Handle custom admonition syntax (#95)

Signed-off-by: Damian Stasik <[email protected]>

frontend/src/components/Markdown/P.tsx

@@ -1,7 +1,70 @@
-import { HTMLAttributes } from "react";
+import { HTMLAttributes, ReactNode } from "react";
 import { Paragraph } from "../Paragraph";
+import clsx from "clsx";
+
+const WARNING_MARK = "~>";
+const DANGER_MARK = "!>";
+const NOTE_MARK = "->";
+
+function getAdmonitionClassName(prefix: string) {
+  switch (prefix) {
+    case NOTE_MARK:
+      return "bg-sky-100 text-sky-800 dark:bg-sky-950 dark:text-sky-100";
+    case DANGER_MARK:
+      return "bg-red-100 text-red-800 dark:bg-red-950 dark:text-red-100";
+    case WARNING_MARK:
+      return "bg-yellow-100 text-yellow-800 dark:bg-yellow-950 dark:text-yellow-100";
+    default:
+      return "";
+  }
+}
+
+function getAdmonitionMatch(children: ReactNode) {
+  let content = "";
+
+  if (typeof children === "string") {
+    content = children;
+  } else if (Array.isArray(children) && typeof children[0] === "string") {
+    content = children[0];
+  }
+
+  if (!content) {
+    return null;
+  }
+
+  if (
+    content.startsWith(WARNING_MARK) ||
+    content.startsWith(DANGER_MARK) ||
+    content.startsWith(NOTE_MARK)
+  ) {
+    return {
+      prefix: content.slice(0, 2),
+      content: content.slice(2).trim(),
+    };
+  }
+
+  return null;
+}
 
 export function MarkdownP({ children }: HTMLAttributes<HTMLParagraphElement>) {
+  const admonitionMatch = getAdmonitionMatch(children);
+
+  if (admonitionMatch) {
+    const { prefix, content } = admonitionMatch;
+    const className = getAdmonitionClassName(prefix);
+    const remainingContent = Array.isArray(children) ? children.slice(1) : null;
+
+    return (
+      <div
+        role="alert"
+        className={clsx("mt-5 px-3 py-2 [li>&:first-child]:mt-0", className)}
+      >
+        {content}
+        {remainingContent}
+      </div>
+    );
+  }
+
   return (
     <Paragraph className="mt-5 leading-7 [li>&:first-child]:mt-0">
       {children}