add users query command, initial fsck admin command

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

src/service/admin/fsck/fsck_commands.rs

@@ -0,0 +1,26 @@
+use ruma::events::room::message::RoomMessageEventContent;
+
+use crate::{services, Result};
+
+/// Uses the iterator in `src/database/key_value/users.rs` to iterator over
+/// every user in our database (remote and local). Reports total count, any
+/// errors if there were any, etc
+pub(super) async fn check_all_users(_body: Vec<&str>) -> Result<RoomMessageEventContent> {
+	let timer = tokio::time::Instant::now();
+	let results = services().users.db.iter();
+	let query_time = timer.elapsed();
+
+	let users = results.collect::<Vec<_>>();
+
+	let total = users.len();
+	let err_count = users.iter().filter(|user| user.is_err()).count();
+	let ok_count = users.iter().filter(|user| user.is_ok()).count();
+
+	let message = format!(
+		"Database query completed in {query_time:?}:\n\n```\nTotal entries: {:?}\nFailure/Invalid user count: \
+		 {:?}\nSuccess/Valid user count: {:?}```",
+		total, err_count, ok_count
+	);
+
+	Ok(RoomMessageEventContent::notice_html(message, String::new()))
+}