from abc import ABC, abstractmethod
from typing import Mapping, Any 
import sqlite3
import os

class DatabaseController(ABC):
    __data_dir = "./data/"
    __db_name = "wmgzon.db"

    # Use test file if necessary
    if os.environ.get("ENVIRON") == "test":
        __db_name = "test_" + __db_name

    __sqlitefile = __data_dir + __db_name


    def __init__(self):
        self._conn = None
        try:
            # Creates a connection and specifies a flag to parse all types back down into
            # Python declared types e.g. date & time
            self._conn = sqlite3.connect(self.__sqlitefile, detect_types=sqlite3.PARSE_DECLTYPES)
        except sqlite3.Error as e:
            # Close the connection if still open
            if self._conn:
                self._conn.close()
            print(e)

    def __del__(self):
          if self._conn != None:
            self._conn.close()

    """ Takes a dictionary of fields and returns the object 
        with those fields populated """
    def new_instance(self, of: type, with_fields: Mapping[str, Any]):
        obj = of.__new__(of)
        for attr, value in with_fields.items():
            setattr(obj, attr, value)
        return obj
    
    """
        Set of CRUD methods to allow for Data manipulation on the backend
    """

    @abstractmethod
    def create(self):
        pass

    @abstractmethod
    def read(self):
        pass

    @abstractmethod
    def update(self):
        pass
    
    @abstractmethod
    def delete(self):
        pass