diff --git a/cms/models.py b/cms/models.py
index 9f803f1..019fb89 100644
--- a/cms/models.py
+++ b/cms/models.py
@@ -24,10 +24,10 @@ class Post (models.Model):
         on_delete=models.SET_NULL,
         blank = True, null = True
     )
-    thread_pk = models.PositiveIntegerField(
+    thread_id = models.PositiveIntegerField(
         blank = True, null = True
     )
-    thread = GenericForeignKey('thread_type', 'thread_pk')
+    thread = GenericForeignKey('thread_type', 'thread_id')
 
     published = models.BooleanField(
         verbose_name = _('public'),
@@ -64,9 +64,21 @@ class Post (models.Model):
         blank = True,
     )
 
+    @classmethod
+    def children_of(cl, thread, queryset = None):
+        """
+        Return children of the given thread of the cl's type. If queryset
+        is not given, use cl.objects as starting queryset.
+        """
+        if not queryset:
+            queryset = cl.objects
+        thread_type = ContentType.objects.get_for_model(thread)
+        qs = queryset.filter(thread_id = thread.pk,
+                              thread_type__pk = thread_type.id)
+        return qs
 
     def detail_url (self):
-        return reverse(self._meta.verbose_name.lower() + '_detail',
+        return reverse(self._website.name_of_model(self.__class__) + '_detail',
                        kwargs = { 'pk': self.pk,
                                   'slug': slugify(self.title) })
 
@@ -145,6 +157,7 @@ class RelatedPostBase (models.base.ModelBase):
 
     def __new__ (cl, name, bases, attrs):
         # TODO: allow proxy models and better inheritance
+        # TODO: check bindings
         if name == 'RelatedPost':
             return super().__new__(cl, name, bases, attrs)
 
@@ -267,18 +280,6 @@ class RelatedPost (Post, metaclass = RelatedPostBase):
             self.related.save()
 
 
-    @classmethod
-    def sync_from_rel(cl, rel, save = True):
-        """
-        Update a rel_to_post from a given rel object. Return -1 if there is no
-        related post to update
-        """
-        self = cl.objects.filter(related = rel)
-        if not self or not self.count():
-            return -1
-        self[0].rel_to_post(save)
-
-
     def rel_to_post(self, save = True):
         """
         Change the post using the related object bound values. Save the
@@ -286,25 +287,30 @@ class RelatedPost (Post, metaclass = RelatedPostBase):
         Note: does not check if Relation.post_to_rel is True
         """
         rel = self._relation
-        if rel.bindings:
+        if not rel.bindings:
             return
 
+        has_changed = False
+        def set_attr(attr, value):
+            if getattr(self, attr) != value:
+                has_changed = True
+                setattr(self, attr, value)
+
         for attr, rel_attr in rel.bindings.items():
             if attr == 'thread':
                 continue
             self.set_rel_attr
-            value = getattr(self.related, attr) \
-                    if hasattr(self.related, attr) else None
-            setattr(self, attr, value)
+            value = getattr(self.related, rel_attr)
+            set_attr(attr, value)
 
         if rel.thread_model:
             thread = self.get_rel_attr('thread')
             thread = rel.thread_model.objects.filter(related = thread) \
                         if thread else None
             thread = thread[0] if thread else None
-            self.thread = thread
+            set_attr('thread', thread)
 
-        if save:
+        if has_changed and save:
             self.save()
 
     def __init__ (self, *kargs, **kwargs):
@@ -329,10 +335,10 @@ class Comment(models.Model):
         on_delete=models.SET_NULL,
         blank = True, null = True
     )
-    thread_pk = models.PositiveIntegerField(
+    thread_id = models.PositiveIntegerField(
         blank = True, null = True
     )
-    thread = GenericForeignKey('thread_type', 'thread_pk')
+    thread = GenericForeignKey('thread_type', 'thread_id')
 
     author = models.TextField(
         verbose_name = _('author'),
diff --git a/cms/routes.py b/cms/routes.py
index 700c090..fda6e03 100644
--- a/cms/routes.py
+++ b/cms/routes.py
@@ -3,65 +3,48 @@ from django.contrib.contenttypes.models import ContentType
 from django.utils import timezone
 from django.utils.translation import ugettext as _, ugettext_lazy
 
-from website.models import *
-from website.views import *
-
-class Router:
-    registry = []
-
-    def register (self, route):
-        if not route in self.registry:
-            self.registry.append(route)
-
-    def register_set (self, view_set):
-        for url in view_set.urls:
-            self.register(url)
-
-    def unregister (self, route):
-        self.registry.remove(route)
-
-    def get_urlpatterns (self):
-        return [ url for url in self.registry ]
-
 
 class Route:
     """
     Base class for routing. Given a model, we generate url specific for each
-    route type. The generated url takes this form:
-        model_name + '/' + route_name + '/' + '/'.join(route_url_args)
+    type of route.
 
