Add “received at” timestamp to all TSMessages so that they may be sorted properly.

// FREEBIE

src/Contacts/TSThread.m

@@ -248,9 +248,11 @@ NS_ASSUME_NONNULL_BEGIN
 - (void)updateWithLastMessage:(TSInteraction *)lastMessage transaction:(YapDatabaseReadWriteTransaction *)transaction {
     NSDate *lastMessageDate = lastMessage.date;
 
-    if ([lastMessage isKindOfClass:[TSIncomingMessage class]]) {
-        TSIncomingMessage *message = (TSIncomingMessage *)lastMessage;
-        lastMessageDate            = message.receivedAt;
+    if ([lastMessage isKindOfClass:[TSMessage class]]) {
+        TSMessage *message = (TSMessage *)lastMessage;
+        if ([message bestReceivedAtDate]) {
+            lastMessageDate = [message bestReceivedAtDate];
+        }
     }
 
     if (!_lastMessageDate || [lastMessageDate timeIntervalSinceDate:self.lastMessageDate] > 0) {

src/Messages/Interactions/TSIncomingMessage.h

@@ -121,6 +121,12 @@ extern NSString *const TSIncomingMessageWasReadOnThisDeviceNotification;
 
 @property (nonatomic, readonly) NSString *authorId;
 @property (nonatomic, readonly, getter=wasRead) BOOL read;
+// _DO NOT_ access this property directly.  You almost certainly
+// want to use bestReceivedAtDate instead.
+//
+// This property has been superceded by TSMessage.receivedAtData.
+// This property only exists for backwards compatability with messages
+// received before TSMessage.receivedAtData was added.
 @property (nonatomic, readonly) NSDate *receivedAt;
 
 /*

src/Messages/Interactions/TSIncomingMessage.m

@@ -61,7 +61,8 @@ NSString *const TSIncomingMessageWasReadOnThisDeviceNotification = @"TSIncomingM
 
     _authorId = authorId;
     _read = NO;
-    _receivedAt = [NSDate date];
+
+    OWSAssert(self.receivedAtDate);
 
     return self;
 }
@@ -134,6 +135,18 @@ NSString *const TSIncomingMessageWasReadOnThisDeviceNotification = @"TSIncomingM
     [self touchThreadWithTransaction:transaction];
 }
 
+- (nullable NSDate *)bestReceivedAtDate
+{
+    NSDate *result = [super bestReceivedAtDate];
+    if (!result) {
+        // For backward compatibility with messages received before
+        // TSMessage.receivedAtData was added, honor TSIncomingMessage.receivedAt
+        // if TSMessage.receivedAtData is not set.
+        result = self.receivedAt;
+    }
+    return result;
+}
+
 #pragma mark - Logging
 
 + (NSString *)tag

src/Messages/Interactions/TSMessage.h

@@ -1,5 +1,6 @@
-//  Created by Frederic Jacobs on 12/11/14.
-//  Copyright (c) 2014 Open Whisper Systems. All rights reserved.
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 #import "TSInteraction.h"
 
@@ -29,6 +30,9 @@ typedef NS_ENUM(NSInteger, TSGroupMetaMessage) {
 @property (nonatomic, readonly) uint64_t expiresAt;
 @property (nonatomic, readonly) BOOL isExpiringMessage;
 @property (nonatomic, readonly) BOOL shouldStartExpireTimer;
+// _DO NOT_ access this property directly.  You almost certainly
+// want to use bestReceivedAtDate instead.
+@property (nonatomic, readonly) NSDate *receivedAtDate;
 
 - (instancetype)initWithTimestamp:(uint64_t)timestamp;
 
@@ -60,6 +64,11 @@ typedef NS_ENUM(NSInteger, TSGroupMetaMessage) {
 
 - (BOOL)hasAttachments;
 
+// This message should return TSMessage.receivedAtDate for most messages.
+// For messages received before TSMessage.receivedAtDate was added, this
+// will try to return TSIncomingMessage.receivedAt.
+- (nullable NSDate *)bestReceivedAtDate;
+
 @end
 
 NS_ASSUME_NONNULL_END

src/Messages/Interactions/TSMessage.m

@@ -102,6 +102,7 @@ static const NSUInteger OWSMessageSchemaVersion = 3;
     _expiresInSeconds = expiresInSeconds;
     _expireStartedAt = expireStartedAt;
     [self updateExpiresAt];
+    _receivedAtDate = [NSDate date];
 
     return self;
 }
@@ -132,6 +133,10 @@ static const NSUInteger OWSMessageSchemaVersion = 3;
     }
 
     _schemaVersion = OWSMessageSchemaVersion;
+
+    // We _DO NOT_ set _receivedAt_ in this constructor.  We don't want to
+    // set the receivedAt time for old messages in the data store.
+
     return self;
 }
 
@@ -215,6 +220,11 @@ static const NSUInteger OWSMessageSchemaVersion = 3;
     return self.expiresInSeconds > 0;
 }
 
+- (nullable NSDate *)bestReceivedAtDate
+{
+    return self.receivedAtDate;
+}
+
 @end
 
 NS_ASSUME_NONNULL_END

src/Messages/Interactions/TSOutgoingMessage.h

@@ -1,5 +1,6 @@
-//  Created by Frederic Jacobs on 15/11/14.
-//  Copyright (c) 2014 Open Whisper Systems. All rights reserved.
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 #import "TSMessage.h"
 

src/Messages/Interactions/TSOutgoingMessage.m

@@ -1,5 +1,6 @@
-//  Created by Frederic Jacobs on 15/11/14.
-//  Copyright (c) 2014 Open Whisper Systems. All rights reserved.
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 #import "TSOutgoingMessage.h"
 #import "NSDate+millisecondTimeStamp.h"
@@ -86,6 +87,8 @@ NS_ASSUME_NONNULL_BEGIN
         self.groupMetaMessage = TSGroupMessageNone;
     }
 
+    OWSAssert(self.receivedAtDate);
+
     return self;
 }
 

src/Storage/TSDatabaseView.m

@@ -9,6 +9,7 @@
 #import "OWSDevice.h"
 #import "OWSReadTracking.h"
 #import "TSIncomingMessage.h"
+#import "TSOutgoingMessage.h"
 #import "TSStorageManager.h"
 #import "TSThread.h"
 
@@ -265,11 +266,10 @@ NSString *TSSecondaryDevicesDatabaseViewExtensionName = @"TSSecondaryDevicesData
 + (NSDate *)localTimeReceiveDateForInteraction:(TSInteraction *)interaction {
     NSDate *interactionDate = interaction.date;
 
-    if ([interaction isKindOfClass:[TSIncomingMessage class]]) {
-        TSIncomingMessage *message = (TSIncomingMessage *)interaction;
-
-        if (message.receivedAt) {
-            interactionDate = message.receivedAt;
+    if ([interaction isKindOfClass:[TSMessage class]]) {
+        TSMessage *message = (TSMessage *)interaction;
+        if ([message bestReceivedAtDate]) {
+            interactionDate = [message bestReceivedAtDate];
         }
     }