Update app.py

app.py

@@ -35,6 +35,11 @@ def generate_review(api_key, uploaded_files, review_question, include_tables):
     if not review_question:
         return "Please enter a review question."
     
+    # File type validation: check if all uploaded files are PDFs
+    for file in uploaded_files:
+        if not file.name.lower().endswith('.pdf'):
+            return f"Invalid file type. Please upload a PDF file, but '{file.name}' is not a PDF."
+    
     system_prompt = """
     You are an expert academic assistant. Create a systematic review in HTML format using <h2>, <h3>, <p>, <ul>, and <table> tags. The Systematic Review must be in great details. Structure it using these steps:
     Step 1: Identify a Research Field
@@ -108,4 +113,4 @@ interface = gr.Interface(
     description="Generate a polished and structured systematic review from multiple uploaded research papers."
 )
 
-interface.launch(share=True)
+interface.launch(share=True)