-    Where model_name by default is the given model's verbose_name (uses plural if
-    Route is for a list).
+    The generated url takes this form:
+        name + '/' + route_name + '/' + '/'.join(route_url_args)
 
-    The given view is considered as a django class view, and has view_
+    And their name (to use for reverse:
+        name + '_' + route_name
+
+    By default name is the verbose name of the model. It is always in
+    singular form.
     """
     name = None         # route name
     url_args = []       # arguments passed from the url [ (name : regex),... ]
 
     @classmethod
-    def get_queryset (cl, website, model, request, **kwargs):
+    def get_queryset(cl, website, model, request, **kwargs):
         """
         Called by the view to get the queryset when it is needed
         """
         pass
 
     @classmethod
-    def get_object (cl, website, model, request, **kwargs):
+    def get_object(cl, website, model, request, **kwargs):
         """
         Called by the view to get the object when it is needed
         """
         pass
 
     @classmethod
-    def get_title (cl, model, request, **kwargs):
+    def get_title(cl, model, request, **kwargs):
         return ''
 
     @classmethod
-    def get_view_name (cl, name):
+    def get_view_name(cl, name):
         return name + '_' + cl.name
 
     @classmethod
-    def as_url (cl, name, model, view, view_kwargs = None):
+    def as_url(cl, name, view, view_kwargs = None):
         pattern = '^{}/{}'.format(name, cl.name)
         if cl.url_args:
             url_args = '/'.join([
@@ -84,7 +67,7 @@ class Route:
                    name = cl.get_view_name(name))
 
 
-class DetailRoute (Route):
+class DetailRoute(Route):
     name = 'detail'
     url_args = [
         ('pk', '[0-9]+'),
@@ -92,25 +75,25 @@ class DetailRoute (Route):
     ]
 
     @classmethod
-    def get_object (cl, website, model, request, pk, **kwargs):
+    def get_object(cl, website, model, request, pk, **kwargs):
         return model.objects.get(pk = int(pk))
 
 
-class AllRoute (Route):
+class AllRoute(Route):
     name = 'all'
 
     @classmethod
-    def get_queryset (cl, website, model, request, **kwargs):
+    def get_queryset(cl, website, model, request, **kwargs):
         return model.objects.all()
 
     @classmethod
-    def get_title (cl, model, request, **kwargs):
+    def get_title(cl, model, request, **kwargs):
         return _('All %(model)s') % {
             'model': model._meta.verbose_name_plural
         }
 
 
-class ThreadRoute (Route):
+class ThreadRoute(Route):
     """
     Select posts using by their assigned thread.
 
@@ -125,7 +108,7 @@ class ThreadRoute (Route):
     ]
 
     @classmethod
-    def get_queryset (cl, website, model, request, thread_model, pk, **kwargs):
+    def get_queryset(cl, website, model, request, thread_model, pk, **kwargs):
         if type(thread_model) is str:
             thread_model = website.registry.get(thread_model)
 
@@ -139,7 +122,7 @@ class ThreadRoute (Route):
         )
 
 
-class DateRoute (Route):
+class DateRoute(Route):
     name = 'date'
     url_args = [
         ('year', '[0-9]{4}'),
@@ -148,7 +131,7 @@ class DateRoute (Route):
     ]
 
     @classmethod
-    def get_queryset (cl, website, model, request, year, month, day, **kwargs):
+    def get_queryset(cl, website, model, request, year, month, day, **kwargs):
         return model.objects.filter(
             date__year = int(year),
             date__month = int(month),
@@ -156,11 +139,11 @@ class DateRoute (Route):
         )
 
 
-class SearchRoute (Route):
+class SearchRoute(Route):
     name = 'search'
 
     @classmethod
-    def get_queryset (cl, website, model, request, q, **kwargs):
+    def get_queryset(cl, website, model, request, q, **kwargs):
         qs = model.objects
         for search_field in model.search_fields or []:
             r = model.objects.filter(**{ search_field + '__icontains': q })
diff --git a/cms/static/aircox_cms/styles.css b/cms/static/aircox/cms/styles.css
similarity index 100%
rename from cms/static/aircox_cms/styles.css
rename to cms/static/aircox/cms/styles.css
diff --git a/cms/templates/aircox/cms/detail.html b/cms/templates/aircox/cms/detail.html
index 2859c4b..dc1d37a 100644
--- a/cms/templates/aircox/cms/detail.html
+++ b/cms/templates/aircox/cms/detail.html
@@ -1,14 +1,31 @@
 {% extends embed|yesno:"aircox/cms/base_content.html,aircox/cms/base_site.html" %}
+{% load aircox_cms %}
 
 {% block title %}
 {{ object.title }}
 {% endblock %}
 
 {% block pre_title %}
+<div class="pre_title">
+{% if object.thread %}
+<div class="threads">
+    {{ object|threads:' > '|safe }}
+</div>
+{% endif %}
+
 <time datetime="{{ object.date }}">
     {{ object.date|date:'l d F Y' }},
     {{ object.date|time:'H\hi' }}
 </time>
+
+{% if object.tags %}
+{# TODO: url to the tags #}
+<div class="tags">
+    {{ object.tags.all|join:', ' }}
+</div>
+{% endif %}
+
+</div>
 {% endblock %}
 
