import { useEffect, useRef, useState } from 'react';
import { apiFetch } from '../api.js';
import {
  VOICE_MAX_RECORDING_MS,
  VOICE_MAX_UPLOAD_BYTES,
  VOICE_MIME_CANDIDATES
} from '../app-core-utils.js';

export function useVoiceInputRecorder({ onVoiceSubmit, onRateLimit, onBeforeStart }) {
  const mediaRecorderRef = useRef(null);
  const voiceChunksRef = useRef([]);
  const voiceStreamRef = useRef(null);
  const voiceTimerRef = useRef(null);
  const voiceErrorTimerRef = useRef(null);
  const [voiceState, setVoiceState] = useState('idle');
  const [voiceError, setVoiceError] = useState('');
  const voiceRecording = voiceState === 'recording';
  const voiceTranscribing = voiceState === 'transcribing';
  const voiceSending = voiceState === 'sending';

  useEffect(() => () => {
    clearVoiceTimer();
    clearVoiceErrorTimer();
    if (mediaRecorderRef.current?.state === 'recording') {
      mediaRecorderRef.current.onstop = null;
      mediaRecorderRef.current.stop();
    }
    stopVoiceStream();
  }, []);

  function setVoiceErrorBriefly(message) {
    clearVoiceErrorTimer();
    setVoiceError(message);
    voiceErrorTimerRef.current = window.setTimeout(() => {
      setVoiceError('');
      voiceErrorTimerRef.current = null;
    }, 2600);
  }

  function clearVoiceErrorTimer() {
    if (voiceErrorTimerRef.current) {
      window.clearTimeout(voiceErrorTimerRef.current);
      voiceErrorTimerRef.current = null;
    }
  }

  function clearVoiceTimer() {
    if (voiceTimerRef.current) {
      window.clearTimeout(voiceTimerRef.current);
      voiceTimerRef.current = null;
    }
  }

  function stopVoiceStream() {
    voiceStreamRef.current?.getTracks?.().forEach((track) => track.stop());
    voiceStreamRef.current = null;
  }

  function voiceMimeType() {
    if (!window.MediaRecorder?.isTypeSupported) {
      return '';
    }
    return VOICE_MIME_CANDIDATES.find((type) => window.MediaRecorder.isTypeSupported(type)) || '';
  }

  async function transcribeVoiceBlob(blob) {
    if (!blob?.size) {
      setVoiceErrorBriefly('没有录到声音');
      return '';
    }
    if (blob.size > VOICE_MAX_UPLOAD_BYTES) {
      setVoiceErrorBriefly('录音超过 10MB');
      return '';
    }

    const formData = new FormData();
    const extension = blob.type.includes('mp4') ? 'm4a' : 'webm';
    formData.append('audio', blob, `voice.${extension}`);

    try {
      const result = await apiFetch('/api/voice/transcribe', {
        method: 'POST',
        body: formData
      });
      if (!result.text?.trim()) {
        setVoiceErrorBriefly('没有识别到文字');
        return '';
      }
      return result.text.trim();
    } catch (error) {
      onRateLimit?.(error, 'voice');
      setVoiceErrorBriefly(error.message || '语音转写失败');
      return '';
    }
  }

  async function startVoiceRecording() {
    onBeforeStart?.();
    clearVoiceErrorTimer();
    setVoiceError('');
    if (window.location.protocol !== 'https:') {
      setVoiceErrorBriefly('请使用 HTTPS 地址或 iOS 键盘听写');
      return;
    }
    if (!navigator.mediaDevices?.getUserMedia || !window.MediaRecorder) {
      setVoiceErrorBriefly('当前浏览器不支持录音');
      return;
    }

    try {
      const stream = await navigator.mediaDevices.getUserMedia({ audio: true });
      const mimeType = voiceMimeType();
      const recorder = new MediaRecorder(stream, mimeType ? { mimeType } : undefined);
      voiceStreamRef.current = stream;
      voiceChunksRef.current = [];
      mediaRecorderRef.current = recorder;

      recorder.ondataavailable = (event) => {
        if (event.data?.size) {
          voiceChunksRef.current.push(event.data);
        }
      };
      recorder.onerror = () => {
        clearVoiceTimer();
        stopVoiceStream();
        setVoiceState('idle');
        setVoiceErrorBriefly('录音失败');
      };
      recorder.onstop = async () => {
        clearVoiceTimer();
        stopVoiceStream();
        const recordedType = recorder.mimeType || mimeType || 'audio/webm';
        const blob = new Blob(voiceChunksRef.current, { type: recordedType });
        voiceChunksRef.current = [];
        mediaRecorderRef.current = null;
        try {
          setVoiceState('transcribing');
          const transcript = await transcribeVoiceBlob(blob);
          if (transcript) {
            setVoiceState('sending');
            await onVoiceSubmit(transcript);
          }
        } catch (error) {
          setVoiceErrorBriefly(error.message || '语音发送失败');
        } finally {
          setVoiceState('idle');
        }
      };

      recorder.start();
      setVoiceState('recording');
      voiceTimerRef.current = window.setTimeout(() => {
        if (mediaRecorderRef.current?.state === 'recording') {
          setVoiceState('transcribing');
          mediaRecorderRef.current.stop();
        }
      }, VOICE_MAX_RECORDING_MS);
    } catch (error) {
      clearVoiceTimer();
      stopVoiceStream();
      mediaRecorderRef.current = null;
      setVoiceState('idle');
      const denied = error?.name === 'NotAllowedError' || error?.name === 'SecurityError';
      setVoiceErrorBriefly(denied ? '麦克风权限被拒绝' : '录音启动失败');
    }
  }

  function stopVoiceRecording() {
    if (mediaRecorderRef.current?.state === 'recording') {
      clearVoiceErrorTimer();
      setVoiceError('');
      setVoiceState('transcribing');
      mediaRecorderRef.current.stop();
      return;
    }
    clearVoiceTimer();
    stopVoiceStream();
    setVoiceState('idle');
  }

  function toggleVoiceInput() {
    if (voiceRecording) {
      stopVoiceRecording();
    } else if (!voiceTranscribing && !voiceSending) {
      startVoiceRecording();
    }
  }

  return {
    voiceState,
    voiceError,
    voiceRecording,
    voiceTranscribing,
    voiceSending,
    toggleVoiceInput
  };
}