/*
 * WorldEdit, a Minecraft world manipulation toolkit
 * Copyright (C) sk89q <http://www.sk89q.com>
 * Copyright (C) WorldEdit team and contributors
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by the
 * Free Software Foundation, either version 3 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 Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

package com.sk89q.worldedit;

/**
 *
 * @author sk89q
 */
public class Vector implements Comparable<Vector> {
    public static final Vector ZERO = new Vector(0, 0, 0);
    public static final Vector UNIT_X = new Vector(1, 0, 0);
    public static final Vector UNIT_Y = new Vector(0, 1, 0);
    public static final Vector UNIT_Z = new Vector(0, 0, 1);
    public static final Vector ONE = new Vector(1, 1, 1);

    protected final double x, y, z;

    /**
     * Construct the Vector object.
     *
     * @param x
     * @param y
     * @param z
     */
    public Vector(double x, double y, double z) {
        this.x = x;
        this.y = y;
        this.z = z;
    }

    /**
     * Construct the Vector object.
     *
     * @param x
     * @param y
     * @param z
     */
    public Vector(int x, int y, int z) {
        this.x = (double) x;
        this.y = (double) y;
        this.z = (double) z;
    }

    /**
     * Construct the Vector object.
     *
     * @param x
     * @param y
     * @param z
     */
    public Vector(float x, float y, float z) {
        this.x = (double) x;
        this.y = (double) y;
        this.z = (double) z;
    }

    /**
     * Construct the Vector object.
     *
     * @param pt
     */
    public Vector(Vector pt) {
        this.x = pt.x;
        this.y = pt.y;
        this.z = pt.z;
    }

    /**
     * Construct the Vector object.
     */
    public Vector() {
        this.x = 0;
        this.y = 0;
        this.z = 0;
    }

    /**
     * @return the x
     */
    public double getX() {
        return x;
    }

    /**
     * @return the x
     */
    public int getBlockX() {
        return (int) Math.round(x);
    }

    /**
     * Set X.
     *
     * @param x
     * @return new vector
     */
    public Vector setX(double x) {
        return new Vector(x, y, z);
    }

    /**
     * Set X.
     *
     * @param x
     * @return new vector
     */
    public Vector setX(int x) {
        return new Vector(x, y, z);
    }

    /**
     * @return the y
     */
    public double getY() {
        return y;
    }

    /**
     * @return the y
     */
    public int getBlockY() {
        return (int) Math.round(y);
    }

    /**
     * Set Y.
     *
     * @param y
     * @return new vector
     */
    public Vector setY(double y) {
        return new Vector(x, y, z);
    }

    /**
     * Set Y.
     *
     * @param y
     * @return new vector
     */
    public Vector setY(int y) {
        return new Vector(x, y, z);
    }

    /**
     * @return the z
     */
    public double getZ() {
        return z;
    }

    /**
     * @return the z
     */
    public int getBlockZ() {
        return (int) Math.round(z);
    }

    /**
     * Set Z.
     *
     * @param z
     * @return new vector
     */
    public Vector setZ(double z) {
        return new Vector(x, y, z);
    }

    /**
     * Set Z.
     *
     * @param z
     * @return new vector
     */
    public Vector setZ(int z) {
        return new Vector(x, y, z);
    }

    /**
     * Adds two points.
     *
     * @param other
     * @return New point
     */
    public Vector add(Vector other) {
        return new Vector(x + other.x, y + other.y, z + other.z);
    }

    /**
     * Adds two points.
     *
     * @param x
     * @param y
     * @param z
     * @return New point
     */
    public Vector add(double x, double y, double z) {
        return new Vector(this.x + x, this.y + y, this.z + z);
    }

    /**
     * Adds two points.
     *
     * @param x
     * @param y
     * @param z
     * @return New point
     */
    public Vector add(int x, int y, int z) {
        return new Vector(this.x + x, this.y + y, this.z + z);
    }

    /**
     * Adds points.
     *
     * @param others
     * @return New point
     */
    public Vector add(Vector... others) {
        double newX = x, newY = y, newZ = z;

        for (int i = 0; i < others.length; ++i) {
            newX += others[i].x;
            newY += others[i].y;
            newZ += others[i].z;
        }
        return new Vector(newX, newY, newZ);
    }

