From b71aec5aa11e83e676a089b7d0660e87e761ea8f Mon Sep 17 00:00:00 2001
From: Luna <git@l4.pm>
Date: Sun, 3 Mar 2019 20:16:17 -0300
Subject: [PATCH] add basic LVSP client implementation

---
 litecord/voice/lvsp_conn.py    | 127 ++++++++++++++++++++++++++++++++-
 litecord/voice/lvsp_opcodes.py |  28 ++++++++
 2 files changed, 153 insertions(+), 2 deletions(-)
 create mode 100644 litecord/voice/lvsp_opcodes.py

diff --git a/litecord/voice/lvsp_conn.py b/litecord/voice/lvsp_conn.py
index f700d2c..366188b 100644
--- a/litecord/voice/lvsp_conn.py
+++ b/litecord/voice/lvsp_conn.py
@@ -17,7 +17,130 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 """
 
+import json
+import asyncio
+
+import websockets
+from logbook import Logger
+
+from litecord.voice.lvsp_opcodes import OPCodes as OP
+
+log = Logger(__name__)
+
 
 class LVSPConnection:
-    def __init__(self, app):
-        self.app = app
+    """Represents a single LVSP connection."""
+    def __init__(self, lvsp, region: str, hostname: str):
+        self.lvsp = lvsp
+        self.app = lvsp.app
+
+        self.region = region
+        self.hostname = hostname
+
+        self.conn = None
+
+        self._hb_task = None
+        self._hb_interval = None
+
+    @property
+    def _log_id(self):
+        return f'region={self.region} hostname={self.hostname}'
+
+    async def send(self, payload):
+        """Send a payload down the websocket."""
+        msg = json.dumps(payload)
+        await self.conn.send(msg)
+
+    async def recv(self):
+        """Receive a payload."""
+        msg = await self.conn.recv()
+        msg = json.dumps(msg)
+        return msg
+
+    async def send_op(self, opcode: int, data: dict):
+        """Send a message with an OP code included"""
+        await self.send({
+            'op': opcode,
+            'd': data
+        })
+
+    async def _heartbeater(self, hb_interval: int):
+        try:
+            await asyncio.sleep(hb_interval)
+
+            # TODO: add self._seq
+            await self.send_op(OP.heartbeat, {
+                's': 0
+            })
+
+            # give the server 300 milliseconds to reply.
+            await asyncio.sleep(300)
+            await self.conn.close(4000, 'heartbeat timeout')
+        except asyncio.CancelledError:
+            pass
+
+    def _start_hb(self):
+        self._hb_task = self.app.loop.create_task(
+            self._heartbeater(self._hb_interval)
+        )
+
+    def _stop_hb(self):
+        self._hb_task.cancel()
+
+    async def _handle_0(self, msg):
+        """Handle HELLO message."""
+        data = msg['d']
+
+        # nonce = data['nonce']
+        self._hb_interval = data['heartbeat_interval']
+
+        # TODO: send identify
+
+    async def _update_health(self, new_health: float):
+        """Update the health value of a given voice server."""
+        await self.app.db.execute("""
+        UPDATE voice_servers
+        SET health = $1
+        WHERE hostname = $2
+        """, new_health, self.hostname)
+
+    async def _handle_3(self, msg):
+        """Handle READY message.
+
+        We only start heartbeating after READY.
+        """
+        await self._update_health(msg['health'])
+        self._start_hb()
+
+    async def _handle_5(self, msg):
+        """Handle HEARTBEAT_ACK."""
+        self._stop_hb()
+        await self._update_health(msg['health'])
+        self._start_hb()
+
+    async def _loop(self):
+        while True:
+            msg = await self.recv()
+
+            try:
+                opcode = msg['op']
+                handler = getattr(self, f'_handle_{opcode}')
+                await handler(msg)
+            except (KeyError, AttributeError):
+                # TODO: error codes in LVSP
+                raise Exception('invalid op code')
+
+    async def run(self):
+        """Start the websocket."""
+        self.conn = await websockets.connect(f'wss://{self.hostname}')
+
+        try:
+            await self._loop()
+        except websockets.exceptions.ConnectionClosed as err:
+            log.warning('conn close, {}, err={}', self._log_id, err)
+        # except WebsocketClose as err:
+        #     log.warning('ws close, state={} err={}', self.state, err)
+        #     await self.conn.close(code=err.code, reason=err.reason)
+        except Exception as err:
+            log.exception('An exception has occoured. {}', self._log_id)
+            await self.conn.close(code=4000, reason=repr(err))
diff --git a/litecord/voice/lvsp_opcodes.py b/litecord/voice/lvsp_opcodes.py
new file mode 100644
index 0000000..4b19249
--- /dev/null
+++ b/litecord/voice/lvsp_opcodes.py
@@ -0,0 +1,28 @@
+"""
+
+Litecord
+Copyright (C) 2018-2019  Luna Mendes
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, version 3 of the License.
+
+This program 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 General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""
+
+class OPCodes:
+    """LVSP OP codes."""
+    hello = 0
+    identify = 1
+    resume = 2
+    ready = 3
+    heartbeat = 4
+    heartbeat_ack = 5
+    info = 6