'use client';

import React from 'react';
import { Bot, Loader2, Paperclip, User } from 'lucide-react';

import type { ChatMessage } from '@/types';
import { getAccessToken, getFileUrl } from '@/lib/api';
import { MarkdownContent } from '@/components/chat-workbench/MarkdownContent';
import { ScrollArea } from '@/components/ui/scroll-area';

function AuthImage({ src, alt, className }: { src: string; alt: string; className?: string }) {
  const [blobUrl, setBlobUrl] = React.useState<string | null>(null);

  React.useEffect(() => {
    const token = getAccessToken();
    const headers: Record<string, string> = {};
    if (token) headers.Authorization = `Bearer ${token}`;

    let revoke: string | null = null;
    fetch(src, { headers })
      .then((res) => res.blob())
      .then((blob) => {
        revoke = URL.createObjectURL(blob);
        setBlobUrl(revoke);
      })
      .catch(() => {});

    return () => {
      if (revoke) URL.revokeObjectURL(revoke);
    };
  }, [src]);

  if (!blobUrl) return <div className="w-32 h-32 bg-muted animate-pulse rounded" />;
  return <img src={blobUrl} alt={alt} className={className} loading="lazy" decoding="async" />;
}

function MessageBubble({ message }: { message: ChatMessage }) {
  const isUser = message.role === 'user';
  const textContent = typeof message.content === 'string' ? message.content : String(message.content || '');

  return (
    <div className={`flex gap-3 ${isUser ? 'justify-end' : ''}`}>
      {!isUser && (
        <div className="w-7 h-7 rounded-full bg-primary/10 flex items-center justify-center flex-shrink-0 mt-0.5">
          <Bot className="w-4 h-4 text-primary" />
        </div>
      )}
      <div
        className={`rounded-xl px-4 py-3 max-w-[88%] shadow-sm ${
          isUser
            ? 'bg-primary text-primary-foreground'
            : 'bg-card border border-border/80'
        }`}
      >
        {message.attachments && message.attachments.length > 0 && (
          <div className="mb-2 space-y-2">
            {message.attachments.map((att) => {
              const fileUrl = getFileUrl(att.file_id);
              if (att.content_type.startsWith('image/')) {
                return (
                  <a key={att.file_id} href={fileUrl} target="_blank" rel="noopener noreferrer">
                    <AuthImage
                      src={fileUrl}
                      alt={att.name}
                      className="max-w-xs max-h-60 rounded border border-border/50 cursor-pointer hover:opacity-90"
                    />
                  </a>
                );
              }
              return (
                <a
                  key={att.file_id}
                  href={fileUrl}
                  download={att.name}
                  className={`flex items-center gap-2 px-3 py-2 rounded-md text-sm ${
                    isUser
                      ? 'bg-primary-foreground/10 hover:bg-primary-foreground/20'
                      : 'bg-muted hover:bg-muted/80'
                  }`}
                >
                  <Paperclip className="w-3.5 h-3.5 flex-shrink-0" />
                  <span className="truncate">{att.name}</span>
                  {att.size && (
                    <span className="text-xs opacity-70 flex-shrink-0">
                      {att.size > 1024 * 1024
                        ? `${(att.size / 1024 / 1024).toFixed(1)}MB`
                        : `${(att.size / 1024).toFixed(0)}KB`}
                    </span>
                  )}
                </a>
              );
            })}
          </div>
        )}

        {isUser ? (
          <p className="text-sm whitespace-pre-wrap">{textContent}</p>
        ) : (
          <MarkdownContent content={textContent} />
        )}
      </div>
      {isUser && (
        <div className="w-7 h-7 rounded-full bg-secondary flex items-center justify-center flex-shrink-0 mt-0.5">
          <User className="w-4 h-4" />
        </div>
      )}
    </div>
  );
}

export function MessageList({
  messages,
  isThinking,
  messagesEndRef,
  viewportRef,
}: {
  messages: ChatMessage[];
  isThinking: boolean;
  messagesEndRef: React.RefObject<HTMLDivElement>;
  viewportRef: React.RefObject<HTMLDivElement>;
}) {
  return (
    <ScrollArea className="h-full px-4" viewportRef={viewportRef}>
      <div className="max-w-4xl mx-auto py-4 space-y-4">
        {messages.length === 0 && !isThinking && (
          <div className="flex flex-col items-center justify-center py-20 text-muted-foreground">
            <Bot className="w-12 h-12 mb-4 opacity-50" />
            <p className="text-lg font-medium">Boardware Agent Sandbox</p>
            <p className="text-sm">发送消息开始对话</p>
          </div>
        )}

        {messages.map((msg, i) => (
          <MessageBubble key={`${msg.role}:${msg.timestamp || i}:${i}`} message={msg} />
        ))}

        {isThinking && (
          <div className="flex items-center gap-2 text-muted-foreground px-1">
            <Bot className="w-5 h-5" />
            <Loader2 className="w-4 h-4 animate-spin" />
            <span className="text-sm">思考中...</span>
          </div>
        )}

        <div ref={messagesEndRef} />
      </div>
    </ScrollArea>
  );
}