/**
 * Global AI Chat - Floating chat widget connected to backend AI
 * Uses backend MCP chat_completion tool via REST API
 * Supports Smart UI visualization rendering via ```ui:ComponentName``` format
 */

import { useState, useRef, useEffect, useCallback } from 'react';
import {
  MessageSquare, X, Send, Loader2, Minimize2, Maximize2,
  Bot, User, Sparkles, RefreshCw
} from 'lucide-react';
import { Button } from '@/components/ui/button';
import { Input } from '@/components/ui/input';
import { ScrollArea } from '@/components/ui/scroll-area';
import { Badge } from '@/components/ui/badge';
import { cn } from '@/lib/utils';
import { API_URL } from '@/config/api';
import {
  SmartComponentRenderer,
  parseMessageForComponents,
  UIComponentMessage,
  getAvailableComponents
} from '@/components/smart-ui/SmartComponentRenderer';

interface ChatMessage {
  id: string;
  role: 'user' | 'assistant' | 'system';
  content: string;
  timestamp: Date;
  toolUsed?: string;
}

interface GlobalAIChatProps {
  defaultOpen?: boolean;
  position?: 'bottom-right' | 'bottom-left';
}

export default function GlobalAIChat({
  defaultOpen = false,
  position = 'bottom-right'
}: GlobalAIChatProps) {
  const [isOpen, setIsOpen] = useState(defaultOpen);
  const [isMinimized, setIsMinimized] = useState(false);
  const [messages, setMessages] = useState<ChatMessage[]>([
    {
      id: '1',
      role: 'assistant',
      content: `Hej! Jeg er din AI assistent med adgang til ${getAvailableComponents().length} Smart UI visualiseringskomponenter og systemets MCP tools. Spørg mig om hvad som helst - jeg kan generere diagrammer, grafer, metrics og meget mere!`,
      timestamp: new Date()
    }
  ]);
  const [input, setInput] = useState('');
  const [isLoading, setIsLoading] = useState(false);
  const [isConnected, setIsConnected] = useState(false);
  const scrollRef = useRef<HTMLDivElement>(null);
  const inputRef = useRef<HTMLInputElement>(null);

  // Check backend connection
  const checkConnection = useCallback(async () => {
    try {
      const response = await fetch(`${API_URL}/health`);
      setIsConnected(response.ok);
    } catch {
      setIsConnected(false);
    }
  }, []);

  useEffect(() => {
    checkConnection();
    const interval = setInterval(checkConnection, 30000);
    return () => clearInterval(interval);
  }, [checkConnection]);

  // Auto-scroll to bottom
  useEffect(() => {
    if (scrollRef.current) {
      scrollRef.current.scrollTop = scrollRef.current.scrollHeight;
    }
  }, [messages]);

  // Focus input when opened
  useEffect(() => {
    if (isOpen && !isMinimized && inputRef.current) {
      inputRef.current.focus();
    }
  }, [isOpen, isMinimized]);

  const sendMessage = async () => {
    if (!input.trim() || isLoading) return;

    const userMessage: ChatMessage = {
      id: Date.now().toString(),
      role: 'user',
      content: input.trim(),
      timestamp: new Date()
    };

    setMessages(prev => [...prev, userMessage]);
    setInput('');
    setIsLoading(true);

    try {
      // Try Autonomous Agent first (AI-driven source selection)
      const response = await fetch(`${API_URL}/api/mcp/autonomous/query`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
          type: 'natural_language',
          params: { query: userMessage.content }
        })
      });

      const data = await response.json();

      if (data.success && data.data) {
        // Autonomous agent found a result
        const assistantMessage: ChatMessage = {
          id: (Date.now() + 1).toString(),
          role: 'assistant',
          content: typeof data.data === 'string' ? data.data : JSON.stringify(data.data, null, 2),
          timestamp: new Date(),
          toolUsed: `autonomous (${data.meta?.source || 'unknown'})`
        };
        setMessages(prev => [...prev, assistantMessage]);
      } else {
        // Fallback: Use MCP route to call chat_completion tool
        const chatResponse = await fetch(`${API_URL}/api/mcp/route`, {
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({
            tool: 'chat_completion',
            params: {
              messages: messages
                .filter(m => m.role !== 'system')
                .concat(userMessage)
                .map(m => ({
                  role: m.role,
                  content: m.content
                })),
              max_tokens: 1000,
              temperature: 0.7
            }
          })
        });

        const chatData = await chatResponse.json();

