"""A base contact form for allowing users to send email messages through

a web interface, and a subclass demonstrating useful functionality.

From

    http://code.google.com/p/django-contact-form/ (Revsion 42)

Modified to remove dependency on sites-framework.

"""

from django import forms

from django.conf import settings

from django.core.mail import send_mail

from django.template import loader as django_loader, RequestContext

__all__ = ('ContactForm', 'AkismetContactForm',)

# I put this on all required fields, because it's easier to pick up

# on them with CSS or JavaScript if they have a class of "required"

# in the HTML. Your mileage may vary.

attrs_dict = { 'class': 'required' }

class ContactForm(forms.Form):

    """

    Base contact form class from which all contact form classes should

    inherit.

    If you don't need any custom functionality, you can simply use

    this form to provide basic contact functionality; it will collect

    name, email address and message.

    The ``contact_form`` view included in this application knows how

    to work with this form and can handle many types of subclasses as

    well (see below for a discussion of the important points), so in

    many cases it will be all that you need. If you'd like to use this

    form or a subclass of it from one of your own views, just do the

    following:

        1. When you instantiate the form, pass the current

           ``HttpRequest`` object to the constructor as the keyword

           argument ``request``; this is used internally by the base

           implementation, and also made available so that subclasses

           can add functionality which relies on inspecting the

           request.

        2. To send the message, call the form's ``save`` method, which

           accepts the keyword argument ``fail_silently`` and defaults

           it to ``False``. This argument is passed directly to

           ``send_mail``, and allows you to suppress or raise

           exceptions as needed for debugging. The ``save`` method has

           no return value.

    Other than that, treat it like any other form; validity checks and

    validated data are handled normally, through the ``is_valid``

    method and the ``cleaned_data`` dictionary.

    Base implementation

    -------------------

    Under the hood, this form uses a somewhat abstracted interface in

    order to make it easier to subclass and add functionality. There

    are several important attributes subclasses may want to look at

    overriding, all of which will work (in the base implementation) as

    either plain attributes or as callable methods:

        * ``from_email`` -- used to get the address to use in the

          ``From:`` header of the message. The base implementation

          returns the value of the ``DEFAULT_FROM_EMAIL`` setting.

        * ``message`` -- used to get the message body as a string. The

          base implementation renders a template using the form's

          ``cleaned_data`` dictionary as context.

        * ``recipient_list`` -- used to generate the list of

          recipients for the message. The base implementation returns

          the email addresses specified in the ``MANAGERS`` setting.

        * ``subject`` -- used to generate the subject line for the

          message. The base implementation returns the string 'Message

          sent through the web site', with the name of the current

          ``Site`` prepended.

        * ``template_name`` -- used by the base ``message`` method to

          determine which template to use for rendering the

          message. Default is ``contact_form/contact_form.txt``.

        * ``default_to_user`` -- defaults to False; If True, and a user is

          currently logged in, this user's name and email are used for the

          sender fields per default.

        * ``default_allow_change`` -- only if ``default_to_user`` is enabled.

          If True, the default sender data will only be used as a suggestion

          via ``initial``. Otherwise it'll be fixed and cannot be changed.

    Internally, the base implementation ``_get_message_dict`` method

    collects ``from_email``, ``message``, ``recipient_list`` and

    ``subject`` into a dictionary, which the ``save`` method then

    passes directly to ``send_mail`` as keyword arguments.

    Particularly important is the ``message`` attribute, with its base

    implementation as a method which renders a template; because it

    passes ``cleaned_data`` as the template context, any additional

    fields added by a subclass will automatically be available in the

    template. This means that many useful subclasses can get by with

    just adding a few fields and possibly overriding

    ``template_name``.

    Much useful functionality can be achieved in subclasses without

    having to override much of the above; adding additional validation

    methods works the same as any other form, and typically only a few

    items -- ``recipient_list`` and ``subject_line``, for example,

    need to be overridden to achieve customized behavior.

    Other notes for subclassing

    ---------------------------

    Subclasses which want to inspect the current ``HttpRequest`` to

    add functionality can access it via the attribute ``request``; the

    base ``message`` takes advantage of this to use ``RequestContext``

    when rendering its template. See the ``AkismetContactForm``

    subclass in this file for an example of using the request to

    perform additional validation.

