/*
 * Copyright (c) 2009-2010 jMonkeyEngine
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
 *   may be used to endorse or promote products derived from this software
 *   without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.aionemu.gameserver.geoEngine.math;

import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.util.logging.Logger;

/**
 * <code>Vector2f</code> defines a Vector for a two float value vector.
 * 
 * @author Mark Powell
 * @author Joshua Slack
 */
public final class Vector2f implements Cloneable {

	private static final Logger logger = Logger.getLogger(Vector2f.class.getName());

	public static final Vector2f ZERO = new Vector2f(0f, 0f);
	public static final Vector2f UNIT_XY = new Vector2f(1f, 1f);

	/**
	 * the x value of the vector.
	 */
	public float x;
	/**
	 * the y value of the vector.
	 */
	public float y;

	/**
	 * Creates a Vector2f with the given initial x and y values.
	 * 
	 * @param x
	 *          The x value of this Vector2f.
	 * @param y
	 *          The y value of this Vector2f.
	 */
	public Vector2f(float x, float y) {
		this.x = x;
		this.y = y;
	}

	/**
	 * Creates a Vector2f with x and y set to 0. Equivalent to Vector2f(0,0).
	 */
	public Vector2f() {
		x = y = 0;
	}

	/**
	 * Creates a new Vector2f that contains the passed vector's information
	 * 
	 * @param vector2f
	 *          The vector to copy
	 */
	public Vector2f(Vector2f vector2f) {
		this.x = vector2f.x;
		this.y = vector2f.y;
	}

	/**
	 * set the x and y values of the vector
	 * 
	 * @param x
	 *          the x value of the vector.
	 * @param y
	 *          the y value of the vector.
	 * @return this vector
	 */
	public Vector2f set(float x, float y) {
		this.x = x;
		this.y = y;
		return this;
	}

	/**
	 * set the x and y values of the vector from another vector
	 * 
	 * @param vec
	 *          the vector to copy from
	 * @return this vector
	 */
	public Vector2f set(Vector2f vec) {
		this.x = vec.x;
		this.y = vec.y;
		return this;
	}

	/**
	 * <code>add</code> adds a provided vector to this vector creating a resultant vector which is returned. If the
	 * provided vector is null, null is returned.
	 * 
	 * @param vec
	 *          the vector to add to this.
	 * @return the resultant vector.
	 */
	public Vector2f add(Vector2f vec) {
		if (null == vec) {
			logger.warning("Provided vector is null, null returned.");
			return null;
		}
		return new Vector2f(x + vec.x, y + vec.y);
	}

	/**
	 * <code>addLocal</code> adds a provided vector to this vector internally, and returns a handle to this vector for
	 * easy chaining of calls. If the provided vector is null, null is returned.
	 * 
	 * @param vec
	 *          the vector to add to this vector.
	 * @return this
	 */
	public Vector2f addLocal(Vector2f vec) {
		if (null == vec) {
			logger.warning("Provided vector is null, null returned.");
			return null;
		}
		x += vec.x;
		y += vec.y;
		return this;
	}

	/**
	 * <code>addLocal</code> adds the provided values to this vector internally, and returns a handle to this vector for
	 * easy chaining of calls.
	 * 
	 * @param addX
	 *          value to add to x
	 * @param addY
	 *          value to add to y
	 * @return this
	 */
	public Vector2f addLocal(float addX, float addY) {
		x += addX;
		y += addY;
		return this;
	}

	/**
	 * <code>add</code> adds this vector by <code>vec</code> and stores the result in <code>result</code>.
	 * 
	 * @param vec
	 *          The vector to add.
	 * @param result
	 *          The vector to store the result in.
	 * @return The result vector, after adding.
	 */
	public Vector2f add(Vector2f vec, Vector2f result) {
		if (null == vec) {
			logger.warning("Provided vector is null, null returned.");
			return null;
		}
		if (result == null)
			result = new Vector2f();
		result.x = x + vec.x;
		result.y = y + vec.y;
		return result;
	}

	/**
	 * <code>dot</code> calculates the dot product of this vector with a provided vector. If the provided vector is null,
	 * 0 is returned.
	 * 
	 * @param vec
	 *          the vector to dot with this vector.
	 * @return the resultant dot product of this vector and a given vector.
	 */
	public float dot(Vector2f vec) {
		if (null == vec) {
			logger.warning("Provided vector is null, 0 returned.");
			return 0;
		}
		return x * vec.x + y * vec.y;
	}

