Implement fromchat.ru/@username and fromchat.ru/?u=userId links, mentions

frontend/src/core/profileLinks.ts

@@ -0,0 +1,39 @@
+/**
+ * @fileoverview Utility functions for handling profile links
+ * @description Functions to parse and handle profile links in markdown content.
+ * Supports two formats:
+ * - fromchat.ru/@username (e.g., fromchat.ru/@john_doe)
+ * - fromchat.ru/?u=<userId> (e.g., fromchat.ru/?u=123)
+ * @author Cursor
+ * @version 1.0.0
+ */
+
+import escapeStringRegexp from "escape-string-regexp";
+
+/**
+ * Parses a profile link URL and extracts user information
+ * @param url - The URL to parse
+ * @returns Object with user ID and username if it's a valid profile link, null otherwise
+ */
+export function parseProfileLink(url: string = location.pathname): { userId?: number; username?: string } | null {
+    try {
+        let host: string = url.startsWith("@") ? "" : !url.startsWith("/") ? "https://fromchat.ru/" : "/";
+
+        // Handle fromchat.ru/@username format
+        const usernameMatch = url.match(new RegExp(`${escapeStringRegexp(host)}@([a-zA-Z0-9_-]+)`));
+        if (usernameMatch) {
+            return { username: usernameMatch[1] };
+        }
+
+        // Handle fromchat.ru/?u=<userId> format
+        const userIdMatch = url.match(new RegExp(`${escapeStringRegexp(host)}\\?u=(\\d+)`));
+        if (userIdMatch) {
+            return { userId: Number(userIdMatch[1]) };
+        }
+
+        return null;
+    } catch (error) {
+        console.error('Error parsing profile link:', error);
+        return null;
+    }
+}