From 1439e29d64066d64a33600355b335309c607f3bd Mon Sep 17 00:00:00 2001
From: Duong Thai <dvthai.dev@gmail.com>
Date: Fri, 15 Mar 2024 10:41:43 +0700
Subject: [PATCH] fix: concurrency code for RSSTools

---
 Packages/RSS/Sources/RSS/RSSTools.swift       | 32 ++++++++++++++-----
 .../RSS/Sources/RSS/Views/RSSAddNewFeed.swift | 10 ++++--
 2 files changed, 31 insertions(+), 11 deletions(-)

diff --git a/Packages/RSS/Sources/RSS/RSSTools.swift b/Packages/RSS/Sources/RSS/RSSTools.swift
index 2b705264..fbeb1e55 100644
--- a/Packages/RSS/Sources/RSS/RSSTools.swift
+++ b/Packages/RSS/Sources/RSS/RSSTools.swift
@@ -191,7 +191,7 @@ enum RSSTools {
   }
 
   @MainActor
-  static func load(feedURL: URL) async -> RSSFeed? {
+  static func load(feedURL: URL) async -> Void? {
     let sendableFeed = await Task.detached {
       await RSSTools.getFeedData(from: feedURL)
     }.value
@@ -203,15 +203,31 @@ enum RSSTools {
       await sendableFeed.getSendableItemData()
     }.value
 
-    return await backgroundContext.perform {
-      let rssFeed = RSSFeed(context: backgroundContext, sendableData: sendableFeed)
+    let rssFeed = RSSFeed(context: backgroundContext, sendableData: sendableFeed)
 
-      let rssItems = sendableItems.compactMap {
-        RSSItem(context: backgroundContext, sendableData: $0)
-      }
-      rssFeed.items = NSSet(array: rssItems)
-      return rssFeed
+    let rssItems = sendableItems.compactMap {
+      RSSItem(context: backgroundContext, sendableData: $0)
     }
+    for item in rssItems { item.feed = rssFeed }
+
+    return try? backgroundContext.save()
+  }
+
+  @MainActor
+  static func fetchFeed(url: URL) async -> RSSFeed? {
+    let request: NSFetchRequest<RSSFeed> = {
+      let request = RSSFeed.fetchRequest()
+      request.fetchLimit = 1
+      request.predicate = NSPredicate(format: "%K = %@",
+                                      #keyPath(RSSFeed.feedURL),
+                                      url as CVarArg)
+      request.relationshipKeyPathsForPrefetching = ["items"]
+      return request
+    }()
+
+    let context = RSSDataController.shared.viewContext
+    guard let feed = (try? context.fetch(request))?.first else { return nil }
+    return feed
   }
 
   @MainActor
diff --git a/Packages/RSS/Sources/RSS/Views/RSSAddNewFeed.swift b/Packages/RSS/Sources/RSS/Views/RSSAddNewFeed.swift
index 001d3bfa..f645325c 100644
--- a/Packages/RSS/Sources/RSS/Views/RSSAddNewFeed.swift
+++ b/Packages/RSS/Sources/RSS/Views/RSSAddNewFeed.swift
@@ -66,10 +66,14 @@ public struct RSSAddNewFeed: View {
           feed?.managedObjectContext?.rollback()
 
           downloadingTask = Task {
-            let rssFeed = await RSSTools.load(feedURL: url)
+            guard let _ = await RSSTools.load(feedURL: url),
+                  let rssFeed = await RSSTools.fetchFeed(url: url)
+            else {
+              self.state = .noData(url: url)
+              return
+            }
             if Task.isCancelled { return }
-            if let rssFeed { self.state = .downloaded(feed: rssFeed, url: url) }
-            else { self.state = .noData(url: url) }
+            self.state = .downloaded(feed: rssFeed, url: url)
           }
         case .downloaded(let feed, _):
           self.feed = feed