# copyright 2003-2014 LOGILAB S.A. (Paris, FRANCE), all rights reserved.

# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr

#

# This file is part of CubicWeb.

#

# CubicWeb is free software: you can redistribute it and/or modify it under the

# terms of the GNU Lesser General Public License as published by the Free

# Software Foundation, either version 2.1 of the License, or (at your option)

# any later version.

#

# CubicWeb is distributed in the hope that it will be useful, but WITHOUT

# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more

# details.

#

# You should have received a copy of the GNU Lesser General Public License along

# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.

"""some views to handle notification on data changes"""

from cubicweb import _

from itertools import repeat

from logilab.common.textutils import normalize_text

from logilab.common.registry import yes

from cubicweb.view import Component, EntityView

from cubicweb.server.hook import SendMailOp

from cubicweb.mail import construct_message_id, format_mail

from cubicweb.server.session import Connection, InternalManager

class RecipientsFinder(Component):

    """this component is responsible to find recipients of a notification

    by default user's with their email set are notified if any, else the default

    email addresses specified in the configuration are used

    """

    __regid__ = 'recipients_finder'

    __select__ = yes()

    user_rql = ('Any X,E,A WHERE X is CWUser, X in_state S, S name "activated",'

                'X primary_email E, E address A')

    def recipients(self):

        mode = self._cw.vreg.config['default-recipients-mode']

        if mode == 'users':

            execute = self._cw.execute

            dests = list(execute(self.user_rql, build_descr=True).entities())

        elif mode == 'default-dest-addrs':

            lang = self._cw.vreg.property_value('ui.language')

            dests = zip(self._cw.vreg.config['default-dest-addrs'], repeat(lang))

        else:  # mode == 'none'

            dests = []

        return dests

# abstract or deactivated notification views and mixin ########################

class SkipEmail(Exception):

    """raise this if you decide to skip an email during its generation"""

class NotificationView(EntityView):

    """abstract view implementing the "email" API (eg to simplify sending

    notification)

    """

    # XXX refactor this class to work with len(rset) > 1

    msgid_timestamp = True

    # to be defined on concrete sub-classes

    content = None  # body of the mail

    message = None  # action verb of the subject

    # this is usually the method to call

    def render_and_send(self, **kwargs):

        """generate and send email messages for this view"""

        # render_emails changes self._cw so cache it here so all mails are sent

        # after we commit our transaction.

        cnx = self._cw

        for msg, recipients in self.render_emails(**kwargs):

            SendMailOp(cnx, recipients=recipients, msg=msg)

    def cell_call(self, row, col=0, **kwargs):

        self.w(self._cw._(self.content) % self.context(**kwargs))

    def render_emails(self, **kwargs):

        """generate and send emails for this view (one per recipient)"""

        self._kwargs = kwargs

        recipients = self.recipients()

        if not recipients:

            self.info('skipping %s notification, no recipients', self.__regid__)

            return

        if self.cw_rset is not None:

            entity = self.cw_rset.get_entity(self.cw_row or 0, self.cw_col or 0)

            # if the view is using timestamp in message ids, no way to reference

            # previous email

            if not self.msgid_timestamp:

                refs = [self.construct_message_id(eid)

                        for eid in entity.cw_adapt_to('INotifiable').notification_references(self)]

            else:

                refs = ()

            msgid = self.construct_message_id(entity.eid)

        else:

            refs = ()

            msgid = None

        req = self._cw

        self.user_data = req.user_data()

        for something in recipients:

            if isinstance(something, tuple):

                emailaddr, lang = something

                user = InternalManager(lang=lang)

            else:

                emailaddr = something.cw_adapt_to('IEmailable').get_email()

                user = something

            # hi-jack self._cw to get a session for the returned user

            with Connection(self._cw.repo, user) as cnx:

                self._cw = cnx

                try:

                    # since the same view (eg self) may be called multiple time and we

                    # need a fresh stream at each iteration, reset it explicitly

                    self._w = None

                    try:

                        # XXX forcing the row & col here may make the content and

                        #     subject inconsistent because subject will depend on

                        #     self.cw_row & self.cw_col if they are set.

                        content = self.render(row=0, col=0, **kwargs)

                        subject = self.subject()

                    except SkipEmail:

                        continue

                    except Exception as ex:

                        # shouldn't make the whole transaction fail because of rendering

                        # error (unauthorized or such) XXX check it doesn't actually

                        # occurs due to rollback on such error

                        self.exception(str(ex))

                        continue

                    msg = format_mail(self.user_data, [emailaddr], content, subject,

                                      config=self._cw.vreg.config, msgid=msgid, references=refs)

                    yield msg, [emailaddr]

                finally:

                    self._cw = req

    # recipients handling ######################################################

    def recipients(self):

        """return a list of either 2-uple (email, language) or user entity to

        whom this email should be sent

        """

        finder = self._cw.vreg['components'].select(

            'recipients_finder', self._cw, rset=self.cw_rset,

            row=self.cw_row or 0, col=self.cw_col or 0)

        return finder.recipients()

