MemoServ: add SET NOTIFY and SET LIMIT

SET NOTIFY {ON|OFF} controls whether you're told about new memos on login;
SET LIMIT <n>|NONE sets your mailbox cap (honoured on SEND, NONE = the
network default). New memo_notify/memo_limit account fields + one
MemoPrefsSet event.

src/engine/db/account.rs

@@ -20,7 +20,7 @@ impl Db {
             verified,
             ajoin: Vec::new(),
             suspension: None,
-            memos: Vec::new(), memo_ignore: Vec::new(),
+            memos: Vec::new(), memo_ignore: Vec::new(), memo_notify: true, memo_limit: None,
             greet: String::new(),
             vhost: None,
             vhost_request: None,
@@ -59,7 +59,7 @@ impl Db {
             verified: true, // the external authority vouches for it
             ajoin: Vec::new(),
             suspension: None,
-            memos: Vec::new(), memo_ignore: Vec::new(),
+            memos: Vec::new(), memo_ignore: Vec::new(), memo_notify: true, memo_limit: None,
             greet: String::new(),
             vhost: None,
             vhost_request: None,

src/engine/db/channel.rs

@@ -688,6 +688,36 @@ impl Db {
         self.accounts.get(&key(account)).is_some_and(|a| a.memo_ignore.iter().any(|t| t.eq_ignore_ascii_case(sender)))
     }
 
+    /// Set whether `account` is notified about new memos on login.
+    pub fn set_memo_notify(&mut self, account: &str, on: bool) -> bool {
+        let k = key(account);
+        let Some(a) = self.accounts.get(&k) else { return false };
+        let limit = a.memo_limit;
+        let _ = self.log.append(Event::MemoPrefsSet { account: account.to_string(), notify: on, limit });
+        self.accounts.get_mut(&k).unwrap().memo_notify = on;
+        true
+    }
+
+    /// Set `account`'s mailbox cap (None = the network default).
+    pub fn set_memo_limit(&mut self, account: &str, limit: Option<u32>) -> bool {
+        let k = key(account);
+        let Some(a) = self.accounts.get(&k) else { return false };
+        let notify = a.memo_notify;
+        let _ = self.log.append(Event::MemoPrefsSet { account: account.to_string(), notify, limit });
+        self.accounts.get_mut(&k).unwrap().memo_limit = limit;
+        true
+    }
+
+    /// Whether `account` wants new-memo notifications (default on / unknown = on).
+    pub fn memo_notify_on(&self, account: &str) -> bool {
+        self.accounts.get(&key(account)).is_none_or(|a| a.memo_notify)
+    }
+
+    /// `account`'s configured mailbox cap, if any.
+    pub fn memo_limit_of(&self, account: &str) -> Option<u32> {
+        self.accounts.get(&key(account)).and_then(|a| a.memo_limit)
+    }
+
     /// How many unread memos an account has.
     pub fn unread_memos(&self, account: &str) -> usize {
         self.accounts.get(&key(account)).map_or(0, |a| a.memos.iter().filter(|m| !m.read).count())

src/engine/db/event.rs

@@ -31,6 +31,7 @@ pub enum Event {
     MemoDeleted { account: String, index: usize },
     MemoIgnoreAdd { account: String, target: String },
     MemoIgnoreDel { account: String, target: String },
+    MemoPrefsSet { account: String, notify: bool, limit: Option<u32> },
     NickGrouped { nick: String, account: String },
     NickUngrouped { nick: String },
     ChannelRegistered { name: String, founder: String, ts: u64 },
@@ -160,6 +161,7 @@ impl Event {
             | Event::MemoDeleted { .. }
             | Event::MemoIgnoreAdd { .. }
             | Event::MemoIgnoreDel { .. }
+            | Event::MemoPrefsSet { .. }
             | Event::NickGrouped { .. }
             | Event::NickUngrouped { .. }
             | Event::AccountSeen { .. }
@@ -354,6 +356,12 @@ pub(crate) fn apply(accounts: &mut HashMap<String, Account>, channels: &mut Hash
                 a.memo_ignore.retain(|t| !t.eq_ignore_ascii_case(&target));
             }
         }
+        Event::MemoPrefsSet { account, notify, limit } => {
+            if let Some(a) = accounts.get_mut(&key(&account)) {
+                a.memo_notify = notify;
+                a.memo_limit = limit;
+            }
+        }
         Event::NickGrouped { nick, account } => {
             grouped.insert(key(&nick), account);
         }

