import { useState, useEffect, useCallback, useRef } from 'react';
import { Settings2, Zap, Mic, MessageSquare } from 'lucide-react';
import VoicePanel from './components/VoicePanel';
import ChatPanel from './components/ChatPanel';
import SettingsPanel from './components/SettingsPanel';
import { getVoiceConfig } from './services/voiceApi';

export default function App() {
  const [showSettings, setShowSettings] = useState(false);
  const [voiceConfig, setVoiceConfig] = useState(null);
  // 'voice' | 'chat'
  const [mode, setMode] = useState('voice');
  // 统一会话 ID（贯穿语音和文字模式，数据库用此 ID 关联所有消息）
  const [currentSessionId, setCurrentSessionId] = useState(null);
  // 语音转文字的交接数据（保留兼容）
  const [handoff, setHandoff] = useState(null);
  // 文字聊天消息（用于切回语音时注入上下文）
  const [chatMessages, setChatMessages] = useState([]);
  const [settings, setSettings] = useState({
    botName: '小智',
    systemRole: '你是一个友善的智能助手，名叫小智。你擅长帮用户解答各类问题。',
    speakingStyle: '请使用温和、清晰的口吻。',
    modelVersion: '1.2.1.0',
    speaker: 'zh_female_vv_jupiter_bigtts',
    enableWebSearch: false,
  });

  useEffect(() => {
    getVoiceConfig()
      .then(setVoiceConfig)
      .catch((err) => console.warn('Failed to load config:', err));
  }, []);

  // 语音通话结束后，无缝切换到文字对话（携带同一个 sessionId）
  const handleVoiceEnd = useCallback((data) => {
    if (data?.sessionId) {
      const sid = data.sessionId;
      setCurrentSessionId(sid);
      setHandoff({
        sessionId: sid,
        subtitles: data.subtitles || [],
      });
      setMode('chat');
      console.log(`[App] Voice→Chat, sessionId=${sid}`);
    }
  }, []);

  // 从文字模式返回语音模式（使用同一个 sessionId，数据库已有完整历史）
  const handleBackToVoice = useCallback(() => {
    console.log(`[App] Chat→Voice, sessionId=${currentSessionId}`);
    setMode('voice');
  }, [currentSessionId]);

  // 直接进入文字模式（新会话）
  const handleStartChat = useCallback(() => {
    const newSid = `chat_${Date.now().toString(36)}`;
    setCurrentSessionId(newSid);
    setHandoff({
      sessionId: newSid,
      subtitles: [],
    });
    setMode('chat');
    console.log(`[App] New chat session: ${newSid}`);
  }, []);

  return (
    <div className="min-h-screen bg-gradient-to-br from-slate-900 via-slate-800 to-slate-900">
      {/* Header */}
      <header className="border-b border-slate-700/50 bg-slate-900/80 backdrop-blur-sm sticky top-0 z-30">
        <div className="max-w-5xl mx-auto px-3 sm:px-4 h-14 flex items-center justify-between">
          <div className="flex items-center gap-2.5">
            <div className="w-8 h-8 rounded-lg bg-gradient-to-br from-violet-500 to-indigo-600 flex items-center justify-center">
              <Zap className="w-4 h-4 text-white" />
            </div>
            <div>
              <h1 className="text-sm font-semibold text-white leading-tight">
                {mode === 'voice' ? '语音通话' : '文字对话'}
              </h1>
              <p className="text-[11px] text-slate-400 leading-tight">
                {mode === 'voice'
                  ? '混合编排模式 · OutputMode=1'
                  : handoff?.subtitles?.length > 0
                    ? '语音转接 · 上下文已延续'
                    : '方舟 LLM · Function Calling'}
              </p>
            </div>
          </div>
          <div className="flex items-center gap-1.5">
            {/* Mode toggle buttons */}
            <div className="flex items-center bg-slate-800/60 rounded-lg border border-slate-700/40 p-0.5 mr-2">
              <button
                onClick={() => { if (mode !== 'voice') handleBackToVoice(); }}
                className={`flex items-center gap-1 px-2.5 py-1 rounded-md text-xs transition-all ${
                  mode === 'voice'
                    ? 'bg-violet-500/20 text-violet-300 font-medium'
                    : 'text-slate-500 hover:text-slate-300'
                }`}
              >
                <Mic className="w-3 h-3" /> 语音
              </button>
              <button
                onClick={() => { if (mode !== 'chat') handleStartChat(); }}
                className={`flex items-center gap-1 px-2.5 py-1 rounded-md text-xs transition-all ${
                  mode === 'chat'
                    ? 'bg-violet-500/20 text-violet-300 font-medium'
                    : 'text-slate-500 hover:text-slate-300'
                }`}
              >
                <MessageSquare className="w-3 h-3" /> 文字
              </button>
            </div>
            {mode === 'voice' && (
              <button
                onClick={() => setShowSettings(!showSettings)}
                className="p-2 rounded-lg hover:bg-slate-700/50 text-slate-400 hover:text-white transition-colors"
                title="语音设置"
              >
                <Settings2 className="w-5 h-5" />
              </button>
            )}
          </div>
        </div>
      </header>

      <main className="max-w-5xl mx-auto px-4 py-6">
        {/* Settings Panel */}
        {showSettings && mode === 'voice' && (
          <SettingsPanel
            settings={settings}
            onChange={setSettings}
            voiceConfig={voiceConfig}
            onClose={() => setShowSettings(false)}
          />
        )}

        {mode === 'voice' ? (
          <>
            {/* Voice Panel */}
            <VoicePanel settings={settings} onVoiceEnd={handleVoiceEnd} chatHistory={chatMessages} sessionId={currentSessionId} />

            {/* Architecture Info */}
            <div className="mt-6 p-4 rounded-xl bg-slate-800/40 border border-slate-700/40">
              <h3 className="text-xs font-semibold text-slate-400 uppercase tracking-wider mb-3">方案B 混合编排架构</h3>
              <div className="grid grid-cols-1 md:grid-cols-3 gap-3 text-xs">
                <div className="p-3 rounded-lg bg-slate-700/30 border border-slate-600/30">
                  <div className="text-emerald-400 font-medium mb-1">闲聊场景</div>
                  <div className="text-slate-400">端到端模型直接回复 · ~300-800ms</div>
                </div>
                <div className="p-3 rounded-lg bg-slate-700/30 border border-slate-600/30">
                  <div className="text-amber-400 font-medium mb-1">工具调用场景</div>
                  <div className="text-slate-400">LLM 决策 + Function Calling · ~1-2s</div>
                </div>
                <div className="p-3 rounded-lg bg-slate-700/30 border border-slate-600/30">
                  <div className="text-violet-400 font-medium mb-1">自动切换</div>
                  <div className="text-slate-400">系统自动判断走 S2S 或 LLM 分支</div>
                </div>
              </div>
            </div>
          </>
        ) : (
          /* Chat Panel */
          handoff && (
            <ChatPanel
              sessionId={handoff.sessionId}
              voiceSubtitles={handoff.subtitles}
              settings={settings}
              onBack={handleBackToVoice}
              onMessagesChange={setChatMessages}
            />
          )
        )}
      </main>
    </div>
  );
}