From 50bc55e84bae8938a34867a83252ee323eb62562 Mon Sep 17 00:00:00 2001
From: Vitor Pamplona <vitor@vitorpamplona.com>
Date: Thu, 9 Feb 2023 17:52:18 -0500
Subject: [PATCH] More Performant UpdateFollows

---
 .../com/vitorpamplona/amethyst/model/Note.kt  | 13 ++--
 .../com/vitorpamplona/amethyst/model/User.kt  | 72 ++++++++++++++-----
 2 files changed, 64 insertions(+), 21 deletions(-)

diff --git a/app/src/main/java/com/vitorpamplona/amethyst/model/Note.kt b/app/src/main/java/com/vitorpamplona/amethyst/model/Note.kt
index 0494b7719..43e5579eb 100644
--- a/app/src/main/java/com/vitorpamplona/amethyst/model/Note.kt
+++ b/app/src/main/java/com/vitorpamplona/amethyst/model/Note.kt
@@ -17,6 +17,7 @@ import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
 import com.vitorpamplona.amethyst.service.relays.Relay
 import java.util.Date
+import java.util.concurrent.atomic.AtomicBoolean
 import java.util.regex.Matcher
 import java.util.regex.Pattern
 import nostr.postr.events.Event
@@ -194,17 +195,19 @@ class Note(val idHex: String) {
 
 class NoteLiveData(val note: Note): LiveData<NoteState>(NoteState(note)) {
     // Refreshes observers in batches.
-    var handlerWaiting = false
+    var handlerWaiting = AtomicBoolean()
+
     @Synchronized
     fun invalidateData() {
-        if (handlerWaiting) return
+        if (!hasActiveObservers()) return
+        if (handlerWaiting.getAndSet(true)) return
 
-        handlerWaiting = true
-        val scope = CoroutineScope(Job() + Dispatchers.Default)
+        handlerWaiting.set(true)
+        val scope = CoroutineScope(Job() + Dispatchers.Main)
         scope.launch {
             delay(100)
             refresh()
-            handlerWaiting = false
+            handlerWaiting.set(false)
         }
     }
 
diff --git a/app/src/main/java/com/vitorpamplona/amethyst/model/User.kt b/app/src/main/java/com/vitorpamplona/amethyst/model/User.kt
index 9faf41648..bb5fc3e9a 100644
--- a/app/src/main/java/com/vitorpamplona/amethyst/model/User.kt
+++ b/app/src/main/java/com/vitorpamplona/amethyst/model/User.kt
@@ -10,6 +10,9 @@ import com.vitorpamplona.amethyst.ui.note.toShortenHex
 import fr.acinq.secp256k1.Hex
 import java.util.Collections
 import java.util.concurrent.ConcurrentHashMap
+import java.util.concurrent.atomic.AtomicBoolean
+import kotlin.time.ExperimentalTime
+import kotlin.time.measureTimedValue
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
@@ -81,7 +84,11 @@ class User(val pubkeyHex: String) {
         liveFollows.invalidateData()
         user.liveFollows.invalidateData()
 
-        listeners.forEach {
+        updateSubscribers {
+            it.onFollowsChange()
+        }
+
+        user.updateSubscribers {
             it.onFollowsChange()
         }
     }
@@ -95,6 +102,40 @@ class User(val pubkeyHex: String) {
         updateSubscribers {
             it.onFollowsChange()
         }
+
+        user.updateSubscribers {
+            it.onFollowsChange()
+        }
+    }
+
+    fun follow(users: Set<User>, followedAt: Long) {
+        follows = follows + users
+        users.forEach {
+            it.followers = it.followers + this
+            it.liveFollows.invalidateData()
+            it.updateSubscribers {
+                it.onFollowsChange()
+            }
+        }
+
+        liveFollows.invalidateData()
+        updateSubscribers {
+            it.onFollowsChange()
+        }
+    }
+    fun unfollow(users: Set<User>) {
+        follows = follows - users
+        users.forEach {
+            it.followers = it.followers - this
+            it.liveFollows.invalidateData()
+            it.updateSubscribers {
+                it.onFollowsChange()
+            }
+        }
+        liveFollows.invalidateData()
+        updateSubscribers {
+            it.onFollowsChange()
+        }
     }
 
     fun addTaggedPost(note: Note) {
@@ -164,17 +205,13 @@ class User(val pubkeyHex: String) {
         updateSubscribers { it.onNewRelayInfo() }
         liveRelayInfo.invalidateData()
     }
-
+    
     fun updateFollows(newFollows: Set<User>, updateAt: Long) {
         val toBeAdded = newFollows - follows
         val toBeRemoved = follows - newFollows
 
-        toBeAdded.forEach {
-            follow(it, updateAt)
-        }
-        toBeRemoved.forEach {
-            unfollow(it)
-        }
+        follow(toBeAdded, updateAt)
+        unfollow(toBeRemoved)
 
         updatedFollowsAt = updateAt
     }
@@ -239,19 +276,20 @@ class User(val pubkeyHex: String) {
     }
 
     // Refreshes observers in batches.
-    var modelHandlerWaiting = false
+    var modelHandlerWaiting = AtomicBoolean()
+
     @Synchronized
     fun updateSubscribers(on: (Listener) -> Unit) {
-        if (modelHandlerWaiting) return
+        if (modelHandlerWaiting.getAndSet(true)) return
 
-        modelHandlerWaiting = true
+        modelHandlerWaiting.set(true)
         val scope = CoroutineScope(Job() + Dispatchers.Default)
         scope.launch {
             delay(100)
             listeners.forEach {
                 on(it)
             }
-            modelHandlerWaiting = false
+            modelHandlerWaiting.set(false)
         }
     }
 
@@ -292,17 +330,19 @@ class UserMetadata {
 class UserLiveData(val user: User): LiveData<UserState>(UserState(user)) {
 
     // Refreshes observers in batches.
-    var handlerWaiting = false
+    var handlerWaiting = AtomicBoolean()
+
     @Synchronized
     fun invalidateData() {
-        if (handlerWaiting) return
+        if (!hasActiveObservers()) return
+        if (handlerWaiting.getAndSet(true)) return
 
-        handlerWaiting = true
+        handlerWaiting.set(true)
         val scope = CoroutineScope(Job() + Dispatchers.Main)
         scope.launch {
             delay(100)
             refresh()
-            handlerWaiting = false
+            handlerWaiting.set(false)
         }
     }