From 0f600543e8efa90929d09301daab3a173ad72684 Mon Sep 17 00:00:00 2001
From: Luna <508270-luna@users.noreply.gitlab.com>
Date: Thu, 30 Jan 2020 01:50:50 +0000
Subject: [PATCH] Refactor GatewayState with proper types

    Make websocket loop be inside app context
---
 litecord/common/users.py      |   5 +-
 litecord/gateway/state.py     |  36 +++---
 litecord/gateway/websocket.py |  72 ++++++------
 litecord/presence.py          | 205 ++++++++++++++--------------------
 litecord/utils.py             |   8 ++
 5 files changed, 154 insertions(+), 172 deletions(-)

diff --git a/litecord/common/users.py b/litecord/common/users.py
index 7edbc33..a3ea268 100644
--- a/litecord/common/users.py
+++ b/litecord/common/users.py
@@ -24,6 +24,7 @@ from quart import current_app as app
 from asyncpg import UniqueViolationError
 from logbook import Logger
 
+from ..presence import BasePresence
 from ..snowflake import get_snowflake
 from ..errors import BadRequest
 from ..auth import hash_data
@@ -268,6 +269,4 @@ async def user_disconnect(user_id: int):
         await state.ws.ws.close(4000)
 
     # force everyone to see the user as offline
-    await app.presence.dispatch_pres(
-        user_id, {"afk": False, "status": "offline", "game": None, "since": 0}
-    )
+    await app.presence.dispatch_pres(user_id, BasePresence(status="offline"))
diff --git a/litecord/gateway/state.py b/litecord/gateway/state.py
index 9df23e3..3bac060 100644
--- a/litecord/gateway/state.py
+++ b/litecord/gateway/state.py
@@ -20,6 +20,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 import hashlib
 import os
 
+from typing import Optional
+from litecord.presence import BasePresence
+
 
 def gen_session_id() -> str:
     """Generate a random session ID."""
@@ -61,34 +64,35 @@ class GatewayState:
     """
 
     def __init__(self, **kwargs):
-        self.session_id = kwargs.get("session_id", gen_session_id())
+        self.session_id: str = kwargs.get("session_id", gen_session_id())
 
-        #: event sequence number
-        self.seq = kwargs.get("seq", 0)
+        #: last seq received by the client
+        self.seq: int = int(kwargs.get("seq") or 0)
 
-        #: last seq sent by us, the backend
-        self.last_seq = 0
+        #: last seq sent by gateway
+        self.last_seq: int = 0
 
-        #: shard information about the state,
-        #  its id and shard count
-        self.shard = kwargs.get("shard", [0, 1])
+        #: shard information (id and total count)
+        shard = kwargs.get("shard") or [0, 1]
+        self.current_shard: int = int(shard[0])
+        self.shard_count: int = int(shard[1])
 
-        self.user_id = kwargs.get("user_id")
-        self.bot = kwargs.get("bot", False)
+        self.user_id: int = int(kwargs["user_id"])
+        self.bot: bool = bool(kwargs.get("bot") or False)
 
         #: set by the gateway connection
         #  on OP STATUS_UPDATE
-        self.presence = {}
+        self.presence: Optional[BasePresence] = None
 
         #: set by the backend once identify happens
         self.ws = None
 
-        #: store (kind of) all payloads sent by us
+        #: store of all payloads sent by the gateway (for recovery purposes)
         self.store = PayloadStore()
 
