From d4c560d7fc22f2e680d7df1353b76ba6e3c591e5 Mon Sep 17 00:00:00 2001
From: Shadowfacts <me@shadowfacts.net>
Date: Sun, 1 Jan 2023 12:58:44 -0500
Subject: [PATCH] Add createdAt to AccountPreferences and TimelinePosition to
 guard against race conditions when creating/migrating

---
 Tusker/API/MastodonController.swift           | 24 ++++++++++++++-----
 Tusker/CoreData/AccountPreferences.swift      |  3 +++
 Tusker/CoreData/TimelinePosition.swift        |  3 +++
 .../Tusker.xcdatamodel/contents               |  4 +++-
 4 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/Tusker/API/MastodonController.swift b/Tusker/API/MastodonController.swift
index 4af44b46..9dfbd0e6 100644
--- a/Tusker/API/MastodonController.swift
+++ b/Tusker/API/MastodonController.swift
@@ -155,12 +155,14 @@ class MastodonController: ObservableObject {
         // are available when Filterers are constructed
         loadCachedFilters()
         
-        if let existing = try? persistentContainer.viewContext.fetch(AccountPreferences.fetchRequest(account: accountInfo!)).first {
-            accountPreferences = existing
-        } else {
-            accountPreferences = AccountPreferences.default(account: accountInfo!, context: persistentContainer.viewContext)
-            persistentContainer.save(context: persistentContainer.viewContext)
-        }
+        loadAccountPreferences()
+        
+        NotificationCenter.default.publisher(for: .NSPersistentStoreRemoteChange, object: persistentContainer.persistentStoreCoordinator)
+            .receive(on: DispatchQueue.main)
+            .sink { [unowned self] _ in
+                self.loadAccountPreferences()
+            }
+            .store(in: &cancellables)
         
         Task {
             do {
@@ -177,6 +179,16 @@ class MastodonController: ObservableObject {
         }
     }
     
+    @MainActor
+    private func loadAccountPreferences() {
+        if let existing = try? persistentContainer.viewContext.fetch(AccountPreferences.fetchRequest(account: accountInfo!)).first {
+            accountPreferences = existing
+        } else {
+            accountPreferences = AccountPreferences.default(account: accountInfo!, context: persistentContainer.viewContext)
+            persistentContainer.save(context: persistentContainer.viewContext)
+        }
+    }
+    
     func getOwnAccount(completion: ((Result<Account, Client.Error>) -> Void)? = nil) {
         if account != nil {
             completion?(.success(account))
diff --git a/Tusker/CoreData/AccountPreferences.swift b/Tusker/CoreData/AccountPreferences.swift
index ebce929c..2f648380 100644
--- a/Tusker/CoreData/AccountPreferences.swift
+++ b/Tusker/CoreData/AccountPreferences.swift
@@ -16,10 +16,12 @@ public final class AccountPreferences: NSManagedObject {
     @nonobjc class func fetchRequest(account: LocalData.UserAccountInfo) -> NSFetchRequest<AccountPreferences> {
         let req = NSFetchRequest<AccountPreferences>(entityName: "AccountPreferences")
         req.predicate = NSPredicate(format: "accountID = %@", account.id)
+        req.sortDescriptors = [NSSortDescriptor(key: "createdAt", ascending: true)]
         return req
     }
     
     @NSManaged public var accountID: String
+    @NSManaged var createdAt: Date
     @NSManaged var pinnedTimelinesData: Data?
     
     @LazilyDecoding(from: \AccountPreferences.pinnedTimelinesData, fallback: [])
@@ -28,6 +30,7 @@ public final class AccountPreferences: NSManagedObject {
     static func `default`(account: LocalData.UserAccountInfo, context: NSManagedObjectContext) -> AccountPreferences {
         let prefs = AccountPreferences(context: context)
         prefs.accountID = account.id
+        prefs.createdAt = Date()
         prefs.pinnedTimelines = [.home, .public(local: true), .public(local: false)]
         return prefs
     }
diff --git a/Tusker/CoreData/TimelinePosition.swift b/Tusker/CoreData/TimelinePosition.swift
index a4756dd6..d093c114 100644
--- a/Tusker/CoreData/TimelinePosition.swift
+++ b/Tusker/CoreData/TimelinePosition.swift
@@ -16,10 +16,12 @@ public final class TimelinePosition: NSManagedObject {
     @nonobjc class func fetchRequest(timeline: Timeline, account: LocalData.UserAccountInfo) -> NSFetchRequest<TimelinePosition> {
         let req = NSFetchRequest<TimelinePosition>(entityName: "TimelinePosition")
         req.predicate = NSPredicate(format: "accountID = %@ AND timelineKind = %@", account.id, toTimelineKind(timeline))
+        req.sortDescriptors = [NSSortDescriptor(key: "createdAt", ascending: true)]
         return req
     }
     
     @NSManaged public var accountID: String
+    @NSManaged public var createdAt: Date
     @NSManaged private var timelineKind: String
     @NSManaged public var centerStatusID: String?
     @NSManaged private var statusIDsData: Data?
@@ -36,6 +38,7 @@ public final class TimelinePosition: NSManagedObject {
         self.init(context: context)
         self.timeline = timeline
         self.accountID = account.id
+        self.createdAt = Date()
     }
     
 }
diff --git a/Tusker/CoreData/Tusker.xcdatamodeld/Tusker.xcdatamodel/contents b/Tusker/CoreData/Tusker.xcdatamodeld/Tusker.xcdatamodel/contents
index a3e87bf8..e2fe0656 100644
--- a/Tusker/CoreData/Tusker.xcdatamodeld/Tusker.xcdatamodel/contents
+++ b/Tusker/CoreData/Tusker.xcdatamodeld/Tusker.xcdatamodel/contents
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<model type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="21513" systemVersion="22A380" minimumToolsVersion="Automatic" sourceLanguage="Swift" userDefinedModelVersionIdentifier="">
+<model type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="21513" systemVersion="22C65" minimumToolsVersion="Automatic" sourceLanguage="Swift" userDefinedModelVersionIdentifier="">
     <entity name="Account" representedClassName="AccountMO" syncable="YES">
         <attribute name="acct" attributeType="String"/>
         <attribute name="avatar" optional="YES" attributeType="URI"/>
@@ -30,6 +30,7 @@
     </entity>
     <entity name="AccountPreferences" representedClassName="AccountPreferences" syncable="YES">
         <attribute name="accountID" optional="YES" attributeType="String"/>
+        <attribute name="createdAt" optional="YES" attributeType="Date" usesScalarValueType="NO"/>
         <attribute name="pinnedTimelinesData" optional="YES" attributeType="Binary"/>
     </entity>
     <entity name="Filter" representedClassName="FilterMO" syncable="YES">
@@ -120,6 +121,7 @@
     <entity name="TimelinePosition" representedClassName="TimelinePosition" syncable="YES">
         <attribute name="accountID" optional="YES" attributeType="String"/>
         <attribute name="centerStatusID" optional="YES" attributeType="String"/>
+        <attribute name="createdAt" optional="YES" attributeType="Date" usesScalarValueType="NO"/>
         <attribute name="statusIDsData" optional="YES" attributeType="Binary" valueTransformerName="TimelinePositionStatusIDsTransformer"/>
         <attribute name="timelineKind" optional="YES" attributeType="String"/>
     </entity>