    /**
     * Subtracts two points.
     *
     * @param other
     * @return New point
     */
    public Vector subtract(Vector other) {
        return new Vector(x - other.x, y - other.y, z - other.z);
    }

    /**
     * Subtract two points.
     *
     * @param x
     * @param y
     * @param z
     * @return New point
     */
    public Vector subtract(double x, double y, double z) {
        return new Vector(this.x - x, this.y - y, this.z - z);
    }

    /**
     * Subtract two points.
     *
     * @param x
     * @param y
     * @param z
     * @return New point
     */
    public Vector subtract(int x, int y, int z) {
        return new Vector(this.x - x, this.y - y, this.z - z);
    }

    /**
     * Subtract points.
     *
     * @param others
     * @return New point
     */
    public Vector subtract(Vector... others) {
        double newX = x, newY = y, newZ = z;

        for (int i = 0; i < others.length; ++i) {
            newX -= others[i].x;
            newY -= others[i].y;
            newZ -= others[i].z;
        }
        return new Vector(newX, newY, newZ);
    }

    /**
     * Component-wise multiplication
     *
     * @param other
     * @return New point
     */
    public Vector multiply(Vector other) {
        return new Vector(x * other.x, y * other.y, z * other.z);
    }

    /**
     * Component-wise multiplication
     *
     * @param x
     * @param y
     * @param z
     * @return New point
     */
    public Vector multiply(double x, double y, double z) {
        return new Vector(this.x * x, this.y * y, this.z * z);
    }

    /**
     * Component-wise multiplication
     *
     * @param x
     * @param y
     * @param z
     * @return New point
     */
    public Vector multiply(int x, int y, int z) {
        return new Vector(this.x * x, this.y * y, this.z * z);
    }

    /**
     * Component-wise multiplication
     *
     * @param others
     * @return New point
     */
    public Vector multiply(Vector... others) {
        double newX = x, newY = y, newZ = z;

        for (int i = 0; i < others.length; ++i) {
            newX *= others[i].x;
            newY *= others[i].y;
            newZ *= others[i].z;
        }
        return new Vector(newX, newY, newZ);
    }

    /**
     * Scalar multiplication.
     *
     * @param n
     * @return New point
     */
    public Vector multiply(double n) {
        return new Vector(this.x * n, this.y * n, this.z * n);
    }

    /**
     * Scalar multiplication.
     *
     * @param n
     * @return New point
     */
    public Vector multiply(float n) {
        return new Vector(this.x * n, this.y * n, this.z * n);
    }

    /**
     * Scalar multiplication.
     *
     * @param n
     * @return New point
     */
    public Vector multiply(int n) {
        return new Vector(this.x * n, this.y * n, this.z * n);
    }

    /**
     * Component-wise division
     *
     * @param other
     * @return New point
     */
    public Vector divide(Vector other) {
        return new Vector(x / other.x, y / other.y, z / other.z);
    }

    /**
     * Component-wise division
     *
     * @param x
     * @param y
     * @param z
     * @return New point
     */
    public Vector divide(double x, double y, double z) {
        return new Vector(this.x / x, this.y / y, this.z / z);
    }

    /**
     * Component-wise division
     *
     * @param x
     * @param y
     * @param z
     * @return New point
     */
    public Vector divide(int x, int y, int z) {
        return new Vector(this.x / x, this.y / y, this.z / z);
    }

    /**
     * Scalar division.
     *
     * @param n
     * @return new point
     */
    public Vector divide(int n) {
        return new Vector(x / n, y / n, z / n);
    }

    /**
     * Scalar division.
     *
     * @param n
     * @return new point
     */
    public Vector divide(double n) {
        return new Vector(x / n, y / n, z / n);
    }

    /**
     * Scalar division.
     *
     * @param n
     * @return new point
     */
    public Vector divide(float n) {
        return new Vector(x / n, y / n, z / n);
    }

    /**
     * Get the length of the vector.
     *
     * @return length
     */
    public double length() {
        return Math.sqrt(x * x + y * y + z * z);
    }

    /**
     * Get the length^2 of the vector.
     *
     * @return length^2
     */
    public double lengthSq() {
        return x * x + y * y + z * z;
    }

    /**
     * Get the distance away from a point.
     *
     * @param pt
     * @return distance
     */
    public double distance(Vector pt) {
        return Math.sqrt(Math.pow(pt.x - x, 2) +
                Math.pow(pt.y - y, 2) +
                Math.pow(pt.z - z, 2));
    }

