frontend/src/hooks/useAudio.js

import { useState, useRef, useCallback } from "react";

export function useAudio() {
  const [isRecording, setIsRecording] = useState(false);
  const [audioBlob, setAudioBlob] = useState(null);
  const [audioUrl, setAudioUrl] = useState(null);
  const mediaRecorderRef = useRef(null);
  const chunksRef = useRef([]);
  const streamRef = useRef(null);

  const startRecording = useCallback(async () => {
    try {
      const stream = await navigator.mediaDevices.getUserMedia({ audio: true });
      streamRef.current = stream;

      // Web Audio API for gain normalization
      const ctx = new AudioContext();
      const source = ctx.createMediaStreamSource(stream);
      const gain = ctx.createGain();
      gain.gain.value = 3.5;
      const compressor = ctx.createDynamicsCompressor();
      compressor.threshold.value = -50;
      compressor.knee.value = 40;
      compressor.ratio.value = 20;
      compressor.attack.value = 0.003;
      compressor.release.value = 0.25;
      const dest = ctx.createMediaStreamDestination();
      source.connect(gain);
      gain.connect(compressor);
      compressor.connect(dest);

      const recorder = new MediaRecorder(dest.stream);
      chunksRef.current = [];
      recorder.ondataavailable = (e) => chunksRef.current.push(e.data);
      recorder.onstop = () => {
        const blob = new Blob(chunksRef.current, { type: "audio/webm" });
        const url = URL.createObjectURL(blob);
        setAudioBlob(blob);
        setAudioUrl(url);
        stream.getTracks().forEach((t) => t.stop());
      };

      mediaRecorderRef.current = recorder;
      recorder.start();
      setIsRecording(true);
    } catch (err) {
      console.error("Mic error:", err);
    }
  }, []);

  const stopRecording = useCallback(() => {
    if (mediaRecorderRef.current && isRecording) {
      mediaRecorderRef.current.stop();
      setIsRecording(false);
    }
  }, [isRecording]);

  const reset = useCallback(() => {
    setAudioBlob(null);
    setAudioUrl(null);
    setIsRecording(false);
  }, []);

  return { isRecording, audioBlob, audioUrl, startRecording, stopRecording, reset };
}