""" some helper functions """

import openpyxl


def excel_value_as_number(value):
    if value is None:
        return 0
    if isinstance(value, str):
        try:
            return float(value)
        except ValueError:
            return 0
    return value


def get_sheet_of_file(excel_file, sheet=None):
    """ returns a sheet from an excel FileCache

    if name is set to None, the function returns the first sheet
    """
    workbook = openpyxl.open(excel_file)
    if sheet is None:
        all_sheets = workbook.sheetnames
        sheet = all_sheets[0]
    return workbook[sheet]


def is_empty_excel_value(value):
    """ is the cell value considered empty """
    if value is None:
        return True
    if isinstance(value, str) and value.strip() == "":
        return True
    return False


def strip_excel_value(value):
    """ remove whitespace from an excel value if it is a string """
    if isinstance(value, str):
        return value.strip()
    return value