	/**
	 * <code>cross</code> calculates the cross product of this vector with a parameter vector v.
	 * 
	 * @param v
	 *          the vector to take the cross product of with this.
	 * @return the cross product vector.
	 */
	public Vector3f cross(Vector2f v) {
		return new Vector3f(0, 0, determinant(v));
	}

	public float determinant(Vector2f v) {
		return (x * v.y) - (y * v.x);
	}

	/**
	 * Sets this vector to the interpolation by changeAmnt from this to the finalVec this=(1-changeAmnt)*this + changeAmnt
	 * * finalVec
	 * 
	 * @param finalVec
	 *          The final vector to interpolate towards
	 * @param changeAmnt
	 *          An amount between 0.0 - 1.0 representing a percentage change from this towards finalVec
	 */
	public Vector2f interpolate(Vector2f finalVec, float changeAmnt) {
		this.x = (1 - changeAmnt) * this.x + changeAmnt * finalVec.x;
		this.y = (1 - changeAmnt) * this.y + changeAmnt * finalVec.y;
		return this;
	}

	/**
	 * Sets this vector to the interpolation by changeAmnt from beginVec to finalVec this=(1-changeAmnt)*beginVec +
	 * changeAmnt * finalVec
	 * 
	 * @param beginVec
	 *          The begining vector (delta=0)
	 * @param finalVec
	 *          The final vector to interpolate towards (delta=1)
	 * @param changeAmnt
	 *          An amount between 0.0 - 1.0 representing a precentage change from beginVec towards finalVec
	 */
	public Vector2f interpolate(Vector2f beginVec, Vector2f finalVec, float changeAmnt) {
		this.x = (1 - changeAmnt) * beginVec.x + changeAmnt * finalVec.x;
		this.y = (1 - changeAmnt) * beginVec.y + changeAmnt * finalVec.y;
		return this;
	}

	/**
	 * Check a vector... if it is null or its floats are NaN or infinite, return false. Else return true.
	 * 
	 * @param vector
	 *          the vector to check
	 * @return true or false as stated above.
	 */
	public static boolean isValidVector(Vector2f vector) {
		if (vector == null)
			return false;
		if (Float.isNaN(vector.x) || Float.isNaN(vector.y))
			return false;
		if (Float.isInfinite(vector.x) || Float.isInfinite(vector.y))
			return false;
		return true;
	}

	/**
	 * <code>length</code> calculates the magnitude of this vector.
	 * 
	 * @return the length or magnitude of the vector.
	 */
	public float length() {
		return FastMath.sqrt(lengthSquared());
	}

	/**
	 * <code>lengthSquared</code> calculates the squared value of the magnitude of the vector.
	 * 
	 * @return the magnitude squared of the vector.
	 */
	public float lengthSquared() {
		return x * x + y * y;
	}

	/**
	 * <code>distanceSquared</code> calculates the distance squared between this vector and vector v.
	 * 
	 * @param v
	 *          the second vector to determine the distance squared.
	 * @return the distance squared between the two vectors.
	 */
	public float distanceSquared(Vector2f v) {
		double dx = x - v.x;
		double dy = y - v.y;
		return (float) (dx * dx + dy * dy);
	}

	/**
	 * <code>distanceSquared</code> calculates the distance squared between this vector and vector v.
	 * 
	 * @param v
	 *          the second vector to determine the distance squared.
	 * @return the distance squared between the two vectors.
	 */
	public float distanceSquared(float otherX, float otherY) {
		double dx = x - otherX;
		double dy = y - otherY;
		return (float) (dx * dx + dy * dy);
	}

	/**
	 * <code>distance</code> calculates the distance between this vector and vector v.
	 * 
	 * @param v
	 *          the second vector to determine the distance.
	 * @return the distance between the two vectors.
	 */
	public float distance(Vector2f v) {
		return FastMath.sqrt(distanceSquared(v));
	}

	/**
	 * <code>mult</code> multiplies this vector by a scalar. The resultant vector is returned.
	 * 
	 * @param scalar
	 *          the value to multiply this vector by.
	 * @return the new vector.
	 */
	public Vector2f mult(float scalar) {
		return new Vector2f(x * scalar, y * scalar);
	}

	/**
	 * <code>multLocal</code> multiplies this vector by a scalar internally, and returns a handle to this vector for easy
	 * chaining of calls.
	 * 
	 * @param scalar
	 *          the value to multiply this vector by.
	 * @return this
	 */
	public Vector2f multLocal(float scalar) {
		x *= scalar;
		y *= scalar;
		return this;
	}

	/**
	 * <code>multLocal</code> multiplies a provided vector to this vector internally, and returns a handle to this vector
	 * for easy chaining of calls. If the provided vector is null, null is returned.
	 * 
	 * @param vec
	 *          the vector to mult to this vector.
	 * @return this
	 */
	public Vector2f multLocal(Vector2f vec) {
		if (null == vec) {
			logger.warning("Provided vector is null, null returned.");
			return null;
		}
		x *= vec.x;
		y *= vec.y;
		return this;
	}

