From c8cef8e055784800e8d66196af872335d0066dab Mon Sep 17 00:00:00 2001
From: Aleksey <bulldog.seregin@gmail.com>
Date: Fri, 4 Jun 2021 12:42:20 +0300
Subject: [PATCH] Flying above hydrotermal vent make elytras fly upward

---
 .../entities/BlockEntityHydrothermalVent.java | 63 ++++++++++++++++---
 1 file changed, 53 insertions(+), 10 deletions(-)

diff --git a/src/main/java/ru/betterend/blocks/entities/BlockEntityHydrothermalVent.java b/src/main/java/ru/betterend/blocks/entities/BlockEntityHydrothermalVent.java
index 79f78183..48cced23 100644
--- a/src/main/java/ru/betterend/blocks/entities/BlockEntityHydrothermalVent.java
+++ b/src/main/java/ru/betterend/blocks/entities/BlockEntityHydrothermalVent.java
@@ -1,34 +1,77 @@
 package ru.betterend.blocks.entities;
 
+import com.mojang.math.Vector3f;
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.BlockPos.MutableBlockPos;
+import net.minecraft.core.Direction;
+import net.minecraft.core.Vec3i;
 import net.minecraft.core.particles.ParticleTypes;
+import net.minecraft.world.entity.Entity;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.LivingEntity;
+import net.minecraft.world.entity.MoverType;
+import net.minecraft.world.item.ElytraItem;
+import net.minecraft.world.item.Item;
+import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.block.entity.BlockEntity;
 import net.minecraft.world.level.block.entity.TickableBlockEntity;
 import net.minecraft.world.level.block.state.BlockState;
+import net.minecraft.world.phys.AABB;
+import net.minecraft.world.phys.Vec3;
 import ru.betterend.blocks.HydrothermalVentBlock;
+import ru.betterend.item.ArmoredElytra;
 import ru.betterend.registry.EndBlockEntities;
 import ru.betterend.registry.EndBlocks;
 import ru.betterend.registry.EndParticles;
 
+import java.util.Comparator;
+import java.util.List;
+
 public class BlockEntityHydrothermalVent extends BlockEntity implements TickableBlockEntity {
+
+	private final static Vec3 POSITIVE_Y = new Vec3(0.0f, 1.0f, 0.0f);
+
 	public BlockEntityHydrothermalVent() {
 		super(EndBlockEntities.HYDROTHERMAL_VENT);
 	}
 
 	@Override
 	public void tick() {
-		if (level.random.nextInt(20) == 0) {
-			double x = worldPosition.getX() + level.random.nextDouble();
-			double y = worldPosition.getY() + 0.9 + level.random.nextDouble() * 0.3;
-			double z = worldPosition.getZ() + level.random.nextDouble();
-			BlockState state = getBlockState();
-			if (state.is(EndBlocks.HYDROTHERMAL_VENT) && state.getValue(HydrothermalVentBlock.ACTIVATED)) {
-				if (state.getValue(HydrothermalVentBlock.WATERLOGGED)) {
-					level.addParticle(EndParticles.GEYSER_PARTICLE, x, y, z, 0, 0, 0);
+		if (level != null) {
+			if (level.random.nextInt(20) == 0) {
+				BlockState state = getBlockState();
+				if (state.is(EndBlocks.HYDROTHERMAL_VENT) && state.getValue(HydrothermalVentBlock.ACTIVATED)) {
+					double x = worldPosition.getX() + level.random.nextDouble();
+					double y = worldPosition.getY() + 0.9 + level.random.nextDouble() * 0.3;
+					double z = worldPosition.getZ() + level.random.nextDouble();
+					if (state.getValue(HydrothermalVentBlock.WATERLOGGED)) {
+						level.addParticle(EndParticles.GEYSER_PARTICLE, x, y, z, 0, 0, 0);
+					} else {
+						level.addParticle(ParticleTypes.BUBBLE, x, y, z, 0, 0, 0);
+					}
 				}
-				else {
-					level.addParticle(ParticleTypes.BUBBLE, x, y, z, 0, 0, 0);
+			}
+			MutableBlockPos mutable = worldPosition.mutable().move(Direction.UP);
+			AABB box = new AABB(mutable.offset(-1, 0, -1), mutable.offset(1, 25, 1));
+			List<LivingEntity> entities = level.getEntitiesOfClass(LivingEntity.class, box);
+			if (entities.size() > 0) {
+				while (mutable.getY() < box.maxY) {
+					BlockState blockState = level.getBlockState(mutable);
+					if (blockState.isSolidRender(level, mutable)) break;
+					if (blockState.isAir()) {
+						float force = (float) ((1.0 - (mutable.getY() / box.maxY)) / 5.0);
+						entities.stream().filter(entity -> (int) entity.getY() == mutable.getY() &&
+								hasElytra(entity) && entity.isFallFlying())
+								.forEach(entity -> entity.moveRelative(force, POSITIVE_Y));
+					}
+					mutable.move(Direction.UP);
 				}
 			}
 		}
 	}
+
+	private boolean hasElytra(LivingEntity entity) {
+		Item item = entity.getItemBySlot(EquipmentSlot.CHEST).getItem();
+		return item instanceof ElytraItem || item instanceof ArmoredElytra;
+	}
 }