perf: debounce incoming dms

This fixes perf issues on startup if you have lots of dms

Changelog-Fixed: Fix lag on startup when you have lots of DMs
Changelog-Fixed: Fix an issues where dm notifications appear without any new events

damus.xcodeproj/project.pbxproj

@@ -42,6 +42,7 @@
 		4C285C8A2838B985008A31F1 /* ProfilePictureSelector.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C285C892838B985008A31F1 /* ProfilePictureSelector.swift */; };
 		4C285C8C28398BC7008A31F1 /* Keys.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C285C8B28398BC6008A31F1 /* Keys.swift */; };
 		4C285C8E28399BFE008A31F1 /* SaveKeysView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C285C8D28399BFD008A31F1 /* SaveKeysView.swift */; };
+		4C2CDDF7299D4A5E00879FD5 /* Debouncer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C2CDDF6299D4A5E00879FD5 /* Debouncer.swift */; };
 		4C363A8428233689006E126D /* Parser.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C363A8328233689006E126D /* Parser.swift */; };
 		4C363A8828236948006E126D /* BlocksView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C363A8728236948006E126D /* BlocksView.swift */; };
 		4C363A8A28236B57006E126D /* MentionView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C363A8928236B57006E126D /* MentionView.swift */; };
@@ -312,6 +313,7 @@
 		4C285C892838B985008A31F1 /* ProfilePictureSelector.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ProfilePictureSelector.swift; sourceTree = "<group>"; };
 		4C285C8B28398BC6008A31F1 /* Keys.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Keys.swift; sourceTree = "<group>"; };
 		4C285C8D28399BFD008A31F1 /* SaveKeysView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SaveKeysView.swift; sourceTree = "<group>"; };
+		4C2CDDF6299D4A5E00879FD5 /* Debouncer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Debouncer.swift; sourceTree = "<group>"; };
 		4C363A8328233689006E126D /* Parser.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Parser.swift; sourceTree = "<group>"; };
 		4C363A8728236948006E126D /* BlocksView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BlocksView.swift; sourceTree = "<group>"; };
 		4C363A8928236B57006E126D /* MentionView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MentionView.swift; sourceTree = "<group>"; };
@@ -780,6 +782,7 @@
 				4CB883A72975FC1800DC99E7 /* Zaps.swift */,
 				4CB883B5297730E400DC99E7 /* LNUrls.swift */,
 				3AB72AB8298ECF30004BB58C /* Translator.swift */,
+				4C2CDDF6299D4A5E00879FD5 /* Debouncer.swift */,
 			);
 			path = Util;
 			sourceTree = "<group>";
@@ -1342,6 +1345,7 @@
 				4CE879552996BAB900F758CC /* RelayPaidDetail.swift in Sources */,
 				4CF0ABD42980996B00D66079 /* Report.swift in Sources */,
 				4C06670B28FDE64700038D2A /* damus.c in Sources */,
+				4C2CDDF7299D4A5E00879FD5 /* Debouncer.swift in Sources */,
 				3AAA95CC298E07E900F3D526 /* DeepLPlan.swift in Sources */,
 				4FE60CDD295E1C5E00105A1F /* Wallet.swift in Sources */,
 				3AA247FF297E3D900090C62D /* RepostsView.swift in Sources */,

damus/Models/HomeModel.swift

@@ -38,6 +38,9 @@ class HomeModel: ObservableObject {
     var channels: [String: NostrEvent] = [:]
     var last_event_of_kind: [String: [Int: NostrEvent]] = [:]
     var done_init: Bool = false
+    var incoming_dms: [NostrEvent] = []
+    let dm_debouncer = Debouncer(interval: 0.5)
+    var should_debounce_dms = true
 
     let home_subid = UUID().description
     let contacts_subid = UUID().description
@@ -56,16 +59,25 @@ class HomeModel: ObservableObject {
     init() {
         self.damus_state = DamusState.empty
         self.dms = DirectMessagesModel(our_pubkey: damus_state.pubkey)
+        self.setup_debouncer()
     }
 
     init(damus_state: DamusState) {
         self.damus_state = damus_state
         self.dms = DirectMessagesModel(our_pubkey: damus_state.pubkey)
+        self.setup_debouncer()
     }
 
     var pool: RelayPool {
         return damus_state.pool
     }
+    
+    func setup_debouncer() {
+        // turn off debouncer after initial load
+        DispatchQueue.main.asyncAfter(deadline: .now() + 5.0) {
+            self.should_debounce_dms = false
+        }
+    }
 
