added error handling for graph display

frontend/src/Components/AiComponents/Graph.js

@@ -2,7 +2,7 @@ import React, { useState, useEffect } from 'react';
 import { FaTimes } from 'react-icons/fa';
 import './Graph.css';
 
-export default function Graph({ open, onClose }) {
+export default function Graph({ open, onClose, onError }) {
   const [graphHtml, setGraphHtml] = useState("");
   const [loading, setLoading] = useState(true);
   const [error, setError] = useState("");
@@ -18,16 +18,25 @@ export default function Graph({ open, onClose }) {
       })
         .then(res => res.json())
         .then(data => {
+          // If the API returns an error, throw it to be caught below.
+          if (data.error) {
+            throw new Error(data.error);
+          }
           setGraphHtml(data.result);
           setLoading(false);
         })
         .catch(err => {
           console.error("Error fetching graph:", err);
-          setError("Error fetching graph.");
+          const errMsg = err.message || "Error fetching graph.";
+          setError(errMsg);
           setLoading(false);
+          // Propagate error to parent using the onError callback.
+          if (onError && typeof onError === 'function') {
+            onError(errMsg);
+          }
         });
     }
-  }, [open]);
+  }, [open, onError]);
 
   if (!open) return null;