from urllib.parse import unquote

class SharePointURLError(ValueError):
    """Custom error for SharePoint URL parsing issues."""
    pass


def get_sharepoint_path(url):
    try:
        url_parts = url.split('/')

        # Find the index of 'Forms'
        forms_index = url_parts.index('Forms')

        # Get the part after 'Forms'
        after_forms = url_parts[forms_index + 1]

        # Find 'id=' and extract after it
        if 'id=' in after_forms:
            id_part = after_forms.split('id=')[1]

            # Only keep the path before '&' (to ignore other parameters)
            id_path = id_part.split('&')[0]

            # Decode the path
            decoded_path = unquote(id_path)

            # Remove the leading '/sites/xxx/Shared Documents/' part
            parts = decoded_path.split('Shared Documents')

            if len(parts) > 1:
                final_path = parts[1].strip('/')
                return final_path
            else:
                return decoded_path.strip('/')
        else:
            raise SharePointURLError(f"The URL does not contain 'id=' parameter. URL: {url}")

    except (IndexError, ValueError) as e:
        raise SharePointURLError(f"Error with SharePoint URL, please check {url}. Reason: {e}")