agent-chat-ui/src/components/thread/markdown-text.tsx

"use client";

import "@assistant-ui/react-markdown/styles/dot.css";

import {
  CodeHeaderProps,
  unstable_memoizeMarkdownComponents as memoizeMarkdownComponents,
  useIsMarkdownCodeBlock,
} from "@assistant-ui/react-markdown";
import ReactMarkdown from "react-markdown";
import remarkGfm from "remark-gfm";
import rehypeKatex from "rehype-katex";
import remarkMath from "remark-math";
import { FC, memo, useState } from "react";
import { CheckIcon, CopyIcon } from "lucide-react";
import { SyntaxHighlighter } from "@/components/thread/syntax-highlighter";

import { TooltipIconButton } from "@/components/thread/tooltip-icon-button";
import { cn } from "@/lib/utils";

import "katex/dist/katex.min.css";

const MarkdownTextImpl = ({ children }: { children: string }) => {
  return (
    <ReactMarkdown
      remarkPlugins={[remarkGfm, remarkMath]}
      rehypePlugins={[rehypeKatex]}
      components={defaultComponents}
    >
      {children}
    </ReactMarkdown>
  );
};

export const MarkdownText = memo(MarkdownTextImpl);

const CodeHeader: FC<CodeHeaderProps> = ({ language, code }) => {
  const { isCopied, copyToClipboard } = useCopyToClipboard();
  const onCopy = () => {
    if (!code || isCopied) return;
    copyToClipboard(code);
  };

  return (
    <div className="flex items-center justify-between gap-4 rounded-t-lg bg-zinc-900 px-4 py-2 text-sm font-semibold text-white">
      <span className="lowercase [&>span]:text-xs">{language}</span>
      <TooltipIconButton tooltip="Copy" onClick={onCopy}>
        {!isCopied && <CopyIcon />}
        {isCopied && <CheckIcon />}
      </TooltipIconButton>
    </div>
  );
};

const useCopyToClipboard = ({
  copiedDuration = 3000,
}: {
  copiedDuration?: number;
} = {}) => {
  const [isCopied, setIsCopied] = useState<boolean>(false);

  const copyToClipboard = (value: string) => {
    if (!value) return;

    navigator.clipboard.writeText(value).then(() => {
      setIsCopied(true);
      setTimeout(() => setIsCopied(false), copiedDuration);
    });
  };

  return { isCopied, copyToClipboard };
};

const defaultComponents = memoizeMarkdownComponents({
  h1: ({ className, ...props }) => (
    <h1
      className={cn(
        "mb-8 scroll-m-20 text-4xl font-extrabold tracking-tight last:mb-0",
        className,
      )}
      {...props}
    />
  ),
  h2: ({ className, ...props }) => (
    <h2
      className={cn(
        "mb-4 mt-8 scroll-m-20 text-3xl font-semibold tracking-tight first:mt-0 last:mb-0",
        className,
      )}
      {...props}
    />
  ),
  h3: ({ className, ...props }) => (
    <h3
      className={cn(
        "mb-4 mt-6 scroll-m-20 text-2xl font-semibold tracking-tight first:mt-0 last:mb-0",
        className,
      )}
      {...props}
    />
  ),
  h4: ({ className, ...props }) => (
    <h4
      className={cn(
        "mb-4 mt-6 scroll-m-20 text-xl font-semibold tracking-tight first:mt-0 last:mb-0",
        className,
      )}
      {...props}
    />
  ),
  h5: ({ className, ...props }) => (
    <h5
      className={cn(
        "my-4 text-lg font-semibold first:mt-0 last:mb-0",
        className,
      )}
      {...props}
    />
  ),
  h6: ({ className, ...props }) => (
    <h6
      className={cn("my-4 font-semibold first:mt-0 last:mb-0", className)}
      {...props}
    />
  ),
  p: ({ className, ...props }) => (
    <p
      className={cn("mb-5 mt-5 leading-7 first:mt-0 last:mb-0", className)}
      {...props}
    />
  ),
  a: ({ className, ...props }) => (
    <a
      className={cn(
        "text-primary font-medium underline underline-offset-4",
        className,
      )}
      {...props}
    />
  ),
  blockquote: ({ className, ...props }) => (
    <blockquote
      className={cn("border-l-2 pl-6 italic", className)}
      {...props}
    />
  ),
  ul: ({ className, ...props }) => (
    <ul
      className={cn("my-5 ml-6 list-disc [&>li]:mt-2", className)}
      {...props}
    />
  ),
  ol: ({ className, ...props }) => (
    <ol
      className={cn("my-5 ml-6 list-decimal [&>li]:mt-2", className)}
      {...props}
    />
  ),
  hr: ({ className, ...props }) => (
    <hr className={cn("my-5 border-b", className)} {...props} />
  ),
  table: ({ className, ...props }) => (
    <table
      className={cn(
        "my-5 w-full border-separate border-spacing-0 overflow-y-auto",
        className,
      )}
      {...props}
    />
  ),
  th: ({ className, ...props }) => (
    <th
      className={cn(
        "bg-muted px-4 py-2 text-left font-bold first:rounded-tl-lg last:rounded-tr-lg [&[align=center]]:text-center [&[align=right]]:text-right",
        className,
      )}
      {...props}
    />
  ),
  td: ({ className, ...props }) => (
    <td
      className={cn(
        "border-b border-l px-4 py-2 text-left last:border-r [&[align=center]]:text-center [&[align=right]]:text-right",
        className,
      )}
      {...props}
    />
  ),
  tr: ({ className, ...props }) => (
    <tr
      className={cn(
        "m-0 border-b p-0 first:border-t [&:last-child>td:first-child]:rounded-bl-lg [&:last-child>td:last-child]:rounded-br-lg",
        className,
      )}
      {...props}
    />
  ),
  sup: ({ className, ...props }) => (
    <sup
      className={cn("[&>a]:text-xs [&>a]:no-underline", className)}
      {...props}
    />
  ),
  pre: ({ className, ...props }) => (
    <pre
      className={cn(
        "overflow-x-auto rounded-b-lg bg-black p-4 text-white max-w-4xl",
        className,
      )}
      {...props}
    />
  ),
  code: function Code({ className, ...props }) {
    const isCodeBlock = useIsMarkdownCodeBlock();
    return (
      <code
        className={cn(!isCodeBlock && "rounded font-semibold", className)}
        {...props}
      />
    );
  },
  CodeHeader,
  SyntaxHighlighter,
});