import { useState, useRef, useEffect, useCallback } from "react";
import { AudioRecorder } from "../audio/AudioRecorder";
import { AudioPlayer } from "../audio/AudioPlayer";
import { createWavBlob, speechToText } from "../services/voiceApi";

export type VoiceState =
  | "IDLE"
  | "CONNECTING"
  | "LISTENING"
  | "PROCESSING"
  | "SPEAKING"
  | "ERROR";

export interface VoiceSessionParams {
  sttProvider?: string;
  ttsProvider?: string;
}

interface UseVoiceSessionOptions {
  onTranscript: (text: string) => void;
  onError?: (code: string, message: string) => void;
  sessionParams?: VoiceSessionParams;
}

export interface UseVoiceSessionReturn {
  voiceState: VoiceState;
  start: () => Promise<void>;
  stop: () => void;
  stopRecording: () => void;
  setStateExternal: (s: VoiceState) => void;
  isActive: boolean;
}

const BUFFER_SOUNDS = [
  "/sounds/01_Baik_Saya_sedang_memproses_pertanyaanmu.wav",
  "/sounds/02_Oke_mohon_ditunggu_saya_sedang_siapkan_P.wav",
  "/sounds/03_Sip_saya_terima_Sedang_saya_proses_Pesan.wav",
];

const RECORDER_SAMPLE_RATE = 16000;

function getVoiceHttpBaseUrl(): string {
  const w = window as unknown as { __APP_CONFIG__?: { VOICE_API_URL?: string } };
  return (
    w.__APP_CONFIG__?.VOICE_API_URL ||
    (import.meta as unknown as { env: Record<string, string> }).env.VITE_API_BASE_VOICE_URL ||
    "http://localhost:7861"
  );
}

export function useVoiceSession(opts: UseVoiceSessionOptions): UseVoiceSessionReturn {
  const [voiceState, setVoiceState] = useState<VoiceState>("IDLE");
  const stateRef = useRef<VoiceState>("IDLE");

  const recorderRef = useRef<AudioRecorder | null>(null);
  const playerRef = useRef<AudioPlayer | null>(null);
  const chunksRef = useRef<ArrayBuffer[]>([]);

  const bufferAudioRef = useRef<HTMLAudioElement | null>(null);
  const lastBufferIndexRef = useRef<number>(-1);

  const optsRef = useRef(opts);
  useEffect(() => { optsRef.current = opts; });

  // Defined before setState so setState can call it without circular deps.
  const stopBufferSound = useCallback(() => {
    if (bufferAudioRef.current) {
      bufferAudioRef.current.pause();
      bufferAudioRef.current.currentTime = 0;
      bufferAudioRef.current = null;
    }
  }, []);

  // Auto-stops the buffer audio when the waiting phase ends (TTS about to start, or session ends).
  const setState = useCallback((s: VoiceState) => {
    if (s === "SPEAKING" || s === "IDLE" || s === "ERROR") {
      stopBufferSound();
    }
    stateRef.current = s;
    setVoiceState(s);
  }, [stopBufferSound]);

  const playBufferSound = useCallback(() => {
    stopBufferSound();
    let idx: number;
    do {
      idx = Math.floor(Math.random() * BUFFER_SOUNDS.length);
    } while (BUFFER_SOUNDS.length > 1 && idx === lastBufferIndexRef.current);
    lastBufferIndexRef.current = idx;
    const audio = new Audio(BUFFER_SOUNDS[idx]);
    bufferAudioRef.current = audio;
    audio.play().catch(() => {});
  }, [stopBufferSound]);

  const stopSession = useCallback(() => {
    recorderRef.current?.stop();
    playerRef.current?.stopImmediately();
    chunksRef.current = [];
    setState("IDLE"); // setState("IDLE") calls stopBufferSound internally
  }, [setState]);

  const stopRecording = useCallback(() => {
    if (stateRef.current !== "LISTENING") return;
    setState("PROCESSING");
    recorderRef.current?.stop();
    // Play buffer audio — it keeps playing through STT and chatbot processing.
    // It stops automatically when setState("SPEAKING"), setState("IDLE"), or setState("ERROR") is called.
    playBufferSound();

    const chunks = chunksRef.current;
    chunksRef.current = [];

    void (async () => {
      try {
        if (chunks.length === 0) {
          setState("IDLE");
          return;
        }

        const wav = createWavBlob(chunks, RECORDER_SAMPLE_RATE);
        const { text } = await speechToText(wav, optsRef.current.sessionParams?.sttProvider ?? "chirp3");

        // Guard: session may have been cancelled while STT was in flight.
        if (stateRef.current !== "PROCESSING") return;

        if (text.trim()) {
          console.log("[Voice] STT transcript →", text);
          // Buffer audio continues to play while Main.tsx calls the chatbot API.
          // It will stop when setStateExternal("SPEAKING") or setStateExternal("IDLE") is called.
          optsRef.current.onTranscript(text);
        } else {
          setState("IDLE");
        }
      } catch (err) {
        console.error("[STT] Request failed:", err);
        optsRef.current.onError?.("STT_ERROR", (err as Error).message);
        setState("ERROR"); // setState("ERROR") calls stopBufferSound internally
      }
    })();
  }, [playBufferSound, setState]);

  const start = useCallback(async () => {
    if (stateRef.current !== "IDLE" && stateRef.current !== "ERROR") return;
    setState("CONNECTING");

    try {
      const res = await fetch(`${getVoiceHttpBaseUrl()}/health`);
      if (res.ok) {
        const data: { status: string; message?: string } = await res.json();
        if (data.status !== "ok") {
          setState("ERROR");
          optsRef.current.onError?.("HEALTH_CHECK_FAILED", data.message ?? "Service not ready");
          return;
        }
      }
    } catch {
      // Network error or CORS — proceed with connect attempt
    }

    try {
      chunksRef.current = [];
      if (!recorderRef.current) recorderRef.current = new AudioRecorder();
      if (!playerRef.current) playerRef.current = new AudioPlayer();

      await recorderRef.current.start((chunk: ArrayBuffer) => {
        if (stateRef.current === "LISTENING") {
          chunksRef.current.push(chunk);
        }
      });

      setState("LISTENING");
    } catch (err) {
      console.error("[Voice] Failed to start recorder:", err);
      recorderRef.current?.stop();
      optsRef.current.onError?.("MIC_ERROR", (err as Error).message ?? "Failed to access microphone");
      setState("ERROR");
    }
  }, [setState]);

  useEffect(() => {
    return () => {
      stopSession();
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  return {
    voiceState,
    start,
    stop: stopSession,
    stopRecording,
    setStateExternal: setState,
    isActive: voiceState !== "IDLE" && voiceState !== "ERROR",
  };
}