"""
Views for the core application. These are mainly shared, common views
used by multiple applications.
"""
from django.contrib.auth.models import User
from django.http import HttpResponse
from django.http import HttpResponseBadRequest
from django.http import HttpResponseForbidden
from django.shortcuts import render_to_response
from django.template import RequestContext
from django.contrib.auth.decorators import login_required
from django.views.decorators.http import require_GET

@login_required
@require_GET
def markdown_help(request):
    """
    This view provides the Markdown help cheat sheet. It is expected
    to be called via AJAX.
    """
    return render_to_response('core/markdown_help.html')


def ajax_users(request):
    """
    If the user is authenticated, return a string of usernames whose names start with
    the 'q' GET parameter, limited by the 'limit' GET parameters. The names are separated
    by newlines. Only active usernames are returned.
    If the user is not authenticated, return an empty string.
    """
    q = request.GET.get('q', None)
    if q is None:
        return HttpResponseBadRequest()

    if request.user.is_authenticated():
        q = request.GET.get('q', ' ')
        limit = int(request.GET.get('limit', 10))
        users = User.objects.filter(is_active=True, 
                username__istartswith=q).values_list('username', flat=True)[:limit]
        user_list = u"\n".join(users)
        return HttpResponse(user_list)
    return HttpResponseForbidden()