JavaScript setInterval 防堆叠策略：确保定时器只运行一次

class ParticleGenerator {
  constructor(/* ... */) {
    // ... 其他属性初始化
    this.spawning = false;
    this.particlesPerSpawn = particlesPerSpawn;
    // 缺少对 spawnManager 的初始化
  }

  start() {
    // 如果 start() 被多次调用，这里会创建多个 setInterval
    this.spawnManager = setInterval(() => {
      // 生成粒子的逻辑
    }, this.spawnRate);
  }

  stop() {
    // 只能停止最后一次 start() 调用创建的定时器
    clearInterval(this.spawnManager);
  }
}

class ParticleGenerator {
  constructor(pgPhyEngine, x, y, width, height, particleSizeRange = {
    min: 3,
    max: 10
  }, spawnRate = 100, particlesPerSpawn = 1, velXRange = {
    min: -15,
    max: 15
  }, velYRange = {
    min: -15,
    max: 15
  }, particleColorsArray = ["#ff8000", "#808080"]) {
    this.parent = pgPhyEngine;
    this.x = x;
    this.y = y;
    this.width = width;
    this.height = height;
    this.particleSizeRange = particleSizeRange;
    this.velXRange = velXRange;
    this.velYRange = velYRange;
    this.particleColors = particleColorsArray;
    this.spawnRate = spawnRate;
    this.spawning = false;
    this.particlesPerSpawn = particlesPerSpawn;
    this.spawnManager = null; // 初始化为 null
  }

  // ... (其他方法)
}

class ParticleGenerator {
  // ... (构造函数及其他属性)

  start() {
    // 在启动新定时器之前，检查是否已有定时器在运行
    if (this.spawnManager !== null) { // 或者简写为 if (this.spawnManager)
      this.stop(); // 如果有，先停止它
    }

    this.spawnManager = setInterval(() => {
      for (var i = 0; i < this.particlesPerSpawn; i++) {
        this.parent.createParticle((this.x - this.width / 2) + (random(0, this.width)), (this.y - this.height / 2) + (random(0, this.height)), random(this.particleSizeRange.min, this.particleSizeRange.max), pickRandomItemFromArray(this.particleColors), true, random(this.velXRange.min, this.velXRange.max), random(this.velYRange.min, this.velYRange.max));
      }
    }, this.spawnRate);
  }

  stop() {
    clearInterval(this.spawnManager);
    this.spawnManager = null; // 清除后将 ID 设回 null，表示没有定时器运行
  }
}

// 假设 random 和 pickRandomItemFromArray 是全局可用的辅助函数
function random(min, max) {
  return Math.random() * (max - min) + min;
}

function pickRandomItemFromArray(arr) {
  return arr[Math.floor(Math.random() * arr.length)];
}

class ParticleGenerator {
  constructor(pgPhyEngine, x, y, width, height, particleSizeRange = {
    min: 3,
    max: 10
  }, spawnRate = 100, particlesPerSpawn = 1, velXRange = {
    min: -15,
    max: 15
  }, velYRange = {
    min: -15,
    max: 15
  }, particleColorsArray = ["#ff8000", "#808080"]) {
    this.parent = pgPhyEngine; // 假设 pgPhyEngine 有 createParticle 方法
    this.x = x;
    this.y = y;
    this.width = width;
    this.height = height;
    this.particleSizeRange = particleSizeRange;
    this.velXRange = velXRange;
    this.velYRange = velYRange;
    this.particleColors = particleColorsArray;
    this.spawnRate = spawnRate;
    this.spawning = false; // 此属性可能不再需要，因为 spawnManager 可以作为状态指示器
    this.particlesPerSpawn = particlesPerSpawn;
    this.spawnManager = null; // 初始化定时器ID
  }

  /**
   * 启动粒子生成定时器。
   * 如果定时器已在运行，则会先停止现有定时器再启动新的。
   */
  start() {
    if (this.spawnManager) { // 检查是否已有定时器在运行
      this.stop(); // 如果有，先停止它
    }

    this.spawnManager = setInterval(() => {
      for (let i = 0; i < this.particlesPerSpawn; i++) {
        const particleX = (this.x - this.width / 2) + (random(0, this.width));
        const particleY = (this.y - this.height / 2) + (random(0, this.height));
        const particleSize = random(this.particleSizeRange.min, this.particleSizeRange.max);
        const particleColor = pickRandomItemFromArray(this.particleColors);
        const velX = random(this.velXRange.min, this.velXRange.max);
        const velY = random(this.velYRange.min, this.velYRange.max);

        // 假设 this.parent.createParticle 接受这些参数
        this.parent.createParticle(particleX, particleY, particleSize, particleColor, true, velX, velY);
      }
    }, this.spawnRate);
    console.log(`Particle generator started with ID: ${this.spawnManager}`);
  }

  /**
   * 停止粒子生成定时器。
   * 如果没有定时器在运行，此操作无效果。
   */
  stop() {
    if (this.spawnManager) { // 仅当有定时器ID时才清除
      clearInterval(this.spawnManager);
      console.log(`Particle generator with ID ${this.spawnManager} stopped.`);
      this.spawnManager = null; // 清除后将 ID 设回 null
    }
  }

  // 示例用法 (需要一个 pgPhyEngine 实例)
  // const engine = {
  //   createParticle: (...args) => console.log("Creating particle:", args)
  // };
  // const generator = new ParticleGenerator(engine, 0, 0, 100, 100);
  // generator.start(); // 启动第一个定时器
  // setTimeout(() => generator.start(), 2000); // 2秒后再次调用 start，会先停止第一个再启动新的
  // setTimeout(() => generator.stop(), 5000); // 5秒后停止定时器
}