/**
 * 狗叫检测器
 * 基于 PCM 数据实时检测「汪」声
 */
export default class BarkDetector {
  constructor(options = {}) {
    this.volumeThreshold = options.volumeThreshold || 0.03;
    this.minBarkDuration = options.minBarkDuration || 0.08;
    this.maxBarkDuration = options.maxBarkDuration || 0.6;
    this.minZCR = options.minZCR || 0.03;
    this.maxZCR = options.maxZCR || 0.35;
    this.comboWindow = options.comboWindow || 1000;

    this.state = 'SILENT';
    this.stateStartTime = 0;
    this.lastBarkTime = 0;
    this.combo = 0;
    this.volume = 0;
    this.isBark = false;
    this.pushPower = 0;

    this.noiseBaseline = 0;
    this.baselineFrames = 0;

    this.onBark = options.onBark || null;
  }

  feed(pcm, sampleRate, time) {
    if (!pcm || pcm.length === 0) return;

    const now = time || Date.now();

    let sum = 0;
    for (let i = 0; i < pcm.length; i++) {
      const v = pcm[i] / 32768;
      sum += v * v;
    }
    const rms = Math.sqrt(sum / pcm.length);

    let zcrCount = 0;
    for (let i = 1; i < pcm.length; i++) {
      if ((pcm[i] >= 0) !== (pcm[i - 1] >= 0)) {
        zcrCount++;
      }
    }
    const zcr = zcrCount / pcm.length;

    if (this.baselineFrames < 20) {
      this.noiseBaseline = this.noiseBaseline * 0.8 + rms * 0.2;
      this.baselineFrames++;
      this.volume = rms;
      return;
    }

    const adaptiveThreshold = Math.max(this.volumeThreshold, this.noiseBaseline + 0.03);

    let diffSum = 0;
    const totalSum = sum || 1;
    for (let i = 1; i < pcm.length; i++) {
      const diff = (pcm[i] - pcm[i - 1]) / 32768;
      diffSum += diff * diff;
    }
    const highFreqRatio = diffSum / totalSum;

    this.volume = rms;

    const isAboveThreshold = rms > adaptiveThreshold;
    const isValidBarkSound = zcr >= this.minZCR && zcr <= this.maxZCR && highFreqRatio > 0.1;

    this.isBark = false;
    this.pushPower = 0;

    switch (this.state) {
      case 'SILENT':
        if (isAboveThreshold && isValidBarkSound) {
          this.state = 'ATTACK';
          this.stateStartTime = now;
        }
        break;

      case 'ATTACK':
        if (isAboveThreshold && isValidBarkSound) {
          this.state = 'SUSTAIN';
        } else if (!isAboveThreshold) {
          this.state = 'SILENT';
        }
        break;

      case 'SUSTAIN':
        if (!isAboveThreshold) {
          this.state = 'RELEASE';
        }
        break;

      case 'RELEASE':
        {
          const duration = (now - this.stateStartTime) / 1000;
          if (duration >= this.minBarkDuration && duration <= this.maxBarkDuration) {
            this._triggerBark(rms, now);
          }
          this.state = 'SILENT';
        }
        break;
    }

    if (this.state === 'SUSTAIN' || this.state === 'ATTACK') {
      const duration = (now - this.stateStartTime) / 1000;
      if (duration > this.maxBarkDuration) {
        this.state = 'SILENT';
      }
    }
  }

  _triggerBark(volume, now) {
    if (now - this.lastBarkTime < this.comboWindow) {
      this.combo++;
    } else {
      this.combo = 1;
    }
    this.lastBarkTime = now;
    this.isBark = true;

    const comboBonus = 1 + (this.combo - 1) * 0.2;
    this.pushPower = Math.min(volume * comboBonus * 3, 0.25);

    if (this.onBark) {
      this.onBark({
        volume,
        combo: this.combo,
        pushPower: this.pushPower,
        time: now
      });
    }
  }

  reset() {
    this.state = 'SILENT';
    this.combo = 0;
    this.volume = 0;
    this.isBark = false;
    this.pushPower = 0;
    this.baselineFrames = 0;
    this.noiseBaseline = 0;
  }

  getStatus() {
    return {
      volume: this.volume,
      isBark: this.isBark,
      combo: this.combo,
      pushPower: this.pushPower,
      state: this.state
    };
  }
}