import json
# this is for django objects only
#from django.core import serializers
from django.http import HttpResponse, HttpResponseForbidden

from manifold.manifoldquery import ManifoldQuery
from manifold.manifoldapi import ManifoldAPI

debug=False
debug=True

# add artificial delay in s
debug_spin=0
#debug_spin=1

# this view is what the javascript talks to when it sends a query
# see also
# myslice/urls.py
# as well as 
# static/js/manifold.js
def proxy (request,format):
    """the view associated with /manifold/proxy/ 
with the query passed using POST"""
    
    # expecting a POST
    if request.method != 'POST':
        print "manifoldproxy.api: unexpected method %s -- exiting"%request.method
        return 
    # we only support json for now
    # if needed in the future we should probably cater for
    # format_in : how is the query encoded in POST
    # format_out: how to serve the results
    if format != 'json':
        print "manifoldproxy.api: unexpected format %s -- exiting"%format
        return
    try:
        # translate incoming POST request into a query object
        if debug: print 'manifoldproxy.proxy: request.POST',request.POST
        manifold_query = ManifoldQuery()
        manifold_query.fill_from_POST(request.POST)
        # retrieve session for request
        manifold_api_session_auth = request.session['manifold']['auth']
        # actually forward
        manifold_api= ManifoldAPI(auth=manifold_api_session_auth)
        if debug: print 'manifoldproxy.proxy: sending to backend', manifold_query
        answer=manifold_api.send_manifold_query (manifold_query)
        if debug_spin:
            import time
            time.sleep(debug_spin)
        # return json-encoded answer
        return HttpResponse (json.dumps(answer), mimetype="application/json")
    except:
        import traceback
        traceback.print_exc()

#################### 
# see CSRF_FAILURE_VIEW in settings.py
# the purpose of redefining this was to display the failure reason somehow
# this however turns out disappointing/not very informative
failure_answer=[ "csrf_failure" ]
def csrf_failure(request, reason=""):
    print "CSRF failure with reason '%s'"%reason
    return HttpResponseForbidden (json.dumps (failure_answer), mimetype="application/json")