#!/usr/bin/python2.5

#

# Copyright 2008 the Melange authors.

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

#

#   http://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

"""Helpers used to render response.

"""

__authors__ = [

  '"Todd Larsen" <tlarsen@google.com>',

  '"Pawel Solyga" <pawel.solyga@gmail.com>',

  ]

import logging

import urlparse

from google.appengine.api import users

from django import http

from django.template import loader

# DeadlineExceededError can live in two different places

try:

  # When deployed

  from google.appengine.runtime import DeadlineExceededError

except ImportError:

  # In the development server

  from google.appengine.runtime.apiproxy_errors import DeadlineExceededError

from soc.logic import system

from soc.logic.site import id_user

from soc.views.helpers import request_helpers

from soc.views.helpers import template_helpers

def respond(request, template, context=None, response_args=None):

  """Helper to render a response, passing standard stuff to the response.

  Args:

    request: the Django HTTP request object

    template: the template (or search list of templates) to render

    context: the context supplied to the template (implements dict)

    response_args: keyword arguments passed to http.HttpResponse()

      (response_args['content'] is created with

      render_to_string(template, dictionary=context) if it is not present)

  Returns:

    django.shortcuts.render_to_response(template, context) results

  Raises:

    Any exceptions that django.template.loader.render_to_string() or

    django.http.HttpResponse() might raise.

  """

  context = getUniversalContext(request, context=context)

  if response_args is None:

    response_args = {}

  try:

    response_args['content'] = response_args.get(

        'content', loader.render_to_string(template, dictionary=context))

    return http.HttpResponse(**response_args)

  except DeadlineExceededError:

    logging.exception('DeadlineExceededError')

    return http.HttpResponse('DeadlineExceededError')

  except MemoryError:

    logging.exception('MemoryError')

    return http.HttpResponse('MemoryError')

  except AssertionError:

    logging.exception('AssertionError')

    return http.HttpResponse('AssertionError')

def getUniversalContext(request, context=None):

  """Constructs a template context dict will many common variables defined.

  Args:

    request: the Django HTTP request object

    context: the template context dict to be updated in-place (pass in a copy

      if the original must not be modified), or None if a new one is to be

      created; any existing fields already present in the context dict passed

      in by the caller are left unaltered 

  Returns:

    updated template context dict supplied by the caller, or a new context

    dict if the caller supplied None

    {

      'request': the Django HTTP request object passed in by the caller

      'id': the logged-in Google Account if there is one

      'user': the User entity corresponding to the Google Account in

        context['id']

      'is_admin': True if users.is_current_user_admin() is True

      'is_debug': True if system.isDebug() is True

      'sign_in': a Google Account login URL

      'sign_out': a Google Account logout URL

    }

  """

  if context is None:

    context = {}

  # set some universal values if caller did not already set them  

  context['request'] = context.get('request', request)

  context['id'] = id_user.getIdIfMissing(context.get('id', None))

  context['user'] = id_user.getUserIfMissing(context.get('user', None),

                                             context['id'])

  context['is_admin'] = context.get(

      'is_admin', id_user.isIdDeveloper(id=context['id']))

  context['is_debug'] = context.get('is_debug', system.isDebug())

  context['sign_in'] = context.get(

      'sign_in', users.create_login_url(request.path))

  context['sign_out'] = context.get(

      'sign_out', users.create_logout_url(request.path))

  return context

def redirectToChangedSuffix(

    request, old_suffix, new_suffix=None, params=None):

  """Changes suffix of URL path and returns an HTTP redirect response.

  Args:

    request: the Django HTTP request object; redirect path is derived from

      request.path

    old_suffix, new_suffix, params:  see request_helpers.replaceSuffix()

  Returns:

    a Django HTTP redirect response pointing to the altered path

  """

  path = request_helpers.replaceSuffix(request.path, old_suffix, new_suffix,

                                       params=params)

  return http.HttpResponseRedirect(path)