    # email generation helpers #################################################

    def construct_message_id(self, eid):

        return construct_message_id(self._cw.vreg.config.appid, eid,

                                    self.msgid_timestamp)

    def format_field(self, attr, value):

        return ':%(attr)s: %(value)s' % {'attr': attr, 'value': value}

    def format_section(self, attr, value):

        return '%(attr)s\n%(ul)s\n%(value)s\n' % {

            'attr': attr, 'ul': '-' * len(attr), 'value': value}

    def subject(self):

        entity = self.cw_rset.get_entity(self.cw_row or 0, self.cw_col or 0)

        subject = self._cw._(self.message)

        etype = entity.dc_type()

        eid = entity.eid

        login = self.user_data['login']

        return self._cw._('%(subject)s %(etype)s #%(eid)s (%(login)s)') % locals()

    def context(self, **kwargs):

        entity = self.cw_rset.get_entity(self.cw_row or 0, self.cw_col or 0)

        for key, val in kwargs.items():

            if val and isinstance(val, str) and val.strip():

                kwargs[key] = self._cw._(val)

        kwargs.update({'user': self.user_data['login'],

                       'eid': entity.eid,

                       'etype': entity.dc_type(),

                       'url': entity.absolute_url(),

                       'title': entity.dc_long_title()})

        return kwargs

class StatusChangeMixIn(object):

    __regid__ = 'notif_status_change'

    msgid_timestamp = True

    message = _('status changed')

    content = _("""

%(user)s changed status from <%(previous_state)s> to <%(current_state)s> for entity

'%(title)s'

%(comment)s

url: %(url)s

""")

###############################################################################

# Actual notification views.                                                  #

#                                                                             #

# disable them at the recipients_finder level if you don't want them          #

###############################################################################

# XXX should be based on dc_title/dc_description, no?

class ContentAddedView(NotificationView):

    """abstract class for notification on entity/relation

    all you have to do by default is :

    * set id and __select__ attributes to match desired events and entity types

    * set a content attribute to define the content of the email (unless you

      override call)

    """

    __abstract__ = True

    __regid__ = 'notif_after_add_entity'

    msgid_timestamp = False

    message = _('new')

    content = """

%(title)s

%(content)s

url: %(url)s

"""

    # to be defined on concrete sub-classes

    content_attr = None

    def context(self, **kwargs):

        entity = self.cw_rset.get_entity(self.cw_row or 0, self.cw_col or 0)

        content = entity.printable_value(self.content_attr, format='text/plain')

        if content:

            contentformat = getattr(entity, self.content_attr + '_format',

                                    'text/rest')

            # XXX don't try to wrap rest until we've a proper transformation (see

            # #103822)

            if contentformat != 'text/rest':

                content = normalize_text(content, 80)

        return super(ContentAddedView, self).context(content=content, **kwargs)

    def subject(self):

        entity = self.cw_rset.get_entity(self.cw_row or 0, self.cw_col or 0)

        return u'%s #%s (%s)' % (self._cw.__('New %s' % entity.e_schema),

                                 entity.eid, self.user_data['login'])

def format_value(value):

    if isinstance(value, str):

        return u'"%s"' % value

    return value

class EntityUpdatedNotificationView(NotificationView):

    """abstract class for notification on entity/relation

    all you have to do by default is :

    * set id and __select__ attributes to match desired events and entity types

    * set a content attribute to define the content of the email (unless you

      override call)

    """

    __abstract__ = True

    __regid__ = 'notif_entity_updated'

    msgid_timestamp = True

    message = _('updated')

    no_detailed_change_attrs = ()

    content = """

Properties have been updated by %(user)s:

%(changes)s

url: %(url)s

"""

    def context(self, changes=(), **kwargs):

        context = super(EntityUpdatedNotificationView, self).context(**kwargs)

        _ = self._cw._

        formatted_changes = []

        entity = self.cw_rset.get_entity(self.cw_row or 0, self.cw_col or 0)

        for attr, oldvalue, newvalue in sorted(changes):

            # check current user has permission to see the attribute

            rschema = self._cw.vreg.schema[attr]

            if rschema.final:

                rdef = entity.e_schema.rdef(rschema)

                if not rdef.has_perm(self._cw, 'read', eid=self.cw_rset[0][0]):

                    continue

            # XXX suppose it's a subject relation...

            elif not rschema.has_perm(self._cw, 'read',

                                      fromeid=self.cw_rset[0][0]):

                continue

            if attr in self.no_detailed_change_attrs:

                msg = _('%s updated') % _(attr)

            elif oldvalue not in (None, ''):

                msg = _('%(attr)s updated from %(oldvalue)s to %(newvalue)s') % {

                    'attr': _(attr),

                    'oldvalue': format_value(oldvalue),

                    'newvalue': format_value(newvalue)}

            else:

                msg = _('%(attr)s set to %(newvalue)s') % {

                    'attr': _(attr), 'newvalue': format_value(newvalue)}

            formatted_changes.append('* ' + msg)

        if not formatted_changes:

            # current user isn't allowed to see changes, skip this notification

            raise SkipEmail()

        context['changes'] = '\n'.join(formatted_changes)

        return context

    def subject(self):

        entity = self.cw_rset.get_entity(self.cw_row or 0, self.cw_col or 0)

        return u'%s #%s (%s)' % (self._cw.__('Updated %s' % entity.e_schema),

                                 entity.eid, self.user_data['login'])