"""
Session helper utilities for managing user profile sessions.
Feature: Fix profile session restoration when Flask session cache expires
"""

import logging
from typing import Optional

from .backend_client import BackendAPIClient

logger = logging.getLogger(__name__)


def ensure_profile_session(user_id: str) -> str:
    """
    Ensure user has a profile session, restoring or creating via API if needed.
    
    This handles cases where Flask session cache expires but the user's profile
    session still exists in the backend API.
    
    Args:
        user_id: User's ID from OAuth
        
    Returns:
        Profile session ID (backend session_id for contact_id="user-profile")
        
    Raises:
        Exception: If unable to restore or create profile session
    """
    backend_api = BackendAPIClient()
    
    # Try to find existing user-profile session in backend
    try:
        sessions = backend_api.list_sessions(user_id=user_id)
        
        # Look for existing profile session (contact_id="user-profile")
        for session_data in sessions:
            contact_id = session_data.get("contact_id")
            if contact_id == "user-profile":
                session_id = session_data.get("session_id")
                logger.info(
                    f"[SESSION_RESTORE] Found existing profile session for user {user_id}: "
                    f"session_id={session_id}"
                )
                return session_id
    except Exception as e:
        logger.warning(
            f"[SESSION_RESTORE] Failed to list sessions for user {user_id}: {e}. "
            f"Will attempt to create new profile session."
        )
    
    # No existing profile session found - create new one
    try:
        logger.info(f"[SESSION_CREATE] Creating new profile session for user {user_id}")
        response = backend_api.create_session(
            user_id=user_id,
            contact_id="user-profile",
            description=f"{user_id}'s Profile",
            is_reference=False
        )
        
        session_id = response.get("session_id")
        if not session_id:
            raise ValueError("Backend did not return session_id")
        
        logger.info(
            f"[SESSION_CREATE] Created new profile session for user {user_id}: "
            f"session_id={session_id}"
        )
        return session_id
        
    except Exception as e:
        logger.error(
            f"[SESSION_CREATE] Failed to create profile session for user {user_id}: {e}",
            exc_info=True
        )
        raise Exception(f"Failed to initialize profile session: {str(e)}")


def get_or_restore_profile_session(user_id: str, cached_session_id: Optional[str]) -> str:
    """
    Get profile session ID from cache or restore from backend.
    
    This is a convenience wrapper that checks the cache first before
    hitting the backend API.
    
    Args:
        user_id: User's ID from OAuth
        cached_session_id: Profile session ID from Flask session (may be None)
        
    Returns:
        Profile session ID
        
    Raises:
        Exception: If unable to restore or create profile session
    """
    if cached_session_id:
        return cached_session_id
    
    logger.warning(
        f"[SESSION_CACHE_MISS] Profile session not in Flask session for user {user_id}, "
        f"restoring from backend"
    )
    return ensure_profile_session(user_id)