import os
from typing import Optional

import pandas as pd

from .rag_service import get_rag_service
from insurance.coverage_explainer import CoverageExplainer

USE_LLM = os.getenv("USE_LLM", "true").lower() == "true"


def parse_intent_simple(user_input: str, services_data: pd.DataFrame) -> Optional[str]:
    """Simple rule-based intent parsing with coverage question support."""
    user_input = user_input.lower()

    # Check coverage questions first (not really used now, but harmless)
    if CoverageExplainer.identify_coverage_question(user_input):
        return "coverage_explanation"

    # Check for help/list requests
    if any(word in user_input for word in ["help", "support", "services", "available"]):
        return "list_services"

    # Service keyword matching - match service descriptions mentioned in the user input
    res = services_data[
        services_data["description"].apply(
            lambda desc: desc.lower() in user_input
        )
    ]

    if not res.empty:
        return res.iloc[0]["intent"]

    return None


def parse_intent_with_llm(
    user_input: str,
    services_data: pd.DataFrame,
    hospital_name: str = "Unknown Hospital",
) -> Optional[str]:
    """LLM-powered intent parsing with coverage question detection."""

    # Coverage questions bypass RAG (though app.py already handles these first)
    if CoverageExplainer.identify_coverage_question(user_input):
        return "coverage_explanation"

    try:
        rag_service = get_rag_service()
        rag_service.initialize_vector_store(
            services_data,
            hospital_name,
            force_reload=False,
        )
        intent = rag_service.parse_intent_with_llm(user_input, services_data)
        return intent

    except Exception as e:
        print(f"Error in LLM parsing: {e}. Falling back to simple parsing.")
        return parse_intent_simple(user_input, services_data)


def parse_intent(
    user_input: str,
    services_data: pd.DataFrame,
    hospital_name: str = "Unknown Hospital",
    use_llm: Optional[bool] = None,
) -> Optional[str]:
    """
    Main intent parser - detects service requests or coverage questions.
    Returns: service intent, "list_services", "coverage_explanation", or None.
    Note: coverage questions are already handled in app.py before this is called.
    """
    should_use_llm = use_llm if use_llm is not None else USE_LLM

    if should_use_llm:
        return parse_intent_with_llm(user_input, services_data, hospital_name)
    else:
        print("Using simple parsing.")
        return parse_intent_simple(user_input, services_data)