from typing import TypedDict, Union

from flask import current_app
from flask_sqlalchemy import BaseQuery
from sqlalchemy import desc


class PaginationResponse(TypedDict):
    items: list
    max_pages: int


def order_by_column_name(query: BaseQuery, model_field: str, order_by_col_name: Union[str, None]) -> BaseQuery:
    if order_by_col_name is not None:
        if order_by_col_name == 'asc':
            query = query.order_by(model_field)
        elif order_by_col_name == 'desc':
            query = query.order_by(desc(model_field))

    return query


def paginate_models(page: int, query: BaseQuery, per_page=10) -> PaginationResponse:
    default_page = 1
    if page is not None:
        query = query.paginate(page=page, per_page=per_page, error_out=False)
    else:
        query = query.paginate(page=default_page, per_page=per_page, error_out=False)

    return {
        'items': query.items,
        'max_pages': query.pages
    }


def is_allowed_extensions(filename: str):
    return '.' in filename and \
           filename.rsplit('.', 1)[1].lower() in current_app.config['ALLOWED_EXTENSIONS']