# -*- coding: utf-8 -*-

from typing import Optional, Any

import abc

from ...log import *

from .DataType import DataType

class Column(abc.ABC): # export

    def __init__(self, table, name, data_type: DataType):
        self.__name: str = name
        self.__table: Any = table
        self.__is_nullable: Optional[bool] = None
        self.__is_null_insertible: Optional[bool] = None
        self.__is_primary_key: Optional[bool] = None
        self.__default_value: Optional[Any] = None
        self.__default_value_cached: bool = False
        self.__is_auto_increment: Optional[bool] = None
        self.__data_type: DataType = data_type

    def __repr__(self):
        return f'{self.__table.name}.{self.__name}: {self.__data_type}'

    @property
    def name(self) -> str:
        return self.__name

    @property
    def data_type(self):
        return self.__data_type

    @property
    def table(self) -> str:
        return self.__table

    @property
    def is_nullable(self) -> bool:
        if self.__is_nullable is None:
            self.__is_nullable = self.__name in self.__table.nullable_columns
        return self.__is_nullable

    @property
    def is_null_insertible(self):
        if self.__is_null_insertible is None:
            ret = False
            if self.is_nullable:
                ret = True
            elif self.is_auto_increment:
                ret = True
            elif self.default_value is not None:
                ret = True
            self.__is_null_insertible = ret
        return self.__is_null_insertible

    @property
    def is_primary_key(self) -> bool:
        if self.__is_primary_key is None:
            self.__is_primary_key = self.__name in self.__table.primary_keys
        return self.__is_primary_key

    @property
    def is_auto_increment(self) -> bool:
        if self.__is_auto_increment is None:
            self.__is_auto_increment = self.__name in self.__table.auto_increment_columns
        return self.__is_auto_increment

    @property
    def default_value(self) -> Optional[Any]:
        if self.__default_value_cached is False:
            self.__default_value = self.__table.column_default(self.name)
            self.__default_value_cached = True
        return self.__default_value