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

from pprint import pformat

# 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 = []
        template_rendered.connect(self._storeTemplateInfo)

    def _storeTemplateInfo(self, sender, **kwargs):
        self.templates.append(kwargs)

    def title(self):
        return 'Templates'

    def url(self):
        return ''

    def content(self):
        template_context = []
        for i, d in enumerate(self.templates):
            info = {}
            # Clean up some info about templates
            t = d.get('template', None)
            # Skip templates that we are generating through the debug toolbar.
            if t.name.startswith('debug_toolbar/'):
                continue
            if t.origin and t.origin.name:
                t.origin_name = t.origin.name
            else:
                t.origin_name = 'No origin'
            info['template'] = t
            # Clean up context for better readability
            c = d.get('context', None)
            info['context'] = '\n'.join([pformat(_d) for _d in c.dicts])
            template_context.append(info)
        context = {
            'templates': template_context,
            'template_dirs': settings.TEMPLATE_DIRS,
        }
        return render_to_string('debug_toolbar/panels/templates.html', context)