 {% block content %}
diff --git a/cms/templates/aircox/cms/section_list.html b/cms/templates/aircox/cms/section_list.html
index f1eb561..c28de59 100644
--- a/cms/templates/aircox/cms/section_list.html
+++ b/cms/templates/aircox/cms/section_list.html
@@ -5,7 +5,7 @@
 {% block section_content %}
 <ul style="padding:0; margin:0">
     {% for item in object_list %}
-    <li>
+    <li class="{{item.css}}">
         {% if item.url %}
         <a href="{{item.url}}">
         {% endif %}
diff --git a/cms/templatetags/__init__.py b/cms/templatetags/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/cms/templatetags/aircox_cms.py b/cms/templatetags/aircox_cms.py
new file mode 100644
index 0000000..86f62ec
--- /dev/null
+++ b/cms/templatetags/aircox_cms.py
@@ -0,0 +1,23 @@
+from django import template
+from django.core.urlresolvers import reverse
+
+register = template.Library()
+
+
+@register.filter(name='threads')
+def threads (post, sep = '/'):
+    """
+    print a list of all parents, from top to bottom
+    """
+    posts = [post]
+    while posts[0].thread:
+        post = posts[0].thread
+        if post not in posts:
+            posts.insert(0, post)
+
+    return sep.join([
+        '<a href="{}">{}</a>'.format(post.detail_url(), post.title)
+        for post in posts if post.published
+    ])
+
+
diff --git a/cms/utils.py b/cms/utils.py
index 8f25573..413d8f6 100644
--- a/cms/utils.py
+++ b/cms/utils.py
@@ -2,7 +2,7 @@ from django.contrib.contenttypes.models import ContentType
 from django.core.urlresolvers import reverse
 
 
-def get_url (website, route, model, kwargs):
+def get_url(website, route, model, kwargs):
     name = website.name_of_model(model)
     if not name:
         return
@@ -10,7 +10,7 @@ def get_url (website, route, model, kwargs):
     return reverse(name, kwargs = kwargs)
 
 
-def filter_thread (qs, object):
+def filter_thread(qs, object):
     model_type = ContentType.objects.get_for_model(object.__class__)
     return qs.filter(
         thread_pk = object.pk,
diff --git a/cms/views.py b/cms/views.py
index 5ac4678..a35a2e4 100644
--- a/cms/views.py
+++ b/cms/views.py
@@ -20,7 +20,7 @@ class PostBaseView:
     embed = False   # page is embed (if True, only post content is printed
     classes = ''    # extra classes for the content
 
-    def get_base_context (self, **kwargs):
+    def get_base_context(self, **kwargs):
         """
         Return a context with all attributes of this classe plus 'view' set
         to self.
@@ -44,7 +44,7 @@ class PostBaseView:
         return context
 
 
-class PostListView (PostBaseView, ListView):
+class PostListView(PostBaseView, ListView):
     """
     List view for posts and children
     """
@@ -59,11 +59,11 @@ class PostListView (PostBaseView, ListView):
         page = 1        # page number
         q = None        # query search
 
-        def __init__ (self, query):
+        def __init__(self, query):
             if query:
                 self.update(query)
 
-        def update (self, query):
+        def update(self, query):
             my_class = self.__class__
             if type(query) is my_class:
                 self.__dict__.update(query.__dict__)
@@ -80,15 +80,15 @@ class PostListView (PostBaseView, ListView):
     fields = [ 'date', 'time', 'image', 'title', 'content' ]
     icon_size = '64x64'
 
-    def __init__ (self, *args, **kwargs):
+    def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.query = PostListView.Query(self.query)
 
-    def dispatch (self, request, *args, **kwargs):
+    def dispatch(self, request, *args, **kwargs):
         self.route = self.kwargs.get('route') or self.route
         return super().dispatch(request, *args, **kwargs)
 
-    def get_queryset (self):
+    def get_queryset(self):
         if self.route:
             qs = self.route.get_queryset(self.website, self.model, self.request,
                                          **self.kwargs)
@@ -116,7 +116,7 @@ class PostListView (PostBaseView, ListView):
 
         return qs
 
-    def get_context_data (self, **kwargs):
+    def get_context_data(self, **kwargs):
         context = super().get_context_data(**kwargs)
         context.update(self.get_base_context(**kwargs))
         context.update({
@@ -124,7 +124,7 @@ class PostListView (PostBaseView, ListView):
         })
         return context
 
-    def get_title (self):
+    def get_title(self):
         if self.title:
             return self.title
 
@@ -132,14 +132,14 @@ class PostListView (PostBaseView, ListView):
                                                     **self.kwargs)
         return title
 
-    def get_url (self):
+    def get_url(self):
         if self.route:
             return utils.get_urls(self.website, self.route,
                                   self.model, self.kwargs)
         return ''
 
 
-class PostDetailView (DetailView, PostBaseView):
+class PostDetailView(DetailView, PostBaseView):
     """
     Detail view for posts and children
     """
@@ -147,11 +147,11 @@ class PostDetailView (DetailView, PostBaseView):
 
     sections = []
 
-    def __init__ (self, sections = None, *args, **kwargs):
+    def __init__(self, sections = None, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.sections = sections or []
 
-    def get_queryset (self):
+    def get_queryset(self):
         if self.request.GET.get('embed'):
             self.embed = True
 
@@ -159,14 +159,14 @@ class PostDetailView (DetailView, PostBaseView):
             return super().get_queryset().filter(published = True)
         return []
 
-    def get_object (self, **kwargs):
+    def get_object(self, **kwargs):
         if self.model:
             object = super().get_object(**kwargs)
             if object.published:
                 return object
         return None
 
