Respect contact id when sending in private chat

Also listen on other enter button and empty entry after sending.

data/ui/chat.ui

@@ -2,7 +2,7 @@
 <!-- Generated with glade 3.22.1 -->
 <interface>
   <requires lib="gtk+" version="3.20"/>
-  <object class="GtkGrid" id="main">
+  <object class="GtkGrid" id="chat">
     <property name="visible">True</property>
     <property name="can_focus">False</property>
     <property name="halign">center</property>

src/briar/api/models/private_chat.py

@@ -23,5 +23,5 @@ class PrivateChat(Model):
                                         contact_id=contact_id)
 
     def send(self, contact_id, message):
-        url = urljoin(BASE_HTTP_URL, 'messages/%s' % contact_id)
+        url = urljoin(BASE_HTTP_URL, 'messages/%i' % contact_id)
         _post(url, headers=self._headers, json={'text': message})

src/briar/gtk/containers/chat.py

@@ -16,36 +16,40 @@ class ChatContainer(Container):
     def __init__(self, contact_id):
         super().__init__()
         self._api = App().api
+        self._contact_id = contact_id
         self._setup_view()
-        self._load_content(contact_id)
+        self._load_content()
 
     def _setup_view(self):
         self.builder.add_from_resource("/app/briar/gtk/ui/chat.ui")
-        self.add(self.builder.get_object("main"))
+        self.add(self.builder.get_object("chat"))
         self.builder.connect_signals(self)
         chat_entry = self.builder.get_object("chat_entry")
         chat_entry.connect("key-press-event", self._key_pressed)
 
-    def _load_content(self, contact_id):
+    def _load_content(self):
         private_chat = PrivateChat(self._api)
-        messages_list = private_chat.get(contact_id)
+        messages_list = private_chat.get(self._contact_id)
         self._messages_list_box = self.builder.get_object("messages_list")
         for message in messages_list:
-            self._add_message(message)
-        private_chat.watch_messages(contact_id, self._add_message_async)
+            self._add_message(message["text"])
+        private_chat.watch_messages(self._contact_id, self._add_message_async)
 
     def _add_message(self, message):
-        message_label = Gtk.Label(message["text"])
+        message_label = Gtk.Label(message)
         message_label.show()
         self._messages_list_box.add(message_label)
 
     def _add_message_async(self, message):
-        GLib.idle_add(self._add_message, message)
+        GLib.idle_add(self._add_message, message["text"])
 
     def _key_pressed(self, widget, event):
-        if event.hardware_keycode != 36:
+        if event.hardware_keycode != 36 and event.hardware_keycode != 104:
             return
-        message = self.builder.get_object("chat_entry").get_text()
+        chat_entry = self.builder.get_object("chat_entry")
+        message = chat_entry.get_text()
         private_chat = PrivateChat(self._api)
-        private_chat.send("1", message)
-        
+        private_chat.send(self._contact_id, message)
+
+        self._add_message(message)
+        chat_entry.set_text("")