Stargate/src/main/java/net/knarcraft/stargate/utility/DirectionHelper.java

package net.knarcraft.stargate.utility;

import net.knarcraft.stargate.BlockLocation;
import net.knarcraft.stargate.RelativeBlockVector;
import org.bukkit.Location;
import org.bukkit.block.BlockFace;
import org.bukkit.util.Vector;

/**
 * This class helps with direction-dependent (modX, modZ) calculations
 */
public final class DirectionHelper {

    private DirectionHelper() {

    }

    /**
     * Gets a yaw by comparing two locations
     *
     * <p>The yaw here is the direction an observer a the first location has to look to face the second location.
     * The yaw is only meant to be calculated for locations with equal x or equal z.</p>
     *
     * @param location1 <p>The first location, which works as the origin</p>
     * @param location2 <p>The second location, which the yaw will point at</p>
     * @return <p>The yaw</p>
     */
    public static float getYawFromLocationDifference(Location location1, Location location2) {
        Location difference = location1.clone().subtract(location2.clone());
        if (difference.getX() > 0) {
            return 90;
        } else if (difference.getX() < 0) {
            return 270;
        } else if (difference.getZ() > 0) {
            return 180;
        } else if (difference.getZ() < 0) {
            return 0;
        }
        throw new IllegalArgumentException("Locations given are equal or at the same x and y axis");
    }

    /**
     * Gets a block face given a yaw
     * @param yaw <p>The yaw to use</p>
     * @return <p>The block face the yaw corresponds to</p>
     */
    public static BlockFace getBlockFaceFromYaw(double yaw) {
        //Make sure the yaw is between 0 and 360
        yaw = normalizeYaw(yaw);

        if (yaw == 0) {
            return BlockFace.SOUTH;
        } else if (yaw == 90) {
            return BlockFace.WEST;
        } else if (yaw == 180) {
            return BlockFace.NORTH;
        } else if (yaw == 270) {
            return BlockFace.EAST;
        } else {
            throw new IllegalArgumentException("Invalid yaw given");
        }
    }

    /**
     * Gets a direction vector given a yaw
     * @param yaw <p>The yaw to use</p>
     * @return <p>The direction vector of the yaw</p>
     */
    public static Vector getDirectionVectorFromYaw(double yaw) {
        //Make sure the yaw is between 0 and 360
        yaw = normalizeYaw(yaw);

        if (yaw == 0) {
            return new Vector(0, 0, 1);
        } else if (yaw == 90) {
            return new Vector(-1, 0, 0);
        } else if (yaw == 180) {
            return new Vector(0, 0, -1);
        } else if (yaw == 270) {
            return new Vector(1, 0, 0);
        } else {
            throw new IllegalArgumentException("Invalid yaw given");
        }
    }

    /**
     * Gets the block at a relative block vector location
     *
     * @param vector <p>The relative block vector</p>
     * @return <p>The block at the given relative position</p>
     */
    public static BlockLocation getBlockAt(BlockLocation topLeft, RelativeBlockVector vector, int modX, int modZ) {
        return topLeft.modRelative(vector.getRight(), vector.getDepth(), vector.getDistance(), modX, 1, modZ);
    }

    /**
     * Adds a relative block vector to a location, accounting for direction
     * @param location <p>The location to adjust</p>
     * @param right <p>The amount of blocks to the right to adjust</p>
     * @param depth <p>The amount of blocks upward to adjust</p>
     * @param distance <p>The distance outward to adjust</p>
     * @param modX <p>The x modifier to use</p>
     * @param modZ <p>The z modifier to use</p>
     * @return <p>The altered location</p>
     */
    public static Location adjustLocation(Location location, double right, double depth, double distance, int modX,
                                          int modZ) {
        return location.add(-right * modX + distance * modZ, depth, -right * modZ + -distance * modX);
    }

    /**
     * Normalizes a yaw to make it positive and no larger than 360 degrees
     * @param yaw <p>The yaw to normalize</p>
     * @return <p>The normalized yaw</p>
     */
    private static double normalizeYaw(double yaw) {
        while (yaw < 0) {
            yaw += 360;
        }
        yaw = yaw % 360;
        return yaw;
    }

}