v) const { return Vector2D(x - v.x, y - v.y); }
	inline Vector2D operator*(float fl) const { return Vector2D(x * fl, y * fl); }
	inline Vector2D operator/(float fl) const { return Vector2D(x / fl, y / fl); }
	inline Vector2D operator/=(float fl) const { return Vector2D(x / fl, y / fl); }
	inline float Length() const { return sqrt(x * x + y * y); }
	inline float LengthSquared() const { return (x * x + y * y); }

	operator float*() { return &x; }
	operator const float*() const { return &x; }

	inline Vector2D Normalize() const
	{
		float flLen = Length();
		if (flLen == 0)
			return Vector2D(0, 0);

		flLen = 1 / flLen;
		return Vector2D(x * flLen, y * flLen);
	}

	inline bool IsLengthLessThan(float length) const { return (LengthSquared() < length * length); }
	inline bool IsLengthGreaterThan(float length) const { return (LengthSquared() > length * length); }
	inline float NormalizeInPlace()
	{
		float flLen = Length();
		if (flLen == 0)
		{
			x = 1; y = 0;
		}
		else
		{
			flLen = 1 / flLen;
			x *= flLen; y *= flLen;
		}

		return flLen;
	}
	inline bool IsZero(float tolerance = 0.01f) const
	{
		return (x > -tolerance && x < tolerance &&
			y > -tolerance && y < tolerance);
	}

	// Members
	vec_t x, y;
};

inline float DotProduct(const Vector2D &a, const Vector2D &b) { return (a.x * b.x + a.y * b.y); }
inline Vector2D operator*(float fl, const Vector2D &v) { return v * fl; }

// 3D Vector
// same data-layout as engine's vec3_t, which is a vec_t[3]
class Vector {
public:
	// Construction/destruction
	inline Vector() : x(0.0), y(0.0), z(0.0) {}
	inline Vector(float X, float Y, float Z) : x(0.0), y(0.0), z(0.0) { x = X; y = Y; z = Z; }

	inline Vector(const Vector &v) : x(0.0), y(0.0), z(0.0) { x = v.x; y = v.y; z = v.z; }
	inline Vector(const float rgfl[3]) : x(0.0), y(0.0), z(0.0) { x = rgfl[0]; y = rgfl[1]; z = rgfl[2]; }

	// Operators
	inline Vector operator-() const { return Vector(-x, -y, -z); }
	inline int operator==(const Vector &v) const { return x == v.x && y == v.y && z == v.z; }
	inline int operator!=(const Vector &v) const { return !(*this == v); }
	inline Vector operator+(const Vector &v) const { return Vector(x + v.x, y + v.y, z + v.z); }
	inline Vector operator-(const Vector &v) const { return Vector(x - v.x, y - v.y, z - v.z); }
	inline Vector operator*(float fl) const { return Vector(x * fl, y * fl, z * fl); }
	inline Vector operator/(float fl) const { return Vector(x / fl, y / fl, z / fl); }
	inline Vector operator/=(float fl) const{ return Vector(x / fl, y / fl, z / fl); }

	// Methods
	inline void CopyToArray(float *rgfl) const { rgfl[0] = x; rgfl[1] = y; rgfl[2] = z; }
	inline float Length() const { return sqrt(x * x + y * y + z * z); }
	inline float LengthSquared() const { return (x * x + y * y + z * z); }

	operator float*() { return &x; }				// Vectors will now automatically convert to float * when needed
	operator const float*() const { return &x; }			// Vectors will now automatically convert to float * when needed

	inline Vector Normalize()
	{
		float flLen = Length();
		if (flLen == 0)
			return Vector(0, 0, 1);

		flLen = 1 / flLen;
		return Vector(x * flLen, y * flLen, z * flLen);
	}
	inline Vector2D Make2D() const { return Vector2D(x, y); }
	inline float Length2D() const { return sqrt(x * x + y * y); }

	inline bool IsLengthLessThan(float length) const { return (LengthSquared() < length * length); }
	inline bool IsLengthGreaterThan(float length) const { return (LengthSquared() > length * length); }

	inline float NormalizeInPlace()
	{
		float flLen = Length();
		if (flLen == 0)
		{
			x = 0; y = 0; z = 1;
		}
		else
		{
			flLen = 1 / flLen;
			x *= flLen; y *= flLen; z *= flLen;
		}

		return flLen;
	}
	inline bool IsZero(float tolerance = 0.01f) const
	{
		return (x > -tolerance && x < tolerance &&
			y > -tolerance && y < tolerance &&
			z > -tolerance && z < tolerance);
	}

	// Members
	vec_t x, y, z;
};

inline Vector operator*(float fl, const Vector &v) { return v * fl; }
inline float DotProduct(const Vector &a, const Vector &b) { return (a.x * b.x + a.y * b.y + a.z * b.z); }
inline float DotProduct2D(const Vector &a, const Vector &b) { return (a.x * b.x + a.y * b.y); }
inline Vector CrossProduct(const Vector &a, const Vector &b) { return Vector(a.y * b.z - a.z * b.y, a.z * b.x - a.x * b.z, a.x * b.y - a.y * b.x); }

template<class T>
inline void SWAP(T &first, T &second)
{
	T temp = first;
	first = second;
	second = temp;
}