package net.minecraft.world.entity.monster;

import java.util.EnumSet;
import java.util.List;
import net.minecraft.core.BlockPos;
import net.minecraft.core.registries.Registries;
import net.minecraft.util.RandomSource;
import net.minecraft.world.DifficultyInstance;
import net.minecraft.world.entity.EntitySpawnReason;
import net.minecraft.world.entity.EntityType;
import net.minecraft.world.entity.EquipmentSlot;
import net.minecraft.world.entity.SpawnGroupData;
import net.minecraft.world.entity.ai.goal.Goal;
import net.minecraft.world.entity.ai.navigation.PathNavigation;
import net.minecraft.world.entity.raid.Raid;
import net.minecraft.world.level.Level;
import net.minecraft.world.level.LevelAccessor;
import net.minecraft.world.level.LightLayer;
import net.minecraft.world.level.ServerLevelAccessor;
import net.minecraft.world.level.levelgen.Heightmap;
import net.minecraft.world.level.storage.ValueInput;
import net.minecraft.world.level.storage.ValueOutput;
import net.minecraft.world.phys.Vec3;
import org.jspecify.annotations.Nullable;

public abstract class PatrollingMonster extends Monster {
	private static final boolean DEFAULT_PATROL_LEADER = false;
	private static final boolean DEFAULT_PATROLLING = false;
	@Nullable
	private BlockPos patrolTarget;
	private boolean patrolLeader = false;
	private boolean patrolling = false;

	protected PatrollingMonster(final EntityType<? extends PatrollingMonster> type, final Level level) {
		super(type, level);
	}

	@Override
	protected void registerGoals() {
		super.registerGoals();
		this.goalSelector.addGoal(4, new PatrollingMonster.LongDistancePatrolGoal<>(this, 0.7, 0.595));
	}

	@Override
	protected void addAdditionalSaveData(final ValueOutput output) {
		super.addAdditionalSaveData(output);
		output.storeNullable("patrol_target", BlockPos.CODEC, this.patrolTarget);
		output.putBoolean("PatrolLeader", this.patrolLeader);
		output.putBoolean("Patrolling", this.patrolling);
	}

	@Override
	protected void readAdditionalSaveData(final ValueInput input) {
		super.readAdditionalSaveData(input);
		this.patrolTarget = (BlockPos)input.read("patrol_target", BlockPos.CODEC).orElse(null);
		this.patrolLeader = input.getBooleanOr("PatrolLeader", false);
		this.patrolling = input.getBooleanOr("Patrolling", false);
	}

	public boolean canBeLeader() {
		return true;
	}

	@Nullable
	@Override
	public SpawnGroupData finalizeSpawn(
		final ServerLevelAccessor level, final DifficultyInstance difficulty, final EntitySpawnReason spawnReason, @Nullable final SpawnGroupData groupData
	) {
		if (spawnReason != EntitySpawnReason.PATROL
			&& spawnReason != EntitySpawnReason.EVENT
			&& spawnReason != EntitySpawnReason.STRUCTURE
			&& level.getRandom().nextFloat() < 0.06F
			&& this.canBeLeader()) {
			this.patrolLeader = true;
		}

		if (this.isPatrolLeader()) {
			this.setItemSlot(EquipmentSlot.HEAD, Raid.getOminousBannerInstance(this.registryAccess().lookupOrThrow(Registries.BANNER_PATTERN)));
			this.setDropChance(EquipmentSlot.HEAD, 2.0F);
		}

		if (spawnReason == EntitySpawnReason.PATROL) {
			this.patrolling = true;
		}

		return super.finalizeSpawn(level, difficulty, spawnReason, groupData);
	}

	public static boolean checkPatrollingMonsterSpawnRules(
		final EntityType<? extends PatrollingMonster> type,
		final LevelAccessor level,
		final EntitySpawnReason spawnReason,
		final BlockPos pos,
		final RandomSource random
	) {
		return level.getBrightness(LightLayer.BLOCK, pos) > 8 ? false : checkAnyLightMonsterSpawnRules(type, level, spawnReason, pos, random);
	}

	@Override
	public boolean removeWhenFarAway(final double distSqr) {
		return !this.patrolling || distSqr > 16384.0;
	}

	public void setPatrolTarget(final BlockPos target) {
		this.patrolTarget = target;
		this.patrolling = true;
	}

