import React, { useState, useEffect, useRef } from 'react';

interface VoiceInputProps {
  onTranscript: (text: string) => void;
  isProcessing: boolean;
  isFullWidth?: boolean;
}

const VoiceInput: React.FC<VoiceInputProps> = ({ onTranscript, isProcessing, isFullWidth = false }) => {
  const [isListening, setIsListening] = useState(false);
  const recognitionRef = useRef<any>(null);
  const isStartingRef = useRef(false);
  const onTranscriptRef = useRef(onTranscript);

  // 始终保持 ref 为最新，避免在 useEffect 中依赖 onTranscript 导致重复初始化
  useEffect(() => {
    onTranscriptRef.current = onTranscript;
  }, [onTranscript]);

  const initRecognition = () => {
    if (!('SpeechRecognition' in window || 'webkitSpeechRecognition' in window)) return;
    
    // 如果已有实例，先清理
    if (recognitionRef.current) {
      try {
        recognitionRef.current.abort();
      } catch (e) {}
    }

    const SpeechRecognition = (window as any).SpeechRecognition || (window as any).webkitSpeechRecognition;
    const recognition = new SpeechRecognition();
    
    recognition.continuous = true;
    recognition.lang = 'zh-CN';
    recognition.interimResults = true;

    recognition.onstart = () => {
      setIsListening(true);
      isStartingRef.current = false;
      console.log('Speech recognition started');
    };

    recognition.onresult = (event: any) => {
      const results = event.results;
      for (let i = event.resultIndex; i < results.length; i++) {
        if (results[i].isFinal) {
          const transcript = results[i][0].transcript;
          if (transcript) onTranscriptRef.current(transcript);
        }
      }
    };

    recognition.onerror = async (event: any) => {
      console.error('Speech recognition error', event.error);
      
      let message = '';
      switch (event.error) {
        case 'network':
          message = "语音识别网络连接失败。请检查网络或尝试切换浏览器（推荐 Chrome/Edge）。";
          break;
        case 'not-allowed':
        case 'service-not-allowed':
          // 移动端初次授权时可能触发 race condition：用户点击“允许”但 start() 已超时失败
          // 此时我们通过 getUserMedia 探测真实权限状态
          try {
            const stream = await navigator.mediaDevices.getUserMedia({ audio: true });
            // 如果能获取到流，说明权限其实是有的，只是刚才 start() 冲突了
            stream.getTracks().forEach(t => t.stop());
            console.log('Permission probe successful, refreshing recognition instance...');
            isStartingRef.current = false;
            setIsListening(false);
            initRecognition(); // 静默重置实例
            return; // 不弹窗，用户再次点击就会成功
          } catch (e) {
            // 探测也失败，说明是真的被拒绝了
            message = "麦克风访问被拒绝。\n\n解决办法：\n1. 点击地址栏左侧的“锁”或“设置”图标\n2. 找到“麦克风”并设为“允许”\n3. 刷新页面后重试";
          }
          break;
        case 'no-speech':
          return;
        case 'aborted':
          return;
        default:
          break;
      }
      
      if (message) alert(message);
      
      setIsListening(false);
      isStartingRef.current = false;
      // 出错后重新初始化，确保下次点击可用
      initRecognition();
    };

    recognition.onend = () => {
      console.log('Speech recognition ended');
      setIsListening(false);
      isStartingRef.current = false;
    };

    recognitionRef.current = recognition;
  };

  useEffect(() => {
    initRecognition();
    return () => {
      if (recognitionRef.current) {
        try {
          recognitionRef.current.abort();
        } catch (e) {}
      }
    };
  }, []);

  const startListening = (e: React.PointerEvent) => {
    e.stopPropagation();
    if (e.cancelable) e.preventDefault();
    
    // 如果已经在处理中、正在监听或正在启动，则忽略
    if (isProcessing || isListening || isStartingRef.current) return;

    // 获取指针捕获，确保即使手指移出按钮范围也能触发 onPointerUp
    try {
      (e.currentTarget as HTMLElement).setPointerCapture(e.pointerId);
    } catch (err) {
      console.warn("Failed to set pointer capture", err);
    }

    if (recognitionRef.current) {
      // 检查是否为安全上下文 (HTTPS 或 localhost)
      if (!window.isSecureContext) {
        alert("语音识别失败：浏览器限制在非 HTTPS 环境下使用麦克风。请确保使用 HTTPS 访问，或在 PC 端 Chrome 的 'Insecure origins treated as secure' 中设置白名单。");
        return;
      }

      try {
        isStartingRef.current = true;
        recognitionRef.current.start();
        // UI 状态会在 onstart 回调中更新，以保证真实感
      } catch (err) {
        console.error("Failed to start recognition", err);
        isStartingRef.current = false;
        setIsListening(false);
      }
    } else {
      if (!window.isSecureContext) {
        alert("浏览器不支持语音识别：当前环境不是安全上下文 (HTTPS)。");
      } else {
        alert("您的浏览器不支持语音识别，请使用 Chrome 或 Edge。");
      }
    }
  };

  const stopListening = (e: React.PointerEvent) => {
    e.stopPropagation();
    
    // 只有在正在运行或正在启动时才尝试停止
    if (isListening || isStartingRef.current) {
      try {
        recognitionRef.current?.stop();
      } catch (err) {
        console.error("Failed to stop recognition", err);
        // 发生错误时强制重置本地状态
        setIsListening(false);
        isStartingRef.current = false;
      }
    }
  };

  return (
    <div className={`${isFullWidth ? 'w-full' : ''} relative select-none touch-none`}>
      <button
        onPointerDown={startListening}
        onPointerUp={stopListening}
        onPointerCancel={stopListening}
        onClick={(e) => e.preventDefault()}
        onContextMenu={(e) => e.preventDefault()}
        disabled={isProcessing}
        style={{ WebkitTouchCallout: 'none' }}
        className={`relative flex items-center justify-center transition-all duration-300 active:scale-95 shadow-lg ${
          isFullWidth 
            ? 'w-full py-4 rounded-2xl font-bold text-sm tracking-widest' 
            : 'w-14 h-14 rounded-full'
        } ${
          isListening
            ? 'bg-rose-500 text-white shadow-rose-200 scale-105'
            : 'bg-indigo-600 text-white shadow-indigo-100'
        } ${isProcessing ? 'opacity-50 grayscale cursor-not-allowed' : ''}`}
      >
        {isListening && (
          <div className="absolute inset-0 rounded-2xl animate-ping bg-rose-400 opacity-20"></div>
        )}
        
        <div className="flex items-center gap-2 z-10">
          <svg xmlns="http://www.w3.org/2000/svg" className={`${isFullWidth ? 'h-5 w-5' : 'h-6 w-6'}`} fill="none" viewBox="0 0 24 24" stroke="currentColor">
            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2.5} d="M19 11a7 7 0 01-7 7m0 0a7 7 0 01-7-7m7 7v4m0 0H8m4 0h4m-4-8a3 3 0 01-3-3V5a3 3 0 116 0v6a3 3 0 01-3 3z" />
          </svg>
          {isFullWidth && <span>{isListening ? '松开 结束' : '按住 说话'}</span>}
        </div>
      </button>
      
      {isListening && isFullWidth && (
        <div className="absolute -top-16 left-0 right-0 flex justify-center animate-bounce">
          <div className="bg-rose-500 text-white px-4 py-2 rounded-full text-xs font-bold shadow-xl border-2 border-white">
            正在录音...
          </div>
        </div>
      )}
    </div>
  );
};

export default VoiceInput;