-        for key in kwargs:
-            value = kwargs[key]
-            self.__dict__[key] = value
+        self.compress: bool = kwargs.get("compress") or False
+
+        self.large: int = kwargs.get("large") or 50
 
     def __repr__(self):
-        return f"GatewayState<seq={self.seq} " f"shard={self.shard} uid={self.user_id}>"
+        return f"GatewayState<seq={self.seq} shard={self.current_shard},{self.shard_count} uid={self.user_id}>"
diff --git a/litecord/gateway/websocket.py b/litecord/gateway/websocket.py
index b295290..a4f10e8 100644
--- a/litecord/gateway/websocket.py
+++ b/litecord/gateway/websocket.py
@@ -31,8 +31,15 @@ from logbook import Logger
 from litecord.auth import raw_token_check
 from litecord.enums import RelationshipType, ChannelType
 from litecord.schemas import validate, GW_STATUS_UPDATE
-from litecord.utils import task_wrapper, yield_chunks, maybe_int
+from litecord.utils import (
+    task_wrapper,
+    yield_chunks,
+    maybe_int,
+    want_bytes,
+    want_string,
+)
 from litecord.permissions import get_permissions
+from litecord.presence import BasePresence
 
 from litecord.gateway.opcodes import OP
 from litecord.gateway.state import GatewayState
@@ -173,13 +180,15 @@ class GatewayWebsocket:
                 payload.get("t"),
             )
 
+        # TODO encode to bytes only when absolutely needed e.g
+        # when compressing, because encoding == json means bytes won't work
         if isinstance(encoded, str):
             encoded = encoded.encode()
 
         if self.wsp.compress == "zlib-stream":
-            await self._zlib_stream_send(encoded)
+            await self._zlib_stream_send(want_bytes(encoded))
         elif self.wsp.compress == "zstd-stream":
-            await self._zstd_stream_send(encoded)
+            await self._zstd_stream_send(want_bytes(encoded))
         elif (
             self.state
             and self.state.compress
@@ -188,9 +197,13 @@ class GatewayWebsocket:
         ):
             # TODO determine better conditions to trigger a compress set
             # by identify
-            await self.ws.send(zlib.compress(encoded))
+            await self.ws.send(zlib.compress(want_bytes(encoded)))
         else:
-            await self.ws.send(encoded)
+            await self.ws.send(
+                want_bytes(encoded)
+                if self.wsp.encoding == "etf"
+                else want_string(encoded)
+            )
 
     async def send_op(self, op_code: int, data: Any):
         """Send a packet but just the OP code information is filled in."""
@@ -343,7 +356,7 @@ class GatewayWebsocket:
             "guilds": guilds,
             "session_id": self.state.session_id,
             "_trace": ["transbian"],
-            "shard": self.state.shard,
+            "shard": [self.state.current_shard, self.state.shard_count],
         }
 
         await self.dispatch("READY", {**base_ready, **user_ready})
@@ -442,7 +455,7 @@ class GatewayWebsocket:
             log.info("subscribing to {} friends", len(friend_ids))
             await self.app.dispatcher.sub_many("friend", user_id, friend_ids)
 
-    async def update_status(self, status: dict):
+    async def update_status(self, incoming_status: dict):
         """Update the status of the current websocket connection."""
         if not self.state:
             return
@@ -452,7 +465,7 @@ class GatewayWebsocket:
             # are just silently dropped.
             return
 
-        default_status = {
+        status = {
             "afk": False,
             # TODO: fetch status from settings
             "status": "online",
@@ -460,8 +473,7 @@ class GatewayWebsocket:
             # TODO: this
             "since": 0,
         }
-
-        status = {**(status or {}), **default_status}
+        status.update(incoming_status or {})
 
         try:
             status = validate(status, GW_STATUS_UPDATE)
@@ -479,15 +491,10 @@ class GatewayWebsocket:
         else:
             game = status["game"]
 
-        # construct final status
-        status = {
-            "afk": status.get("afk", False),
-            "status": status.get("status", "online"),
-            "game": game,
-            "since": status.get("since", 0),
-        }
+        pres_status = status.get("status") or "online"
+        pres_status = "offline" if pres_status == "invisible" else pres_status
+        self.state.presence = BasePresence(status=pres_status, game=game)
 
-        self.state.presence = status
         log.info(
             f'Updating presence status={status["status"]} for '
             f"uid={self.state.user_id}"
@@ -523,6 +530,8 @@ class GatewayWebsocket:
         except KeyError:
             raise DecodeError("Invalid identify parameters")
 
