from langgraph.graph import StateGraph
from llm_node import llm_node
from formatter_node import formatter_node

def build_graph():
    graph = StateGraph(dict)

    def llm_step(state):
        question = state.get("question")
        if not question:
            raise ValueError("Missing 'question' in state")
        llm_output = llm_node(question)  # ✅ uses HuggingFaceHub now
        state["llm_output"] = llm_output
        return state

    def formatter_step(state):
        llm_output = state.get("llm_output")
        if not llm_output:
            raise ValueError("Missing 'llm_output' in state")
        final_answer = formatter_node(llm_output)
        state["final_answer"] = final_answer
        return state

    graph.add_node("llm", llm_step)
    graph.add_node("formatter", formatter_step)
    graph.set_entry_point("llm")
    graph.add_edge("llm", "formatter")
    graph.set_finish_point("formatter")

    return graph