#!/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.

"""Out-of-band responses to render instead of the usual HTTP response.

"""

__authors__ = [

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

  '"Sverre Rabbelier" <sverre@rabbelier.nl>',

  ]

from django.utils.translation import ugettext_lazy

from soc.views import helper

import soc.views.helper.responses

import soc.views.helper.templates

class Error(Exception):

  """Base exception for out-of-band responses raised by logic or views.

  """

  TEMPLATE_NAME = 'error.html'

  DEF_TEMPLATE = 'soc/error.html'

  def __init__(self, message_fmt, context=None, **response_args):

    """Constructor used to set response message and HTTP response arguments.

    Args:

      message_fmt: format string, when combined with a context supplied to

        the response() method, produces the message to display on the

        response page; this can be a simple string containing *no* named

        format specifiers

      context: see response()

      **response_args: keyword arguments that are supplied directly to

        django.http.HttpResponse; the most commonly used is 'status' to

        set the HTTP status code for the response

    """

    self.message_fmt = message_fmt

    self._context = context

    self._response_args = response_args

  def response(self, request, template=None, context=None):

    """Creates an HTTP response from the OutOfBandResponse exception.

    Args:

      request: a Django HTTP request

      template: the "sibling" template (or a search list of such templates)

        from which to construct the actual template name (or names)

      context: optional context dict supplied to the template, which is

        modified (so supply a copy if such modification is not acceptable)

    """

    if not context:

      context = self._context

    if not context:

      context = helper.responses.getUniversalContext(request)

    if not template:

      template = []

    # make a list of possible "sibling" templates, then append a default

    templates = helper.templates.makeSiblingTemplatesList(template,

        self.TEMPLATE_NAME, default_template=self.DEF_TEMPLATE)

    context['status'] = self._response_args.get('status')

    if not context.get('message'):

      # supplied context did not explicitly override the message

      context['message'] = self.message_fmt % context

    return helper.responses.respond(request, templates, context=context,

                                    response_args=self._response_args)

class LoginRequest(Error):

  """Out of band error raised when login is requested.

  """

  TEMPLATE_NAME = 'login.html'

  DEF_TEMPLATE = 'soc/login.html'

  DEF_LOGIN_MSG_FMT = ugettext_lazy(

      'Please <a href="%(sign_in)s">sign in</a> to continue.')

  def __init__(self, message_fmt=None, **response_args):

    """Constructor used to set response message and HTTP response arguments.

    Args:

      message_fmt: same as Error.__init__() message_fmt, with the addition

        of a default value of None, in which case self.DEF_LOGIN_MSG_FMT is

        used

      **response_args: see Error.__init__()

    """

    if not message_fmt:

      message_fmt = self.DEF_LOGIN_MSG_FMT

    Error.__init__(self, message_fmt, **response_args)

class AccessViolation(Error):

  """"Out of band error raised when an access requirement was not met.

  """

  pass