-    def get_context_data (self, **kwargs):
+    def get_context_data(self, **kwargs):
         context = super().get_context_data(**kwargs)
         context.update(self.get_base_context())
         context.update({
@@ -178,7 +178,7 @@ class PostDetailView (DetailView, PostBaseView):
         return context
 
 
-class Menu (View):
+class Menu(View):
     template_name = 'aircox/cms/menu.html'
 
     name = ''
@@ -188,11 +188,11 @@ class Menu (View):
     position = ''   # top, left, bottom, right, header, footer, page_top, page_bottom
     sections = None
 
-    def __init__ (self, *args, **kwargs):
+    def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.name = self.name or ('menu_' + self.position)
 
-    def get_context_data (self, **kwargs):
+    def get_context_data(self, **kwargs):
         return {
             'name': self.name,
             'tag': self.tag,
@@ -205,7 +205,7 @@ class Menu (View):
             ]
         }
 
-    def get (self, request, website, **kwargs):
+    def get(self, request, website, **kwargs):
         self.request = request
         self.website = website
         context = self.get_context_data(**kwargs)
@@ -213,7 +213,7 @@ class Menu (View):
 
 
 
-class BaseSection (View):
+class BaseSection(View):
     """
     Base class for sections. Sections are view that can be used in detail view
     in order to have extra content about a post, or in menus.
@@ -227,7 +227,7 @@ class BaseSection (View):
     visible = True  # if false renders an empty string
 
 
-    def get_context_data (self):
+    def get_context_data(self):
         return {
             'view': self,
             'tag': self.tag,
@@ -237,7 +237,7 @@ class BaseSection (View):
             'content': self.content,
         }
 
-    def get (self, request, website, **kwargs):
+    def get(self, request, website, **kwargs):
         self.request = request
         self.website = website
         self.kwargs = kwargs
@@ -249,7 +249,7 @@ class BaseSection (View):
         return ''
 
 
-class Section (BaseSection):
+class Section(BaseSection):
     """
     A Section that can be related to an object.
     """
@@ -260,7 +260,7 @@ class Section (BaseSection):
     header = ''
     footer = ''
 
-    def get_context_data (self):
+    def get_context_data(self):
         context = super().get_context_data()
         context.update({
             'title': self.title,
@@ -269,7 +269,7 @@ class Section (BaseSection):
         })
         return context
 
-    def get (self, request, object = None, **kwargs):
+    def get(self, request, object = None, **kwargs):
         self.object = object or self.object
         if self.object_required and not self.object:
             raise ValueError('object is required by this Section but not given')
@@ -277,43 +277,43 @@ class Section (BaseSection):
 
 
 class Sections:
-    class Image (BaseSection):
+    class Image(BaseSection):
         """
         Render an image with the given relative url.
         """
         url = None
 
         @property
-        def content (self):
+        def content(self):
             return '<img src="{}">'.format(
                         static(self.url),
                     )
 
-    class PostContent (Section):
+    class PostContent(Section):
         """
         Render the content of the Post (format the text a bit and escape HTML
         tags).
         """
         @property
-        def content (self):
+        def content(self):
             content = escape(self.object.content)
             content = re.sub(r'(^|\n\n)((\n?[^\n])+)', r'<p>\2</p>', content)
             content = re.sub(r'\n', r'<br>', content)
             return content
 
-    class PostImage (Section):
+    class PostImage(Section):
         """
         Render the image of the Post
         """
         @property
-        def content (self):
+        def content(self):
             if not self.object.image:
                 return ''
             return '<img src="{}" class="post_image">'.format(
                         self.object.image.url
                     )
 
-    class List (Section):
+    class List(Section):
         """
         Section to render list. The context item 'object_list' is used as list of
         items to render.
@@ -323,11 +323,13 @@ class Sections:
             title = None
             text = None
             url = None
+            css = None
 
-            def __init__ (self, icon, title = None, text = None, url = None):
+            def __init__(self, icon, title = None, text = None, url = None, css = None):
                 self.icon = icon
                 self.title = title
                 self.text = text
+                self.css = css
 
         hide_empty = False      # hides the section if the list is empty
         use_icons = True        # print icons
@@ -335,13 +337,13 @@ class Sections:
         icon_size = '32x32'     # icons size
         template_name = 'aircox/cms/section_list.html'
 
-        def get_object_list (self):
+        def get_object_list(self):
             return []
 
-        def get_context_data (self, **kwargs):
+        def get_context_data(self, **kwargs):
             object_list = self.get_object_list()
             self.visibility = True
-            if not object_list and hide_empty:
+            if not object_list and self.hide_empty:
                 self.visibility = False
 
             context = super().get_context_data(**kwargs)
@@ -353,14 +355,14 @@ class Sections:
             })
             return context
 
-    class Urls (List):
+    class Urls(List):
         """
         Render a list of urls of targets that are Posts
         """
         classes = 'section_urls'
         targets = None
 
-        def get_object_list (self):
+        def get_object_list(self):
             return [
                 List.Item(
                     target.image or None,
@@ -370,7 +372,7 @@ class Sections:
                 for target in self.targets
             ]
 
-    class Posts (PostBaseView, Section):
+    class Posts(PostBaseView, Section):
         """
         Render a list using PostListView's template.
         """
@@ -379,13 +381,13 @@ class Sections:
         icon_size = '64x64'
         fields = [ 'date', 'time', 'image', 'title', 'content' ]
 
