# Copyright (c) 2025 Patrick Motsch
# All rights reserved.
"""
Dynamic database registry — each interface self-registers its DB on import.

Usage in any interfaceDb*.py / interfaceFeature*.py:
    from modules.shared.dbRegistry import registerDatabase
    registerDatabase("poweron_xyz")
"""

import logging
import threading
from typing import Dict, Optional

from modules.connectors.connectorDbPostgre import DatabaseConnector
from modules.shared.configuration import APP_CONFIG

logger = logging.getLogger(__name__)

_lock = threading.Lock()
_registry: Dict[str, str] = {}


def registerDatabase(dbName: str, configPrefix: str = "DB") -> None:
    """Register a database for health monitoring.

    Called at module-level by each interface so that the registry
    is populated automatically as interfaces are imported.

    Args:
        dbName: PostgreSQL database name (e.g. "poweron_app").
        configPrefix: Config key prefix for host/port/user/password.
                      Default "DB" reads DB_HOST, DB_PORT, etc.
    """
    with _lock:
        if dbName in _registry:
            return
        _registry[dbName] = configPrefix
        logger.debug(f"Database registered: {dbName} (configPrefix={configPrefix})")


def getRegisteredDatabases() -> Dict[str, str]:
    """Return snapshot of all registered databases {dbName: configPrefix}."""
    with _lock:
        return dict(_registry)


def _getConnectorForDb(dbName: str) -> DatabaseConnector:
    """Create a lightweight DatabaseConnector for the given registered DB.

    Intended for read-only health queries (pg_stat, orphan scans).
    Uses the same APP_CONFIG credentials as the application connectors.
    """
    with _lock:
        configPrefix = _registry.get(dbName)
    if configPrefix is None:
        raise ValueError(f"Database '{dbName}' is not registered.")

    hostKey = f"{configPrefix}_HOST" if configPrefix != "DB" else "DB_HOST"
    portKey = f"{configPrefix}_PORT" if configPrefix != "DB" else "DB_PORT"
    userKey = f"{configPrefix}_USER" if configPrefix != "DB" else "DB_USER"
    passwordKey = f"{configPrefix}_PASSWORD_SECRET" if configPrefix != "DB" else "DB_PASSWORD_SECRET"

    return DatabaseConnector(
        dbHost=APP_CONFIG.get(hostKey, "localhost"),
        dbDatabase=dbName,
        dbUser=APP_CONFIG.get(userKey),
        dbPassword=APP_CONFIG.get(passwordKey),
        dbPort=int(APP_CONFIG.get(portKey, 5432)),
    )