adminroom: add user ID parsing utils

Signed-off-by: strawberry <strawberry@puppygock.gay>

src/admin/utils.rs

 pub(crate) use conduit::utils::HtmlEscape;
-use ruma::{OwnedRoomId, RoomId};
+use conduit_core::Error;
+use ruma::{OwnedRoomId, OwnedUserId, RoomId, UserId};
+use service::user_is_local;
 
-use crate::services;
+use crate::{services, Result};
 
 pub(crate) fn escape_html(s: &str) -> String {
 	s.replace('&', "&")
@@ -28,3 +30,35 @@ pub(crate) fn get_room_info(id: &RoomId) -> (OwnedRoomId, u64, String) {
 			.unwrap_or_else(|| id.to_string()),
 	)
 }
+
+/// Parses user ID
+pub(crate) fn parse_user_id(user_id: &str) -> Result<OwnedUserId> {
+	UserId::parse_with_server_name(user_id.to_lowercase(), services().globals.server_name())
+		.map_err(|e| Error::Err(format!("The supplied username is not a valid username: {e}")))
+}
+
+/// Parses user ID as our local user
+pub(crate) fn parse_local_user_id(user_id: &str) -> Result<OwnedUserId> {
+	let user_id = parse_user_id(user_id)?;
+
+	if !user_is_local(&user_id) {
+		return Err(Error::Err(String::from("User does not belong to our server.")));
+	}
+
+	Ok(user_id)
+}
+
+/// Parses user ID that is an active (not guest or deactivated) local user
+pub(crate) fn parse_active_local_user_id(user_id: &str) -> Result<OwnedUserId> {
+	let user_id = parse_local_user_id(user_id)?;
+
+	if !services().users.exists(&user_id)? {
+		return Err(Error::Err(String::from("User does not exist on this server.")));
+	}
+
+	if services().users.is_deactivated(&user_id)? {
+		return Err(Error::Err(String::from("User is deactivated.")));
+	}
+
+	Ok(user_id)
+}