litecord: add system_messages module

- channel.pins: send a CHANNEL_PINNED_MESSAGE system message

litecord/blueprints/channel/pins.py

@@ -5,6 +5,9 @@ from litecord.blueprints.checks import channel_check, channel_perm_check
 from litecord.snowflake import snowflake_datetime
 from litecord.types import timestamp_
 
+from litecord.system_messages import send_sys_message
+from litecord.enums import MessageType
+
 bp = Blueprint('channel_pins', __name__)
 
 
@@ -63,6 +66,10 @@ async def add_pin(channel_id, message_id):
         }
     )
 
+    await send_sys_message(app, channel_id,
+                           MessageType.CHANNEL_PINNED_MESSAGE,
+                           message_id, user_id)
+
     return '', 204
 
 

litecord/storage.py

@@ -699,6 +699,9 @@ class Storage:
         # TODO: res['embeds']
         res['embeds'] = []
 
+        # TODO: res['member'] for partial member data
+        #  of the author
+
         pin_id = await self.db.fetchval("""
         SELECT message_id
         FROM channel_pins

litecord/system_messages.py

@@ -0,0 +1,38 @@
+from litecord.snowflake import get_snowflake
+from litecord.enums import MessageType
+
+
+async def _handle_pin_msg(app, channel_id, pinned_id, author_id):
+    """Handle a message pin."""
+    new_id = get_snowflake()
+
+    await app.db.execute(
+        """
+        INSERT INTO messages
+            (id, channel_id, guild_id, author_id,
+             webhook_id, content, message_type)
+        VALUES
+            ($1, $2, NULL, $3, NULL, '',
+             $4)
+        """,
+        new_id, channel_id, author_id,
+        MessageType.CHANNEL_PINNED_MESSAGE.value
+    )
+
+    return new_id
+
+
+async def send_sys_message(app, channel_id: int, m_type: MessageType,
+                           *args, **kwargs):
+    """Send a system message."""
+    handler = {
+        MessageType.CHANNEL_PINNED_MESSAGE: _handle_pin_msg,
+    }[m_type]
+
+    message_id = await handler(app, channel_id, *args, **kwargs)
+
+    message = await app.storage.get_message(message_id)
+
+    await app.dispatcher.dispatch(
+        'channel', channel_id, 'MESSAGE_CREATE', message
+    )