package net.minecraft.util;

import java.util.Optional;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.tags.BlockTags;
import net.minecraft.world.entity.EntitySpawnReason;
import net.minecraft.world.entity.EntityType;
import net.minecraft.world.entity.Mob;
import net.minecraft.world.level.block.Block;
import net.minecraft.world.level.block.Blocks;
import net.minecraft.world.level.block.LeavesBlock;
import net.minecraft.world.level.block.StainedGlassBlock;
import net.minecraft.world.level.block.StainedGlassPaneBlock;
import net.minecraft.world.level.block.state.BlockState;

public class SpawnUtil {
	public static <T extends Mob> Optional<T> trySpawnMob(
		EntityType<T> entityType,
		EntitySpawnReason spawnReason,
		ServerLevel level,
		BlockPos pos,
		int attempts,
		int range,
		int yOffset,
		SpawnUtil.Strategy strategy,
		boolean checkCollision
	) {
		BlockPos.MutableBlockPos mutableBlockPos = pos.mutable();

		for (int i = 0; i < attempts; i++) {
			int j = Mth.randomBetweenInclusive(level.random, -range, range);
			int k = Mth.randomBetweenInclusive(level.random, -range, range);
			mutableBlockPos.setWithOffset(pos, j, yOffset, k);
			if (level.getWorldBorder().isWithinBounds(mutableBlockPos)
				&& moveToPossibleSpawnPosition(level, yOffset, mutableBlockPos, strategy)
				&& (!checkCollision || level.noCollision(entityType.getSpawnAABB(mutableBlockPos.getX() + 0.5, mutableBlockPos.getY(), mutableBlockPos.getZ() + 0.5)))) {
				T mob = (T)entityType.create(level, null, mutableBlockPos, spawnReason, false, false);
				if (mob != null) {
					if (mob.checkSpawnRules(level, spawnReason) && mob.checkSpawnObstruction(level)) {
						level.addFreshEntityWithPassengers(mob);
						mob.playAmbientSound();
						return Optional.of(mob);
					}

					mob.discard();
				}
			}
		}

		return Optional.empty();
	}

	private static boolean moveToPossibleSpawnPosition(ServerLevel level, int yOffset, BlockPos.MutableBlockPos pos, SpawnUtil.Strategy strategy) {
		BlockPos.MutableBlockPos mutableBlockPos = new BlockPos.MutableBlockPos().set(pos);
		BlockState blockState = level.getBlockState(mutableBlockPos);

		for (int i = yOffset; i >= -yOffset; i--) {
			pos.move(Direction.DOWN);
			mutableBlockPos.setWithOffset(pos, Direction.UP);
			BlockState blockState2 = level.getBlockState(pos);
			if (strategy.canSpawnOn(level, pos, blockState2, mutableBlockPos, blockState)) {
				pos.move(Direction.UP);
				return true;
			}

			blockState = blockState2;
		}

		return false;
	}

	public interface Strategy {
		@Deprecated
		SpawnUtil.Strategy LEGACY_IRON_GOLEM = (serverLevel, blockPos, blockState, blockPos2, blockState2) -> !blockState.is(Blocks.COBWEB)
				&& !blockState.is(Blocks.CACTUS)
				&& !blockState.is(Blocks.GLASS_PANE)
				&& !(blockState.getBlock() instanceof StainedGlassPaneBlock)
				&& !(blockState.getBlock() instanceof StainedGlassBlock)
				&& !(blockState.getBlock() instanceof LeavesBlock)
				&& !blockState.is(Blocks.CONDUIT)
				&& !blockState.is(Blocks.ICE)
				&& !blockState.is(Blocks.TNT)
				&& !blockState.is(Blocks.GLOWSTONE)
				&& !blockState.is(Blocks.BEACON)
				&& !blockState.is(Blocks.SEA_LANTERN)
				&& !blockState.is(Blocks.FROSTED_ICE)
				&& !blockState.is(Blocks.TINTED_GLASS)
				&& !blockState.is(Blocks.GLASS)
			? (blockState2.isAir() || blockState2.liquid()) && (blockState.isSolid() || blockState.is(Blocks.POWDER_SNOW))
			: false;
		SpawnUtil.Strategy ON_TOP_OF_COLLIDER = (serverLevel, blockPos, blockState, blockPos2, blockState2) -> blockState2.getCollisionShape(serverLevel, blockPos2)
				.isEmpty()
			&& Block.isFaceFull(blockState.getCollisionShape(serverLevel, blockPos), Direction.UP);
		SpawnUtil.Strategy ON_TOP_OF_COLLIDER_NO_LEAVES = (serverLevel, blockPos, blockState, blockPos2, blockState2) -> blockState2.getCollisionShape(
					serverLevel, blockPos2
				)
				.isEmpty()
			&& !blockState.is(BlockTags.LEAVES)
			&& Block.isFaceFull(blockState.getCollisionShape(serverLevel, blockPos), Direction.UP);

		boolean canSpawnOn(ServerLevel serverLevel, BlockPos blockPos, BlockState blockState, BlockPos blockPos2, BlockState blockState2);
	}
}