+        # TODO proper validation of this payload
+
         compress = data.get("compress", False)
         large = data.get("large_threshold", 50)
 
@@ -552,12 +561,12 @@ class GatewayWebsocket:
             bot=bot,
             compress=compress,
             large=large,
-            shard=shard,
             current_shard=shard[0],
             shard_count=shard[1],
-            ws=self,
         )
 
+        self.state.ws = self
+
         # link the state to the user
         self.app.state_manager.insert(self.state)
 
@@ -1004,24 +1013,23 @@ class GatewayWebsocket:
         if not user_id:
             return
 
-        # TODO: account for sharding
-        # this only updates status to offline once
-        # ALL shards have come offline
+        # TODO: account for sharding. this only checks to dispatch an offline
+        # when all the shards have come fully offline, which is inefficient.
+
+        # TODO why is this inneficient?
         states = self.app.state_manager.user_states(user_id)
-        with_ws = [s for s in states if s.ws]
-
-        # there arent any other states with websocket
-        if not with_ws:
-            offline = {"afk": False, "status": "offline", "game": None, "since": 0}
-
-            await self.app.presence.dispatch_pres(user_id, offline)
+        if not any(s.ws for s in states):
+            await self.app.presence.dispatch_pres(
+                user_id, BasePresence(status="offline")
+            )
 
     async def run(self):
         """Wrap :meth:`listen_messages` inside
         a try/except block for WebsocketClose handling."""
         try:
-            await self._send_hello()
-            await self._listen_messages()
+            async with self.app.app_context():
+                await self._send_hello()
+                await self._listen_messages()
         except websockets.exceptions.ConnectionClosed as err:
             log.warning("conn close, state={}, err={}", self.state, err)
         except WebsocketClose as err:
diff --git a/litecord/presence.py b/litecord/presence.py
index 55d7832..9911daf 100644
--- a/litecord/presence.py
+++ b/litecord/presence.py
@@ -17,13 +17,33 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 """
 
-from typing import List, Dict, Any, Iterable
+from typing import List, Dict, Any, Iterable, Optional
 from random import choice
+from dataclasses import dataclass
+from quart import current_app as app
 
 from logbook import Logger
 
 log = Logger(__name__)
 
+
+@dataclass
+class BasePresence:
+    status: str
+    game: Optional[dict] = None
+
+    @property
+    def partial_dict(self) -> dict:
+        return {
+            "status": self.status,
+            "game": self.game,
+            "since": 0,
+            "client_status": {},
+            "mobile": False,
+            "activities": [self.game] if self.game else [],
+        }
+
+
 Presence = Dict[str, Any]
 
 
@@ -37,69 +57,29 @@ def status_cmp(status: str, other_status: str) -> bool:
     return hierarchy[status] > hierarchy[other_status]
 
 
-def _best_presence(shards):
-    """Find the 'best' presence given a list of GatewayState."""
-    best = {"status": None, "game": None}
+def _merge_state_presences(shards: list) -> BasePresence:
+    """create a 'best' presence given a list of states."""
+    best = BasePresence(status="offline")
 
     for state in shards:
-        presence = state.presence
-
-        status = presence["status"]
-
-        if not presence:
+        if state.presence is None:
             continue
 
         # shards with a better status
         # in the hierarchy are treated as best
-        if status_cmp(status, best["status"]):
-            best["status"] = status
+        if status_cmp(state.presence.status, best.status):
+            best.status = state.presence.status
 
         # if we have any game, use it
-        if presence["game"] is not None:
-            best["game"] = presence["game"]
+        if state.presence.game:
+            best.game = state.presence.game
 
-    # best['status'] is None when no
-    # status was good enough.
-    return None if not best["status"] else best
+    return best
 
