from sqlalchemy import create_engine
from sqlalchemy.orm import DeclarativeBase, Session
import os
import importlib


class Db:
    class Model(DeclarativeBase):
        __table_args__ = dict(extend_existing=True)
        pass

    def __init__(self, db, echo=False):
        self.db = db
        self.echo_output = echo
        self.Engine = self.create_engine()
        self.session = Session(bind=self.Engine)
        self.import_models()
        self.create_tables()

    def create_engine(self):
        return create_engine(self.db, echo=self.echo_output)

    def create_tables(self):
        self.Model.metadata.create_all(bind=self.Engine)

    def import_models(self):
        for filename in os.listdir('./data/models'):
            if filename.endswith('.py'):
                importlib.import_module('.' + filename[:-3], 'data.models')

    def role_exists(self, model: Model, role: str):
        does_exist = False
        language = self.session.query(model).filter(model.label == role).first()
        if language is not None:
            does_exist = True
        return does_exist

    def add_record(self, model):
        self.session.add(model)
        self.session.commit()