Tweak biases of the message status logic.

// FREEBIE

Signal/src/ViewControllers/Utils/MessageRecipientStatusUtils.swift

@@ -13,6 +13,21 @@ import Foundation
     case failed
 }
 
+// Our per-recipient status messages are "biased towards success"
+// and reflect the most successful known state for that recipient.
+//
+// Our per-message status messages are "biased towards failure"
+// and reflect the least successful known state for that message.
+//
+// Why?
+//
+// When showing the per-recipient status, we want to show the message
+// as "read" even if delivery failed to another recipient of the same
+// message.
+//
+// When showing the per-message status, we want to show the message
+// as "failed" if delivery failed to any recipient, even if another 
+// receipient has read the message.
 class MessageRecipientStatusUtils: NSObject {
     // MARK: Initializers
 
@@ -20,6 +35,8 @@ class MessageRecipientStatusUtils: NSObject {
     private override init() {
     }
 
+    // This method is per-recipient and "biased towards success".
+    // See comments above.
     public class func recipientStatus(outgoingMessage: TSOutgoingMessage,
                                       recipientId: String,
                                       referenceView: UIView) -> MessageRecipientStatus {
@@ -29,6 +46,8 @@ class MessageRecipientStatusUtils: NSObject {
         return messageRecipientStatus
     }
 
+    // This method is per-recipient and "biased towards success".
+    // See comments above.
     public class func statusMessage(outgoingMessage: TSOutgoingMessage,
                                       recipientId: String,
                                       referenceView: UIView) -> String {
@@ -38,6 +57,8 @@ class MessageRecipientStatusUtils: NSObject {
         return statusMessage
     }
 
+    // This method is per-recipient and "biased towards success".  
+    // See comments above.
     public class func recipientStatusAndStatusMessage(outgoingMessage: TSOutgoingMessage,
                                                       recipientId: String,
                                                       referenceView: UIView) -> (MessageRecipientStatus, String) {
@@ -94,9 +115,27 @@ class MessageRecipientStatusUtils: NSObject {
         }
     }
 
+    // This method is per-message and "biased towards failure".
+    // See comments above.
     public class func statusMessage(outgoingMessage: TSOutgoingMessage,
                                     referenceView: UIView) -> String {
 
+        if outgoingMessage.messageState == .unsent {
+            return NSLocalizedString("MESSAGE_STATUS_FAILED", comment:"message footer for failed messages")
+        } else if outgoingMessage.messageState == .attemptingOut {
+            if outgoingMessage.hasAttachments() {
+                assert(outgoingMessage.messageState == .attemptingOut)
+
+                return NSLocalizedString("MESSAGE_STATUS_UPLOADING",
+                                         comment:"message footer while attachment is uploading")
+            } else {
+                assert(outgoingMessage.messageState == .attemptingOut)
+
+                return NSLocalizedString("MESSAGE_STATUS_SENDING",
+                                         comment:"message status while message is sending.")
+            }
+        }
+
         let recipientReadMap = outgoingMessage.recipientReadMap
         if recipientReadMap.count > 0 {
             assert(outgoingMessage.messageState == .sentToService)
@@ -115,28 +154,29 @@ class MessageRecipientStatusUtils: NSObject {
                                                   comment:"message status for message delivered to their recipient.")
         }
 
-        if outgoingMessage.messageState == .unsent {
-            return NSLocalizedString("MESSAGE_STATUS_FAILED", comment:"message footer for failed messages")
-        } else if outgoingMessage.messageState == .sentToService {
-            return NSLocalizedString("MESSAGE_STATUS_SENT",
-                                  comment:"message footer for sent messages")
-        } else if outgoingMessage.hasAttachments() {
-            assert(outgoingMessage.messageState == .attemptingOut)
-
-            return NSLocalizedString("MESSAGE_STATUS_UPLOADING",
-                                                  comment:"message footer while attachment is uploading")
-        } else {
-            assert(outgoingMessage.messageState == .attemptingOut)
-
-            return NSLocalizedString("MESSAGE_STATUS_SENDING",
-                                                  comment:"message status while message is sending.")
-        }
+        return NSLocalizedString("MESSAGE_STATUS_SENT",
+                                 comment:"message footer for sent messages")
     }
 
+    // This method is per-message and "biased towards failure".
+    // See comments above.
     public class func recipientStatus(outgoingMessage: TSOutgoingMessage) -> MessageRecipientStatus {
+        if outgoingMessage.messageState == .unsent {
+            return .failed
+        } else if outgoingMessage.messageState == .attemptingOut {
+            if outgoingMessage.hasAttachments() {
+                assert(outgoingMessage.messageState == .attemptingOut)
+                return .uploading
+            } else {
+                assert(outgoingMessage.messageState == .attemptingOut)
+                return .sending
+            }
+        }
+
+        assert(outgoingMessage.messageState == .sentToService)
+
         let recipientReadMap = outgoingMessage.recipientReadMap
         if recipientReadMap.count > 0 {
-            assert(outgoingMessage.messageState == .sentToService)
             return .read
         }
 
@@ -149,16 +189,6 @@ class MessageRecipientStatusUtils: NSObject {
             return .delivered
         }
 
-        if outgoingMessage.messageState == .unsent {
-            return .failed
-        } else if outgoingMessage.messageState == .sentToService {
-            return .sent
-        } else if outgoingMessage.hasAttachments() {
-            assert(outgoingMessage.messageState == .attemptingOut)
-            return .uploading
-        } else {
-            assert(outgoingMessage.messageState == .attemptingOut)
-            return .sending
-        }
+        return .sent
     }
 }