        // Extract response from various possible formats
        let responseText: string | null = null;
        let toolUsed = 'chat_completion';

        // Format 1: DeepSeek response { result: { content: [{ text: "..." }] } }
        if (chatData.result?.content?.[0]?.text) {
          responseText = chatData.result.content[0].text;
        }
        // Format 2: SRAG response { result: { response: "..." } or { answer: "..." } }
        else if (chatData.result?.response || chatData.result?.answer) {
          responseText = chatData.result.answer || chatData.result.response;
        }
        // Format 3: success with response
        else if (chatData.result?.success && chatData.result?.response) {
          responseText = chatData.result.response;
        }

        if (responseText) {
          const assistantMessage: ChatMessage = {
            id: (Date.now() + 1).toString(),
            role: 'assistant',
            content: responseText,
            timestamp: new Date(),
            toolUsed
          };
          setMessages(prev => [...prev, assistantMessage]);
        } else {
          // Try fallback to srag.query for knowledge-based questions
          const fallbackResponse = await fetch(`${API_URL}/api/mcp/route`, {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({
              tool: 'srag.query',
              params: {
                naturalLanguageQuery: userMessage.content,
                model: 'deepseek'
              }
            })
          });

          const fallbackData = await fallbackResponse.json();

          // Extract from fallback response
          const fallbackText = fallbackData.result?.answer
            || fallbackData.result?.response
            || fallbackData.result?.content?.[0]?.text
            || 'Beklager, jeg kunne ikke behandle din forespørgsel. Prøv igen.';

          const assistantMessage: ChatMessage = {
            id: (Date.now() + 1).toString(),
            role: 'assistant',
            content: fallbackText,
            timestamp: new Date(),
            toolUsed: 'srag.query'
          };
          setMessages(prev => [...prev, assistantMessage]);
        }
      }
    } catch (error) {
      console.error('Chat error:', error);
      const errorMessage: ChatMessage = {
        id: (Date.now() + 1).toString(),
        role: 'assistant',
        content: 'Der opstod en fejl. Tjek at backend kører på port 3001.',
        timestamp: new Date()
      };
      setMessages(prev => [...prev, errorMessage]);
    } finally {
      setIsLoading(false);
    }
  };

  const clearChat = () => {
    setMessages([{
      id: '1',
      role: 'assistant',
      content: `Chat ryddet. Jeg kan generere visualiseringer med ${getAvailableComponents().length} komponenter. Hvordan kan jeg hjælpe?`,
      timestamp: new Date()
    }]);
  };

  const positionClasses = position === 'bottom-right'
    ? 'right-4 bottom-4'
    : 'left-4 bottom-4';

  if (!isOpen) {
    return (
      <Button
        onClick={() => setIsOpen(true)}
        className={cn(
          "fixed z-50 h-14 w-14 rounded-full shadow-lg",
          "bg-gradient-to-br from-primary to-primary/80 hover:from-primary/90 hover:to-primary/70",
          "transition-all duration-300 hover:scale-110",
          positionClasses
        )}
      >
        <MessageSquare className="h-6 w-6" />
        {!isConnected && (
          <span className="absolute -top-1 -right-1 h-3 w-3 rounded-full bg-destructive animate-pulse" />
        )}
      </Button>
    );
  }

  return (
    <div
      className={cn(
        "fixed z-50 flex flex-col bg-background border border-border rounded-lg shadow-2xl",
        "transition-all duration-300",
        isMinimized ? "h-12 w-80" : "h-[500px] w-[380px]",
        positionClasses
      )}
    >
      {/* Header */}
      <div className="flex items-center justify-between px-4 py-2 border-b border-border bg-secondary/30 rounded-t-lg">
        <div className="flex items-center gap-2">
          <Bot className="h-5 w-5 text-primary" />
          <span className="font-semibold text-sm">AI Assistent</span>
          <div className={cn(
            "h-2 w-2 rounded-full",
            isConnected ? "bg-green-500" : "bg-red-500"
          )} />
        </div>
        <div className="flex items-center gap-1">
          <Button
            variant="ghost"
            size="icon"
            className="h-7 w-7"
            onClick={clearChat}
            title="Ryd chat"
          >
            <RefreshCw className="h-3.5 w-3.5" />
          </Button>
          <Button
            variant="ghost"
            size="icon"
            className="h-7 w-7"
            onClick={() => setIsMinimized(!isMinimized)}
          >
            {isMinimized ? <Maximize2 className="h-3.5 w-3.5" /> : <Minimize2 className="h-3.5 w-3.5" />}
          </Button>
          <Button
            variant="ghost"
            size="icon"
            className="h-7 w-7"
            onClick={() => setIsOpen(false)}
          >
            <X className="h-3.5 w-3.5" />
          </Button>
        </div>
      </div>