     func has_sub_id_event(sub_id: String, ev_id: String) -> Bool {
         if !has_event.keys.contains(sub_id) {
@@ -303,7 +315,8 @@ class HomeModel: ObservableObject {
             case .eose(let sub_id):
                 
                 if sub_id == dms_subid {
-                    let dms = dms.dms.flatMap { $0.1.events }
+                    var dms = dms.dms.flatMap { $0.1.events }
+                    dms.append(contentsOf: incoming_dms)
                     load_profiles(profiles_subid: profiles_subid, relay_id: relay_id, events: dms, damus_state: damus_state)
                 } else if sub_id == notifications_subid {
                     load_profiles(profiles_subid: profiles_subid, relay_id: relay_id, events: notifications, damus_state: damus_state)
@@ -477,10 +490,28 @@ class HomeModel: ObservableObject {
             handle_notification(ev: ev)
         }
     }
-
+    
     func handle_dm(_ ev: NostrEvent) {
-        if let notifs = handle_incoming_dm(contacts: damus_state.contacts, prev_events: self.new_events, dms: self.dms, our_pubkey: self.damus_state.pubkey, ev: ev) {
+        guard should_show_event(contacts: damus_state.contacts, ev: ev) else {
-            self.new_events = notifs
+            return
+        }
+        
+        if !should_debounce_dms {
+            self.incoming_dms.append(ev)
+            if let notifs = handle_incoming_dms(contacts: self.damus_state.contacts, prev_events: self.new_events, dms: self.dms, our_pubkey: self.damus_state.pubkey, evs: self.incoming_dms) {
+                self.new_events = notifs
+            }
+            self.incoming_dms = []
+            return
+        }
+        
+        incoming_dms.append(ev)
+        
+        dm_debouncer.debounce {
+            if let notifs = handle_incoming_dms(contacts: self.damus_state.contacts, prev_events: self.new_events, dms: self.dms, our_pubkey: self.damus_state.pubkey, evs: self.incoming_dms) {
+                self.new_events = notifs
+            }
+            self.incoming_dms = []
         }
     }
 }
@@ -761,14 +792,10 @@ func fetch_relay_metadata(relay_id: String) async throws -> RelayMetadata? {
 func process_relay_metadata() {
 }
 
-func handle_incoming_dm(contacts: Contacts, prev_events: NewEventsBits, dms: DirectMessagesModel, our_pubkey: String, ev: NostrEvent) -> NewEventsBits? {
+func handle_incoming_dm(ev: NostrEvent, our_pubkey: String, dms: DirectMessagesModel, prev_events: NewEventsBits) -> (Bool, NewEventsBits?) {
-    // hide blocked users
-    guard should_show_event(contacts: contacts, ev: ev) else {
-        return prev_events
-    }
-    
     var inserted = false
     var found = false
+    
     let ours = ev.pubkey == our_pubkey
     var i = 0
 
@@ -795,15 +822,32 @@ func handle_incoming_dm(contacts: Contacts, prev_events: NewEventsBits, dms: Dir
     }
 
     if !found {
-        inserted = true
         let model = DirectMessageModel(events: [ev], our_pubkey: our_pubkey)
         dms.dms.append((the_pk, model))
     }
+    
+    var new_bits: NewEventsBits? = nil
+    if inserted {
+        new_bits = handle_last_events(new_events: prev_events, ev: ev, timeline: .dms, shouldNotify: !ours)
+    }
+    
+    return (inserted, new_bits)
+}
+
+func handle_incoming_dms(contacts: Contacts, prev_events: NewEventsBits, dms: DirectMessagesModel, our_pubkey: String, evs: [NostrEvent]) -> NewEventsBits? {
+    var inserted = false
 
     var new_events: NewEventsBits? = nil
+    
+    for ev in evs {
+        let res = handle_incoming_dm(ev: ev, our_pubkey: our_pubkey, dms: dms, prev_events: prev_events)
+        inserted = res.0 || inserted
+        if let new = res.1 {
+            new_events = new
+        }
+    }
+    
     if inserted {
-        new_events = handle_last_events(new_events: prev_events, ev: ev, timeline: .dms, shouldNotify: !ours)
-
         dms.dms = dms.dms.filter({ $0.1.events.count > 0 }).sorted { a, b in
             return a.1.events.last!.created_at > b.1.events.last!.created_at
         }