	/**
	 * Multiplies this Vector2f's x and y by the scalar and stores the result in product. The result is returned for
	 * chaining. Similar to product=this*scalar;
	 * 
	 * @param scalar
	 *          The scalar to multiply by.
	 * @param product
	 *          The vector2f to store the result in.
	 * @return product, after multiplication.
	 */
	public Vector2f mult(float scalar, Vector2f product) {
		if (null == product) {
			product = new Vector2f();
		}

		product.x = x * scalar;
		product.y = y * scalar;
		return product;
	}

	/**
	 * <code>divide</code> divides the values of this vector by a scalar and returns the result. The values of this vector
	 * remain untouched.
	 * 
	 * @param scalar
	 *          the value to divide this vectors attributes by.
	 * @return the result <code>Vector</code>.
	 */
	public Vector2f divide(float scalar) {
		return new Vector2f(x / scalar, y / scalar);
	}

	/**
	 * <code>divideLocal</code> divides this vector by a scalar internally, and returns a handle to this vector for easy
	 * chaining of calls. Dividing by zero will result in an exception.
	 * 
	 * @param scalar
	 *          the value to divides this vector by.
	 * @return this
	 */
	public Vector2f divideLocal(float scalar) {
		x /= scalar;
		y /= scalar;
		return this;
	}

	/**
	 * <code>negate</code> returns the negative of this vector. All values are negated and set to a new vector.
	 * 
	 * @return the negated vector.
	 */
	public Vector2f negate() {
		return new Vector2f(-x, -y);
	}

	/**
	 * <code>negateLocal</code> negates the internal values of this vector.
	 * 
	 * @return this.
	 */
	public Vector2f negateLocal() {
		x = -x;
		y = -y;
		return this;
	}

	/**
	 * <code>subtract</code> subtracts the values of a given vector from those of this vector creating a new vector
	 * object. If the provided vector is null, an exception is thrown.
	 * 
	 * @param vec
	 *          the vector to subtract from this vector.
	 * @return the result vector.
	 */
	public Vector2f subtract(Vector2f vec) {
		return subtract(vec, null);
	}

	/**
	 * <code>subtract</code> subtracts the values of a given vector from those of this vector storing the result in the
	 * given vector object. If the provided vector is null, an exception is thrown.
	 * 
	 * @param vec
	 *          the vector to subtract from this vector.
	 * @param store
	 *          the vector to store the result in. It is safe for this to be the same as vec. If null, a new vector is
	 *          created.
	 * @return the result vector.
	 */
	public Vector2f subtract(Vector2f vec, Vector2f store) {
		if (store == null)
			store = new Vector2f();
		store.x = x - vec.x;
		store.y = y - vec.y;
		return store;
	}

	/**
	 * <code>subtract</code> subtracts the given x,y values from those of this vector creating a new vector object.
	 * 
	 * @param valX
	 *          value to subtract from x
	 * @param valY
	 *          value to subtract from y
	 * @return this
	 */
	public Vector2f subtract(float valX, float valY) {
		return new Vector2f(x - valX, y - valY);
	}

	/**
	 * <code>subtractLocal</code> subtracts a provided vector to this vector internally, and returns a handle to this
	 * vector for easy chaining of calls. If the provided vector is null, null is returned.
	 * 
	 * @param vec
	 *          the vector to subtract
	 * @return this
	 */
	public Vector2f subtractLocal(Vector2f vec) {
		if (null == vec) {
			logger.warning("Provided vector is null, null returned.");
			return null;
		}
		x -= vec.x;
		y -= vec.y;
		return this;
	}

	/**
	 * <code>subtractLocal</code> subtracts the provided values from this vector internally, and returns a handle to this
	 * vector for easy chaining of calls.
	 * 
	 * @param valX
	 *          value to subtract from x
	 * @param valY
	 *          value to subtract from y
	 * @return this
	 */
	public Vector2f subtractLocal(float valX, float valY) {
		x -= valX;
		y -= valY;
		return this;
	}

	/**
	 * <code>normalize</code> returns the unit vector of this vector.
	 * 
	 * @return unit vector of this vector.
	 */
	public Vector2f normalize() {
		float length = length();
		if (length != 0) {
			return divide(length);
		}

		return divide(1);
	}

	/**
	 * <code>normalizeLocal</code> makes this vector into a unit vector of itself.
	 * 
	 * @return this.
	 */
	public Vector2f normalizeLocal() {
		float length = length();
		if (length != 0) {
			return divideLocal(length);
		}

		return divideLocal(1);
	}

	/**
	 * <code>smallestAngleBetween</code> returns (in radians) the minimum angle between two vectors. It is assumed that
	 * both this vector and the given vector are unit vectors (iow, normalized).
	 * 
	 * @param otherVector
	 *          a unit vector to find the angle against
	 * @return the angle in radians.
	 */
	public float smallestAngleBetween(Vector2f otherVector) {
		float dotProduct = dot(otherVector);
		float angle = FastMath.acos(dotProduct);
		return angle;
	}

