From 4ef8428151bdf28a8f96c63e3c2353520b91bf79 Mon Sep 17 00:00:00 2001
From: Brandon Evans <brandon@brandonevans.ca>
Date: Thu, 24 Dec 2020 11:08:13 -0700
Subject: [PATCH 1/9] Convert XcodeList to Combine

---
 Xcodes/Backend/AppState.swift    | 22 ++++-------
 Xcodes/Backend/Environment.swift |  8 ++--
 Xcodes/Backend/XcodeList.swift   | 67 ++++++++++++++++----------------
 3 files changed, 45 insertions(+), 52 deletions(-)

diff --git a/Xcodes/Backend/AppState.swift b/Xcodes/Backend/AppState.swift
index a554e15..3aac23c 100644
--- a/Xcodes/Backend/AppState.swift
+++ b/Xcodes/Backend/AppState.swift
@@ -2,7 +2,6 @@ import AppKit
 import AppleAPI
 import Combine
 import Path
-import PromiseKit
 import LegibleError
 import KeychainAccess
 
@@ -173,22 +172,15 @@ class AppState: ObservableObject {
     public func update() -> AnyPublisher<[Xcode], Never> {
         signInIfNeeded()
             .flatMap {
-                // Wrap the Promise API in a Publisher for now
-                Deferred {
-                    Future { promise in
-                        self.list.update()
-                            .done { promise(.success($0)) }
-                            .catch { promise(.failure($0)) }                
+                self.list.update()
+            }
+            .handleEvents(
+                receiveCompletion: { completion in
+                    if case let .failure(error) = completion {
+                        self.error = AlertContent(title: "Update Error", message: error.legibleLocalizedDescription)
                     }
                 }
-                .handleEvents(
-                    receiveCompletion: { completion in
-                        if case let .failure(error) = completion {
-                            self.error = AlertContent(title: "Update Error", message: error.legibleLocalizedDescription)
-                        }
-                    }
-                )
-            }
+            )
             .catch { _ in
                 Just(self.list.availableXcodes)
             }
diff --git a/Xcodes/Backend/Environment.swift b/Xcodes/Backend/Environment.swift
index 166cbab..c0c6c73 100644
--- a/Xcodes/Backend/Environment.swift
+++ b/Xcodes/Backend/Environment.swift
@@ -111,10 +111,10 @@ private func _installedXcodes(destination: Path) -> [InstalledXcode] {
 
 public struct Network {
     private static let client = AppleAPI.Client()
-
-    public var dataTask: (URLRequestConvertible) -> Promise<(data: Data, response: URLResponse)> = { AppleAPI.Current.network.session.dataTask(.promise, with: $0) }
-    public func dataTask(with convertible: URLRequestConvertible) -> Promise<(data: Data, response: URLResponse)> {
-        dataTask(convertible)
+    
+    public var dataTask: (URLRequest) -> URLSession.DataTaskPublisher = { AppleAPI.Current.network.session.dataTaskPublisher(for: $0) }
+    public func dataTask(with request: URLRequest) -> URLSession.DataTaskPublisher {
+        dataTask(request)
     }
 
     public var downloadTask: (URLRequestConvertible, URL, Data?) -> (Progress, Promise<(saveLocation: URL, response: URLResponse)>) = { AppleAPI.Current.network.session.downloadTask(with: $0, to: $1, resumingWith: $2) }
diff --git a/Xcodes/Backend/XcodeList.swift b/Xcodes/Backend/XcodeList.swift
index dae4046..25967d6 100644
--- a/Xcodes/Backend/XcodeList.swift
+++ b/Xcodes/Backend/XcodeList.swift
@@ -1,10 +1,10 @@
+import Combine
 import Foundation
 import Path
 import Version
-import PromiseKit
 import SwiftSoup
 
-/// Provides lists of available and installed Xcodes
+/// Provides lists of available Xcodes
 public final class XcodeList {
     public init() {
         try? loadCachedAvailableXcodes()
@@ -16,8 +16,9 @@ public final class XcodeList {
         return availableXcodes.isEmpty
     }
 
-    public func update() -> Promise<[Xcode]> {
-        return when(fulfilled: releasedXcodes(), prereleaseXcodes())
+    public func update() -> AnyPublisher<[Xcode], Error> {
+        releasedXcodes().combineLatest(prereleaseXcodes())
+            .receive(on: DispatchQueue.main)
             .map { releasedXcodes, prereleaseXcodes in
                 // Starting with Xcode 11 beta 6, developer.apple.com/download and developer.apple.com/download/more both list some pre-release versions of Xcode.
                 // Previously pre-release versions only appeared on developer.apple.com/download.
@@ -30,6 +31,7 @@ public final class XcodeList {
                 try? self.cacheAvailableXcodes(xcodes)
                 return xcodes
             }
+            .eraseToAnyPublisher()
     }
 }
 
