Move Presence class to its own python file

It's not a ModelItem

src/backend/models/items.py

@@ -10,8 +10,10 @@ from typing import Any, Dict, List, Optional, Tuple, Type, Union
 from uuid import UUID
 
 import lxml  # nosec
+
 import nio
 
+from ..presence import Presence
 from ..utils import AutoStrEnum, auto
 from .model_item import ModelItem
 
@@ -19,12 +21,6 @@ OptionalExceptionType = Union[Type[None], Type[Exception]]
 
 ZERO_DATE = datetime.fromtimestamp(0)
 
-PRESENCE_ORDER: Dict[str, int] = {
-    "online":      0,
-    "unavailable": 1,
-    "offline":     2,
-}
-
 
 class TypeSpecifier(AutoStrEnum):
     """Enum providing clarification of purpose for some matrix events."""
@@ -34,104 +30,6 @@ class TypeSpecifier(AutoStrEnum):
     MembershipChange = auto()
 
 
-@dataclass
-class Presence:
-    """Represents a single matrix user's presence fields.
-
-    These objects are stored in `Backend.presences`, indexed by user ID.
-    It must only be instanced when receiving a `PresenceEvent` or
-    registering an `Account` model item.
-
-    When receiving a `PresenceEvent`, we get or create a `Presence` object in
-    `Backend.presences` for the targeted user. If the user is registered in any
-    room, add its `Member` model item to `members`. Finally, update every
-    `Member` presence fields inside `members`.
-
-    When a room member is registered, we try to find a `Presence` in
-    `Backend.presences` for that user ID. If found, the `Member` item is added
-    to `members`.
-
-    When an Account model is registered, we create a `Presence` in
-    `Backend.presences` for the accountu's user ID whether the server supports
-    presence or not (we cannot know yet at this point),
-    and assign that `Account` to the `Presence.account` field.
-
-    Special attributes:
-        members: A `{room_id: Member}` dict for storing room members related to
-            this `Presence`. As each room has its own `Member`s objects, we
-            have to keep track of their presence fields. `Member`s are indexed
-            by room ID.
-
-        account: `Account` related to this `Presence`, if any. Should be
-            assigned when client starts (`MatrixClient._start()`) and
-            cleared when client stops (`MatrixClient._start()`).
-    """
-
-    class State(AutoStrEnum):
-        offline     = auto()  # can mean offline, invisible or unknwon
-        unavailable = auto()
-        online      = auto()
-        invisible   = auto()
-
-        echo_unavailable = auto()
-        echo_online      = auto()
-        echo_invisible   = auto()
-
-        def __lt__(self, other: "Presence.State") -> bool:
-            return PRESENCE_ORDER[self.value] < PRESENCE_ORDER[other.value]
-
-
-    presence:         State    = State.offline
-    currently_active: bool     = False
-    last_active_at:   datetime = ZERO_DATE
-    status_msg:       str      = ""
-
-    members: Dict[str, "Member"] = field(default_factory=dict)
-    account: Optional["Account"] = None
-
-    def update_members(self) -> None:
-        """Update presence fields of every `M̀ember` in `members`.
-
-        Currently it is only called when receiving a `PresenceEvent` and when
-        registering room members.
-        """
-
-        for member in self.members.values():
-            member.set_fields(
-                presence         = self.presence,
-                status_msg       = self.status_msg,
-                last_active_at   = self.last_active_at,
-                currently_active = self.currently_active,
-            )
-
-    def update_account(self) -> None:
-        """Update presence fields of `Account` related to this `Presence`."""
-
-        # Do not update if account is changing to invisible.
-        # When setting presence to invisible, the server will give us a
-        # presence event telling us we are offline, but we do not want to set
-        # account presence to offline.
-        if (
-            not self.account or
-            self.presence         == self.State.offline and
-            self.account.presence != self.State.echo_invisible
-        ):
-            return
-
-        fields: Dict[str, Any] = {}
-
-        if self.account.presence == self.State.echo_invisible:
-            fields["presence"] = self.State.invisible
-        else:
-            fields["presence"]   = self.presence
-            fields["status_msg"] = self.status_msg
-
-        fields["last_active_at"]   = self.last_active_at
-        fields["currently_active"] = self.currently_active
-
-        self.account.set_fields(**fields)
-
-
 @dataclass
 class Account(ModelItem):
     """A logged in matrix account."""