# File: src/response_generator.py
# Purpose: Generate patient-facing voice responses using ONLY verified backend data

from pathlib import Path

import sys
sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
from src.verification_engine import VerificationResult


def generate_success_response(result: VerificationResult) -> str:
    """
    Generate a confirmation response using only verified API data.
    No LLM generation here — template-based to prevent hallucination.

    Args:
        result: Verified VerificationResult with verified=True

    Returns:
        Patient-facing spoken response string.
    """
    assert result.verified, "generate_success_response called with unverified result"
    assert result.appointment_id, "Appointment ID missing from verified result"

    response = (
        f"Your appointment has been confirmed. "
        f"Your reference number is {result.appointment_id}. "
    )
    if result.doctor:
        response += f"You will be seen by {result.doctor} "
    if result.department:
        response += f"in the {result.department} department "
    if result.date and result.slot:
        response += f"on {result.date} at {result.slot}. "
    response += "Please arrive 15 minutes early. Is there anything else I can help you with?"
    return response.strip()


def generate_failure_response(result: VerificationResult, alternative_slots: list[str]) -> str:
    """
    Generate a failure response using only verified failure reason from the API.
    Offers alternatives if available.

    Args:
        result: VerificationResult with verified=False
        alternative_slots: List of other available slots (from API, not LLM)

    Returns:
        Patient-facing spoken response string.
    """
    assert not result.verified, "generate_failure_response called with verified=True result"

    reason = result.failure_reason or "The slot is no longer available"
    response = f"I'm sorry, I was unable to book your appointment. {reason}. "

    if alternative_slots:
        options = ", ".join(alternative_slots[:3])
        response += f"However, the following slots are available for {result.department}: {options}. "
        response += "Would you like me to book one of these instead?"
    else:
        response += "Unfortunately, there are no other slots available at this time. "
        response += "I'll transfer you to our scheduling team who can assist you further."

    return response.strip()


def generate_escalation_response() -> str:
    """
    Response when agent confidence is below threshold.
    Used to prevent low-confidence actions from proceeding.
    """
    return (
        "I want to make sure I understood your request correctly. "
        "Let me connect you with one of our scheduling specialists "
        "who can assist you directly."
    )


def generate_response(
    result: VerificationResult,
    alternative_slots: list[str] | None = None,
) -> str:
    """
    Top-level response dispatcher. Routes to the correct template
    based on verification outcome.

    Args:
        result: VerificationResult from the verification engine.
        alternative_slots: Fallback slots to offer on failure (from API).

    Returns:
        Final patient-facing response string.
    """
    if result.verified:
        return generate_success_response(result)
    else:
        return generate_failure_response(result, alternative_slots or [])


if __name__ == "__main__":
    from src.verification_engine import VerificationResult

    # Test success path
    mock_success = VerificationResult(
        verified=True,
        appointment_id="APT-AB1234",
        patient_name="Ranjith Kumar",
        department="Cardiology",
        date="2025-06-01",
        slot="2:00 PM",
        doctor="Dr. Sample_3",
        failure_reason=None,
        attempts=1,
    )
    print("[Success]:", generate_response(mock_success))

    # Test failure path
    mock_failure = VerificationResult(
        verified=False,
        appointment_id=None,
        patient_name="Ranjith Kumar",
        department="Cardiology",
        date="2025-06-01",
        slot="2:00 PM",
        doctor=None,
        failure_reason="Slot unavailable. Please choose another time.",
        attempts=2,
    )
    alt_slots = ["10:00 AM", "11:00 AM", "3:00 PM"]
    print("[Failure]:", generate_response(mock_failure, alt_slots))