@@ -49,38 +51,37 @@ extension XcodeList {
 }
 
 extension XcodeList {
-    private func releasedXcodes() -> Promise<[Xcode]> {
-        return firstly { () -> Promise<(data: Data, response: URLResponse)> in
-            Current.network.dataTask(with: URLRequest.downloads)
-        }
-        .map { (data, response) -> [Xcode] in
-            let decoder = JSONDecoder()
-            decoder.dateDecodingStrategy = .formatted(.downloadsDateModified)
-            let downloads = try decoder.decode(Downloads.self, from: data)
-            let xcodes = downloads
-                .downloads
-                .filter { $0.name.range(of: "^Xcode [0-9]", options: .regularExpression) != nil }
-                .compactMap { download -> Xcode? in
-                    let urlPrefix = URL(string: "https://download.developer.apple.com/")!
-                    guard 
-                        let xcodeFile = download.files.first(where: { $0.remotePath.hasSuffix("dmg") || $0.remotePath.hasSuffix("xip") }),
-                        let version = Version(xcodeVersion: download.name)
-                    else { return nil }
+    private func releasedXcodes() -> AnyPublisher<[Xcode], Error> {
+        Current.network.dataTask(with: URLRequest.downloads)
+            .map(\.data)
+            .decode(type: Downloads.self, decoder: configure(JSONDecoder()) {
+                $0.dateDecodingStrategy = .formatted(.downloadsDateModified)
+            })
+            .map { downloads -> [Xcode] in
+                let xcodes = downloads
+                    .downloads
+                    .filter { $0.name.range(of: "^Xcode [0-9]", options: .regularExpression) != nil }
+                    .compactMap { download -> Xcode? in
+                        let urlPrefix = URL(string: "https://download.developer.apple.com/")!
+                        guard 
+                            let xcodeFile = download.files.first(where: { $0.remotePath.hasSuffix("dmg") || $0.remotePath.hasSuffix("xip") }),
+                            let version = Version(xcodeVersion: download.name)
+                        else { return nil }
 
-                    let url = urlPrefix.appendingPathComponent(xcodeFile.remotePath)
-                    return Xcode(version: version, url: url, filename: String(xcodeFile.remotePath.suffix(fromLast: "/")), releaseDate: download.dateModified)
-                }
-            return xcodes
-        }
+                        let url = urlPrefix.appendingPathComponent(xcodeFile.remotePath)
+                        return Xcode(version: version, url: url, filename: String(xcodeFile.remotePath.suffix(fromLast: "/")), releaseDate: download.dateModified)
+                    }
+                return xcodes
+            }
+            .eraseToAnyPublisher()
     }
 
-    private func prereleaseXcodes() -> Promise<[Xcode]> {
-        return firstly { () -> Promise<(data: Data, response: URLResponse)> in
-            Current.network.dataTask(with: URLRequest.download)
-        }
-        .map { (data, _) -> [Xcode] in
-            try self.parsePrereleaseXcodes(from: data)
-        }
+    private func prereleaseXcodes() -> AnyPublisher<[Xcode], Error> {
+        Current.network.dataTask(with: URLRequest.download)
+            .tryMap { (data, _) -> [Xcode] in
+                try self.parsePrereleaseXcodes(from: data)
+            }
+            .eraseToAnyPublisher()
     }
 
     func parsePrereleaseXcodes(from data: Data) throws -> [Xcode] {

From 9b26688255e0566cc383ca66a357382c5b617b0a Mon Sep 17 00:00:00 2001
From: Brandon Evans <brandon@brandonevans.ca>
Date: Thu, 24 Dec 2020 11:30:59 -0700
Subject: [PATCH 2/9] Add refresh menu item and progress view