      {!isMinimized && (
        <>
          {/* Messages */}
          <ScrollArea className="flex-1 p-4" ref={scrollRef}>
            <div className="space-y-4">
              {messages.map((message) => (
                <div
                  key={message.id}
                  className={cn(
                    "flex gap-3",
                    message.role === 'user' ? "flex-row-reverse" : "flex-row"
                  )}
                >
                  <div className={cn(
                    "flex-shrink-0 h-8 w-8 rounded-full flex items-center justify-center",
                    message.role === 'user'
                      ? "bg-primary text-primary-foreground"
                      : "bg-secondary"
                  )}>
                    {message.role === 'user' ? (
                      <User className="h-4 w-4" />
                    ) : (
                      <Sparkles className="h-4 w-4 text-primary" />
                    )}
                  </div>
                  <div className={cn(
                    "flex-1 max-w-[280px]",
                    message.role === 'user' ? "text-right" : "text-left"
                  )}>
                    <div className={cn(
                      "inline-block p-3 rounded-lg text-sm",
                      message.role === 'user'
                        ? "bg-primary text-primary-foreground rounded-br-none"
                        : "bg-secondary rounded-bl-none"
                    )}>
                      {/* Parse and render Smart UI components from message content */}
                      {message.role === 'assistant' ? (
                        <div className="space-y-2">
                          {parseMessageForComponents(message.content).map((part, idx) => (
                            typeof part === 'string' ? (
                              <p key={idx} className="whitespace-pre-wrap">{part}</p>
                            ) : (
                              <SmartComponentRenderer
                                key={part.id || idx}
                                message={part as UIComponentMessage}
                                className="my-2"
                              />
                            )
                          ))}
                        </div>
                      ) : (
                        <p className="whitespace-pre-wrap">{message.content}</p>
                      )}
                    </div>
                    <div className="flex items-center gap-2 mt-1 text-[10px] text-muted-foreground">
                      <span>
                        {message.timestamp.toLocaleTimeString('da-DK', {
                          hour: '2-digit',
                          minute: '2-digit'
                        })}
                      </span>
                      {message.toolUsed && (
                        <Badge variant="outline" className="text-[8px] py-0 h-4">
                          {message.toolUsed}
                        </Badge>
                      )}
                    </div>
                  </div>
                </div>
              ))}
              {isLoading && (
                <div className="flex gap-3">
                  <div className="h-8 w-8 rounded-full bg-secondary flex items-center justify-center">
                    <Loader2 className="h-4 w-4 animate-spin text-primary" />
                  </div>
                  <div className="bg-secondary p-3 rounded-lg rounded-bl-none">
                    <div className="flex gap-1">
                      <span className="w-2 h-2 bg-primary/50 rounded-full animate-bounce" style={{ animationDelay: '0ms' }} />
                      <span className="w-2 h-2 bg-primary/50 rounded-full animate-bounce" style={{ animationDelay: '150ms' }} />
                      <span className="w-2 h-2 bg-primary/50 rounded-full animate-bounce" style={{ animationDelay: '300ms' }} />
                    </div>
                  </div>
                </div>
              )}
            </div>
          </ScrollArea>

          {/* Input */}
          <div className="p-4 border-t border-border">
            <div className="flex gap-2">
              <Input
                ref={inputRef}
                value={input}
                onChange={(e) => setInput(e.target.value)}
                onKeyDown={(e) => {
                  if (e.key === 'Enter' && !e.shiftKey) {
                    e.preventDefault();
                    sendMessage();
                  }
                }}
                placeholder="Skriv din besked..."
                className="flex-1"
                disabled={isLoading || !isConnected}
              />
              <Button
                onClick={sendMessage}
                disabled={isLoading || !input.trim() || !isConnected}
                size="icon"
              >
                {isLoading ? (
                  <Loader2 className="h-4 w-4 animate-spin" />
                ) : (
                  <Send className="h-4 w-4" />
                )}
              </Button>
            </div>
            {!isConnected && (
              <p className="text-[10px] text-destructive mt-2">
                Ikke forbundet til backend. Tjek at serveren kører.
              </p>
            )}
          </div>
        </>
      )}
    </div>
  );
}