2. Add tools, agent with tools created and functionnal

+ Small clean up on main.py

main.py

@@ -1,19 +1,30 @@
-# from src.graph_builder import build_graph
-from src.graph_builder import graph_builder
-from src.nodes import chatbot
+# imports from langgraph
 from langgraph.graph import START, END
 
+# imports from local files
+from src.graph_builder import graph_builder
+from src.nodes import chatbot, BasicToolNode
+from src.utils import route_tools
+from src.tools import tool
 
-# The first argument is the unique node name
-# The second argument is the function or object that will be called whenever
-# the node is used.
 
-if __name__ == "__main__":
-    graph_builder.add_node("chatbot", chatbot)
-    graph_builder.add_edge(START, "chatbot")
-    graph_builder.add_edge("chatbot", END)
+def main():
+    # The first argument is the unique node name
+    # The second argument is the function or object that will be called whenever
+    # the node is used.
+    graph_builder.add_node("chatbot", chatbot)      # Create the chatbot node
+    graph_builder.add_edge("chatbot", END)          # Add the edge from chatbot node to END
+    tool_node = BasicToolNode(tools=[tool])         # Intermediate variable creation to create a tool node with the tools
+    graph_builder.add_node("tools", tool_node)      # Create a tool node with the tools
+    graph_builder.add_conditional_edges(            # Create the conditionnal edges from chatbot to tools
+        "chatbot",
+        route_tools,
+        {"tools": "tools", END: END},
+        )
+    graph_builder.add_edge("tools", "chatbot")      # Add the edge from tools node back to chatbot
+    graph_builder.add_edge(START, "chatbot")        # Add the edge from START to chatbot node
     graph = graph_builder.compile()
-
+    
     def stream_graph_updates(user_input: str):
         for event in graph.stream({"messages": [{"role": "user", "content": user_input}]}):
             for value in event.values():
@@ -32,4 +43,7 @@ if __name__ == "__main__":
             user_input = "What do you know about LangGraph?"
             print("User: " + user_input)
             stream_graph_updates(user_input)
-            break
+            break
+
+if __name__ == "__main__":
+    main()