"""
Enterprise Knowledge Assistant - Multi-Agent Graph
Router -> Hybrid Retrieval -> Generation, orchestrated via LangGraph.
"""

from langgraph.graph import StateGraph, END
from typing import TypedDict

class AgentState(TypedDict):
    query: str
    domain: str
    confidence: float
    retrieved_chunks: list
    answer: str


def build_agent_graph(router_model, tokenizer, label_encoder, embedding_model, 
                       domain_indices, domain_chunks_map, index, all_chunks, groq_client,
                       classify_query_fn, retrieve_hybrid_fn, generate_with_groq_fn):
    
    def router_node(state):
        domain, confidence_or_probs = classify_query_fn(state['query'], router_model, tokenizer, label_encoder)
        if hasattr(confidence_or_probs, 'shape') and confidence_or_probs.numel() > 1:
            confidence = float(confidence_or_probs.max())
        else:
            confidence = float(confidence_or_probs)
        print(f"[Router] Domain: {domain} (confidence: {confidence:.2f})")
        return {**state, 'domain': domain, 'confidence': confidence}

    def retrieval_node(state):
        results = retrieve_hybrid_fn(
            state['query'], state['domain'],
            embedding_model, domain_indices, domain_chunks_map, index, all_chunks
        )
        return {**state, 'retrieved_chunks': results}

    def generation_node(state):
        context_text = "\n\n".join([f"[Source: {c['domain']} - {c['title']}]\n{c['text']}"
                                      for dist, c in state['retrieved_chunks']])
        prompt = f"""You are an enterprise knowledge assistant. Answer using ONLY the context below.
If the context doesn't fully answer the question, say what's missing honestly.

Context:
{context_text}

Question: {state['query']}

Answer:"""
        answer = generate_with_groq_fn(prompt, groq_client)
        return {**state, 'answer': answer}

    graph = StateGraph(AgentState)
    graph.add_node("router", router_node)
    graph.add_node("retrieval", retrieval_node)
    graph.add_node("generation", generation_node)

    graph.set_entry_point("router")
    graph.add_edge("router", "retrieval")
    graph.add_edge("retrieval", "generation")
    graph.add_edge("generation", END)

    return graph.compile()