-        def get_url (self):
+        def get_url(self):
             return ''
 
-        def get_object_list (self):
+        def get_object_list(self):
             return []
 
-        def render_list (self):
+        def render_list(self):
             self.embed = True
             context = self.get_base_context(**self.kwargs)
             context.update({
@@ -395,7 +397,7 @@ class Sections:
             })
             return render_to_string(PostListView.template_name, context)
 
-        def get_context_data (self, **kwargs):
+        def get_context_data(self, **kwargs):
             context = super().get_context_data(**kwargs)
             context['content'] = self.render_list()
             return context
diff --git a/cms/website.py b/cms/website.py
index a9de41b..e1f70ab 100644
--- a/cms/website.py
+++ b/cms/website.py
@@ -35,6 +35,7 @@ class Website:
             raise ValueError('A model has yet been registered under "{}"'
                              .format(name))
         self.registry[name] = model
+        model._website = self
         return name
 
     def register_detail (self, name, model, view = views.PostDetailView,
@@ -48,7 +49,7 @@ class Website:
             model = model,
             **view_kwargs,
         )
-        self.urls.append(routes.DetailRoute.as_url(name, model, view))
+        self.urls.append(routes.DetailRoute.as_url(name, view))
         self.registry[name] = model
 
     def register_list (self, name, model, view = views.PostListView,
@@ -62,7 +63,7 @@ class Website:
             model = model,
             **view_kwargs
         )
-        self.urls += [ route.as_url(name, model, view) for route in routes ]
+        self.urls += [ route.as_url(name, view) for route in routes ]
         self.registry[name] = model
 
     def register (self, name, model, sections = None, routes = None,
diff --git a/liquidsoap/management/commands/liquidsoap.py b/liquidsoap/management/commands/liquidsoap.py
index e6ca1b5..c68ef7d 100644
--- a/liquidsoap/management/commands/liquidsoap.py
+++ b/liquidsoap/management/commands/liquidsoap.py
@@ -97,7 +97,9 @@ class Monitor:
         args = {'start__gt': prev_diff.start } if prev_diff else {}
         next_diff = programs.Diffusion \
                         .get(controller.station, now, now = True,
-                             sounds__isnull = False, **args) \
+                             type = programs.Diffusion.Type.normal,
+                             sounds__isnull = False,
+                             **args) \
                         .prefetch_related('sounds')
         if next_diff:
             next_diff = next_diff[0]
diff --git a/programs/admin.py b/programs/admin.py
index 163b8c3..7d49e4b 100755
--- a/programs/admin.py
+++ b/programs/admin.py
@@ -91,7 +91,7 @@ class DiffusionAdmin (admin.ModelAdmin):
         return ', '.join(sounds) if sounds else ''
 
     def conflicts (self, obj):
-        if obj.type == Diffusion.Type['unconfirmed']:
+        if obj.type == Diffusion.Type.unconfirmed:
             return ', '.join([ str(d) for d in obj.get_conflicts()])
         return ''
 
@@ -115,9 +115,9 @@ class DiffusionAdmin (admin.ModelAdmin):
         qs = super(DiffusionAdmin, self).get_queryset(request)
         if '_changelist_filters' in request.GET or \
             'type__exact' in request.GET and \
-                str(Diffusion.Type['unconfirmed']) in request.GET['type__exact']:
+                str(Diffusion.Type.unconfirmed) in request.GET['type__exact']:
             return qs
-        return qs.exclude(type = Diffusion.Type['unconfirmed'])
+        return qs.exclude(type = Diffusion.Type.unconfirmed)
 
 
 @admin.register(Log)
diff --git a/programs/management/commands/diffusions_monitor.py b/programs/management/commands/diffusions_monitor.py
index 78c48e0..5568092 100644
--- a/programs/management/commands/diffusions_monitor.py
+++ b/programs/management/commands/diffusions_monitor.py
@@ -46,15 +46,15 @@ class Actions:
                 continue
 
             if conflict.pk in saved_items and \
-                    conflict.type != Diffusion.Type['unconfirmed']:
-                conflict.type = Diffusion.Type['unconfirmed']
+                    conflict.type != Diffusion.Type.unconfirmed:
+                conflict.type = Diffusion.Type.unconfirmed
                 conflict.save()
 
         if not conflicts:
-            item.type = Diffusion.Type['normal']
+            item.type = Diffusion.Type.normal
             return 0
 
-        item.type = Diffusion.Type['unconfirmed']
+        item.type = Diffusion.Type.unconfirmed
         return len(conflicts)
 
     @classmethod
@@ -93,14 +93,14 @@ class Actions:
 
     @staticmethod
     def clean (date):
-        qs = Diffusion.objects.filter(type = Diffusion.Type['unconfirmed'],
+        qs = Diffusion.objects.filter(type = Diffusion.Type.unconfirmed,
                                       start__lt = date)
         logger.info('[clean] %d diffusions will be removed', qs.count())
         qs.delete()
 
