def upload_file(filepath, bucket_name=None, namekey=None, wait=False):
    """Uploads the given file to S3 storage.

    Arguments
    ---------
    filepath : str
        The full path, from root, to the desired file.
    bucket_name (optional) : str
        The name of the bucket to upload the file to. If not given, it will be
        inferred from any defined base directory that is present on the path
        (there is no guarentee which base directory will be used if several are
        present in the given path). If base directory inferrence fails the
        default bukcet will be used, if defined, else the operation will fail.
    namekey (optional) : bool
        Indicate whether to use the name of the file as the key when uploading
        to the bucket. If set, or if no base directory is found in the
        filepath, the file name will be used as key. Otherwise, the path
        rooted at the detected base directory will be used, resulting in a
        directory-like structure in the S3 bucket.
    wait (optional) : bool
        Defaults to False. If set to True, the function will wait on the upload
        operation. Otherwise, the upload will be performed asynchronously in a
        separate thread.
    """
    filepath = _parse_file_path(filepath)
    bucket, key = _get_bucket_and_key(filepath, bucket_name, namekey)
    if wait:
        bucket.upload_file(filepath, key)
    else:
        _get_executor().submit(_file_upload_thread, bucket, filepath, key)