retry attachments downloads failed in NSE when user goes to corresponding conversation

Signal/src/ViewControllers/ConversationView/ConversationViewModel.m

@@ -1235,6 +1235,18 @@ static const int kYapDatabaseRangeMaxLength = 25000;
               OWSAssertDebug(!viewItemCache[interaction.uniqueId]);
               viewItemCache[interaction.uniqueId] = viewItem;
               [viewItems addObject:viewItem];
+              TSMessage *message = (TSMessage *)viewItem.interaction;
+              if (message.hasAttachmentsInNSE) {
+                  [SSKEnvironment.shared.attachmentDownloads downloadAttachmentsForMessage:message
+                      transaction:transaction
+                      success:^(NSArray<TSAttachmentStream *> *attachmentStreams) {
+                          OWSLogInfo(@"Successfully redownloaded attachment in thread: %@", message.thread);
+                      }
+                      failure:^(NSError *error) {
+                          OWSLogWarn(@"Failed to redownload message with error: %@", error);
+                      }];
+              }
+              
 
               return viewItem;
           };

SignalServiceKit/src/Messages/Attachments/OWSAttachmentDownloads.m

@@ -290,6 +290,13 @@ typedef void (^AttachmentDownloadFailure)(NSError *error);
             [job.attachmentPointer saveWithTransaction:transaction];
 
             if (job.message) {
+                if (!CurrentAppContext().isMainApp) {
+                    job.message.hasAttachmentsInNSE = true;
+                } else {
+                    job.message.hasAttachmentsInNSE = false;
+                }
+                
+                [job.message saveWithTransaction:transaction];
                 [job.message touchWithTransaction:transaction];
             }
         }];

SignalServiceKit/src/Messages/Interactions/TSMessage.h

@@ -34,6 +34,8 @@ NS_ASSUME_NONNULL_BEGIN
 // Open groups
 @property (nonatomic) uint64_t openGroupServerMessageID;
 @property (nonatomic, readonly) BOOL isOpenGroupMessage;
+// Attachments in NSE
+@property (nonatomic) BOOL hasAttachmentsInNSE;
 
 - (instancetype)initInteractionWithTimestamp:(uint64_t)timestamp inThread:(TSThread *)thread NS_UNAVAILABLE;
 

SignalServiceKit/src/Messages/OWSFailedAttachmentDownloadsJob.m

@@ -3,6 +3,8 @@
 //
 
 #import "OWSFailedAttachmentDownloadsJob.h"
+#import "SSKEnvironment.h"
+#import "OWSAttachmentDownloads.h"
 #import "OWSPrimaryStorage.h"
 #import "TSAttachmentPointer.h"
 #import <YapDatabase/YapDatabase.h>
@@ -25,6 +27,12 @@ static NSString *const OWSFailedAttachmentDownloadsJobAttachmentStateIndex = @"i
 
 @implementation OWSFailedAttachmentDownloadsJob
 
+- (OWSAttachmentDownloads *)attachmentDownloads
+{
+    return SSKEnvironment.shared.attachmentDownloads;
+}
+
+
 - (instancetype)initWithPrimaryStorage:(OWSPrimaryStorage *)primaryStorage
 {
     self = [super init];