split presence data object into file; improve service encapsulations

Signed-off-by: Jason Volk <jason@zemos.net>

src/service/presence/presence.rs

@@ -0,0 +1,65 @@
+use std::sync::Arc;
+
+use conduit::{utils, Error, Result};
+use ruma::{
+	events::presence::{PresenceEvent, PresenceEventContent},
+	presence::PresenceState,
+	UInt, UserId,
+};
+use serde::{Deserialize, Serialize};
+
+use crate::users;
+
+/// Represents data required to be kept in order to implement the presence
+/// specification.
+#[derive(Serialize, Deserialize, Debug, Clone)]
+pub(super) struct Presence {
+	state: PresenceState,
+	currently_active: bool,
+	last_active_ts: u64,
+	status_msg: Option<String>,
+}
+
+impl Presence {
+	#[must_use]
+	pub(super) fn new(
+		state: PresenceState, currently_active: bool, last_active_ts: u64, status_msg: Option<String>,
+	) -> Self {
+		Self {
+			state,
+			currently_active,
+			last_active_ts,
+			status_msg,
+		}
+	}
+
+	pub(super) fn from_json_bytes(bytes: &[u8]) -> Result<Self> {
+		serde_json::from_slice(bytes).map_err(|_| Error::bad_database("Invalid presence data in database"))
+	}
+
+	pub(super) fn to_json_bytes(&self) -> Result<Vec<u8>> {
+		serde_json::to_vec(self).map_err(|_| Error::bad_database("Could not serialize Presence to JSON"))
+	}
+
+	/// Creates a PresenceEvent from available data.
+	pub(super) fn to_presence_event(&self, user_id: &UserId, users: &Arc<users::Service>) -> Result<PresenceEvent> {
+		let now = utils::millis_since_unix_epoch();
+		let last_active_ago = if self.currently_active {
+			None
+		} else {
+			Some(UInt::new_saturating(now.saturating_sub(self.last_active_ts)))
+		};
+
+		Ok(PresenceEvent {
+			sender: user_id.to_owned(),
+			content: PresenceEventContent {
+				presence: self.state.clone(),
+				status_msg: self.status_msg.clone(),
+				currently_active: Some(self.currently_active),
+				last_active_ago,
+				displayname: users.displayname(user_id)?,
+				avatar_url: users.avatar_url(user_id)?,
+			},
+		})
+	}
+}