Add missing implementation to delete member's message on swarm (#815)

* Add missing implementation to delete member's message on swarm

* Add comment

app/src/main/java/org/thoughtcrime/securesms/attachments/DatabaseAttachmentProvider.kt

@@ -189,6 +189,18 @@ class DatabaseAttachmentProvider(context: Context, helper: SQLCipherOpenHelper)
         return messageDB.getMessageIDs(serverIds, threadId)
     }
 
+    override fun getUserMessageHashes(threadId: Long, userPubKey: String): List<String> {
+        val component = DatabaseComponent.get(context)
+        val messages = component.mmsSmsDatabase().getUserMessages(threadId, userPubKey)
+        val messageDatabase = component.lokiMessageDatabase()
+        return messages.mapNotNull {
+            messageDatabase.getMessageServerHash(
+                messageID = it.id,
+                mms = it.isMms
+            )
+        }
+    }
+
     override fun deleteMessage(messageID: Long, isSms: Boolean) {
         val messagingDatabase: MessagingDatabase = if (isSms)  DatabaseComponent.get(context).smsDatabase()
                                                    else DatabaseComponent.get(context).mmsDatabase()

app/src/main/java/org/thoughtcrime/securesms/groups/GroupManagerV2Impl.kt

@@ -1012,15 +1012,18 @@ class GroupManagerV2Impl @Inject constructor(
             }
         }
 
+        // Delete from swarm if we are admin
         val adminKey = configFactory.getGroup(groupId)?.adminKey
-        if (!senderIsVerifiedAdmin && adminKey != null && hashes.isNotEmpty()) {
-            // If the deletion request comes from a non-admin, and we as an admin, will also delete
-            // the content from the swarm, provided that the messages are actually sent by that user
-            if (storage.ensureMessageHashesAreSender(
-                    hashes.toSet(),
-                    sender.hexString,
-                    groupId.hexString
-                )
+        if (adminKey != null) {
+
+            // If hashes are given, these are the messages to delete. To be able to delete these
+            // messages from the swarm, the deletion request must be sent by an admin, or the messages
+            // belong to the requester.
+            if (hashes.isNotEmpty() && (
+                        senderIsVerifiedAdmin || storage.ensureMessageHashesAreSender(
+                            hashes = hashes.toSet(),
+                            sender = sender.hexString,
+                            closedGroupId = groupId.hexString))
             ) {
                 SnodeAPI.deleteMessage(
                     groupId.hexString,
@@ -1029,8 +1032,21 @@ class GroupManagerV2Impl @Inject constructor(
                 )
             }
 
-            // The non-admin user shouldn't be able to delete other user's messages so we will
-            // ignore the memberIds in the message
+            // If memberIds are given, all messages belong to these members will be deleted on the
+            // swarm. These requests must be sent by an admin.
+            if (memberIds.isNotEmpty() && senderIsVerifiedAdmin) {
+                val userMessageHashes = memberIds.flatMap { memberId ->
+                    messageDataProvider.getUserMessageHashes(threadId, memberId)
+                }
+
+                if (userMessageHashes.isNotEmpty()) {
+                    SnodeAPI.deleteMessage(
+                        groupId.hexString,
+                        OwnedSwarmAuth.ofClosedGroup(groupId, adminKey),
+                        userMessageHashes
+                    )
+                }
+            }
         }
     }
 

libsession/src/main/java/org/session/libsession/database/MessageDataProvider.kt

@@ -22,6 +22,7 @@ interface MessageDataProvider {
      */
     fun getMessageID(serverId: Long, threadId: Long): Pair<Long, Boolean>?
     fun getMessageIDs(serverIDs: List<Long>, threadID: Long): Pair<List<Long>, List<Long>>
+    fun getUserMessageHashes(threadId: Long, userPubKey: String): List<String>
     fun deleteMessage(messageID: Long, isSms: Boolean)
     fun deleteMessages(messageIDs: List<Long>, threadId: Long, isSms: Boolean)
     fun markMessageAsDeleted(timestamp: Long, author: String, displayedMessage: String)