    /**
     * Get the distance away from a point, squared.
     *
     * @param pt
     * @return distance
     */
    public double distanceSq(Vector pt) {
        return Math.pow(pt.x - x, 2) +
                Math.pow(pt.y - y, 2) +
                Math.pow(pt.z - z, 2);
    }

    /**
     * Get the normalized vector.
     *
     * @return vector
     */
    public Vector normalize() {
        return divide(length());
    }

    /**
     * Gets the dot product of this and another vector.
     *
     * @param other
     * @return the dot product of this and the other vector
     */
    public double dot(Vector other) {
        return x * other.x + y * other.y + z * other.z;
    }

    /**
     * Gets the cross product of this and another vector.
     *
     * @param other
     * @return the cross product of this and the other vector
     */
    public Vector cross(Vector other) {
        return new Vector(
            y * other.z - z * other.y,
            z * other.x - x * other.z,
            x * other.y - y * other.x
        );
    }

    /**
     * Checks to see if a vector is contained with another.
     *
     * @param min
     * @param max
     * @return
     */
    public boolean containedWithin(Vector min, Vector max) {
        return x >= min.x && x <= max.x
                && y >= min.y && y <= max.y
                && z >= min.z && z <= max.z;
    }

    /**
     * Checks to see if a vector is contained with another.
     *
     * @param min
     * @param max
     * @return
     */
    public boolean containedWithinBlock(Vector min, Vector max) {
        return getBlockX() >= min.getBlockX() && getBlockX() <= max.getBlockX()
                && getBlockY() >= min.getBlockY() && getBlockY() <= max.getBlockY()
                && getBlockZ() >= min.getBlockZ() && getBlockZ() <= max.getBlockZ();
    }

    /**
     * Clamp the Y component.
     *
     * @param min
     * @param max
     * @return
     */
    public Vector clampY(int min, int max) {
        return new Vector(x, Math.max(min, Math.min(max, y)), z);
    }

    /**
     * Rounds all components down.
     *
     * @return
     */
    public Vector floor() {
        return new Vector(Math.floor(x), Math.floor(y), Math.floor(z));
    }

    /**
     * Rounds all components up.
     *
     * @return
     */
    public Vector ceil() {
        return new Vector(Math.ceil(x), Math.ceil(y), Math.ceil(z));
    }

    /**
     * Rounds all components to the closest integer.<br>
     *<br>
     * Components < 0.5 are rounded down, otherwise up
     *
     * @return
     */
    public Vector round() {
        return new Vector(Math.floor(x + 0.5), Math.floor(y + 0.5), Math.floor(z + 0.5));
    }

    /**
     * Returns a vector with the absolute values of the components of this vector.
     *
     * @return
     */
    public Vector positive() {
        return new Vector(Math.abs(x), Math.abs(y), Math.abs(z));
    }

    /**
     * 2D transformation.
     *
     * @param angle in degrees
     * @param aboutX about which x coordinate to rotate
     * @param aboutZ about which z coordinate to rotate
     * @param translateX what to add after rotation
     * @param translateZ what to add after rotation
     * @return
     */
    public Vector transform2D(double angle,
            double aboutX, double aboutZ, double translateX, double translateZ) {
        angle = Math.toRadians(angle);
        double x = this.x - aboutX;
        double z = this.z - aboutZ;
        double x2 = x * Math.cos(angle) - z * Math.sin(angle);
        double z2 = x * Math.sin(angle) + z * Math.cos(angle);

        return new Vector(
            x2 + aboutX + translateX,
            y,
            z2 + aboutZ + translateZ
        );
    }

    public boolean isCollinearWith(Vector other) {
        if (x == 0 && y == 0 && z == 0) {
            // this is a zero vector
            return true;
        }

        final double otherX = other.x;
        final double otherY = other.y;
        final double otherZ = other.z;

        if (otherX == 0 && otherY == 0 && otherZ == 0) {
            // other is a zero vector
            return true;
        }

        if ((x == 0) != (otherX == 0)) return false;
        if ((y == 0) != (otherY == 0)) return false;
        if ((z == 0) != (otherZ == 0)) return false;

        final double quotientX = otherX / x;
        if (!Double.isNaN(quotientX)) {
            return other.equals(multiply(quotientX));
        }

