import { useState, useRef, useEffect } from "react";
import { ChatMessage, type Message } from "./ChatMessage";
import { ChatInput } from "./ChatInput";
import { CodePanel } from "./CodePanel";
import { FileUploadZone } from "./FileUploadZone";
import { TypingIndicator } from "./TypingIndicator";
import { Button } from "@/components/ui/button";
import { SidebarTrigger } from "@/components/ui/sidebar";
import { Moon, Sun, Code2 } from "lucide-react";
import { useTheme } from "./ThemeProvider";
import { ScrollArea } from "@/components/ui/scroll-area";

type ChatInterfaceProps = {
  buddyName: string;
  onSettingsClick: () => void;
};

export function ChatInterface({ buddyName, onSettingsClick }: ChatInterfaceProps) {
  const { theme, toggleTheme } = useTheme();
  const [messages, setMessages] = useState<Message[]>([]);
  const [isTyping, setIsTyping] = useState(false);
  const [showFileUpload, setShowFileUpload] = useState(false);
  const [showCodePanel, setShowCodePanel] = useState(false);
  const scrollRef = useRef<HTMLDivElement>(null);

  useEffect(() => {
    if (scrollRef.current) {
      scrollRef.current.scrollTop = scrollRef.current.scrollHeight;
    }
  }, [messages, isTyping]);

  const handleSendMessage = (content: string) => {
    const userMessage: Message = {
      id: Date.now().toString(),
      role: "user",
      content,
      timestamp: new Date(),
    };
    
    setMessages((prev) => [...prev, userMessage]);
    setIsTyping(true);

    setTimeout(() => {
      const aiMessage: Message = {
        id: (Date.now() + 1).toString(),
        role: "assistant",
        content: `I'm ${buddyName}, powered by Dolphin-Mistral! I'd be happy to help you with that. This is a demo response showing how I would assist you with coding, debugging, or any other development tasks.`,
        timestamp: new Date(),
      };
      setMessages((prev) => [...prev, aiMessage]);
      setIsTyping(false);
    }, 2000);
  };

  const handleFileUpload = () => {
    setShowFileUpload(!showFileUpload);
  };

  const handleFilesSelected = (files: File[]) => {
    console.log('Files selected:', files);
    setShowFileUpload(false);
    setShowCodePanel(true);
  };

  return (
    <div className="flex flex-col h-screen">
      <header className="flex items-center justify-between p-4 border-b border-border bg-card">
        <div className="flex items-center gap-3">
          <SidebarTrigger data-testid="button-sidebar-toggle" />
          <div>
            <h2 className="font-semibold">{buddyName}</h2>
            <p className="text-xs text-muted-foreground">Online • Dolphin-Mistral 3.0</p>
          </div>
        </div>
        <div className="flex items-center gap-2">
          <Button
            variant="outline"
            size="icon"
            onClick={() => setShowCodePanel(!showCodePanel)}
            data-testid="button-toggle-code-panel"
          >
            <Code2 className="h-5 w-5" />
          </Button>
          <Button
            variant="outline"
            size="icon"
            onClick={toggleTheme}
            data-testid="button-theme-toggle"
          >
            {theme === "light" ? <Moon className="h-5 w-5" /> : <Sun className="h-5 w-5" />}
          </Button>
        </div>
      </header>

      <div className="flex flex-1 overflow-hidden">
        <div className="flex-1 flex flex-col">
          {showFileUpload ? (
            <div className="flex-1 overflow-auto p-6">
              <FileUploadZone
                onFilesSelected={handleFilesSelected}
                onClose={() => setShowFileUpload(false)}
              />
            </div>
          ) : (
            <>
              <div ref={scrollRef} className="flex-1 overflow-auto">
                {messages.length === 0 ? (
                  <div className="h-full flex flex-col items-center justify-center p-8 text-center">
                    <div className="max-w-md space-y-4">
                      <h3 className="text-2xl font-semibold">Welcome to AI Buddy</h3>
                      <p className="text-muted-foreground">
                        Start a conversation with your AI coding companion. I can help you with:
                      </p>
                      <ul className="text-sm text-muted-foreground space-y-2">
                        <li>• Code analysis and debugging</li>
                        <li>• Multi-language support</li>
                        <li>• File uploads and code modification</li>
                        <li>• Best practices and optimization</li>
                      </ul>
                    </div>
                  </div>
                ) : (
                  <div className="space-y-1">
                    {messages.map((message) => (
                      <ChatMessage key={message.id} message={message} buddyName={buddyName} />
                    ))}
                    {isTyping && (
                      <div className="flex gap-3 py-3 px-4">
                        <div className="w-10 h-10 rounded-full bg-chart-2 flex items-center justify-center" />
                        <div className="flex flex-col gap-1">
                          <span className="text-xs text-muted-foreground px-1">{buddyName}</span>
                          <div className="rounded-2xl px-4 py-3 bg-card border border-card-border">
                            <TypingIndicator />
                          </div>
                        </div>
                      </div>
                    )}
                  </div>
                )}
              </div>

              <ChatInput
                onSend={handleSendMessage}
                onFileUpload={handleFileUpload}
                disabled={isTyping}
              />
            </>
          )}
        </div>

        {showCodePanel && (
          <div className="w-[480px] hidden lg:block">
            <CodePanel
              fileName="example.js"
              language="JavaScript"
              code={`// Sample code uploaded by user
function reverseString(str) {
  return str.split('').reverse().join('');
}

console.log(reverseString("Hello"));`}
              onClose={() => setShowCodePanel(false)}
              onRun={() => console.log('Run code')}
            />
          </div>
        )}
      </div>
    </div>
  );
}