     @staticmethod
     def check (date):
-        qs = Diffusion.objects.filter(type = Diffusion.Type['unconfirmed'],
+        qs = Diffusion.objects.filter(type = Diffusion.Type.unconfirmed,
                                       start__gt = date)
         items = []
         for diffusion in qs:
diff --git a/programs/management/commands/sounds_monitor.py b/programs/management/commands/sounds_monitor.py
index 15240eb..b84bff7 100644
--- a/programs/management/commands/sounds_monitor.py
+++ b/programs/management/commands/sounds_monitor.py
@@ -162,9 +162,9 @@ class MonitorHandler (PatternMatchingEventHandler):
         """
         self.subdir = subdir
         if self.subdir == settings.AIRCOX_SOUND_ARCHIVES_SUBDIR:
-            self.sound_kwargs = { 'type': Sound.Type['archive'] }
+            self.sound_kwargs = { 'type': Sound.Type.archive }
         else:
-            self.sound_kwargs = { 'type': Sound.Type['excerpt'] }
+            self.sound_kwargs = { 'type': Sound.Type.excerpt }
 
         patterns = ['*/{}/*{}'.format(self.subdir, ext)
                     for ext in settings.AIRCOX_SOUND_FILE_EXT ]
@@ -264,11 +264,11 @@ class Command (BaseCommand):
             logger.info('#%d %s', program.id, program.name)
             self.scan_for_program(
                 program, settings.AIRCOX_SOUND_ARCHIVES_SUBDIR,
-                type = Sound.Type['archive'],
+                type = Sound.Type.archive,
             )
             self.scan_for_program(
                 program, settings.AIRCOX_SOUND_EXCERPTS_SUBDIR,
-                type = Sound.Type['excerpt'],
+                type = Sound.Type.excerpt,
             )
 
     def scan_for_program (self, program, subdir, **sound_kwargs):
diff --git a/programs/models.py b/programs/models.py
index 3140154..6165d2e 100755
--- a/programs/models.py
+++ b/programs/models.py
@@ -1,6 +1,7 @@
 import os
 import shutil
 import logging
+from enum import Enum, IntEnum
 
 from django.db import models
 from django.template.defaultfilters import slugify
@@ -19,7 +20,7 @@ import aircox.programs.settings as settings
 logger = logging.getLogger('aircox.core')
 
 
-def date_or_default (date, date_only = False):
+def date_or_default(date, date_only = False):
     """
     Return date or default value (now) if not defined, and remove time info
     if date_only is True
@@ -32,20 +33,20 @@ def date_or_default (date, date_only = False):
     return date
 
 
-class Nameable (models.Model):
+class Nameable(models.Model):
     name = models.CharField (
         _('name'),
         max_length = 128,
     )
 
     @property
-    def slug (self):
+    def slug(self):
         """
         Slug based on the name. We replace '-' by '_'
         """
         return slugify(self.name).replace('-', '_')
 
-    def __str__ (self):
+    def __str__(self):
         #if self.pk:
         #    return '#{} {}'.format(self.pk, self.name)
         return '{}'.format(self.name)
@@ -54,7 +55,7 @@ class Nameable (models.Model):
         abstract = True
 
 
-class Track (Nameable):
+class Track(Nameable):
     """
     Track of a playlist of a diffusion. The position can either be expressed
     as the position in the playlist or as the moment in seconds it started.
@@ -87,7 +88,7 @@ class Track (Nameable):
         verbose_name_plural = _('Tracks')
 
 
-class Sound (Nameable):
+class Sound(Nameable):
     """
     A Sound is the representation of a sound file that can be either an excerpt
     or a complete archive of the related diffusion.
@@ -95,17 +96,14 @@ class Sound (Nameable):
     The podcasting and public access permissions of a Sound are managed through
     the related program info.
     """
-    Type = {
-        'other': 0x00,
-        'archive': 0x01,
-        'excerpt': 0x02,
-    }
-    for key, value in Type.items():
-        ugettext_lazy(key)
+    class Type(IntEnum):
+        other = 0x00,
+        archive = 0x01,
+        excerpt = 0x02,
 
     type = models.SmallIntegerField(
         verbose_name = _('type'),
-        choices = [ (y, x) for x,y in Type.items() ],
+        choices = [ (y, _(x)) for x,y in Type.__members__.items() ],
         blank = True, null = True
     )
     path = models.FilePathField(
@@ -148,7 +146,7 @@ class Sound (Nameable):
         help_text = _('sound\'s is accessible through the website')
     )
 
-    def get_mtime (self):
+    def get_mtime(self):
         """
         Get the last modification date from file
         """
@@ -158,13 +156,13 @@ class Sound (Nameable):
         mtime = mtime.replace(microsecond = 0)
         return tz.make_aware(mtime, tz.get_current_timezone())
 
-    def file_exists (self):
+    def file_exists(self):
         """
         Return true if the file still exists
         """
         return os.path.exists(self.path)
 
-    def check_on_file (self):
+    def check_on_file(self):
         """
         Check sound file info again'st self, and update informations if
         needed (do not save). Return True if there was changes.
@@ -188,7 +186,7 @@ class Sound (Nameable):
             return True
         return old_removed != self.removed
 
-    def save (self, check = True, *args, **kwargs):
+    def save(self, check = True, *args, **kwargs):
         if check:
             self.check_on_file()
 
@@ -198,7 +196,7 @@ class Sound (Nameable):
             self.name = self.name.replace('_', ' ')
         super().save(*args, **kwargs)
 
