Create and use anyLocalOriCloudAccountHasAtLeastOneTwitterFeed in Acc…

…ountManager, so both iOS and Mac apps can use it. Also: simplify the Date comparison in presentTwitterDeprecationAlertIfRequired by using Dates instead of TimeInterval.

Account/Sources/Account/AccountManager.swift

@@ -351,6 +351,26 @@ public final class AccountManager: UnreadCountProvider {
 		return false
 	}
 
+    public func anyLocalOriCloudAccountHasAtLeastOneTwitterFeed() -> Bool {
+        // We removed our Twitter code, and the ability to read feeds from Twitter,
+        // when Twitter announced the end of the free tier for the Twitter API.
+        // We are cheering on Twitter’s increasing irrelevancy.
+
+        for account in accounts {
+            if account.type == .cloudKit || account.type == .onMyMac {
+                for webfeed in account.flattenedWebFeeds() {
+                    if let components = URLComponents(string: webfeed.url), let host = components.host {
+                        if host == "twitter.com" { // Allow, for instance, blog.twitter.com, which might have an actual RSS feed
+                            return true
+                        }
+                    }
+                }
+            }
+        }
+
+        return false
+    }
+
 	// MARK: - Fetching Articles
 
 	// These fetch articles from active accounts and return a merged Set<Article>.

iOS/MasterFeed/MasterFeedViewController.swift

@@ -717,28 +717,13 @@ class MasterFeedViewController: UITableViewController, UndoableCommandRunner {
 	private func presentTwitterDeprecationAlertIfRequired() {
 		if AppDefaults.shared.twitterDeprecationAlertShown { return }
 
-		let expiryDate = Date(timeIntervalSince1970: 1691539200).timeIntervalSince1970 // August 9th 2023, 00:00 UTC
-		let currentDate = Date().timeIntervalSince1970
+		let expiryDate = Date(timeIntervalSince1970: 1691539200) // August 9th 2023, 00:00 UTC
+		let currentDate = Date()
 		if currentDate > expiryDate {
 			return // If after August 9th, don't show
 		}
 
-		var twitterIsActive: Bool = false
-		AccountManager.shared.accounts.forEach({ account in
-			if account.type == .cloudKit || account.type == .onMyMac {
-				account.flattenedWebFeeds().forEach({ webfeed in
-					guard let components = URLComponents(string: webfeed.url),
-					   let host = components.host else {
-						return
-					}
-					if host == "twitter.com" {
-						twitterIsActive = true
-						return
-					}
-				})
-			}
-		})
-		if twitterIsActive {
+		if AccountManager.shared.anyLocalOriCloudAccountHasAtLeastOneTwitterFeed() {
 			showTwitterDeprecationAlert()
 		}
 		AppDefaults.shared.twitterDeprecationAlertShown = true
@@ -752,7 +737,6 @@ class MasterFeedViewController: UITableViewController, UndoableCommandRunner {
 		alert.addAction(UIAlertAction(title: "OK", style: .cancel))
 		present(alert, animated: true)
 	}
-
 }
 
 // MARK: UIContextMenuInteractionDelegate