/**
 * Chat Message Component
 * Renders user / assistant / system / toolresult messages
 * with markdown, thinking sections, images, and tool cards.
 */
import { useState, useCallback, memo } from 'react';
import { User, Sparkles, Copy, Check, ChevronDown, ChevronRight, Wrench } from 'lucide-react';
import ReactMarkdown from 'react-markdown';
import remarkGfm from 'remark-gfm';
import { Button } from '@/components/ui/button';
import { cn } from '@/lib/utils';
import type { RawMessage } from '@/stores/chat';
import { extractText, extractThinking, extractImages, extractToolUse, formatTimestamp } from './message-utils';

interface ChatMessageProps {
  message: RawMessage;
  showThinking: boolean;
  isStreaming?: boolean;
}

export const ChatMessage = memo(function ChatMessage({
  message,
  showThinking,
  isStreaming = false,
}: ChatMessageProps) {
  const isUser = message.role === 'user';
  const isToolResult = message.role === 'toolresult';
  const text = extractText(message);
  const thinking = extractThinking(message);
  const images = extractImages(message);
  const tools = extractToolUse(message);

  // Don't render empty tool results when thinking is hidden
  if (isToolResult && !showThinking) return null;

  // Don't render empty messages
  if (!text && !thinking && images.length === 0 && tools.length === 0) return null;

  return (
    <div
      className={cn(
        'flex gap-3 group',
        isUser ? 'flex-row-reverse' : 'flex-row',
      )}
    >
      {/* Avatar */}
      <div
        className={cn(
          'flex h-8 w-8 shrink-0 items-center justify-center rounded-full mt-1',
          isUser
            ? 'bg-primary text-primary-foreground'
            : 'bg-gradient-to-br from-indigo-500 to-purple-600 text-white',
        )}
      >
        {isUser ? <User className="h-4 w-4" /> : <Sparkles className="h-4 w-4" />}
      </div>

      {/* Content */}
      <div className={cn('max-w-[80%] space-y-2', isUser && 'items-end')}>
        {/* Thinking section */}
        {showThinking && thinking && (
          <ThinkingBlock content={thinking} />
        )}

        {/* Tool use cards */}
        {showThinking && tools.length > 0 && (
          <div className="space-y-1">
            {tools.map((tool, i) => (
              <ToolCard key={tool.id || i} name={tool.name} input={tool.input} />
            ))}
          </div>
        )}

        {/* Main text bubble */}
        {text && (
          <MessageBubble
            text={text}
            isUser={isUser}
            isStreaming={isStreaming}
            timestamp={message.timestamp}
          />
        )}

        {/* Images */}
        {images.length > 0 && (
          <div className="flex flex-wrap gap-2">
            {images.map((img, i) => (
              <img
                key={i}
                src={`data:${img.mimeType};base64,${img.data}`}
                alt="attachment"
                className="max-w-xs rounded-lg border"
              />
            ))}
          </div>
        )}
      </div>
    </div>
  );
});

// ── Message Bubble ──────────────────────────────────────────────

function MessageBubble({
  text,
  isUser,
  isStreaming,
  timestamp,
}: {
  text: string;
  isUser: boolean;
  isStreaming: boolean;
  timestamp?: number;
}) {
  const [copied, setCopied] = useState(false);

  const copyContent = useCallback(() => {
    navigator.clipboard.writeText(text);
    setCopied(true);
    setTimeout(() => setCopied(false), 2000);
  }, [text]);

  return (
    <div
      className={cn(
        'relative rounded-2xl px-4 py-3',
        isUser
          ? 'bg-primary text-primary-foreground'
          : 'bg-muted',
      )}
    >
      {isUser ? (
        <p className="whitespace-pre-wrap text-sm">{text}</p>
      ) : (
        <div className="prose prose-sm dark:prose-invert max-w-none">
          <ReactMarkdown
            remarkPlugins={[remarkGfm]}
            components={{
              code({ className, children, ...props }) {
                const match = /language-(\w+)/.exec(className || '');
                const isInline = !match && !className;
                if (isInline) {
                  return (
                    <code className="bg-background/50 px-1.5 py-0.5 rounded text-sm font-mono" {...props}>
                      {children}
                    </code>
                  );
                }
                return (
                  <pre className="bg-background/50 rounded-lg p-4 overflow-x-auto">
                    <code className={cn('text-sm font-mono', className)} {...props}>
                      {children}
                    </code>
                  </pre>
                );
              },
              a({ href, children }) {
                return (
                  <a href={href} target="_blank" rel="noopener noreferrer" className="text-primary hover:underline">
                    {children}
                  </a>
                );
              },
            }}
          >
            {text}
          </ReactMarkdown>
          {isStreaming && (
            <span className="inline-block w-2 h-4 bg-foreground/50 animate-pulse ml-0.5" />
          )}
        </div>
      )}

      {/* Footer: timestamp + copy */}
      <div className={cn(
        'flex items-center gap-2 mt-2',
        isUser ? 'justify-end' : 'justify-between',
      )}>
        {timestamp && (
          <span className={cn(
            'text-xs',
            isUser ? 'text-primary-foreground/60' : 'text-muted-foreground',
          )}>
            {formatTimestamp(timestamp)}
          </span>
        )}
        {!isUser && (
          <Button
            variant="ghost"
            size="icon"
            className="h-6 w-6 opacity-0 group-hover:opacity-100 transition-opacity"
            onClick={copyContent}
          >
            {copied ? <Check className="h-3 w-3 text-green-500" /> : <Copy className="h-3 w-3" />}
          </Button>
        )}
      </div>
    </div>
  );
}

// ── Thinking Block ──────────────────────────────────────────────

function ThinkingBlock({ content }: { content: string }) {
  const [expanded, setExpanded] = useState(false);

  return (
    <div className="rounded-lg border border-border/50 bg-muted/30 text-sm">
      <button
        className="flex items-center gap-2 w-full px-3 py-2 text-muted-foreground hover:text-foreground transition-colors"
        onClick={() => setExpanded(!expanded)}
      >
        {expanded ? <ChevronDown className="h-3.5 w-3.5" /> : <ChevronRight className="h-3.5 w-3.5" />}
        <span className="font-medium">Thinking</span>
      </button>
      {expanded && (
        <div className="px-3 pb-3 text-muted-foreground">
          <div className="prose prose-sm dark:prose-invert max-w-none opacity-75">
            <ReactMarkdown remarkPlugins={[remarkGfm]}>{content}</ReactMarkdown>
          </div>
        </div>
      )}
    </div>
  );
}

// ── Tool Card ───────────────────────────────────────────────────

function ToolCard({ name, input }: { name: string; input: unknown }) {
  const [expanded, setExpanded] = useState(false);

  return (
    <div className="rounded-lg border border-border/50 bg-muted/20 text-sm">
      <button
        className="flex items-center gap-2 w-full px-3 py-1.5 text-muted-foreground hover:text-foreground transition-colors"
        onClick={() => setExpanded(!expanded)}
      >
        <Wrench className="h-3.5 w-3.5" />
        <span className="font-mono text-xs">{name}</span>
        {expanded ? <ChevronDown className="h-3 w-3 ml-auto" /> : <ChevronRight className="h-3 w-3 ml-auto" />}
      </button>
      {expanded && input != null && (
        <pre className="px-3 pb-2 text-xs text-muted-foreground overflow-x-auto">
          {typeof input === 'string' ? input : JSON.stringify(input, null, 2) as string}
        </pre>
      )}
    </div>
  );
}