Adding and testing explain solution

app.py

@@ -159,6 +159,18 @@ def random_problem(token: str) -> Dict[str, Any]:
     
     return {"problem": problem}
 
+def explain_solution(token: str) -> Dict[str, Any]:
+    if not verify_token(token):
+        return {"error": "Invalid token"}
+    
+    if token not in user_data or not user_data[token].get("solution"):
+        return {"error": "No solution available to explain. Please generate a solution first."}
+    
+    problem = user_data[token]["problem"]
+    solution = user_data[token]["solution"]
+    
+    return generate_explanation(problem, solution, token)
+
 # Create Gradio interfaces
 generate_interface = gr.Interface(
     fn=generate_solution,
@@ -176,6 +188,14 @@ random_problem_interface = gr.Interface(
     description="Provide a valid JWT token to get a random LeetCode problem."
 )
 
+explain_interface = gr.Interface(
+    fn=explain_solution,
+    inputs=gr.Textbox(label="JWT Token"),
+    outputs=gr.JSON(),
+    title="Explain Solution API",
+    description="Provide a valid JWT token to get an explanation of the last generated solution."
+)
+
 demo = gr.TabbedInterface(
     [generate_interface, explain_interface, random_problem_interface],
     ["Generate Solution", "Explain Solution", "Random Problem"]