src/engine/db/mod.rs

@@ -82,6 +82,12 @@ pub struct Account {
     // Accounts this user won't receive memos from (MemoServ IGNORE).
     #[serde(default)]
     pub memo_ignore: Vec<String>,
+    // MemoServ SET NOTIFY: be told about new memos on login (default on).
+    #[serde(default = "verified_default")]
+    pub memo_notify: bool,
+    // MemoServ SET LIMIT: mailbox cap (None = the network default).
+    #[serde(default)]
+    pub memo_limit: Option<u32>,
     // Personal greet a bot shows when this account joins a greet-enabled channel.
     #[serde(default)]
     pub greet: String,

src/engine/db/store.rs

@@ -468,6 +468,18 @@ impl Store for Db {
     fn memo_is_ignored(&self, account: &str, sender: &str) -> bool {
         Db::memo_is_ignored(self, account, sender)
     }
+    fn set_memo_notify(&mut self, account: &str, on: bool) -> bool {
+        Db::set_memo_notify(self, account, on)
+    }
+    fn set_memo_limit(&mut self, account: &str, limit: Option<u32>) -> bool {
+        Db::set_memo_limit(self, account, limit)
+    }
+    fn memo_notify_on(&self, account: &str) -> bool {
+        Db::memo_notify_on(self, account)
+    }
+    fn memo_limit_of(&self, account: &str) -> Option<u32> {
+        Db::memo_limit_of(self, account)
+    }
     fn memo_check(&self, account: &str, sender: &str) -> Option<(bool, u64)> {
         Db::memo_check(self, account, sender)
     }

src/engine/db/tests.rs

@@ -32,7 +32,7 @@
         // which of the two competing registrations we're looking at.
         let alice = |tag: &str, ts: u64, home: &str| Account {
             name: "alice".into(), email: Some(tag.into()),
-            ts, home: home.into(), scram256: None, scram512: None, certfps: vec![], verified: true, ajoin: vec![], suspension: None, memos: vec![], memo_ignore: vec![], greet: String::new(), vhost: None, vhost_request: None, last_seen: ts, noexpire: false, expiry_warned: false, oper_note: None,
+            ts, home: home.into(), scram256: None, scram512: None, certfps: vec![], verified: true, ajoin: vec![], suspension: None, memos: vec![], memo_ignore: vec![], memo_notify: true, memo_limit: None, greet: String::new(), vhost: None, vhost_request: None, last_seen: ts, noexpire: false, expiry_warned: false, oper_note: None,
         };
         let converge = |first: &Account, second: &Account| {
             let (mut acc, mut ch, mut gr, mut bo, mut hc, mut nd) = (HashMap::new(), HashMap::new(), HashMap::new(), HashMap::new(), HostConfig::default(), NetData::default());
@@ -329,7 +329,7 @@
         db.register("alice", "pw", None).unwrap();
         let bob = Account {
             name: "bob".into(), email: None,
-            ts: 0, home: "peer".into(), scram256: None, scram512: None, certfps: vec![], verified: true, ajoin: vec![], suspension: None, memos: vec![], memo_ignore: vec![], greet: String::new(), vhost: None, vhost_request: None, last_seen: 0, noexpire: false, expiry_warned: false, oper_note: None,
+            ts: 0, home: "peer".into(), scram256: None, scram512: None, certfps: vec![], verified: true, ajoin: vec![], suspension: None, memos: vec![], memo_ignore: vec![], memo_notify: true, memo_limit: None, greet: String::new(), vhost: None, vhost_request: None, last_seen: 0, noexpire: false, expiry_warned: false, oper_note: None,
         };
         let entry = LogEntry { origin: "peer".into(), seq: 0, lamport: 1, event: Event::AccountRegistered(Box::new(bob)) };
         db.ingest(entry).unwrap();

src/engine/mod.rs

@@ -1171,7 +1171,7 @@ fn audit_summary(event: &db::Event) -> Option<String> {
         // Private, self-service, or cosmetic — not surfaced.
         AjoinAdded { .. } | AjoinRemoved { .. } | AccountGreetSet { .. } | VhostRequested { .. }
         | VhostRequestCleared { .. } | MemoSent { .. } | MemoRead { .. } | MemoDeleted { .. }
-        | MemoIgnoreAdd { .. } | MemoIgnoreDel { .. }
+        | MemoIgnoreAdd { .. } | MemoIgnoreDel { .. } | MemoPrefsSet { .. }
         | ChannelMlock { .. } | ChannelDescSet { .. } | ChannelEntryMsgSet { .. } | ChannelSettingsSet { .. }
         | ChannelKickerSet { .. } | ChannelBadwordsSet { .. } | ChannelTriggersSet { .. }
         | ChannelTopicSet { .. } | AccountSeen { .. } | ChannelUsed { .. }

