Update app.py

app.py

@@ -1,3 +1,4 @@
+import os
 import streamlit as st  
 import pandas as pd  
 import requests  
@@ -169,14 +170,39 @@ def save_openweather_historical_to_csv():
     df = pd.DataFrame(openweather_historical_readings)
     return df  
 
-def save_openweather_forecast_to_csv():  
-    """Save forecast OpenWeather data to CSV."""  
-    if not openweather_forecast_readings:  
-        st.error("No forecast weather data to save!")  
-        return  
+def save_openweather_historical_to_csv(openweather_historical_readings):  
+    """Save historical OpenWeather data to CSV."""  
+    try:  
+        # Validate input data  
+        if not openweather_historical_readings:  
+            raise ValueError("No historical data available.")  
+        
+        # Create a DataFrame from the readings  
+        df = pd.DataFrame(openweather_historical_readings)  
+        
+        # Ensure the DataFrame is not empty  
+        if df.empty:  
+            raise ValueError("DataFrame is empty.")  
+        
+        # Create a timestamped file name  
+        file_name = f"openweather_historical_data_{datetime.now().strftime('%Y%m%d_%H%M%S')}.csv"  
+        
+        # Define a safe file path to save the CSV  
+        file_path = os.path.join("data", file_name)  
+        os.makedirs(os.path.dirname(file_path), exist_ok=True)  
+        
+        # Save the DataFrame to a CSV file  
+        df.to_csv(file_path, index=False)  
+        
+        print(f"Successfully saved historical data to {file_path}")  
+        return file_path  # Return the file path for verification  
     
-    df = pd.DataFrame(openweather_forecast_readings)  
-    return df  
+    except ValueError as ve:  
+        print(f"Validation error: {ve}")  
+        return None  
+    except Exception as e:  
+        print(f"Error saving historical data: {str(e)}")  
+        return None   
 
 def save_stormglass_marine_to_csv():  
     """Save Stormglass marine data to CSV."""  
@@ -279,20 +305,30 @@ def main():
                         ).add_to(m)  
                         folium_static(m)  
 
-        # Download button for historical data
-        if st.button("Download Historical Weather Data"):
-            df = save_openweather_historical_to_csv()
-            if isinstance(df, pd.DataFrame) and not df.empty:
-                csv = df.to_csv(index=False).encode('utf-8')
-                st.download_button(
-                    label="Download Historical Weather Data CSV",
-                    data=csv,
-                    file_name=f"openweather_historical_data_{datetime.now().strftime('%Y%m%d_%H%M%S')}.csv",
-                    mime="text/csv",
-                )
-                st.success("Historical weather data saved and ready for download!")
-            else:
-                st.error("No historical weather data available.")
+        
+        # Download button for historical data  
+        if st.button("Download Historical Weather Data"):  
+            file_path = save_openweather_historical_to_csv(openweather_historical_readings)  
+    
+            if file_path:  
+                try:  
+                    # Read the saved CSV file  
+                    with open(file_path, 'rb') as file:  
+                        csv_data = file.read()  
+            
+                    # Create a download button  
+                    st.download_button(  
+                        label="Download Historical Weather Data CSV",  
+                        data=csv_data,  
+                        file_name=os.path.basename(file_path),  
+                        mime="text/csv",  
+                    )  
+                    st.success("Historical weather data saved and ready for download!")  
+            
+                except Exception as e:  
+                    st.error(f"Error preparing download: {str(e)}")  
+            else:  
+                st.error("No historical weather data available.")