add comments and minor refactor

SessionMessagingKit/Database/Models/DisappearingMessageConfiguration.swift

@@ -219,6 +219,7 @@ public extension DisappearingMessagesConfiguration {
 // MARK: - UI Constraints
 
 extension DisappearingMessagesConfiguration {
+    // TODO: Remove this when disappearing messages V2 is up and running
     public static var validDurationsSeconds: [TimeInterval] {
         return [
             5,

SessionMessagingKit/Messages/Control Messages/ExpirationTimerUpdate.swift

@@ -4,6 +4,7 @@ import Foundation
 import GRDB
 import SessionUtilitiesKit
 
+// TODO: Refactor this when disappearing messages V2 is up and running
 public final class ExpirationTimerUpdate: ControlMessage {
     private enum CodingKeys: String, CodingKey {
         case syncTarget

SessionMessagingKit/Sending & Receiving/Message Handling/MessageReceiver+ExpirationTimers.swift

@@ -5,6 +5,7 @@ import GRDB
 import SessionUtilitiesKit
 
 extension MessageReceiver {
+    // TODO: Remove this when disappearing messages V2 is up and running
     internal static func handleExpirationTimerUpdate(
         _ db: Database,
         threadId: String,

SessionMessagingKit/Sending & Receiving/MessageSender.swift

@@ -963,40 +963,45 @@ public final class MessageSender {
                         openGroupServerMessageId: message.openGroupServerMessageId.map { Int64($0) }
                     ).update(db)
                     
-                    if
-                        interaction.isExpiringMessage && isSyncMessage,
-                        let startedAtMs: Double = interaction.expiresStartedAtMs,
-                        let expiresInSeconds: TimeInterval = interaction.expiresInSeconds,
-                        let serverHash: String = message.serverHash
-                    {
-                        let expirationTimestampMs: Int64 = Int64(startedAtMs + expiresInSeconds * 1000)
-                        dependencies.jobRunner.add(
+                    if interaction.isExpiringMessage {
+                        // Start disappearing messages job after a message is successfully sent.
+                        // For DAR and DAS outgoing messages, the expiration start time are the
+                        // same as message sentTimestamp. So do this once, DAR and DAS messages
+                        // should all be covered.
+                        dependencies.jobRunner.upsert(
                             db,
-                            job: Job(
-                                variant: .expirationUpdate,
-                                behaviour: .runOnce,
-                                threadId: interaction.threadId,
-                                details: ExpirationUpdateJob.Details(
-                                    serverHashes: [serverHash],
-                                    expirationTimestampMs: expirationTimestampMs
-                                )
+                            job: DisappearingMessagesJob.updateNextRunIfNeeded(
+                                db,
+                                interaction: interaction,
+                                startedAtMs: Double(interaction.timestampMs)
                             ),
                             canStartJob: true,
                             using: dependencies
                         )
+                        
+                        if
+                            isSyncMessage,
+                            let startedAtMs: Double = interaction.expiresStartedAtMs,
+                            let expiresInSeconds: TimeInterval = interaction.expiresInSeconds,
+                            let serverHash: String = message.serverHash
+                        {
+                            let expirationTimestampMs: Int64 = Int64(startedAtMs + expiresInSeconds * 1000)
+                            dependencies.jobRunner.add(
+                                db,
+                                job: Job(
+                                    variant: .expirationUpdate,
+                                    behaviour: .runOnce,
+                                    threadId: interaction.threadId,
+                                    details: ExpirationUpdateJob.Details(
+                                        serverHashes: [serverHash],
+                                        expirationTimestampMs: expirationTimestampMs
+                                    )
+                                ),
+                                canStartJob: true,
+                                using: dependencies
+                            )
+                        }
                     }
-                    
-                    dependencies.jobRunner.upsert(
-                        db,
-                        job: DisappearingMessagesJob.updateNextRunIfNeeded(
-                            db,
-                            interaction: interaction,
-                            startedAtMs: Double(interaction.timestampMs)
-                        ),
-                        canStartJob: true,
-                        using: dependencies
-                    )
-                                            
                 }
                 
                 // Mark the message as sent