from django.conf import settings
from django.core.signals import request_started
from django.dispatch import Signal
from django.template.loader import render_to_string
from django.test.signals import template_rendered
from debug_toolbar.panels import DebugPanel

# Code taken and adapted from Simon Willison and Django Snippets:
# http://www.djangosnippets.org/snippets/766/

# Monkeypatch instrumented test renderer from django.test.utils - we could use
# django.test.utils.setup_test_environment for this but that would also set up
# e-mail interception, which we don't want
from django.test.utils import instrumented_test_render
from django.template import Template
if Template.render != instrumented_test_render:
    Template.original_render = Template.render
    Template.render = instrumented_test_render
# MONSTER monkey-patch
old_template_init = Template.__init__
def new_template_init(self, template_string, origin=None, name='<Unknown Template>'):
    old_template_init(self, template_string, origin, name)
    self.origin = origin
Template.__init__ = new_template_init

class TemplateDebugPanel(DebugPanel):
    """
    A panel that lists all templates used during processing of a response.
    """
    name = 'Template'
    has_content = True

    def __init__(self, request):
        super(TemplateDebugPanel, self).__init__(request)
        self.templates_used = []
        template_rendered.connect(self._storeRenderedTemplates)

    def _storeRenderedTemplates(self, sender, **kwargs):
        self.templates_used.append(kwargs['template'])

    def title(self):
        return 'Templates'

    def url(self):
        return ''

    def content(self):
        templates = [
            (t.name, t.origin and t.origin.name or 'No origin')
            for t in self.templates_used
        ]
        context = {
            'templates': templates,
            'template_dirs': settings.TEMPLATE_DIRS,
        }
        return render_to_string('debug_toolbar/panels/templates.html', context)