-    def __str__ (self):
+    def __str__(self):
         return '/'.join(self.path.split('/')[-3:])
 
     class Meta:
@@ -206,7 +204,7 @@ class Sound (Nameable):
         verbose_name_plural = _('Sounds')
 
 
-class Stream (models.Model):
+class Stream(models.Model):
     """
     When there are no program scheduled, it is possible to play sounds
     in order to avoid blanks. A Stream is a Program that plays this role,
@@ -238,7 +236,7 @@ class Stream (models.Model):
     )
 
 
-class Schedule (models.Model):
+class Schedule(models.Model):
     """
     A Schedule defines time slots of programs' diffusions. It can be an initial
     run or a rerun (in such case it is linked to the related schedule).
@@ -282,7 +280,7 @@ class Schedule (models.Model):
         help_text = 'this schedule is a rerun of this one',
     )
 
-    def match (self, date = None, check_time = True):
+    def match(self, date = None, check_time = True):
         """
         Return True if the given datetime matches the schedule
         """
@@ -292,7 +290,7 @@ class Schedule (models.Model):
             return self.date.time() == date.time() if check_time else True
         return False
 
-    def match_week (self, date = None):
+    def match_week(self, date = None):
         """
         Return True if the given week number matches the schedule, False
         otherwise.
@@ -313,13 +311,13 @@ class Schedule (models.Model):
             return self.frequency == 0b1111
         return (self.frequency & (0b0001 << week) > 0)
 
-    def normalize (self, date):
+    def normalize(self, date):
         """
         Set the time of a datetime to the schedule's one
         """
         return date.replace(hour = self.date.hour, minute = self.date.minute)
 
-    def dates_of_month (self, date = None):
+    def dates_of_month(self, date = None):
         """
         Return a list with all matching dates of date.month (=today)
         """
@@ -361,7 +359,7 @@ class Schedule (models.Model):
                 date += tz.timedelta(days = 7)
         return [self.normalize(date) for date in dates]
 
-    def diffusions_of_month (self, date, exclude_saved = False):
+    def diffusions_of_month(self, date, exclude_saved = False):
         """
         Return a list of Diffusion instances, from month of the given date, that
         can be not in the database.
@@ -394,19 +392,19 @@ class Schedule (models.Model):
                               else None
             diffusions.append(Diffusion(
                                  program = self.program,
-                                 type = Diffusion.Type['unconfirmed'],
+                                 type = Diffusion.Type.unconfirmed,
                                  initial = first_diffusion if self.initial else None,
                                  start = date,
                                  end = date + duration,
                              ))
         return diffusions
 
-    def __str__ (self):
+    def __str__(self):
         return ' | '.join([ '#' + str(self.id), self.program.name,
                             self.get_frequency_display(),
                             self.date.strftime('%a %H:%M') ])
 
-    def save (self, *args, **kwargs):
+    def save(self, *args, **kwargs):
         if self.initial:
             self.program = self.initial.program
             self.duration = self.initial.duration
@@ -418,7 +416,7 @@ class Schedule (models.Model):
         verbose_name_plural = _('Schedules')
 
 
-class Station (Nameable):
+class Station(Nameable):
     """
     A Station regroup one or more programs (stream and normal), and is the top
     element used to generate streams outputs and configuration.
@@ -444,7 +442,7 @@ class Station (Nameable):
     )
 
 
-class Program (Nameable):
+class Program(Nameable):
     """
     A Program can either be a Streamed or a Scheduled program.
 
@@ -473,14 +471,14 @@ class Program (Nameable):
     )
 
     @property
-    def path (self):
+    def path(self):
         """
         Return the path to the programs directory
         """
         return os.path.join(settings.AIRCOX_PROGRAMS_DIR,
                             self.slug + '_' + str(self.id) )
 
-    def ensure_dir (self, subdir = None):
+    def ensure_dir(self, subdir = None):
         """
         Make sur the program's dir exists (and optionally subdir). Return True
         if the dir (or subdir) exists.
@@ -490,7 +488,7 @@ class Program (Nameable):
         os.makedirs(path, exist_ok = True)
         return os.path.exists(path)
 
-    def find_schedule (self, date):
+    def find_schedule(self, date):
         """
         Return the first schedule that matches a given date.
         """
@@ -499,12 +497,12 @@ class Program (Nameable):
             if schedule.match(date, check_time = False):
                 return schedule
 
-    def __init__ (self, *kargs, **kwargs):
+    def __init__(self, *kargs, **kwargs):
         super().__init__(*kargs, **kwargs)
         if self.name:
             self.__original_path = self.path
 
-    def save (self, *kargs, **kwargs):
+    def save(self, *kargs, **kwargs):
         super().save(*kargs, **kwargs)
         if hasattr(self, '__original_path') and \
                 self.__original_path != self.path and \
@@ -520,7 +518,7 @@ class Program (Nameable):
                 sound.save()
 
     @classmethod
-    def get_from_path (cl, path):
+    def get_from_path(cl, path):
         """
         Return a Program from the given path. We assume the path has been
         given in a previous time by this model (Program.path getter).
@@ -537,7 +535,7 @@ class Program (Nameable):
         return qs[0] if qs else None
 
