--- a/sat/memory/encryption.py	Sat Aug 11 18:24:55 2018 +0200
+++ b/sat/memory/encryption.py	Sat Aug 11 18:24:55 2018 +0200
@@ -17,69 +17,120 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from sat.core.i18n import _
+from sat.core.i18n import D_, _
 from sat.core.constants import Const as C
 from sat.core import exceptions
 from collections import namedtuple
 from sat.core.log import getLogger
 log = getLogger(__name__)
+from sat.tools.common import data_format
 
 
 EncryptionPlugin = namedtuple("EncryptionPlugin", ("instance",
                                                    "name",
                                                    "namespace",
-                                                   "priority"))
+                                                   "priority",
+                                                   "directed"))
 
 
 class EncryptionHandler(object):
     """Class to handle encryption sessions for a client"""
     plugins = []  # plugin able to encrypt messages
 
-    def __init__(self, host):
+    def __init__(self, client):
+        self.client = client
         self._sessions = {}  # bare_jid ==> encryption_data
 
+    @property
+    def host(self):
+        return self.client.host_app
+
     @classmethod
-    def registerPlugin(cls, plg_instance, name, namespace, priority=0):
+    def registerPlugin(cls, plg_instance, name, namespace, priority=0, directed=False):
         """Register a plugin handling an encryption algorithm
 
         @param plg_instance(object): instance of the plugin
             it must have the following methods:
                 - startEncryption(jid.JID): start an encryption session with a bare jid
                 - stopEncryption(jid.JID): stop an encryption session with a bare jid
-        @param name(unicode): human readable name of the encryption alrgorithm
+        @param name(unicode): human readable name of the encryption algorithm
         @param namespace(unicode): namespace of the encryption algorithm
         @param priority(int): priority of this plugin to encrypt an message when not
             selected manually
+        @param directed(bool): True if this plugin is directed (if it works with one
+                               device only at a time)
         """
-        existing_ns = [p.namespace for p in cls.plugins]
-        if namespace in existing_ns:
+        existing_ns = set()
+        existing_names = set()
+        for p in cls.plugins:
+            existing_ns.add(p.namespace.lower())
+            existing_names.add(p.name.lower())
+        if namespace.lower() in existing_ns:
             raise exceptions.ConflictError("A plugin with this namespace already exists!")
-        plg = EncryptionPlugin(
+        if name.lower() in existing_names:
+            raise exceptions.ConflictError("A plugin with this name already exists!")
+        plugin = EncryptionPlugin(
             instance=plg_instance,
             name=name,
             namespace=namespace,
-            priority=priority)
-        cls.plugins.append(plg)
+            priority=priority,
+            directed=directed)
+        cls.plugins.append(plugin)
         cls.plugins.sort(key=lambda p: p.priority)
         log.info(_(u"Encryption plugin registered: {name}").format(name=name))
 
-    def start(self, entity, namespace=None):
-        """Start an encrypted session with an entity
+    @classmethod
+    def getPlugins(cls):
+        return cls.plugins
+
+    @classmethod
+    def getNSFromName(cls, name):
+        """Retrieve plugin namespace from its name
+
+        @param name(unicode): name of the plugin (case insensitive)
+        @return (unicode): namespace of the plugin
+        @raise exceptions.NotFound: there is not encryption plugin of this name
+        """
+        for p in cls.plugins:
+            if p.name.lower() == name.lower():
+                return p.namespace
+        raise exceptions.NotFound
 
-        @param entity(jid.JID): entity to start an encrypted session with
+    def getBridgeData(self, session):
+        """Retrieve session data serialized for bridge.
+
+        @param session(dict): encryption session
+        @return (unicode): serialized data for bridge
+        """
+        if session is None:
+            return u''
+        plugin = session[u'plugin']
+        bridge_data = {'name': plugin.name,
+                       'namespace': plugin.namespace}
+        if u'directed_devices' in session:
+            bridge_data[u'directed_devices'] = session[u'directed_devices']
+
+        return data_format.serialise(bridge_data)
+
+    def start(self, entity, namespace=None, replace=False):
+        """Start an encryption session with an entity
+
+        @param entity(jid.JID): entity to start an encryption session with
             must be bare jid is the algorithm encrypt for all devices
         @param namespace(unicode, None): namespace of the encryption algorithm to use
             None to select automatically an algorithm
+        @param replace(bool): if True and an encrypted session already exists,
+            it will be replaced by the new one
         """
         if not self.plugins:
             raise exceptions.NotFound(_(u"No encryption plugin is registered, "
                                         u"an encryption session can't be started"))
 
         if namespace is None:
-            plg = self.plugins[0]
+            plugin = self.plugins[0]
         else:
             try:
-                plg = next(p for p in self.plugins if p.namespace == namespace)
+                plugin = next(p for p in self.plugins if p.namespace == namespace)
             except StopIteration:
                 raise exceptions.NotFound(_(
                     u"Can't find requested encryption plugin: {namespace}").format(
@@ -87,44 +138,76 @@
 
         bare_jid = entity.userhostJID()
         if bare_jid in self._sessions:
-            plg = self._sessions[bare_jid]['plugin']
-            if plg.namespace == namespace:
-                log.info(_(u"Session with {bare_jid} is already encrypted with {name}."
-                     u"Nothing to do.")
-                   .format(bare_jid=bare_jid, name=plg.name))
+            # we have already an encryption session with this contact
+            former_plugin = self._sessions[bare_jid]['plugin']
+            if former_plugin.namespace == namespace:
+                log.info(_(u"Session with {bare_jid} is already encrypted with {name}. "
+                           u"Nothing to do.").format(bare_jid=bare_jid, name=plugin.name))
                 return
 
