from django.http import HttpResponse
from django.views.generic import TemplateView

from wiki_groups.models import WikiGroup


def dot_graph(request):
    response = HttpResponse(content_type="text/vnd.graphviz")
    response["Content-Disposition"] = 'attachment; filename="groups.dot"'

    response.write("digraph {\n")
    nodes = WikiGroup.objects.values_list("id", "django_group__name")
    edges = WikiGroup.includes_groups.through.objects.values_list(
        "to_wikigroup", "from_wikigroup"
    )
    for id, name in nodes:
        response.write('  {} ["label"="{}"];\n'.format(id, name))
    for u, v in edges:
        response.write("  {} -> {};\n".format(u, v))
    response.write("}\n")

    return response


graph = TemplateView.as_view(template_name="wiki_groups/graph.html")