From cffda791a80fe320d181a744ed0ea0dc79870514 Mon Sep 17 00:00:00 2001
From: Satindar Dhillon <satindar@gmail.com>
Date: Wed, 27 Apr 2022 11:54:03 -0700
Subject: [PATCH] convert newsletter email publisher to async

---
 .../Views/Profile/NewsletterEmailsView.swift  | 22 ++++-------
 .../Queries/NewsletterEmailsQuery.swift       | 38 +++++++++----------
 2 files changed, 25 insertions(+), 35 deletions(-)

diff --git a/apple/OmnivoreKit/Sources/App/Views/Profile/NewsletterEmailsView.swift b/apple/OmnivoreKit/Sources/App/Views/Profile/NewsletterEmailsView.swift
index dcd233a9e..c9f693d73 100644
--- a/apple/OmnivoreKit/Sources/App/Views/Profile/NewsletterEmailsView.swift
+++ b/apple/OmnivoreKit/Sources/App/Views/Profile/NewsletterEmailsView.swift
@@ -1,4 +1,3 @@
-import Combine
 import Models
 import Services
 import SwiftUI
@@ -8,21 +7,16 @@ import Views
   @Published var isLoading = false
   @Published var emails = [NewsletterEmail]()
 
-  var subscriptions = Set<AnyCancellable>()
-
-  func loadEmails(dataService: DataService) {
+  func loadEmails(dataService: DataService) async {
     isLoading = true
 
-    dataService.newsletterEmailsPublisher().sink(
-      receiveCompletion: { _ in },
-      receiveValue: { [weak self] objectIDs in
-        self?.isLoading = false
-        dataService.viewContext.perform {
-          self?.emails = objectIDs.compactMap { dataService.viewContext.object(with: $0) as? NewsletterEmail }
-        }
+    if let objectIDs = try? await dataService.newsletterEmails() {
+      await dataService.viewContext.perform { [weak self] in
+        self?.emails = objectIDs.compactMap { dataService.viewContext.object(with: $0) as? NewsletterEmail }
       }
-    )
-    .store(in: &subscriptions)
+    }
+
+    isLoading = false
   }
 
   func createEmail(dataService: DataService) async {
@@ -58,7 +52,7 @@ struct NewsletterEmailsView: View {
         .listStyle(InsetListStyle())
       #endif
     }
-    .task { viewModel.loadEmails(dataService: dataService) }
+    .task { await viewModel.loadEmails(dataService: dataService) }
   }
 
   private var innerBody: some View {
diff --git a/apple/OmnivoreKit/Sources/Services/DataService/Queries/NewsletterEmailsQuery.swift b/apple/OmnivoreKit/Sources/Services/DataService/Queries/NewsletterEmailsQuery.swift
index 1465c15e0..49545956c 100644
--- a/apple/OmnivoreKit/Sources/Services/DataService/Queries/NewsletterEmailsQuery.swift
+++ b/apple/OmnivoreKit/Sources/Services/DataService/Queries/NewsletterEmailsQuery.swift
@@ -1,11 +1,10 @@
-import Combine
 import CoreData
 import Foundation
 import Models
 import SwiftGraphQL
 
 public extension DataService {
-  func newsletterEmailsPublisher() -> AnyPublisher<[NSManagedObjectID], ServerError> {
+  func newsletterEmails() async throws -> [NSManagedObjectID] {
     enum QueryResult {
       case success(result: [InternalNewsletterEmail])
       case error(error: String)
@@ -36,29 +35,26 @@ public extension DataService {
 
     let path = appEnvironment.graphqlPath
     let headers = networker.defaultHeaders
+    let context = backgroundContext
 
-    return Deferred {
-      Future { promise in
-        send(query, to: path, headers: headers) { result in
-          switch result {
-          case let .success(payload):
-            switch payload.data {
-            case let .success(result: result):
-              if let newsletterEmailObjectIDs = result.persist(context: self.backgroundContext) {
-                promise(.success(newsletterEmailObjectIDs))
-              } else {
-                promise(.failure(.unknown))
-              }
-            case .error:
-              promise(.failure(.unknown))
-            }
-          case .failure:
-            promise(.failure(.unknown))
+    return try await withCheckedThrowingContinuation { continuation in
+      send(query, to: path, headers: headers) { queryResult in
+        guard let payload = try? queryResult.get() else {
+          continuation.resume(throwing: BasicError.message(messageText: "network request failed"))
+          return
+        }
+
+        switch payload.data {
+        case let .success(result: result):
+          if let newsletterEmailObjectIDs = result.persist(context: context) {
+            continuation.resume(returning: newsletterEmailObjectIDs)
+          } else {
+            continuation.resume(throwing: BasicError.message(messageText: "CoreData error"))
           }
+        case .error:
+          continuation.resume(throwing: BasicError.message(messageText: "Newsletter Email fetch error"))
         }
       }
     }
-    .receive(on: DispatchQueue.main)
-    .eraseToAnyPublisher()
   }
 }