src/lib/audio-recorder.ts

// src/lib/audio-recorder.ts

import EventEmitter from "eventemitter3";
import { audioContext } from "./utils";
import VolMeterWorket from "./worklets/vol-meter";

const CHUNK_SIZE = 2048;

export class AudioRecorder extends EventEmitter {
  recording = false;
  private audioCtx: AudioContext | null = null;
  private microphone: MediaStreamAudioSourceNode | null = null;
  private processor: ScriptProcessorNode | null = null;
  private worklet: AudioWorkletNode | null = null;
  private stream: MediaStream | null = null;

  async start(): Promise<void> {
    if (this.recording) return;

    try {
      this.stream = await navigator.mediaDevices.getUserMedia({ audio: true });
      this.audioCtx = await audioContext({ id: "audio-in" });

      if (this.audioCtx.state === "suspended") {
        await this.audioCtx.resume();
      }

      await this.audioCtx.audioWorklet.addModule(VolMeterWorket);
      
      this.microphone = this.audioCtx.createMediaStreamSource(this.stream);
      this.processor = this.audioCtx.createScriptProcessor(CHUNK_SIZE, 1, 1);
      
      this.worklet = new AudioWorkletNode(this.audioCtx, "vumeter-in");
      this.worklet.port.onmessage = (ev) => {
        // رویداد جدید برای ارسال ولوم
        this.emit("volume", ev.data.volume);
      };

      this.processor.onaudioprocess = (e: AudioProcessingEvent) => {
        if (!this.recording) return;
        const inputData = e.inputBuffer.getChannelData(0);
        const pcm16Data = this.convertToPCM16(inputData);
        const base64 = this.toBase64(pcm16Data);
        // محاسبه ولوم در اینجا و ارسال آن همراه با داده‌ها
        const volume = this.getVolume(inputData);
        this.emit("data", base64, volume);
      };

      this.microphone.connect(this.processor);
      this.microphone.connect(this.worklet); // اتصال worklet برای گرفتن ولوم
      this.processor.connect(this.audioCtx.destination);

      this.recording = true;
      this.emit("start");
    } catch (err) {
      console.error("Error starting audio recording:", err);
      this.emit("error", err);
    }
  }

  stop(): void {
    if (!this.recording) return;

    this.recording = false;
    this.emit("stop");

    if (this.stream) {
      this.stream.getTracks().forEach((track) => track.stop());
    }
    if (this.microphone) {
      this.microphone.disconnect();
    }
    if (this.processor) {
      this.processor.disconnect();
    }
    if (this.worklet) {
        this.worklet.disconnect();
    }
  }

  private getVolume(data: Float32Array): number {
    let sum = 0;
    for (let i = 0; i < data.length; i++) {
        sum += data[i] * data[i];
    }
    const rms = Math.sqrt(sum / data.length);
    // نرمال‌سازی ولوم به یک مقدار بین 0 و 1
    return Math.min(1, rms * 5); // ضریب 5 برای محسوس‌تر کردن
  }

  private convertToPCM16(input: Float32Array): Int16Array {
    const output = new Int16Array(input.length);
    for (let i = 0; i < input.length; i++) {
      const s = Math.max(-1, Math.min(1, input[i]));
      output[i] = s < 0 ? s * 0x8000 : s * 0x7fff;
    }
    return output;
  }

  private toBase64(pcm16Data: Int16Array): string {
    const bytes = new Uint8Array(pcm16Data.buffer);
    let binary = "";
    for (let i = 0; i < bytes.byteLength; i++) {
      binary += String.fromCharCode(bytes[i]);
    }
    return btoa(binary);
  }
}