Update app/main.py

app/main.py

@@ -83,6 +83,11 @@ class HVACCalculator:
             self.heating_calculator = HeatingLoadCalculator()
             self.reference_data = ReferenceData()
 
+            # Validate DataExport has display method
+            if not hasattr(self.data_export, 'display'):
+                logger.error("DataExport object missing 'display' method")
+                raise AttributeError("DataExport object missing 'display' method")
+
             # Initialize climate data
             self._initialize_climate_data()
 
@@ -163,9 +168,27 @@ class HVACCalculator:
             "Building Components": self.component_selection.display_component_selection,
             "Internal Loads": self.display_internal_loads,
             "Calculation Results": self.display_calculation_results,
-            "Export Data": self.data_export.display
+            "Export Data": lambda state: self._display_export_data(state)
         }
-        page_functions[page](st.session_state)
+        try:
+            page_functions[page](st.session_state)
+        except AttributeError as e:
+            logger.error(f"Error displaying page {page}: {str(e)}")
+            st.error(f"Error displaying {page} page: {str(e)}")
+        except Exception as e:
+            logger.error(f"Unexpected error displaying page {page}: {str(e)}")
+            st.error(f"Unexpected error displaying {page} page: {str(e)}")
+
+    def _display_export_data(self, state):
+        """Wrapper for DataExport.display with error handling."""
+        try:
+            self.data_export.display(state)
+        except AttributeError as e:
+            logger.error(f"DataExport.display failed: {str(e)}")
+            st.error("Export Data functionality is unavailable. Please check DataExport implementation.")
+            st.write("Placeholder for Export Data page. Select export options below:")
+            st.button("Export to CSV (Not Implemented)")
+            st.button("Export to JSON (Not Implemented)")
 
     def generate_climate_id(self, country: str, city: str) -> str:
         """Generate a climate ID from country and city names."""