 
-def fill_presence(presence: dict, *, game=None) -> dict:
-    """Fill a given presence object with some specific fields."""
-    presence["client_status"] = {}
-    presence["mobile"] = False
-
-    if "since" not in presence:
-        presence["since"] = 0
-
-    # fill game and activities array depending if game
-    # is there or not
-    game = game or presence.get("game")
-
-    # casting to bool since a game of {} is still invalid
-    if game:
-        presence["game"] = game
-        presence["activities"] = [game]
-    else:
-        presence["game"] = None
-        presence["activities"] = []
-
-    return presence
-
-
-async def _pres(storage, user_id: int, status_obj: dict) -> dict:
-    """Convert a given status into a presence, given the User ID and the
-    :class:`Storage` instance."""
-    ext = {
-        "user": await storage.get_user(user_id),
-        "activities": [],
-        # NOTE: we are purposefully overwriting the fields, as there
-        # isn't any push for us to actually implement mobile detection, or
-        # web detection, etc.
-        "client_status": {},
-        "mobile": False,
-    }
-
-    return fill_presence({**status_obj, **ext})
+async def _pres(user_id: int, presence: BasePresence) -> dict:
+    """Take a given base presence and convert it to a full friend presence."""
+    return {**presence.partial_dict, **{"user": await app.storage.get_user(user_id)}}
 
 
 class PresenceManager:
@@ -123,39 +103,30 @@ class PresenceManager:
         # then fetching its respective member and merging that info with
         # the state's set presence.
         states = self.state_manager.guild_states(member_ids, guild_id)
-
         presences = []
 
         for state in states:
             member = await self.storage.get_member_data_one(guild_id, state.user_id)
-
-            game = state.presence.get("game", None)
-
-            # only use the data we need.
             presences.append(
-                fill_presence(
-                    {
+                {
+                    **(state.presence or BasePresence(status="offline")).partial_dict,
+                    **{
                         "user": member["user"],
                         "roles": member["roles"],
                         "guild_id": str(guild_id),
-                        # if a state is connected to the guild
-                        # we assume its online.
-                        "status": state.presence.get("status", "online"),
                     },
-                    game=game,
-                )
+                }
             )
 
         return presences
 
-    async def dispatch_guild_pres(self, guild_id: int, user_id: int, new_state: dict):
+    async def dispatch_guild_pres(
+        self, guild_id: int, user_id: int, presence: BasePresence
+    ):
         """Dispatch a Presence update to an entire guild."""
-        state = dict(new_state)
 
         member = await self.storage.get_member_data_one(guild_id, user_id)
 
-        game = state["game"]
-
         lazy_guild_store = self.dispatcher.backends["lazy_guild"]
         lists = lazy_guild_store.get_gml_guild(guild_id)
 
@@ -166,7 +137,11 @@ class PresenceManager:
         for member_list in lists:
             session_ids = await member_list.pres_update(
                 int(member["user"]["id"]),
-                {"roles": member["roles"], "status": state["status"], "game": game},
+                {
+                    "roles": member["roles"],
+                    "status": presence.status,
+                    "game": presence.game,
+                },
             )
 
             log.debug("Lazy Dispatch to {}", len(session_ids))
@@ -176,15 +151,14 @@ class PresenceManager:
             if member_list.channel_id == member_list.guild_id:
                 in_lazy.extend(session_ids)
 
-        pres_update_payload = fill_presence(
-            {
+        event_payload = {
+            **presence.partial_dict,
+            **{
                 "guild_id": str(guild_id),
                 "user": member["user"],
                 "roles": member["roles"],
-                "status": state["status"],
             },
-            game=game,
-        )
+        }
 
         # given a session id, return if the session id actually connects to
         # a given user, and if the state has not been dispatched via lazy guild.
@@ -202,79 +176,68 @@ class PresenceManager:
         # everyone not in lazy guild mode
         # gets a PRESENCE_UPDATE
         await self.dispatcher.dispatch_filter(
-            "guild", guild_id, _session_check, "PRESENCE_UPDATE", pres_update_payload
+            "guild", guild_id, _session_check, "PRESENCE_UPDATE", event_payload
         )
 
         return in_lazy
 
-    async def dispatch_pres(self, user_id: int, state: dict):
+    async def dispatch_pres(self, user_id: int, presence: BasePresence) -> None:
         """Dispatch a new presence to all guilds the user is in.
 