	/**
	 * <code>angleBetween</code> returns (in radians) the angle required to rotate a ray represented by this vector to lie
	 * colinear to a ray described by the given vector. It is assumed that both this vector and the given vector are unit
	 * vectors (iow, normalized).
	 * 
	 * @param otherVector
	 *          the "destination" unit vector
	 * @return the angle in radians.
	 */
	public float angleBetween(Vector2f otherVector) {
		float angle = FastMath.atan2(otherVector.y, otherVector.x) - FastMath.atan2(y, x);
		return angle;
	}

	public float getX() {
		return x;
	}

	public Vector2f setX(float x) {
		this.x = x;
		return this;
	}

	public float getY() {
		return y;
	}

	public Vector2f setY(float y) {
		this.y = y;
		return this;
	}

	/**
	 * <code>getAngle</code> returns (in radians) the angle represented by this Vector2f as expressed by a conversion from
	 * rectangular coordinates (<code>x</code>,&nbsp;<code>y</code>) to polar coordinates (r,&nbsp;<i>theta</i>).
	 * 
	 * @return the angle in radians. [-pi, pi)
	 */
	public float getAngle() {
		return -FastMath.atan2(y, x);
	}

	/**
	 * <code>zero</code> resets this vector's data to zero internally.
	 */
	public Vector2f zero() {
		x = y = 0;
		return this;
	}

	/**
	 * <code>hashCode</code> returns a unique code for this vector object based on it's values. If two vectors are
	 * logically equivalent, they will return the same hash code value.
	 * 
	 * @return the hash code value of this vector.
	 */
	public int hashCode() {
		int hash = 37;
		hash += 37 * hash + Float.floatToIntBits(x);
		hash += 37 * hash + Float.floatToIntBits(y);
		return hash;
	}

	@Override
	public Vector2f clone() {
		try {
			return (Vector2f) super.clone();
		}
		catch (CloneNotSupportedException e) {
			throw new AssertionError(); // can not happen
		}
	}

	/**
	 * Saves this Vector2f into the given float[] object.
	 * 
	 * @param floats
	 *          The float[] to take this Vector2f. If null, a new float[2] is created.
	 * @return The array, with X, Y float values in that order
	 */
	public float[] toArray(float[] floats) {
		if (floats == null) {
			floats = new float[2];
		}
		floats[0] = x;
		floats[1] = y;
		return floats;
	}

	/**
	 * are these two vectors the same? they are is they both have the same x and y values.
	 * 
	 * @param o
	 *          the object to compare for equality
	 * @return true if they are equal
	 */
	public boolean equals(Object o) {
		if (!(o instanceof Vector2f)) {
			return false;
		}

		if (this == o) {
			return true;
		}

		Vector2f comp = (Vector2f) o;
		if (Float.compare(x, comp.x) != 0)
			return false;
		if (Float.compare(y, comp.y) != 0)
			return false;
		return true;
	}

	/**
	 * <code>toString</code> returns the string representation of this vector object. The format of the string is such:
	 * com.jme.math.Vector2f [X=XX.XXXX, Y=YY.YYYY]
	 * 
	 * @return the string representation of this vector.
	 */
	public String toString() {
		return "(" + x + ", " + y + ")";
	}

	/**
	 * Used with serialization. Not to be called manually.
	 * 
	 * @param in
	 *          ObjectInput
	 * @throws IOException
	 * @throws ClassNotFoundException
	 * @see java.io.Externalizable
	 */
	public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
		x = in.readFloat();
		y = in.readFloat();
	}

	/**
	 * Used with serialization. Not to be called manually.
	 * 
	 * @param out
	 *          ObjectOutput
	 * @throws IOException
	 * @see java.io.Externalizable
	 */
	public void writeExternal(ObjectOutput out) throws IOException {
		out.writeFloat(x);
		out.writeFloat(y);
	}

	public Class<? extends Vector2f> getClassTag() {
		return this.getClass();
	}

	public void rotateAroundOrigin(float angle, boolean cw) {
		if (cw)
			angle = -angle;
		float newX = FastMath.cos(angle) * x - FastMath.sin(angle) * y;
		float newY = FastMath.sin(angle) * x + FastMath.cos(angle) * y;
		x = newX;
		y = newY;
	}
}