From 90f9a0bcf57cd7508d5971dbbbecaf761ee29d71 Mon Sep 17 00:00:00 2001
From: "Hedden, Kyle Matthew" <kyle.hedden@verizonwireless.com>
Date: Wed, 3 Jul 2024 18:39:28 -0400
Subject: [PATCH] Digital PCT265 defect CXTDT-579050: Code simplification and
 fixes of combine pipeline for page updates.

---
 .../Atomic/Organisms/Carousel/Carousel.swift  | 11 ++++++++
 .../BaseControllers/ViewController.swift      | 26 +++++++------------
 2 files changed, 20 insertions(+), 17 deletions(-)

diff --git a/MVMCoreUI/Atomic/Organisms/Carousel/Carousel.swift b/MVMCoreUI/Atomic/Organisms/Carousel/Carousel.swift
index fc79b5bd..84124880 100644
--- a/MVMCoreUI/Atomic/Organisms/Carousel/Carousel.swift
+++ b/MVMCoreUI/Atomic/Organisms/Carousel/Carousel.swift
@@ -285,6 +285,17 @@ open class Carousel: View {
     /// Registers the cells with the collection view
     func registerCells(with carouselModel: CarouselModel, delegateObject: MVMCoreUIDelegateObject?) {
         
+        for molecule in carouselModel.molecules {
+            if let info = getMoleculeInfo(with: molecule, delegateObject: delegateObject) {
+                collectionView.register(info.class, forCellWithReuseIdentifier: info.identifier)
+            }
+        }
+        let moleculeInfo = carouselModel.molecules.map {
+            getMoleculeInfo(with: $0, delegateObject: delegateObject)
+        }
+        // For each molecule with info, register it.
+        moleculeInfo.compactMap({ $0 }).forEach { collectionView.register($0.class, forCellWithReuseIdentifier: $0.identifier) }
+        
         for molecule in carouselModel.molecules {
             if let info = getMoleculeInfo(with: molecule, delegateObject: delegateObject) {
                 collectionView.register(info.class, forCellWithReuseIdentifier: info.identifier)
diff --git a/MVMCoreUI/BaseControllers/ViewController.swift b/MVMCoreUI/BaseControllers/ViewController.swift
index 950b330e..a6c43b2d 100644
--- a/MVMCoreUI/BaseControllers/ViewController.swift
+++ b/MVMCoreUI/BaseControllers/ViewController.swift
@@ -69,27 +69,16 @@ import Combine
         
         observingForResponses = NotificationCenter.default.publisher(for: NSNotification.Name(rawValue: NotificationResponseLoaded))
             .receive(on: self.pageUpdateQueue) // Background serial queue.
-            .map { [weak self] notification in
-                self?.pullUpdates(from: notification) ?? (nil, nil, nil)
-            }
-            .filter { (pageUpdates: [String : Any]?, pageModel: PageModelProtocol?, moduleUpdates: [String : Any]?) in
-                // Skip any non-updates.
-                (pageUpdates != nil && pageModel != nil) || (moduleUpdates != nil && moduleUpdates!.count > 0)
+            .compactMap { [weak self] notification in
+                self?.pullUpdates(from: notification) ?? nil
             }
             // Merge all page and module updates into one update event.
-            //.print("[Update pipe] merging")
             .scan((nil, nil, nil)) { accumulator, next in
                 // Always take the latest page and the latest modules with same key.
-                return (next.0, next.1, next.2?.mergingRight(accumulator.2 ?? [:]))
+                return (next.0 ?? accumulator.0, next.1 ?? accumulator.1, next.2?.mergingRight(accumulator.2 ?? [:]))
             }
-            //.print("[Update pipe] into buffer")
-            // Hold onto the latest merged state until UI is ready for an update. Keep only the latest from scan.
-            .buffer(size: 1, prefetch: .byRequest, whenFull: .dropOldest)
-            //.print("[Update pipe] out of buffer")
             // Delay allowing the previous model update to settle before triggering a re-render.
-            .flatMap(maxPublishers: .max(1)) { buffer in
-                Just(buffer).delay(for: .seconds(0.1), scheduler: RunLoop.main)
-            }
+            .throttle(for: .seconds(0.05), scheduler: RunLoop.main, latest: true)
             .sink { [weak self] (pageUpdates: [String : Any]?, pageModel: PageModelProtocol?, moduleUpdates: [String : Any]?) in
                 guard let self = self else { return }
                 if let pageUpdates, pageModel != nil {
@@ -108,7 +97,7 @@ import Combine
         self.observingForResponses = nil
     }
     
-    func pullUpdates(from notification: Notification) -> (pageUpdates: [String : Any]?, pageModel: PageModelProtocol?, moduleUpdates: [String : Any]?) {
+    func pullUpdates(from notification: Notification) -> (pageUpdates: [String : Any]?, pageModel: PageModelProtocol?, moduleUpdates: [String : Any]?)? {
        // Get the page data.
        let pageUpdates = extractInterestedPageType(from: notification.userInfo?.optionalDictionaryForKey(KeyPageMap) ?? [:])
        // Convert the page data into a new model.
@@ -125,7 +114,10 @@ import Combine
        }
        // Get the module data.
        let moduleUpdates = extractInterestedModules(from: notification.userInfo?.optionalDictionaryForKey(KeyModuleMap) ?? [:])
-        debugLog("Receiving page \(pageModel?.pageType ?? "none") & \(moduleUpdates?.keys.description ?? "none") modules from  \((notification.userInfo?["MVMCoreLoadObject"] as? MVMCoreLoadObject)?.requestParameters?.url?.absoluteString ?? "")")
+       debugLog("Receiving page \(pageModel?.pageType ?? "none") & \(moduleUpdates?.keys.description ?? "none") modules from  \((notification.userInfo?["MVMCoreLoadObject"] as? MVMCoreLoadObject)?.requestParameters?.url?.absoluteString ?? "")")
+        
+       guard (pageUpdates != nil && pageModel != nil) || (moduleUpdates != nil && moduleUpdates!.count > 0) else { return nil }
+        
        // Bundle the transformations.
        return (pageUpdates, pageModel, moduleUpdates)
     }