#!/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.

"""Functions used to send email messages.

The following are the possible fields of an email message:

  sender: The email address of the sender, the From address. This must be the

    email address of a registered administrator for the application, or the

    address of the current signed-in user. Administrators can be added to

    an application using the Administration Console. The current user's email

    address can be determined with the Users API.

  to: A recipient's email address (a string) or a list of email addresses to

    appear on the To: line in the message header.

  cc: A recipient's email address (a string) or a list of email addresses to

    appear on the Cc: line in the message header.

  bcc: A recipient's email address (a string) or a list of email addresses to

    receive the message, but not appear in the message header ("blind carbon

    copy").

  reply_to: An email address to which a recipient should reply instead of the

    sender address, the Reply-To: field.

  subject: The subject of the message, the Subject: line.

  body: The plaintext body content of the message.

  html: An HTML version of the body content, for recipients that

    prefer HTML email.

  attachments: The file attachments for the message, as a list of two-value

    tuples, one tuple for each attachment. Each tuple contains a filename as

    the first element, and the file contents as the second element.

    An attachment file must be one of the allowed file types, and the

    filename must end with an extension that corresponds with the type.

    For a list of allowed types and filename extensions, see Allowed

    Attachment Types.

Usage:

  context = { 'sender': 'melange-noreply@example.com',

              'to': 'test@example.com',

              'subject': 'You have been invited to become a Host',

              'sender_name': 'Alice',

              'to_name': 'Melange Team',

              'role': 'Host',

              'group': 'Google Summer of Code 2009',

              'invitation_url': 'http://invitation-url'}

  sendMailFromTemplate('soc/mail/invitation.html', context)

"""

__authors__ = [

  '"Lennard de Rijk" <ljvderijk@gmail.com>',

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

  ]

from django.template import loader

from google.appengine.api import mail

from soc.logic import dicts

def sendMailFromTemplate(template, context):

  """Sends out an email using a Django template.

  If 'html' is present in context dictionary it is overwritten with

  template HTML output.

  Args:

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

    context: The context supplied to the template and email (dictionary)

  Raises:

    Error that corresponds with the first problem it finds iff the message

    is not properly initialized.

    List of all possible errors:

      http://code.google.com/appengine/docs/mail/exceptions.html

  """

  # render the template and put in context with 'html' as key

  context['html'] = loader.render_to_string(template, dictionary=context)

  # filter out the unneeded values in context to keep sendMail happy

  sendMail(dicts.filter(context, mail.EmailMessage.PROPERTIES))

def sendMail(context):

  """Sends out an email using context to supply the needed information.

  Args:

    context : The context supplied to the email message (dictionary)

  Raises:

    Error that corresponds with the first problem it finds iff the message

    is not properly initialized.

    List of all possible errors:

      http://code.google.com/appengine/docs/mail/exceptions.html

  """

  # construct the EmailMessage from the given context

  message = mail.EmailMessage(**context)

  message.check_initialized()

  # send the message

  message.send()

def getDefaultMailSender():

  """Returns the email address that currently can be used to send emails.

  Returns:

    - If available the noreply email address from the site singleton

    - Or the email address of the current logged in User

    - None if there is no address to return

  """

  import logging

  from google.appengine.api import users

  from soc.logic.models import site as site_logic

  site_entity = site_logic.logic.getSingleton()

  if site_entity.noreply_email:

    return site_entity.noreply_email

  # use the email address of the current logged in user

  account_entity = users.get_current_user()

  if not account_entity:

    logging.warning('Non-Authenticated user triggered getDefaultMailSender')

    return None