    Subclasses which override ``__init__`` need to accept ``*args``

    and ``**kwargs``, and pass them via ``super`` in order to ensure

    proper behavior.

    Subclasses should be careful if overriding ``_get_message_dict``,

    since that method **must** return a dictionary suitable for

    passing directly to ``send_mail`` (unless ``save`` is overridden

    as well).

    Overriding ``save`` is relatively safe, though remember that code

    which uses your form will expect ``save`` to accept the

    ``fail_silently`` keyword argument. In the base implementation,

    that argument defaults to ``False``, on the assumption that it's

    far better to notice errors than to silently not send mail from

    the contact form (see also the Zen of Python: "Errors should never

    pass silently, unless explicitly silenced").

    """

    def __init__(self, data=None, request=None, template_loader=None, 

                  *args, **kwargs):

        if request is None:

            raise TypeError("Keyword argument 'request' must be supplied")

        super(ContactForm, self).__init__(data, *args, **kwargs)

        self.request = request

        if template_loader:

            self.template_loader = template_loader

        # Optionally, we can use the currently logged in user as default from

        default_to_user = callable(self.default_to_user) and \

            self.default_to_user() or self.default_to_user

        default_allow_change = callable(self.default_allow_change) and \

            self.default_allow_change() or self.default_allow_change

        if default_to_user and request.user.is_authenticated():

            if default_allow_change:

                self.fields['name'].initial = request.user.username

                self.fields['email'].initial = request.user.email

            else:

                from djutils.forms.widgets import DefaultValueWidget

                self.fields['name'].widget = DefaultValueWidget(request.user.username)

                self.fields['email'].widget = DefaultValueWidget(request.user.email)

    name = forms.CharField(max_length=100,

                           widget=forms.TextInput(attrs=attrs_dict),

                           label=u'Your name')

    email = forms.EmailField(widget=forms.TextInput(attrs=dict(attrs_dict,

                                                               maxlength=200)),

                             label=u'Your email address')

    body = forms.CharField(widget=forms.Textarea(attrs=attrs_dict),

                              label=u'Your message')

    from_email = settings.DEFAULT_FROM_EMAIL

    recipient_list = [mail_tuple[1] for mail_tuple in settings.MANAGERS]

    subject = "Message sent through the web site"

    template_name = 'contact_form/contact_form.txt'

    template_loader = django_loader

    default_to_user = True

    default_allow_change = True

    def message(self):

        """

        Renders the body of the message to a string.

        """

        if callable(self.template_name):

            template_name = self.template_name()

        else:

            template_name = self.template_name

        t = self.template_loader.get_template(template_name)

        return t.render(RequestContext(self.request, self.cleaned_data))

    def _get_message_dict(self):

        if not self.is_valid():

            raise ValueError("Message cannot be sent from invalid contact form")

        message_dict = {}

        for message_part in ('from_email', 'message', 'recipient_list', 'subject'):

            attr = getattr(self, message_part)

            message_dict[message_part] = callable(attr) and attr() or attr

        return message_dict

    def save(self, fail_silently=False):

        """

        Builds and sends the email message.

        """

        send_mail(fail_silently=fail_silently, **self._get_message_dict())

class AkismetContactForm(ContactForm):

    """

    Contact form which doesn't add any extra fields, but does add an

    Akismet spam check to the validation routine.

    Requires the setting ``AKISMET_API_KEY``, which should be a valid

    Akismet API key.

    """

    def clean_body(self):

        if 'body' in self.cleaned_data and hasattr(settings, 'AKISMET_API_KEY') and settings.AKISMET_API_KEY:

            from akismet import Akismet

            akismet_api = Akismet(key=settings.AKISMET_API_KEY,

                                  blog_url='http://%s/' % Site.objects.get_current().domain)

            if akismet_api.verify_key():

                akismet_data = { 'comment_type': 'comment',

                                 'referer': self.request.META.get('HTTP_REFERER', ''),

                                 'user_ip': self.request.META.get('REMOTE_ADDR', ''),

                                 'user_agent': self.request.META.get('HTTP_USER_AGENT', '') }

                if akismet_api.comment_check(self.cleaned_data['body'], data=akismet_data, build_data=True):

                    raise forms.ValidationError(u"Akismet thinks this message is spam")

        return self.cleaned_data['body']