#!/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

from google.appengine.api import users
from google.appengine.runtime import DeadlineExceededError

from django import http
from django.template import loader

from soc.logic import system
from soc.logic.site import id_user
from soc.logic.site import sidebar
from soc.views import helper
from soc.views.helper import html_menu

import soc.logic
import soc.logic.models.user
import soc.views.helper.requests


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.
  """

  if not context:
    context = getUniversalContext(request)

  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):
  """Constructs a template context dict will many common variables defined.
  
  Args:
    request: the Django HTTP request object

  Returns:
    a new context dict containing:
    
    {
      '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
      'sidebar_menu_html': an HTML string that renders the sidebar menu
    }
  """

  id = users.get_current_user()

  context = {}
  context['request'] = request

  if id:
    context['id'] = id
    context['user'] = soc.logic.models.user.logic.getFromFields(email=id.email())
    context['is_admin'] = id_user.isIdDeveloper(id=id)

  context['is_debug'] = system.isDebug()
  context['sign_in'] = users.create_login_url(request.path)
  context['sign_out'] = users.create_logout_url(request.path)
  context['sidebar_menu_html'] = str(html_menu.UlMenu(
      sidebar.buildSidebar(**context)))

  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 helper.requests.replaceSuffix()
      
  Returns:
    a Django HTTP redirect response pointing to the altered path
  """
  path = helper.requests.replaceSuffix(request.path, old_suffix, new_suffix,
                                       params=params)
  return http.HttpResponseRedirect(path)