        final double quotientY = otherY / y;
        if (!Double.isNaN(quotientY)) {
            return other.equals(multiply(quotientY));
        }

        final double quotientZ = otherZ / z;
        if (!Double.isNaN(quotientZ)) {
            return other.equals(multiply(quotientZ));
        }

        throw new RuntimeException("This should not happen");
    }

    /**
     * Get this vector's pitch as used within the game.
     *
     * @return pitch in radians
     */
    public float toPitch() {
        double x = getX();
        double z = getZ();

        if (x == 0 && z == 0) {
            return getY() > 0 ? -90 : 90;
        } else {
            double x2 = x * x;
            double z2 = z * z;
            double xz = Math.sqrt(x2 + z2);
            return (float) Math.atan(-getY() / xz);
        }
    }

    /**
     * Get this vector's yaw as used within the game.
     *
     * @return yaw in radians
     */
    public float toYaw() {
        double x = getX();
        double z = getZ();

        double t = Math.atan2(-x, z);
        double _2pi = 2 * Math.PI;

        return (float) ((t + _2pi) % _2pi);
    }

    /**
     * Get a block point from a point.
     *
     * @param x
     * @param y
     * @param z
     * @return point
     */
    public static BlockVector toBlockPoint(double x, double y, double z) {
        return new BlockVector(
            Math.floor(x),
            Math.floor(y),
            Math.floor(z)
        );
    }

    /**
     * Get a block point from a point.
     *
     * @return point
     */
    public BlockVector toBlockPoint() {
        return new BlockVector(
            Math.floor(x),
            Math.floor(y),
            Math.floor(z)
        );
    }

    /**
     * Checks if another object is equivalent.
     *
     * @param obj
     * @return whether the other object is equivalent
     */
    @Override
    public boolean equals(Object obj) {
        if (!(obj instanceof Vector)) {
            return false;
        }

        Vector other = (Vector) obj;
        return other.x == this.x && other.y == this.y && other.z == this.z;
    }

    @Override
    public int compareTo(Vector other) {
        if (y != other.y) return Double.compare(y, other.y);
        if (z != other.z) return Double.compare(z, other.z);
        if (x != other.x) return Double.compare(x, other.x);
        return 0;
    }

    /**
     * Gets the hash code.
     *
     * @return hash code
     */
    @Override
    public int hashCode() {
        int hash = 7;

        hash = 79 * hash + (int) (Double.doubleToLongBits(this.x) ^ (Double.doubleToLongBits(this.x) >>> 32));
        hash = 79 * hash + (int) (Double.doubleToLongBits(this.y) ^ (Double.doubleToLongBits(this.y) >>> 32));
        hash = 79 * hash + (int) (Double.doubleToLongBits(this.z) ^ (Double.doubleToLongBits(this.z) >>> 32));
        return hash;
    }

    /**
     * Returns string representation "(x, y, z)".
     *
     * @return string
     */
    @Override
    public String toString() {
        return "(" + x + ", " + y + ", " + z + ")";
    }

    /**
     * Gets a BlockVector version.
     *
     * @return BlockVector
     */
    public BlockVector toBlockVector() {
        return new BlockVector(this);
    }

    /**
     * Creates a 2D vector by dropping the Y component from this vector.
     *
     * @return Vector2D
     */
    public Vector2D toVector2D() {
        return new Vector2D(x, z);
    }

    /**
     * Gets the minimum components of two vectors.
     *
     * @param v1
     * @param v2
     * @return minimum
     */
    public static Vector getMinimum(Vector v1, Vector v2) {
        return new Vector(
            Math.min(v1.x, v2.x),
            Math.min(v1.y, v2.y),
            Math.min(v1.z, v2.z)
        );
    }

    /**
     * Gets the maximum components of two vectors.
     *
     * @param v1
     * @param v2
     * @return maximum
     */
    public static Vector getMaximum(Vector v1, Vector v2) {
        return new Vector(
            Math.max(v1.x, v2.x),
            Math.max(v1.y, v2.y),
            Math.max(v1.z, v2.z)
        );
    }

    /**
     * Gets the midpoint of two vectors.
     *
     * @param v1
     * @param v2
     * @return maximum
     */
    public static Vector getMidpoint(Vector v1, Vector v2) {
        return new Vector(
            (v1.x + v2.x) / 2,
            (v1.y + v2.y) / 2,
            (v1.z + v2.z) / 2
        );
    }

}