Update app.py

app.py

@@ -1,8 +1,64 @@
 import os
+from dotenv import load_dotenv
 import gradio as gr
 import requests
 import inspect
 import pandas as pd
+from langchain_core.messages import HumanMessage
+from langchain_core.messages import SystemMessage
+from langchain_openai import ChatOpenAI
+from langgraph.graph import START, StateGraph, MessagesState
+from langgraph.prebuilt import tools_condition, ToolNode
+
+load_dotenv()
+
+def convert_currency(amount: float, from_currency: str, to_currency: str) -> float:
+    """Convert an amount from one currency to another using fixed exchange rates.
+
+    Args:
+        amount: monetary amount to convert
+        from_currency: source currency code (e.g., "USD")
+        to_currency: target currency code (e.g., "CLP")
+
+    Returns:
+        The converted amount rounded to two decimal places
+    """
+    exchange_rates = {
+        ('USD', 'EUR'): 0.91,
+        ('EUR', 'USD'): 1.10,
+        ('USD', 'CLP'): 920.0,
+        ('CLP', 'USD'): 1 / 920.0,
+        ('EUR', 'CLP'): 1010.0,
+        ('CLP', 'EUR'): 1 / 1010.0,
+    }
+
+    rate = exchange_rates.get((from_currency.upper(), to_currency.upper()))
+    if rate is None:
+        raise ValueError(f"No exchange rate for {from_currency} → {to_currency}")
+    return round(amount * rate, 2)
+
+
+tools = [convert_currency]
+llm = ChatOpenAI(model="gpt-3.5-turbo-0125", temperature=0)
+llm_with_tools = llm.bind_tools(tools, parallel_tool_calls=False)
+
+# System message
+sys_msg = SystemMessage(content="You are a helpful assistant tasked with performing money exchange convert calculations")
+
+# Node
+def assistant(state: MessagesState):
+   return {"messages": [llm_with_tools.invoke([sys_msg] + state["messages"])]}
+
+# Build graph
+builder = StateGraph(MessagesState)
+builder.add_node("assistant", assistant)
+builder.add_node("tools", ToolNode(tools))
+builder.add_edge(START, "assistant")
+builder.add_conditional_edges(
+    "assistant",
+    tools_condition,
+)
+builder.add_edge("tools", "assistant")
 
 # (Keep Constants as is)
 # --- Constants ---
@@ -13,11 +69,13 @@ DEFAULT_API_URL = "https://agents-course-unit4-scoring.hf.space"
 class BasicAgent:
     def __init__(self):
         print("BasicAgent initialized.")
+        self.graph = builder.compile()
     def __call__(self, question: str) -> str:
         print(f"Agent received question (first 50 chars): {question[:50]}...")
-        fixed_answer = "This is a default answer."
-        print(f"Agent returning fixed answer: {fixed_answer}")
-        return fixed_answer
+        messages = [HumanMessage(content=question)]
+        result = self.graph.invoke({"messages": messages})
+        answer = result['messages'][-1].content
+        return answer 
 
 def run_and_submit_all( profile: gr.OAuthProfile | None):
     """