"""
DBServiceConfig - Configuration for DB Service permissions and filtering.

Allows application layer to register model scopes and column names,
making the DB service completely generic and plug-and-play.
"""

import logging
from typing import Type, Set, Optional

logger = logging.getLogger(__name__)


class DBServiceConfig:
    """
    Centralized configuration for DB Service.
    
    Register your application's models and permissions at startup.
    """
    
    # Configuration state
    _registered = False
    
    # Database metadata
    db_base = None  # SQLAlchemy declarative base
    all_models: list = []  # All model classes
    
    # Column names (generic)
    user_filter_column: str = "user_id"
    user_id_column: str = "id"
    soft_delete_column: str = "deleted_at"
    
    # Special models
    special_user_model: Optional[Type] = None
    
    # USER scopes
    user_read_scoped: Set[Type] = set()
    user_create_scoped: Set[Type] = set()
    user_update_scoped: Set[Type] = set()
    user_delete_scoped: Set[Type] = set()
    
    # ADMIN scopes
    admin_read_only: Set[Type] = set()
    admin_create_only: Set[Type] = set()
    admin_update_only: Set[Type] = set()
    admin_delete_only: Set[Type] = set()
    
    # SYSTEM scopes
    system_read_scoped: Set[Type] = set()
    system_create_scoped: Set[Type] = set()
    system_update_scoped: Set[Type] = set()
    system_delete_scoped: Set[Type] = set()
    
    @classmethod
    def register(
        cls,
        # Database metadata
        db_base=None,          # SQLAlchemy Base (for table creation)
        all_models: list = None,  # All model classes
        # Column names
        user_filter_column: str = "user_id",
        user_id_column: str = "id",
        soft_delete_column: str = "deleted_at",
        # Special models
        special_user_model: Optional[Type] = None,
        # USER scopes
        user_read_scoped: list = None,
        user_create_scoped: list = None,
        user_update_scoped: list = None,
        user_delete_scoped: list = None,
        # ADMIN scopes
        admin_read_only: list = None,
        admin_create_only: list = None,
        admin_update_only: list = None,
        admin_delete_only: list = None,
        # SYSTEM scopes
        system_read_scoped: list = None,
        system_create_scoped: list = None,
        system_update_scoped: list = None,
        system_delete_scoped: list = None,
    ) -> None:
        """Register DB Service configuration at application startup."""
        # Database metadata
        cls.db_base = db_base
        cls.all_models = all_models or []
        
        # Column names
        cls.user_filter_column = user_filter_column
        cls.user_id_column = user_id_column
        cls.soft_delete_column = soft_delete_column
        
        # Special models
        cls.special_user_model = special_user_model
        
        # USER scopes
        cls.user_read_scoped = set(user_read_scoped or [])
        cls.user_create_scoped = set(user_create_scoped or [])
        cls.user_update_scoped = set(user_update_scoped or [])
        cls.user_delete_scoped = set(user_delete_scoped or [])
        
        # ADMIN scopes
        cls.admin_read_only = set(admin_read_only or [])
        cls.admin_create_only = set(admin_create_only or [])
        cls.admin_update_only = set(admin_update_only or [])
        cls.admin_delete_only = set(admin_delete_only or [])
        
        # SYSTEM scopes
        cls.system_read_scoped = set(system_read_scoped or [])
        cls.system_create_scoped = set(system_create_scoped or [])
        cls.system_update_scoped = set(system_update_scoped or [])
        cls.system_delete_scoped = set(system_delete_scoped or [])
        
        cls._registered = True
        
        logger.info("✅ DBServiceConfig registered successfully")
        logger.info(f"   Models registered: {len(cls.all_models)}")
        logger.info(f"   User filter column: {cls.user_filter_column}")
        logger.info(f"   Soft delete column: {cls.soft_delete_column}")
        logger.info(f"   USER scopes: {len(cls.user_read_scoped)} read, {len(cls.user_create_scoped)} create")
        logger.info(f"   ADMIN scopes: {len(cls.admin_read_only)} read, {len(cls.admin_create_only)} create")
        logger.info(f"   SYSTEM scopes: {len(cls.system_read_scoped)} read, {len(cls.system_create_scoped)} create")
    
    @classmethod
    def is_registered(cls) -> bool:
        """Check if configuration has been registered."""
        return cls._registered
    
    @classmethod
    def assert_registered(cls) -> None:
        """Assert that configuration has been registered, raise if not."""
        if not cls._registered:
            raise RuntimeError(
                "DBServiceConfig not registered! "
                "Call DBServiceConfig.register() at application startup."
            )