determine if recipient identity change is unseen

// FREEBIE

src/Storage/AxolotlStore/TSStorageManager+IdentityKeyStore.h

@@ -40,6 +40,13 @@ extern NSString *const TSStorageManagerTrustedKeysCollection;
  */
 - (nullable OWSRecipientIdentity *)unconfirmedIdentityThatShouldBlockSendingForRecipientId:(NSString *)recipientId;
 
+/**
+ * @param   recipientId unique stable identifier for the recipient, e.g. e164 phone number
+ * @returns YES if the recipient's id has not been marked as seen (and it's not a TOFU situation)
+ *          NO if the recipient's current id has been seen, or if it's the users first key
+ */
+- (BOOL)hasUnseenIdentityChangeForRecipientId:(NSString *)recipientId;
+
 - (void)generateNewIdentityKey;
 - (nullable NSData *)identityKeyForRecipientId:(NSString *)recipientId;
 - (void)removeIdentityKeyForRecipient:(NSString *)receipientId;

src/Storage/AxolotlStore/TSStorageManager+IdentityKeyStore.m

@@ -278,6 +278,24 @@ const NSTimeInterval kIdentityKeyStoreNonBlockingSecondsThreshold = 5.0;
     }
 }
 
+
+- (BOOL)hasUnseenIdentityChangeForRecipientId:(NSString *)recipientId
+{
+    OWSAssert(recipientId != nil);
+
+    OWSRecipientIdentity *recipientIdentity = [OWSRecipientIdentity fetchObjectWithUniqueID:recipientId];
+
+    if (!recipientIdentity) {
+        return NO;
+    }
+
+    if (recipientIdentity.isFirstKnownKey) {
+        return NO;
+    }
+
+    return !recipientIdentity.wasSeen;
+}
+
 @end
 
 NS_ASSUME_NONNULL_END