import React, { useState, useRef, useEffect } from 'react';
import { Send, Image as ImageIcon, Loader2, Bot, User, X, Leaf, Globe, Search, AlertTriangle, Camera } from 'lucide-react';
import { Message, LoadingState } from '../types';
import { geminiService } from '../services/geminiService';

const ChatInterface: React.FC = () => {
  const [messages, setMessages] = useState<Message[]>([
    {
      id: 'welcome',
      role: 'model',
      text: "Welcome to Budtender AI. I can help you find strain information or analyze your cannabis products. Upload a photo or use your camera to show me a strain!"
    }
  ]);
  const [inputValue, setInputValue] = useState('');
  const [selectedImage, setSelectedImage] = useState<File | null>(null);
  const [imagePreview, setImagePreview] = useState<string | null>(null);
  const [loadingState, setLoadingState] = useState<LoadingState>(LoadingState.IDLE);
  
  // Camera State
  const [isCameraOpen, setIsCameraOpen] = useState(false);
  const videoRef = useRef<HTMLVideoElement>(null);
  const canvasRef = useRef<HTMLCanvasElement>(null);
  const streamRef = useRef<MediaStream | null>(null);

  const messagesEndRef = useRef<HTMLDivElement>(null);
  const fileInputRef = useRef<HTMLInputElement>(null);

  // Auto-scroll to bottom
  useEffect(() => {
    messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' });
  }, [messages, loadingState]);

  // Clean up camera stream when component unmounts
  useEffect(() => {
    return () => {
      stopCamera();
    };
  }, []);

  const startCamera = async () => {
    setIsCameraOpen(true);
    try {
      const stream = await navigator.mediaDevices.getUserMedia({ 
        video: { facingMode: 'environment' } // Prefer back camera on mobile
      });
      streamRef.current = stream;
      if (videoRef.current) {
        videoRef.current.srcObject = stream;
      }
    } catch (err) {
      console.error("Error accessing camera:", err);
      setIsCameraOpen(false);
      alert("Could not access camera. Please allow permissions.");
    }
  };

  const stopCamera = () => {
    if (streamRef.current) {
      streamRef.current.getTracks().forEach(track => track.stop());
      streamRef.current = null;
    }
    setIsCameraOpen(false);
  };

  const capturePhoto = () => {
    if (videoRef.current && canvasRef.current) {
      const video = videoRef.current;
      const canvas = canvasRef.current;
      
      // Set canvas dimensions to match video
      canvas.width = video.videoWidth;
      canvas.height = video.videoHeight;
      
      // Draw video frame to canvas
      const context = canvas.getContext('2d');
      if (context) {
        context.drawImage(video, 0, 0, canvas.width, canvas.height);
        
        // Convert to data URL
        const dataUrl = canvas.toDataURL('image/jpeg');
        setImagePreview(dataUrl);
        
        // Convert to File object (optional, but good for consistency)
        fetch(dataUrl)
          .then(res => res.blob())
          .then(blob => {
            const file = new File([blob], "camera-capture.jpg", { type: "image/jpeg" });
            setSelectedImage(file);
          });
          
        stopCamera();
      }
    }
  };

  const handleImageSelect = (e: React.ChangeEvent<HTMLInputElement>) => {
    if (e.target.files && e.target.files[0]) {
      const file = e.target.files[0];
      setSelectedImage(file);
      
      const reader = new FileReader();
      reader.onloadend = () => {
        setImagePreview(reader.result as string);
      };
      reader.readAsDataURL(file);
    }
  };

  const clearImage = () => {
    setSelectedImage(null);
    setImagePreview(null);
    if (fileInputRef.current) fileInputRef.current.value = '';
  };

  const handleSendMessage = async () => {
    if ((!inputValue.trim() && !selectedImage) || loadingState !== LoadingState.IDLE) return;

    const userText = inputValue.trim();
    const currentImage = imagePreview; // Store ref for the message bubble
    
    // Clear inputs immediately
    setInputValue('');
    clearImage();
    setLoadingState(LoadingState.SEARCHING); // Default to searching/thinking since we use Google Search

    // Add user message to UI
    const newMessage: Message = {
      id: Date.now().toString(),
      role: 'user',
      text: userText,
      image: currentImage || undefined
    };
    setMessages(prev => [...prev, newMessage]);

    try {
      // Prepare image for API (strip base64 header)
      let base64Data: string | undefined = undefined;
      if (currentImage) {
        base64Data = currentImage.split(',')[1];
      }

      // Call Gemini
      const response = await geminiService.sendMessage(
        userText || (base64Data ? "Analyze this image and tell me about it." : "Hello"),
        base64Data
      );

      setMessages(prev => [
        ...prev,
        {
          id: (Date.now() + 1).toString(),
          role: 'model',
          text: response.text,
          groundingMetadata: response.groundingMetadata
        }
      ]);