 
-class Diffusion (models.Model):
+class Diffusion(models.Model):
     """
     A Diffusion is an occurrence of a Program that is scheduled on the
     station's timetable. It can be a rerun of a previous diffusion. In such
@@ -555,13 +553,10 @@ class Diffusion (models.Model):
     - cancel: the diffusion has been canceled
     - stop: the diffusion has been manually stopped
     """
-    Type = {
-        'normal':       0x00,   # diffusion is planified
-        'unconfirmed':  0x01,   # scheduled by the generator but not confirmed for diffusion
-        'cancel':       0x02,   # diffusion canceled
-    }
-    for key, value in Type.items():
-        ugettext_lazy(key)
+    class Type(IntEnum):
+        normal = 0x00
+        unconfirmed = 0x01
+        canceled = 0x02
 
     # common
     program = models.ForeignKey (
@@ -576,7 +571,7 @@ class Diffusion (models.Model):
     # specific
     type = models.SmallIntegerField(
         verbose_name = _('type'),
-        choices = [ (y, x) for x,y in Type.items() ],
+        choices = [ (y, _(x)) for x,y in Type.__members__.items() ],
     )
     initial = models.ForeignKey (
         'self',
@@ -588,11 +583,11 @@ class Diffusion (models.Model):
     end = models.DateTimeField( _('end of the diffusion') )
 
     @property
-    def duration (self):
+    def duration(self):
         return self.end - self.start
 
     @property
-    def date (self):
+    def date(self):
         return self.start
 
     @property
@@ -604,29 +599,30 @@ class Diffusion (models.Model):
         playlist.sort()
         return playlist
 
-    def archives_duration (self):
+    def archives_duration(self):
         """
         Get total duration of the archives. May differ from the schedule
         duration.
         """
         sounds = self.initial.sounds if self.initial else self.sounds
         r = [ sound.duration
-                for sound in sounds.filter(type = Sound.Type['archive'])
+                for sound in sounds.filter(type = Sound.Type.archive)
                 if sound.duration ]
         return utils.time_sum(r)
 
-    def get_archives (self):
+    def get_archives(self):
         """
         Return an ordered list of archives sounds for the given episode.
         """
         sounds = self.initial.sounds if self.initial else self.sounds
         r = [ sound for sound in sounds.all().order_by('path')
-              if sound.type == Sound.Type['archive'] ]
+              if sound.type == Sound.Type.archive ]
         return r
 
     @classmethod
-    def get (cl, station = None, date = None,
+    def get(cl, station = None, date = None,
              now = False, next = False, prev = False,
+             queryset = None,
              **filter_args):
         """
         Return a queryset of diffusions, depending on value of now/next/prev
@@ -634,6 +630,8 @@ class Diffusion (models.Model):
         - next: that start after date
         - prev: that end before date
 
+        If queryset is not given, use self.objects.all
+
         Diffusions are ordered by +start for now and next; -start for prev
         """
         #FIXME: conflicts? ( + calling functions)
@@ -669,7 +667,7 @@ class Diffusion (models.Model):
         """
         return self.start < date_or_default(date) < self.end
 
-    def get_conflicts (self):
+    def get_conflicts(self):
         """
         Return a list of conflictual diffusions, based on the scheduled duration.
         """
@@ -681,7 +679,7 @@ class Diffusion (models.Model):
         )
         return r
 
-    def save (self, *args, **kwargs):
+    def save(self, *args, **kwargs):
         if self.initial:
             # force link to the top initial diffusion
             if self.initial.initial:
@@ -689,7 +687,7 @@ class Diffusion (models.Model):
             self.program = self.initial.program
         super().save(*args, **kwargs)
 
-    def __str__ (self):
+    def __str__(self):
         return '{self.program.name} {date} #{self.pk}'.format(
             self=self, date=self.date.strftime('%Y-%m-%d %H:%M')
         )
@@ -702,7 +700,7 @@ class Diffusion (models.Model):
             ('programming', _('edit the diffusion\'s planification')),
         )
 
-class Log (models.Model):
+class Log(models.Model):
     """
     Log a played sound start and stop, or a single message
     """
@@ -733,14 +731,14 @@ class Log (models.Model):
 
 
     @classmethod
-    def get_for_related_model (cl, model):
+    def get_for_related_model(cl, model):
         """
         Return a queryset that filter related_type to the given one.
         """
         return cl.objects.filter(related_type__pk =
                                     ContentType.objects.get_for_model(model).id)
 
-    def print (self):
+    def print(self):
         logger.info('log #%s: %s%s',
             str(self),
             self.comment or '',
@@ -748,7 +746,7 @@ class Log (models.Model):
                 if self.related_object else ''
         )
 
-    def __str__ (self):
+    def __str__(self):
         return '#{} ({}, {})'.format(
                 self.id, self.date.strftime('%Y-%m-%d %H:%M'), self.source
         )
diff --git a/programs/tests.py b/programs/tests.py
index cf833fa..ce26860 100755
--- a/programs/tests.py
+++ b/programs/tests.py
@@ -10,7 +10,7 @@ class Programs (TestCase):
     def setUp (self):
         stream = Stream.objects.get_or_create(
             name = 'diffusions',
-            defaults = { 'type': Stream.Type['schedule'] }
+            defaults = { 'type': Stream.Type.schedule }
         )[0]
         Program.objects.create(name = 'source', stream = stream)
         Program.objects.create(name = 'microouvert', stream = stream)