package net.minecraft.world.level.lighting;

import it.unimi.dsi.fastutil.longs.LongLinkedOpenHashSet;

public class LeveledPriorityQueue {
	private final int levelCount;
	private final LongLinkedOpenHashSet[] queues;
	private int firstQueuedLevel;

	public LeveledPriorityQueue(int levelCount, int expectedSize) {
		this.levelCount = levelCount;
		this.queues = new LongLinkedOpenHashSet[levelCount];

		for (int i = 0; i < levelCount; i++) {
			this.queues[i] = new LongLinkedOpenHashSet(expectedSize, 0.5F) {
				@Override
				protected void rehash(int i) {
					if (i > expectedSize) {
						super.rehash(i);
					}
				}
			};
		}

		this.firstQueuedLevel = levelCount;
	}

	public long removeFirstLong() {
		LongLinkedOpenHashSet longLinkedOpenHashSet = this.queues[this.firstQueuedLevel];
		long l = longLinkedOpenHashSet.removeFirstLong();
		if (longLinkedOpenHashSet.isEmpty()) {
			this.checkFirstQueuedLevel(this.levelCount);
		}

		return l;
	}

	public boolean isEmpty() {
		return this.firstQueuedLevel >= this.levelCount;
	}

	public void dequeue(long value, int levelIndex, int endIndex) {
		LongLinkedOpenHashSet longLinkedOpenHashSet = this.queues[levelIndex];
		longLinkedOpenHashSet.remove(value);
		if (longLinkedOpenHashSet.isEmpty() && this.firstQueuedLevel == levelIndex) {
			this.checkFirstQueuedLevel(endIndex);
		}
	}

	public void enqueue(long value, int levelIndex) {
		this.queues[levelIndex].add(value);
		if (this.firstQueuedLevel > levelIndex) {
			this.firstQueuedLevel = levelIndex;
		}
	}

	private void checkFirstQueuedLevel(int endLevelIndex) {
		int i = this.firstQueuedLevel;
		this.firstQueuedLevel = endLevelIndex;

		for (int j = i + 1; j < endLevelIndex; j++) {
			if (!this.queues[j].isEmpty()) {
				this.firstQueuedLevel = j;
				break;
			}
		}
	}
}