Wizardry/src/main/java/electroblob/wizardry/entity/construct/EntityIceBarrier.java

package electroblob.wizardry.entity.construct;

import electroblob.wizardry.entity.ICustomHitbox;
import electroblob.wizardry.registry.WizardrySounds;
import net.minecraft.entity.Entity;
import net.minecraft.entity.MoverType;
import net.minecraft.entity.player.EntityPlayerMP;
import net.minecraft.nbt.NBTTagCompound;
import net.minecraft.network.play.server.SPacketEntityVelocity;
import net.minecraft.util.DamageSource;
import net.minecraft.util.math.AxisAlignedBB;
import net.minecraft.util.math.MathHelper;
import net.minecraft.util.math.Vec3d;
import net.minecraft.world.World;

public class EntityIceBarrier extends EntityScaledConstruct implements ICustomHitbox {

	private static final double THICKNESS = 0.4;

	private int delay = 0;

	public EntityIceBarrier(World world){
		super(world);
		this.setSize(1.8f, 1.05f);
	}

	public void setDelay(int delay){
		this.delay = delay;
		this.lifetime += delay;
	}

	@Override
	public void setRotation(float yaw, float pitch){
		super.setRotation(yaw, pitch);
		float a = MathHelper.cos((float)Math.toRadians(rotationYaw));
		float b = MathHelper.sin((float)Math.toRadians(rotationYaw));
		double x = width/2 * a + THICKNESS/2 * b;
		double z = width/2 * b + THICKNESS/2 * a;
		setEntityBoundingBox(new AxisAlignedBB(this.posX - x, this.posY, this.posZ - z, this.posX + x, this.posY + height, this.posZ + z));
	}

	@Override
	public boolean canBeCollidedWith(){
		return true;
	}

	@Override
	public void onUpdate(){

		// Bit of a cheat but it's easier than trying to sync FrostBarrier#addConstructExtras
		if(world.isRemote && firstUpdate){
			setSizeMultiplier(sizeMultiplier); // Do this first or it'll overwrite the bounding box
			setRotation(rotationYaw, rotationPitch);
		}

		this.prevPosX = posX;
		this.prevPosY = posY;
		this.prevPosZ = posZ;

		if(!world.isRemote){

			double extensionSpeed = 0;

			if(lifetime - this.ticksExisted < 20){
				extensionSpeed = -0.01 * (this.ticksExisted - (lifetime - 20)) * sizeMultiplier;
			}else if(ticksExisted > 3 + delay){
				extensionSpeed = 0;
			}else if(ticksExisted > delay){
				extensionSpeed = 0.5 * sizeMultiplier;
			}

			this.move(MoverType.SELF, 0, extensionSpeed, 0);
		}

		if(ticksExisted == delay + 1) this.playSound(WizardrySounds.ENTITY_ICE_BARRIER_EXTEND, 1, 1.5f);

		super.onUpdate();

		Vec3d look = this.getLookVec();

		if(!world.isRemote){

			for(Entity entity : world.getEntitiesWithinAABBExcludingEntity(this, getEntityBoundingBox().grow(2))){

				if(entity instanceof EntityMagicConstruct) continue;

				if(!entity.getEntityBoundingBox().intersects(this.getEntityBoundingBox())) continue;

				// For some reason the player position seems to be off by 1 block in x and z, no idea how so for now
				// I've just fudged it by adding 1 to x and z
				double perpendicularDist = getSignedPerpendicularDistance(entity.getPositionVector().add(1, 0, 1));

				if(Math.abs(perpendicularDist) < entity.width/2 + THICKNESS/2){

					double velocity = 0.25 * Math.signum(perpendicularDist);
					entity.addVelocity(velocity * look.x, 0, velocity * look.z);
					// Player motion is handled on that player's client so needs packets
					if(entity instanceof EntityPlayerMP){
						((EntityPlayerMP)entity).connection.sendPacket(new SPacketEntityVelocity(entity));
					}
				}
			}
		}

	}

	@Override
	public boolean isBurning(){
		return false;
	}

	@Override
	public boolean attackEntityFrom(DamageSource source, float amount){
		this.playSound(WizardrySounds.ENTITY_ICE_BARRIER_DEFLECT, 0.7f, 2.5f);
		return super.attackEntityFrom(source, amount);
	}

//	@Override
//	public int getBrightnessForRender(){
//		return 15728880;
//	}

	@Override
	protected void readEntityFromNBT(NBTTagCompound nbt){
		super.readEntityFromNBT(nbt);
		delay = nbt.getInteger("delay");
	}

	@Override
	protected void writeEntityToNBT(NBTTagCompound nbt){
		super.writeEntityToNBT(nbt);
		nbt.setInteger("delay", delay);
	}

	@Override
	public Vec3d calculateIntercept(Vec3d origin, Vec3d endpoint, float fuzziness){
		// Calculate the point at which the line intersects the barrier plane
		Vec3d vec = endpoint.subtract(origin);

		double perpendicularDist = getPerpendicularDistance(origin);
		double perpendicularDist2 = getPerpendicularDistance(endpoint);

		Vec3d intercept = origin.add(vec.scale(perpendicularDist / (perpendicularDist + perpendicularDist2)));

		// This seems to be all over the palce, but the calculation MUST be right because it works for entity collisions!
//		world.spawnParticle(EnumParticleTypes.END_ROD, intercept.x, intercept.y, intercept.z, 0, 0, 0);

		// If the point is within the hitbox (expanded by the fuzziness), it was a hit
		return getEntityBoundingBox().grow(fuzziness).contains(intercept) ? intercept : null;
	}

	@Override
	public boolean contains(Vec3d point){
		return this.getEntityBoundingBox().contains(point) && getPerpendicularDistance(point) < THICKNESS/2;
	}

	private double getPerpendicularDistance(Vec3d point){
		return Math.abs(getSignedPerpendicularDistance(point));
	}

	private double getSignedPerpendicularDistance(Vec3d point){
		Vec3d look = this.getLookVec();
		Vec3d delta = new Vec3d(point.x - this.posX, 0, point.z - this.posZ);
		return delta.dotProduct(look);
	}

}