"""some hooks and views to handle notification on entity's changes

:organization: Logilab

:copyright: 2001-2010 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.

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

:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses

"""

__docformat__ = "restructuredtext en"

_ = unicode

from itertools import repeat

from logilab.common.textutils import normalize_text

from logilab.common.deprecation import class_renamed, deprecated

from cubicweb import RegistryException

from cubicweb.selectors import implements, yes

from cubicweb.view import Component

from cubicweb.common.mail import NotificationView, parse_message_id, SkipEmail

from cubicweb.server.pool import PreCommitOperation, SingleLastOperation

from cubicweb.server.hookhelper import SendMailOp

from cubicweb.server.hooksmanager import Hook

parse_message_id = deprecated('parse_message_id is now defined in cubicweb.common.mail')(parse_message_id)

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

    """

    id = '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.config['default-recipients-mode']

        if mode == 'users':

            # use unsafe execute else we may don't have the right to see users

            # to notify...

            execute = self.req.unsafe_execute

            dests = [(u.get_email(), u.property_value('ui.language'))

                     for u in execute(self.user_rql, build_descr=True, propagate=True).entities()]

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

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

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

        else: # mode == 'none'

            dests = []

        return dests

# hooks #######################################################################

class EntityUpdatedNotificationOp(SingleLastOperation):

    def precommit_event(self):

        session = self.session

        for eid in session.transaction_data['changes']:

            view = session.vreg['views'].select('notif_entity_updated', session,

                                                rset=session.eid_rset(eid),

                                                row=0)

            RenderAndSendNotificationView(session, view=view)

    def commit_event(self):

        pass

class RenderAndSendNotificationView(PreCommitOperation):

    """delay rendering of notification view until precommit"""

    def precommit_event(self):

        view = self.view

        if view.rset is not None and not view.rset:

            return # entity added and deleted in the same transaction (cache effect)

        if view.rset and view.rset[0][0] in self.session.transaction_data.get('pendingeids', ()):

            return # entity added and deleted in the same transaction

        self.view.render_and_send(**getattr(self, 'viewargs', {}))

class StatusChangeHook(Hook):

    """notify when a workflowable entity has its state modified"""

    events = ('after_add_entity',)

    accepts = ('TrInfo',)

    def call(self, session, entity):

        if not entity.from_state: # not a transition

            return

        rset = entity.related('wf_info_for')

        try:

            view = session.vreg['views'].select('notif_status_change', session,

                                                rset=rset, row=0)

        except RegistryException:

            return

        comment = entity.printable_value('comment', format='text/plain')

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

        # #103822)

        if comment and entity.comment_format != 'text/rest':

            comment = normalize_text(comment, 80)

        RenderAndSendNotificationView(session, view=view, viewargs={

            'comment': comment, 'previous_state': entity.previous_state.name,

            'current_state': entity.new_state.name})

class RelationChangeHook(Hook):

    events = ('before_add_relation', 'after_add_relation',

              'before_delete_relation', 'after_delete_relation')

    accepts = ('Any',)

    def call(self, session, fromeid, rtype, toeid):

        """if a notification view is defined for the event, send notification

        email defined by the view

        """

        rset = session.eid_rset(fromeid)

        vid = 'notif_%s_%s' % (self.event,  rtype)

        try:

            view = session.vreg['views'].select(vid, session, rset=rset, row=0)

        except RegistryException:

            return

        RenderAndSendNotificationView(session, view=view)

class EntityChangeHook(Hook):

    events = ('after_add_entity',

              'after_update_entity')

    accepts = ('Any',)

    def call(self, session, entity):

        """if a notification view is defined for the event, send notification

        email defined by the view

        """

        rset = entity.as_rset()

        vid = 'notif_%s' % self.event

        try:

            view = session.vreg['views'].select(vid, session, rset=rset, row=0)

        except RegistryException:

            return

        RenderAndSendNotificationView(session, view=view)

class EntityUpdateHook(Hook):

    events = ('before_update_entity',)

    accepts = ()

    skip_attrs = set()

    def call(self, session, entity):

        if entity.eid in session.transaction_data.get('neweids', ()):

            return # entity is being created

        if session.is_super_session:

            return # ignore changes triggered by hooks

        # then compute changes

        changes = session.transaction_data.setdefault('changes', {})

        thisentitychanges = changes.setdefault(entity.eid, set())

        attrs = [k for k in entity.edited_attributes if not k in self.skip_attrs]

        if not attrs:

            return

        rqlsel, rqlrestr = [], ['X eid %(x)s']

        for i, attr in enumerate(attrs):

            var = chr(65+i)

            rqlsel.append(var)

            rqlrestr.append('X %s %s' % (attr, var))

        rql = 'Any %s WHERE %s' % (','.join(rqlsel), ','.join(rqlrestr))

        rset = session.execute(rql, {'x': entity.eid}, 'x')

        for i, attr in enumerate(attrs):

            oldvalue = rset[0][i]

            newvalue = entity[attr]

            if oldvalue != newvalue:

                thisentitychanges.add((attr, oldvalue, newvalue))

        if thisentitychanges:

            EntityUpdatedNotificationOp(session)

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

class NotificationView(NotificationView):

    """overriden to delay actual sending of mails to a commit operation by

    default

    """

    def send_on_commit(self, recipients, msg):

        SendMailOp(self.req, recipients=recipients, msg=msg)

    send = send_on_commit

class StatusChangeMixIn(object):

    id = '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

    id = 'notif_after_add_entity'

    msgid_timestamp = False

    message = _('new')

    content = """

%(title)s

%(content)s

url: %(url)s

"""

    def context(self, **kwargs):

        entity = self.entity(self.row or 0, self.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.entity(self.row or 0, self.col or 0)

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

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

NormalizedTextView = class_renamed('NormalizedTextView', ContentAddedView)

def format_value(value):

    if isinstance(value, unicode):

        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

    id = 'notif_entity_updated'

    msgid_timestamp = False

    message = _('updated')

    no_detailed_change_attrs = ()

    content = """

Properties have been updated by %(user)s:

%(changes)s

url: %(url)s

"""

    def context(self, **kwargs):

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

        changes = self.req.transaction_data['changes'][self.rset[0][0]]

        _ = self.req._

        formatted_changes = []

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

            # check current user has permission to see the attribute

            rschema = self.vreg.schema[attr]

            if rschema.final:

                if not rschema.has_perm(self.req, 'read', eid=self.rset[0][0]):

                    continue

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

            elif not rschema.has_perm(self.req, 'read', fromeid=self.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.entity(self.row or 0, self.col or 0)

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

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