feat: add XML handling in ChatPanel and utility function for legal XML conversion

lib/utils.ts

@@ -4,3 +4,55 @@ import { twMerge } from "tailwind-merge"
 export function cn(...inputs: ClassValue[]) {
   return twMerge(clsx(inputs))
 }
+
+/**
+ * Efficiently converts a potentially incomplete XML string to a legal XML string
+ * by closing any open tags properly.
+ * 
+ * @param xmlString The potentially incomplete XML string
+ * @returns A legal XML string with properly closed tags
+ */
+export function convertToLegalXml(xmlString: string): string {
+  const stack: string[] = [];
+  let result = '';
+  let tagStart = -1;
+
+  for (let i = 0; i < xmlString.length; i++) {
+    const char = xmlString[i];
+    result += char;
+
+    if (char === '<' && tagStart === -1) {
+      // Start of a new tag
+      tagStart = i;
+    } else if (char === '>' && tagStart !== -1) {
+      // End of a tag
+      const tagContent = xmlString.substring(tagStart + 1, i);
+
+      if (tagContent.startsWith('/')) {
+        // Closing tag
+        const tagName = tagContent.substring(1).trim().split(/\s+/)[0];
+        if (stack.length && stack[stack.length - 1] === tagName) {
+          stack.pop();
+        }
+      } else if (!tagContent.endsWith('/') && !tagContent.startsWith('?') && !tagContent.startsWith('!')) {
+        // Opening tag (not self-closing, processing instruction, or comment)
+        const tagName = tagContent.trim().split(/\s+/)[0];
+        stack.push(tagName);
+      }
+
+      tagStart = -1;
+    }
+  }
+
+  // If we have an incomplete tag at the end, don't include it in the result
+  if (tagStart !== -1) {
+    result = result.substring(0, tagStart);
+  }
+
+  // Close all remaining open tags
+  for (let j = stack.length - 1; j >= 0; j--) {
+    result += `</${stack[j]}>`;
+  }
+
+  return result;
+}