    } catch (error: any) {
      console.error("Chat Error:", error);
      let errorMessage = "I'm sorry, I encountered an error connecting to the knowledge base.";
      
      if (error.message?.includes('API key')) {
        errorMessage = "Error: API Key is missing or invalid. Please check your configuration.";
      } else if (error.message) {
        errorMessage = `Error: ${error.message}`;
      }

      setMessages(prev => [
        ...prev,
        {
          id: (Date.now() + 1).toString(),
          role: 'model',
          text: errorMessage,
          isError: true
        }
      ]);
    } finally {
      setLoadingState(LoadingState.IDLE);
    }
  };

  const handleKeyDown = (e: React.KeyboardEvent) => {
    if (e.key === 'Enter' && !e.shiftKey) {
      e.preventDefault();
      handleSendMessage();
    }
  };

  const getLoadingText = (state: LoadingState) => {
    switch (state) {
        case LoadingState.SEARCHING: return "Searching the Web...";
        case LoadingState.THINKING: return "Thinking...";
        default: return "Processing...";
    }
  };

  return (
    <div className="flex flex-col h-full bg-gray-900 relative">
      {/* Header */}
      <header className="bg-gray-800/50 backdrop-blur-sm border-b border-gray-700 p-4 flex items-center justify-between sticky top-0 z-10">
        <div className="flex items-center gap-3">
          <div className="w-10 h-10 rounded-full bg-emerald-600 flex items-center justify-center shadow-lg shadow-emerald-900/20">
            <Leaf className="w-6 h-6 text-emerald-100" />
          </div>
          <div>
            <h1 className="font-bold text-white text-lg">Budtender AI</h1>
            <p className="text-xs text-gray-400">Powered by Gemini & Google Search</p>
          </div>
        </div>
      </header>

      {/* Camera Modal */}
      {isCameraOpen && (
        <div className="fixed inset-0 z-50 bg-black/90 flex flex-col items-center justify-center p-4">
          <div className="relative w-full max-w-lg bg-gray-900 rounded-2xl overflow-hidden shadow-2xl border border-gray-800">
            <video 
              ref={videoRef} 
              autoPlay 
              playsInline 
              className="w-full h-[60vh] object-cover bg-black"
            />
            <canvas ref={canvasRef} className="hidden" />
            
            <div className="absolute bottom-0 left-0 right-0 p-6 bg-gradient-to-t from-black/80 to-transparent flex items-center justify-between">
              <button 
                onClick={stopCamera}
                className="p-3 bg-gray-800/80 text-white rounded-full hover:bg-gray-700 transition-colors"
              >
                <X size={24} />
              </button>
              
              <button 
                onClick={capturePhoto}
                className="w-16 h-16 rounded-full border-4 border-white flex items-center justify-center bg-transparent hover:bg-white/20 transition-all active:scale-95"
              >
                <div className="w-12 h-12 bg-emerald-500 rounded-full"></div>
              </button>
              
              <div className="w-12"></div> {/* Spacer for alignment */}
            </div>
          </div>
          <p className="text-white mt-4 text-sm font-medium">Position plant or product in frame</p>
        </div>
      )}

      {/* Messages Area */}
      <div className="flex-1 overflow-y-auto p-4 space-y-6 scrollbar-thin scrollbar-thumb-gray-700 scrollbar-track-transparent">
        {messages.map((msg) => (
          <div 
            key={msg.id} 
            className={`flex items-start gap-3 ${msg.role === 'user' ? 'flex-row-reverse' : 'animate-in fade-in slide-in-from-bottom-2 duration-300'}`}
          >
            {/* Avatar */}
            <div className={`w-8 h-8 rounded-full flex-shrink-0 flex items-center justify-center shadow-lg ${
              msg.role === 'model' 
                ? (msg.isError ? 'bg-red-900/50 border border-red-500/30' : 'bg-gradient-to-br from-emerald-600 to-emerald-800') 
                : 'bg-gray-700'
            }`}>
              {msg.role === 'model' ? (
                msg.isError ? <AlertTriangle size={16} className="text-red-400" /> : <Bot size={16} className="text-white" />
              ) : (
                <User size={16} className="text-gray-300" />
              )}
            </div>

            {/* Bubble */}
            <div className={`max-w-[85%] rounded-2xl p-4 shadow-md ${
              msg.role === 'user' 
                ? 'bg-emerald-600 text-white rounded-tr-none' 
                : (msg.isError 
                    ? 'bg-red-950/30 border border-red-500/20 text-red-200 rounded-tl-none' 
                    : 'bg-gray-800 text-gray-100 border border-gray-700 rounded-tl-none')
            }`}>
              {msg.image && (
                <div className="mb-3 rounded-lg overflow-hidden border border-white/10 shadow-sm">
                  <img src={msg.image} alt="User upload" className="max-w-full h-auto max-h-64 object-cover" />
                </div>
              )}
              <div className="whitespace-pre-wrap leading-relaxed">
                {msg.text}
              </div>

