import { useCallback, useRef, useState } from "react";
import { encodeWav, resampleTo16kMono, TARGET_SAMPLE_RATE } from "../utils/wavEncoder";

export type RecorderStatus = "idle" | "recording" | "recorded" | "error";

export function useAudioRecorder() {
  const [status, setStatus] = useState<RecorderStatus>("idle");
  const [seconds, setSeconds] = useState(0);
  const [error, setError] = useState<string | null>(null);
  const [audioUrl, setAudioUrl] = useState<string | null>(null);
  const [audioFile, setAudioFile] = useState<File | null>(null);

  const streamRef = useRef<MediaStream | null>(null);
  const contextRef = useRef<AudioContext | null>(null);
  const processorRef = useRef<ScriptProcessorNode | null>(null);
  const chunksRef = useRef<Float32Array[]>([]);
  const timerRef = useRef<number | null>(null);
  const recordingRef = useRef(false);

  const cleanupStream = useCallback(() => {
    streamRef.current?.getTracks().forEach((track) => track.stop());
    streamRef.current = null;
    processorRef.current?.disconnect();
    processorRef.current = null;
    if (contextRef.current?.state !== "closed") {
      void contextRef.current?.close();
    }
    contextRef.current = null;
  }, []);

  const reset = useCallback(() => {
    if (timerRef.current) {
      window.clearInterval(timerRef.current);
      timerRef.current = null;
    }
    recordingRef.current = false;
    cleanupStream();
    chunksRef.current = [];
    if (audioUrl) URL.revokeObjectURL(audioUrl);
    setAudioUrl(null);
    setAudioFile(null);
    setSeconds(0);
    setError(null);
    setStatus("idle");
  }, [audioUrl, cleanupStream]);

  const start = useCallback(async () => {
    reset();

    if (!navigator.mediaDevices?.getUserMedia) {
      setError("المتصفح لا يدعم التسجيل الصوتي.");
      setStatus("error");
      return;
    }

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

      const context = new AudioContext();
      contextRef.current = context;

      const source = context.createMediaStreamSource(stream);
      const processor = context.createScriptProcessor(4096, 1, 1);
      processorRef.current = processor;
      chunksRef.current = [];
      recordingRef.current = true;

      processor.onaudioprocess = (event) => {
        if (!recordingRef.current) return;
        const channel = event.inputBuffer.getChannelData(0);
        chunksRef.current.push(new Float32Array(channel));
      };

      source.connect(processor);
      processor.connect(context.destination);

      setStatus("recording");
      setSeconds(0);
      timerRef.current = window.setInterval(() => {
        setSeconds((s) => s + 1);
      }, 1000);
    } catch {
      setError("تعذّر الوصول للميكروفون. تأكّد من منح الإذن.");
      setStatus("error");
      cleanupStream();
    }
  }, [cleanupStream, reset]);

  const stop = useCallback(async () => {
    recordingRef.current = false;

    if (timerRef.current) {
      window.clearInterval(timerRef.current);
      timerRef.current = null;
    }

    const context = contextRef.current;
    const chunks = chunksRef.current;

    cleanupStream();

    if (!context || chunks.length === 0) {
      setError("لم يُسجَّل أي صوت.");
      setStatus("error");
      return;
    }

    try {
      const sampleRate = context.sampleRate;
      const totalLength = chunks.reduce((sum, c) => sum + c.length, 0);
      const merged = new Float32Array(totalLength);
      let offset = 0;
      for (const chunk of chunks) {
        merged.set(chunk, offset);
        offset += chunk.length;
      }

      const audioBuffer = context.createBuffer(1, merged.length, sampleRate);
      audioBuffer.copyToChannel(merged, 0);

      const samples = await resampleTo16kMono(audioBuffer);
      const wavBlob = encodeWav(samples, TARGET_SAMPLE_RATE);
      const url = URL.createObjectURL(wavBlob);
      const file = new File([wavBlob], "recording.wav", { type: "audio/wav" });

      setAudioUrl(url);
      setAudioFile(file);
      setStatus("recorded");
    } catch {
      setError("تعذّر تحضير التسجيل الصوتي.");
      setStatus("error");
    }
  }, [cleanupStream]);

  return {
    status,
    seconds,
    error,
    audioUrl,
    audioFile,
    start,
    stop,
    reset,
  };
}

export function formatTime(totalSeconds: number): string {
  const m = Math.floor(totalSeconds / 60)
    .toString()
    .padStart(2, "0");
  const s = (totalSeconds % 60).toString().padStart(2, "0");
  return `${m}:${s}`;
}