# Standard library imports.
import re

# Django-specific imports.
from django.template import Context, loader


def generate_entity_iptables(entity):
    """
    Generates full iptables rules for the supplied entity. The generated rules
    can be fed directly to the iptables-restore utility.

    Arguments:

        entity - An Entity instance for which the iptables rules should be
        generated.

    Returns:

        String containing the iptables rules for entity.
    """

    # Render the iptables template.
    template = loader.get_template('conntrackt/entity_iptables.html')
    context = Context({'entity': entity})
    content = template.render(context)

    # Remove the blank lines.
    content = re.sub('^\s*\n', '', content)
    content = re.sub('\n\s*\n', '\n', content)

    return content