src/graph/graph_builder.py

from langgraph.graph import StateGraph
from src.state.state import State
from src.basic_bot.chatbot_node import ChatbotNode
from src.basic_bot.chatbot_with_tool_node import ChatbotWithToolNode


from langgraph.graph import StateGraph
from langgraph.prebuilt import tools_condition
from src.tools.search_tool import get_tools, create_tool_node
from src.basic_bot.chatbot_with_tool_node import ChatbotWithToolNode

class GraphBuilder:
    """
    Manages the creation and setup of the StateGraph based on use cases.
    """
    def __init__(self,model):
        self.llm = model
        self.graph_builder = StateGraph(State)
        self.chatbot_node = ChatbotNode(model)
        self.chatbot_with_tool_node = ChatbotWithToolNode(model)
        
        
    def build_graph(self):
        """
        Builds and returns the LangGraph graph based on the defined nodes and edges.
        """
        # Initialize state graph
        graph_builder = StateGraph(State)

        # Define tools and tool node
        tools = get_tools()
        tool_node = create_tool_node(tools)

        # Define LLM
        llm = self.llm

        # Define chatbot node
        obj_chatbot_with_node = ChatbotWithToolNode(llm)
        chatbot_node = obj_chatbot_with_node.create_chatbot(tools)

        # Add nodes
        graph_builder.add_node("chatbot", chatbot_node)
        graph_builder.add_node("tools", tool_node)

        # Define conditional and direct edges
        graph_builder.add_conditional_edges("chatbot", tools_condition)
        graph_builder.add_edge("tools", "chatbot")

        # Set entry point and compile graph
        graph_builder.set_entry_point("chatbot")
        return graph_builder
    

    def setup_graph(self, usecase: str):
        """
        Sets up the graph for the selected use case.
        """
        if usecase == "Basic Chatbot":
            self.graph_builder.add_node("chatbot", self.chatbot_node.process)
            self.graph_builder.set_entry_point("chatbot")
            self.graph_builder.set_finish_point("chatbot")
        elif usecase == "Chatbot with Tool":
            self.graph_builder = self.build_graph()
        else:
            raise ValueError("Invalid use case selected.")
        return self.graph_builder.compile()