	@Nullable
	public BlockPos getPatrolTarget() {
		return this.patrolTarget;
	}

	public boolean hasPatrolTarget() {
		return this.patrolTarget != null;
	}

	public void setPatrolLeader(final boolean isLeader) {
		this.patrolLeader = isLeader;
		this.patrolling = true;
	}

	public boolean isPatrolLeader() {
		return this.patrolLeader;
	}

	public boolean canJoinPatrol() {
		return true;
	}

	public void findPatrolTarget() {
		this.patrolTarget = this.blockPosition().offset(-500 + this.random.nextInt(1000), 0, -500 + this.random.nextInt(1000));
		this.patrolling = true;
	}

	protected boolean isPatrolling() {
		return this.patrolling;
	}

	protected void setPatrolling(final boolean value) {
		this.patrolling = value;
	}

	public static class LongDistancePatrolGoal<T extends PatrollingMonster> extends Goal {
		private static final int NAVIGATION_FAILED_COOLDOWN = 200;
		private final T mob;
		private final double speedModifier;
		private final double leaderSpeedModifier;
		private long cooldownUntil;

		public LongDistancePatrolGoal(final T mob, final double speedModifier, final double leaderSpeedModifier) {
			this.mob = mob;
			this.speedModifier = speedModifier;
			this.leaderSpeedModifier = leaderSpeedModifier;
			this.cooldownUntil = -1L;
			this.setFlags(EnumSet.of(Goal.Flag.MOVE));
		}

		@Override
		public boolean canUse() {
			boolean isOnCooldown = this.mob.level().getGameTime() < this.cooldownUntil;
			return this.mob.isPatrolling() && this.mob.getTarget() == null && !this.mob.hasControllingPassenger() && this.mob.hasPatrolTarget() && !isOnCooldown;
		}

		@Override
		public void start() {
		}

		@Override
		public void stop() {
		}

		@Override
		public void tick() {
			boolean patrolLeader = this.mob.isPatrolLeader();
			PathNavigation navigation = this.mob.getNavigation();
			if (navigation.isDone()) {
				List<PatrollingMonster> companions = this.findPatrolCompanions();
				if (this.mob.isPatrolling() && companions.isEmpty()) {
					this.mob.setPatrolling(false);
				} else if (patrolLeader && this.mob.getPatrolTarget().closerToCenterThan(this.mob.position(), 10.0)) {
					this.mob.findPatrolTarget();
				} else {
					Vec3 longDistanceTarget = Vec3.atBottomCenterOf(this.mob.getPatrolTarget());
					Vec3 selfVector = this.mob.position();
					Vec3 distance = selfVector.subtract(longDistanceTarget);
					longDistanceTarget = distance.yRot(90.0F).scale(0.4).add(longDistanceTarget);
					Vec3 moveTarget = longDistanceTarget.subtract(selfVector).normalize().scale(10.0).add(selfVector);
					BlockPos pathTarget = BlockPos.containing(moveTarget);
					pathTarget = this.mob.level().getHeightmapPos(Heightmap.Types.MOTION_BLOCKING_NO_LEAVES, pathTarget);
					if (!navigation.moveTo(pathTarget.getX(), pathTarget.getY(), pathTarget.getZ(), patrolLeader ? this.leaderSpeedModifier : this.speedModifier)) {
						this.moveRandomly();
						this.cooldownUntil = this.mob.level().getGameTime() + 200L;
					} else if (patrolLeader) {
						for (PatrollingMonster companion : companions) {
							companion.setPatrolTarget(pathTarget);
						}
					}
				}
			}
		}

		private List<PatrollingMonster> findPatrolCompanions() {
			return this.mob
				.level()
				.getEntitiesOfClass(PatrollingMonster.class, this.mob.getBoundingBox().inflate(16.0), mob -> mob.canJoinPatrol() && !mob.is(this.mob));
		}

		private boolean moveRandomly() {
			RandomSource random = this.mob.getRandom();
			BlockPos pathTarget = this.mob
				.level()
				.getHeightmapPos(Heightmap.Types.MOTION_BLOCKING_NO_LEAVES, this.mob.blockPosition().offset(-8 + random.nextInt(16), 0, -8 + random.nextInt(16)));
			return this.mob.getNavigation().moveTo(pathTarget.getX(), pathTarget.getY(), pathTarget.getZ(), this.speedModifier);
		}
	}
}