src/engine/tests.rs

@@ -411,7 +411,7 @@
         // An earlier claim from another node wins and takes the name over.
         let winner = db::Account {
             name: "alice".into(), email: None,
-            ts: 0, home: "peer".into(), scram256: None, scram512: None, certfps: vec![], verified: true, ajoin: vec![], suspension: None, memos: vec![], memo_ignore: vec![], greet: String::new(), vhost: None, vhost_request: None, last_seen: 0, noexpire: false, expiry_warned: false, oper_note: None,
+            ts: 0, home: "peer".into(), scram256: None, scram512: None, certfps: vec![], verified: true, ajoin: vec![], suspension: None, memos: vec![], memo_ignore: vec![], memo_notify: true, memo_limit: None, greet: String::new(), vhost: None, vhost_request: None, last_seen: 0, noexpire: false, expiry_warned: false, oper_note: None,
         };
         let entry = LogEntry::for_test("peer", 0, 1, db::Event::AccountRegistered(Box::new(winner)));
         e.gossip_ingest(entry).unwrap();
@@ -875,6 +875,44 @@
         assert_eq!(e.db.unread_memos("alice"), 1, "delivered once no longer ignored");
     }
 
+    // MemoServ SET NOTIFY/LIMIT change the account's memo preferences, and LIMIT
+    // caps the mailbox on SEND.
+    #[test]
+    fn memoserv_set_notify_and_limit() {
+        use echo_memoserv::MemoServ;
+        use echo_nickserv::NickServ;
+        let path = std::env::temp_dir().join("echo-msset.jsonl");
+        let _ = std::fs::remove_file(&path);
+        let mut db = Db::open(&path, "42S");
+        db.scram_iterations = 4096;
+        db.register("alice", "pw", None).unwrap();
+        db.register("bob", "pw", None).unwrap();
+        let mut e = Engine::new(
+            vec![
+                Box::new(NickServ { uid: "42SAAAAAA".into(), guest_nick: "Guest".into(), guest_seq: 0 }),
+                Box::new(MemoServ { uid: "42SAAAAAE".into() }),
+            ],
+            db,
+        );
+        let ms = |e: &mut Engine, uid: &str, t: &str| e.handle(NetEvent::Privmsg { from: uid.into(), to: "42SAAAAAE".into(), text: t.into() });
+        let notice = |out: &[NetAction], n: &str| out.iter().any(|a| matches!(a, NetAction::Notice { text, .. } if text.contains(n)));
+        e.handle(NetEvent::UserConnect { uid: "000AAAAAB".into(), nick: "alice".into(), host: "h".into(), ip: "0.0.0.0".into() });
+        e.handle(NetEvent::Privmsg { from: "000AAAAAB".into(), to: "42SAAAAAA".into(), text: "IDENTIFY pw".into() });
+        e.handle(NetEvent::UserConnect { uid: "000AAAAAC".into(), nick: "bob".into(), host: "h".into(), ip: "0.0.0.0".into() });
+        e.handle(NetEvent::Privmsg { from: "000AAAAAC".into(), to: "42SAAAAAA".into(), text: "IDENTIFY pw".into() });
+
+        assert!(notice(&ms(&mut e, "000AAAAAB", "SET NOTIFY OFF"), "off"), "notify off");
+        assert!(!e.db.memo_notify_on("alice"), "notify pref stored");
+        assert!(notice(&ms(&mut e, "000AAAAAB", "SET LIMIT 2"), "2"), "limit set");
+        assert_eq!(e.db.memo_limit_of("alice"), Some(2), "limit stored");
+
+        // bob fills alice's 2-memo mailbox; the third is rejected.
+        ms(&mut e, "000AAAAAC", "SEND alice one");
+        ms(&mut e, "000AAAAAC", "SEND alice two");
+        assert!(notice(&ms(&mut e, "000AAAAAC", "SEND alice three"), "mailbox is full"), "limit enforced on SEND");
+        assert_eq!(e.db.unread_memos("alice"), 2, "capped at the limit");
+    }
+
     // ChanServ AKICK CLEAR empties the auto-kick list.
     #[test]
     fn chanserv_akick_clear() {

src/grpc.rs

@@ -141,6 +141,7 @@ fn to_wire(entry: &LogEntry) -> Option<ReplicationEvent> {
         | Event::MemoDeleted { .. }
         | Event::MemoIgnoreAdd { .. }
         | Event::MemoIgnoreDel { .. }
+        | Event::MemoPrefsSet { .. }
         | Event::ChannelMlock { .. }
         | Event::ChannelAccessAdd { .. }
         | Event::ChannelAccessDel { .. }
@@ -457,6 +458,8 @@ mod tests {
             suspension: None,
             memos: vec![],
             memo_ignore: vec![],
+            memo_notify: true,
+            memo_limit: None,
             greet: String::new(),
             vhost: None,
             vhost_request: None,