-            msg = (_(u"Session with {bare_jid} is already encrypted with {name}. "
-                     u"Please stop encryption session before changing algorithm.")
-                   .format(bare_jid=bare_jid, name=plg.name))
-            log.warning(msg)
-            raise exceptions.ConflictError(msg)
+            if replace:
+                # there is a conflict, but replacement is requested
+                # so we stop previous encryption to use new one
+                del self._sessions[bare_jid]
+            else:
+                msg = (_(u"Session with {bare_jid} is already encrypted with {name}. "
+                         u"Please stop encryption session before changing algorithm.")
+                       .format(bare_jid=bare_jid, name=plugin.name))
+                log.warning(msg)
+                raise exceptions.ConflictError(msg)
 
-        data = {"plugin": plg}
-        if entity.resource:
+        data = {"plugin": plugin}
+        if plugin.directed:
+            if not entity.resource:
+                entity.resource = self.host.memory.getMainResource(self.client, entity)
+                if not entity.resource:
+                    raise exceptions.NotFound(
+                        _(u"No resource found for {destinee}, can't encrypt with {name}")
+                        .format(destinee=entity.full(), name=plugin.name))
+                log.info(_(u"No resource specified to encrypt with {name}, using "
+                           u"{destinee}.").format(destinee=entity.full(),
+                                                  name=plugin.name))
             # indicate that we encrypt only for some devices
-            data['directed_devices'] = [entity.resource]
+            directed_devices = data[u'directed_devices'] = [entity.resource]
+        elif entity.resource:
+            raise ValueError(_(u"{name} encryption must be used with bare jids."))
 
         self._sessions[entity.userhostJID()] = data
-        log.info(_(u"Encryption session has been set for {bare_jid} with "
+        log.info(_(u"Encryption session has been set for {entity_jid} with "
                    u"{encryption_name}").format(
-                   bare_jid=bare_jid.userhost(), encryption_name=plg.name))
+                   entity_jid=entity.full(), encryption_name=plugin.name))
+        self.host.bridge.messageEncryptionStarted(
+            entity.full(),
+            self.getBridgeData(data),
+            self.client.profile)
+        msg = D_(u"Encryption session started: your messages with {destinee} are "
+                 u"now end to end encrypted using {name} algorithm.").format(
+                 destinee=entity.full(), name=plugin.name)
+        directed_devices = data.get(u'directed_devices')
+        if directed_devices:
+            msg += u"\n" + D_(u"Message are encrypted only for {nb_devices} device(s): "
+                              u"{devices_list}.").format(
+                              nb_devices=len(directed_devices),
+                              devices_list = u', '.join(directed_devices))
+
+        self.client.feedback(bare_jid, msg)
 
     def stop(self, entity, namespace=None):
-        """Stop an encrypted session with an entity
+        """Stop an encryption session with an entity
 
-        @param entity(jid.JID): entity with who the encrypted session must be stopped
+        @param entity(jid.JID): entity with who the encryption session must be stopped
             must be bare jid is the algorithm encrypt for all devices
         @param namespace(unicode): namespace of the session to stop
             when specified, used to check we stop the right encryption session
         """
         session = self.getSession(entity.userhostJID())
         if not session:
-            raise exceptions.NotFound(_(u"There is no encrypted session with this "
+            raise exceptions.NotFound(_(u"There is no encryption session with this "
                                         u"entity."))
-        if namespace is not None and session[u'plugin'].namespace != namespace:
+        plugin = session['plugin']
+        if namespace is not None and plugin.namespace != namespace:
             raise exceptions.InternalError(_(
-                u"The encrypted session is not run with the expected plugin: encrypted "
+                u"The encryption session is not run with the expected plugin: encrypted "
                 u"with {current_name} and was expecting {expected_name}").format(
                 current_name=session[u'plugin'].namespace,
                 expected_name=namespace))
@@ -142,18 +225,33 @@
             except ValueError:
                 raise exceptions.NotFound(_(u"There is no directed session with this "
                                             u"entity."))
+            else:
+                if not directed_devices:
+                    del session[u'directed_devices']
         else:
             del self._sessions[entity]
 
-        log.info(_(u"Encrypted session stopped with entity {entity}").format(
+        log.info(_(u"encryption session stopped with entity {entity}").format(
             entity=entity.full()))
+        self.host.bridge.messageEncryptionStopped(
+            entity.full(),
+            {'name': plugin.name,
+             'namespace': plugin.namespace,
+            },
+            self.client.profile)
+        msg = D_(u"Encryption session finished: your messages with {destinee} are "
+                 u"NOT end to end encrypted anymore.\nYour server administrators or "
+                 u"{destinee} server administrators will be able to read them.").format(
+                 destinee=entity.full())
+
+        self.client.feedback(entity, msg)
 
     def getSession(self, entity):
         """Get encryption session for this contact
 
         @param entity(jid.JID): get the session for this entity
             must be a bare jid
-        @return (dict, None): encrypted session data
+        @return (dict, None): encryption session data
             None if there is not encryption for this session with this jid
         """
         if entity.resource:
@@ -173,3 +271,15 @@
         encryption = self._sessions.get(to_jid.userhostJID())
         if encryption is not None:
             mess_data[C.MESS_KEY_ENCRYPTION] = encryption
+
+    ## Misc ##
+
+    def markAsEncrypted(self, mess_data):
+        """Helper method to mark a message as having been e2e encrypted.
+
+        This should be used in the post_treat workflow of MessageReceived trigger of
+        the plugin
+        @param mess_data(dict): message data as used in post treat workflow
+        """
+        mess_data['encrypted'] = True
+        return mess_data