              {/* Grounding Sources */}
              {msg.groundingMetadata?.groundingChunks && msg.groundingMetadata.groundingChunks.length > 0 && (
                <div className="mt-4 pt-3 border-t border-gray-700/50 text-xs">
                    <p className="font-semibold mb-2 text-emerald-400 flex items-center gap-1.5 uppercase tracking-wider text-[10px]">
                        <Globe size={12} /> Sources
                    </p>
                    <div className="flex flex-wrap gap-2">
                    {msg.groundingMetadata.groundingChunks.map((chunk: any, i: number) => {
                        if (chunk.web?.uri) {
                            return (
                                <a 
                                    key={i} 
                                    href={chunk.web.uri} 
                                    target="_blank" 
                                    rel="noopener noreferrer" 
                                    className="bg-gray-900/50 hover:bg-emerald-900/30 border border-gray-700/50 hover:border-emerald-500/30 px-2 py-1.5 rounded-md text-emerald-300/80 hover:text-emerald-300 transition-colors truncate max-w-[200px] flex items-center gap-1.5"
                                >
                                    <Search size={10} />
                                    {chunk.web.title || new URL(chunk.web.uri).hostname}
                                </a>
                            );
                        }
                        return null;
                    })}
                    </div>
                </div>
              )}
            </div>
          </div>
        ))}

        {/* Loading Indicator */}
        {loadingState !== LoadingState.IDLE && (
          <div className="flex items-center gap-3 animate-pulse">
            <div className="w-8 h-8 rounded-full bg-emerald-900/50 border border-emerald-500/30 flex items-center justify-center">
              <Globe size={16} className="text-emerald-400 animate-pulse" />
            </div>
            <div className="text-sm text-gray-400 flex items-center gap-2 bg-gray-800/80 px-4 py-2 rounded-full border border-gray-700/50 shadow-sm">
              <Loader2 className="w-3.5 h-3.5 animate-spin text-emerald-500" />
              <span className="font-medium tracking-wide text-xs uppercase">
                {getLoadingText(loadingState)}
              </span>
            </div>
          </div>
        )}
        <div ref={messagesEndRef} />
      </div>

      {/* Input Area */}
      <div className="p-4 bg-gray-800/80 backdrop-blur-md border-t border-gray-700">
        <div className="max-w-4xl mx-auto">
          {imagePreview && (
            <div className="mb-3 relative inline-block group">
              <div className="absolute inset-0 bg-emerald-500/20 rounded-lg blur-sm group-hover:bg-emerald-500/30 transition-all"></div>
              <img src={imagePreview} alt="Preview" className="h-20 w-20 object-cover rounded-lg border border-emerald-500/50 relative z-10" />
              <button 
                onClick={clearImage}
                className="absolute -top-2 -right-2 z-20 bg-gray-700 text-white rounded-full p-1 hover:bg-red-500 transition-colors shadow-lg border border-gray-600"
              >
                <X size={12} />
              </button>
            </div>
          )}
          
          <div className="flex gap-3">
             <button 
              onClick={startCamera}
              className="p-3 text-gray-400 hover:text-emerald-400 hover:bg-gray-700/50 rounded-xl transition-colors active:scale-95 transform duration-100"
              title="Use Camera"
            >
              <Camera size={24} />
            </button>

            <button 
              onClick={() => fileInputRef.current?.click()}
              className="p-3 text-gray-400 hover:text-emerald-400 hover:bg-gray-700/50 rounded-xl transition-colors active:scale-95 transform duration-100"
              title="Upload image"
            >
              <ImageIcon size={24} />
            </button>
            <input 
              type="file" 
              ref={fileInputRef}
              className="hidden"
              accept="image/*"
              onChange={handleImageSelect}
            />
            
            <div className="flex-1 relative group">
              <div className="absolute -inset-0.5 bg-gradient-to-r from-emerald-600 to-teal-600 rounded-xl opacity-20 group-focus-within:opacity-100 transition duration-500 blur-sm"></div>
              <input
                type="text"
                value={inputValue}
                onChange={(e) => setInputValue(e.target.value)}
                onKeyDown={handleKeyDown}
                placeholder="Ask about a strain..."
                className="relative w-full bg-gray-900 text-white border border-gray-700 rounded-xl py-3 pl-4 pr-12 focus:outline-none focus:border-transparent placeholder-gray-500 transition-all shadow-inner"
              />
              <button 
                onClick={handleSendMessage}
                disabled={(!inputValue.trim() && !selectedImage) || loadingState !== LoadingState.IDLE}
                className="absolute right-2 top-1/2 -translate-y-1/2 p-2 bg-emerald-600 hover:bg-emerald-500 text-white rounded-lg disabled:opacity-50 disabled:hover:bg-emerald-600 transition-all shadow-lg shadow-emerald-900/50 active:scale-90"
              >
                <Send size={16} />
              </button>
            </div>
          </div>
        </div>
      </div>
    </div>
  );
};

export default ChatInterface;