continuwuity/src/database/key_value/presence.rs

use std::time::Duration;

use ruma::{events::presence::PresenceEvent, presence::PresenceState, OwnedUserId, RoomId, UInt, UserId};
use tracing::error;

use crate::{
	database::KeyValueDatabase,
	service::{self, presence::Presence},
	services,
	utils::{self, user_id_from_bytes},
	Error, Result,
};

impl service::presence::Data for KeyValueDatabase {
	fn get_presence(&self, room_id: &RoomId, user_id: &UserId) -> Result<Option<PresenceEvent>> {
		let key = presence_key(room_id, user_id);

		self.roomuserid_presence
			.get(&key)?
			.map(|presence_bytes| -> Result<PresenceEvent> {
				Presence::from_json_bytes(&presence_bytes)?.to_presence_event(user_id)
			})
			.transpose()
	}

	fn ping_presence(&self, user_id: &UserId, new_state: PresenceState) -> Result<()> {
		let now = utils::millis_since_unix_epoch();
		let mut state_changed = false;

		for room_id in services().rooms.state_cache.rooms_joined(user_id) {
			let key = presence_key(&room_id?, user_id);

			let presence_bytes = self.roomuserid_presence.get(&key)?;

			if let Some(presence_bytes) = presence_bytes {
				let presence = Presence::from_json_bytes(&presence_bytes)?;
				if presence.state != new_state {
					state_changed = true;
					break;
				}
			}
		}

		let count = if state_changed {
			services().globals.next_count()?
		} else {
			services().globals.current_count()?
		};

		for room_id in services().rooms.state_cache.rooms_joined(user_id) {
			let key = presence_key(&room_id?, user_id);

			let presence_bytes = self.roomuserid_presence.get(&key)?;

			let new_presence = match presence_bytes {
				Some(presence_bytes) => {
					let mut presence = Presence::from_json_bytes(&presence_bytes)?;
					presence.state = new_state.clone();
					presence.currently_active = presence.state == PresenceState::Online;
					presence.last_active_ts = now;
					presence.last_count = count;

					presence
				},
				None => Presence::new(new_state.clone(), new_state == PresenceState::Online, now, count, None),
			};

			self.roomuserid_presence
				.insert(&key, &new_presence.to_json_bytes()?)?;
		}

		let timeout = match new_state {
			PresenceState::Online => services().globals.config.presence_idle_timeout_s,
			_ => services().globals.config.presence_offline_timeout_s,
		};

		self.presence_timer_sender
			.send((user_id.to_owned(), Duration::from_secs(timeout)))
			.map_err(|e| {
				error!("Failed to add presence timer: {}", e);
				Error::bad_database("Failed to add presence timer")
			})
	}

	fn set_presence(
		&self, room_id: &RoomId, user_id: &UserId, presence_state: PresenceState, currently_active: Option<bool>,
		last_active_ago: Option<UInt>, status_msg: Option<String>,
	) -> Result<()> {
		let now = utils::millis_since_unix_epoch();
		let last_active_ts = match last_active_ago {
			Some(last_active_ago) => now.saturating_sub(last_active_ago.into()),
			None => now,
		};

		let key = presence_key(room_id, user_id);

		let presence = Presence::new(
			presence_state,
			currently_active.unwrap_or(false),
			last_active_ts,
			services().globals.next_count()?,
			status_msg,
		);

		let timeout = match presence.state {
			PresenceState::Online => services().globals.config.presence_idle_timeout_s,
			_ => services().globals.config.presence_offline_timeout_s,
		};

		self.presence_timer_sender
			.send((user_id.to_owned(), Duration::from_secs(timeout)))
			.map_err(|e| {
				error!("Failed to add presence timer: {}", e);
				Error::bad_database("Failed to add presence timer")
			})?;

		self.roomuserid_presence
			.insert(&key, &presence.to_json_bytes()?)?;

		Ok(())
	}

	fn remove_presence(&self, user_id: &UserId) -> Result<()> {
		for room_id in services().rooms.state_cache.rooms_joined(user_id) {
			let key = presence_key(&room_id?, user_id);

			self.roomuserid_presence.remove(&key)?;
		}

		Ok(())
	}

	fn presence_since<'a>(
		&'a self, room_id: &RoomId, since: u64,
	) -> Box<dyn Iterator<Item = (OwnedUserId, u64, PresenceEvent)> + 'a> {
		let prefix = [room_id.as_bytes(), &[0xFF]].concat();

		Box::new(
			self.roomuserid_presence
				.scan_prefix(prefix)
				.flat_map(|(key, presence_bytes)| -> Result<(OwnedUserId, u64, PresenceEvent)> {
					let user_id = user_id_from_bytes(
						key.rsplit(|byte| *byte == 0xFF)
							.next()
							.ok_or_else(|| Error::bad_database("No UserID bytes in presence key"))?,
					)?;

					let presence = Presence::from_json_bytes(&presence_bytes)?;
					let presence_event = presence.to_presence_event(&user_id)?;

					Ok((user_id, presence.last_count, presence_event))
				})
				.filter(move |(_, count, _)| *count > since),
		)
	}
}

#[inline]
fn presence_key(room_id: &RoomId, user_id: &UserId) -> Vec<u8> {
	[room_id.as_bytes(), &[0xFF], user_id.as_bytes()].concat()
}