         Also dispatches the presence to all the users' friends
         """
-        if state["status"] == "invisible":
-            state["status"] = "offline"
-
-        # TODO: shard-aware
+        # TODO: shard-aware (needs to only dispatch guilds of the shard)
         guild_ids = await self.user_storage.get_user_guilds(user_id)
-
         for guild_id in guild_ids:
-            await self.dispatch_guild_pres(guild_id, user_id, state)
+            await self.dispatch_guild_pres(guild_id, user_id, presence)
 
         # dispatch to all friends that are subscribed to them
         user = await self.storage.get_user(user_id)
-        game = state["game"]
-
         await self.dispatcher.dispatch(
             "friend",
             user_id,
             "PRESENCE_UPDATE",
-            fill_presence({"user": user, "status": state["status"]}, game=game),
+            {**presence.partial_dict, **{"user": user}},
         )
 
+    def fetch_friend_presence(self, friend_id: int) -> BasePresence:
+        """Fetch a presence for a friend.
+
+        This is a different algorithm than guild presence.
+        """
+        friend_states = self.state_manager.user_states(friend_id)
+
+        if not friend_states:
+            return BasePresence(status="offline")
+
+        # filter the best shards:
+        #  - all with id 0 (are the first shards in the collection) or
+        #  - all shards with count = 1 (single shards)
+        good_shards = list(
+            filter(
+                lambda state: state.shard[0] == 0 or state.shard[1] == 1, friend_states
+            )
+        )
+
+        if good_shards:
+            return _merge_state_presences(good_shards)
+
+        # if there aren't any shards with id 0
+        # AND none that are single, just go with a random one.
+        shard = choice([s for s in friend_states if s.presence])
+        assert shard.presence is not None
+        return shard.presence
+
     async def friend_presences(self, friend_ids: Iterable[int]) -> List[Presence]:
         """Fetch presences for a group of users.
 
         This assumes the users are friends and so
         only gets states that are single or have ID 0.
         """
-        storage = self.storage
         res = []
 
         for friend_id in friend_ids:
-            friend_states = self.state_manager.user_states(friend_id)
-
-            if not friend_states:
-                # append offline
-                res.append(
-                    await _pres(
-                        storage,
-                        friend_id,
-                        {"afk": False, "status": "offline", "game": None, "since": 0},
-                    )
-                )
-
-                continue
-
-            # filter the best shards:
-            #  - all with id 0 (are the first shards in the collection) or
-            #  - all shards with count = 1 (single shards)
-            good_shards = list(
-                filter(
-                    lambda state: state.shard[0] == 0 or state.shard[1] == 1,
-                    friend_states,
-                )
-            )
-
-            if good_shards:
-                best_pres = _best_presence(good_shards)
-                best_pres = await _pres(storage, friend_id, best_pres)
-                res.append(best_pres)
-                continue
-
-            # if there aren't any shards with id 0
-            # AND none that are single, just go with a random
-            shard = choice(friend_states)
-            res.append(await _pres(storage, friend_id, shard.presence))
+            presence = self.fetch_friend_presence(friend_id)
+            res.append(await _pres(friend_id, presence))
 
         return res
diff --git a/litecord/utils.py b/litecord/utils.py
index 91e7d8a..fe3c2d4 100644
--- a/litecord/utils.py
+++ b/litecord/utils.py
@@ -290,3 +290,11 @@ def query_tuple_from_args(args: dict, limit: int) -> tuple:
 def rand_hex(length: int = 8) -> str:
     """Generate random hex characters."""
     return secrets.token_hex(length)[:length]
+
+
+def want_bytes(data: Union[str, bytes]) -> bytes:
+    return data if isinstance(data, bytes) else data.encode()
+
+
+def want_string(data: Union[str, bytes]) -> str:
+    return data.decode() if isinstance(data, bytes) else data