---
 Xcodes.xcodeproj/project.pbxproj              |  4 ++++
 Xcodes/Backend/AppState.swift                 | 12 ++++++----
 Xcodes/Frontend/View+IsHidden.swift           | 24 +++++++++++++++++++
 Xcodes/Frontend/XcodeList/XcodeListView.swift |  9 ++++++-
 Xcodes/XcodesApp.swift                        |  7 ++++++
 5 files changed, 51 insertions(+), 5 deletions(-)
 create mode 100644 Xcodes/Frontend/View+IsHidden.swift

diff --git a/Xcodes.xcodeproj/project.pbxproj b/Xcodes.xcodeproj/project.pbxproj
index 85fea2d..cdada1e 100644
--- a/Xcodes.xcodeproj/project.pbxproj
+++ b/Xcodes.xcodeproj/project.pbxproj
@@ -17,6 +17,7 @@
 		CA9FF83F2594FBC000E47BAF /* Licenses.rtf in Resources */ = {isa = PBXBuildFile; fileRef = CA9FF83E2594FBC000E47BAF /* Licenses.rtf */; };
 		CA9FF84E2595079F00E47BAF /* ScrollingTextView.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA9FF84D2595079F00E47BAF /* ScrollingTextView.swift */; };
 		CA9FF8522595080100E47BAF /* AcknowledgementsView.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA9FF8512595080100E47BAF /* AcknowledgementsView.swift */; };
+		CA9FF8662595130600E47BAF /* View+IsHidden.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA9FF8652595130600E47BAF /* View+IsHidden.swift */; };
 		CAA1CB2D255A5262003FD669 /* AppleAPI in Frameworks */ = {isa = PBXBuildFile; productRef = CAA1CB2C255A5262003FD669 /* AppleAPI */; };
 		CAA1CB35255A5AD5003FD669 /* SignInCredentialsView.swift in Sources */ = {isa = PBXBuildFile; fileRef = CAA1CB34255A5AD5003FD669 /* SignInCredentialsView.swift */; };
 		CAA1CB45255A5B60003FD669 /* SignIn2FAView.swift in Sources */ = {isa = PBXBuildFile; fileRef = CAA1CB44255A5B60003FD669 /* SignIn2FAView.swift */; };
@@ -80,6 +81,7 @@
 		CA9FF83E2594FBC000E47BAF /* Licenses.rtf */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.rtf; path = Licenses.rtf; sourceTree = "<group>"; };
 		CA9FF84D2595079F00E47BAF /* ScrollingTextView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ScrollingTextView.swift; sourceTree = "<group>"; };
 		CA9FF8512595080100E47BAF /* AcknowledgementsView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AcknowledgementsView.swift; sourceTree = "<group>"; };
+		CA9FF8652595130600E47BAF /* View+IsHidden.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "View+IsHidden.swift"; sourceTree = "<group>"; };
 		CAA1CB34255A5AD5003FD669 /* SignInCredentialsView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SignInCredentialsView.swift; sourceTree = "<group>"; };
 		CAA1CB44255A5B60003FD669 /* SignIn2FAView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SignIn2FAView.swift; sourceTree = "<group>"; };
 		CAA1CB48255A5C97003FD669 /* SignInSMSView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SignInSMSView.swift; sourceTree = "<group>"; };
@@ -225,6 +227,7 @@
 				CAA1CB50255A5D16003FD669 /* SignIn */,
 				CABFAA142592F73000380FEE /* XcodeList */,
 				CABFAA2A2592FBFC00380FEE /* SettingsView.swift */,
+				CA9FF8652595130600E47BAF /* View+IsHidden.swift */,
 			);
 			path = Frontend;
 			sourceTree = "<group>";
@@ -441,6 +444,7 @@
 			files = (
 				CA735109257BF96D00EA9CF8 /* AttributedText.swift in Sources */,
 				CABFAA492593162500380FEE /* Bundle+InfoPlistValues.swift in Sources */,
+				CA9FF8662595130600E47BAF /* View+IsHidden.swift in Sources */,
 				CABFA9CA2592EEEA00380FEE /* XcodeList.swift in Sources */,
 				CA44901F2463AD34003D8213 /* Tag.swift in Sources */,
 				CABFA9BF2592EEEA00380FEE /* URLSession+Promise.swift in Sources */,
diff --git a/Xcodes/Backend/AppState.swift b/Xcodes/Backend/AppState.swift
index 3aac23c..68dec29 100644
--- a/Xcodes/Backend/AppState.swift
+++ b/Xcodes/Backend/AppState.swift
@@ -12,6 +12,8 @@ class AppState: ObservableObject {
     
     @Published var authenticationState: AuthenticationState = .unauthenticated
     @Published var allVersions: [XcodeVersion] = []
+    @Published var updatePublisher: AnyCancellable?
+    var isUpdating: Bool { updatePublisher != nil }
     @Published var error: AlertContent?
     @Published var authError: AlertContent?
     @Published var presentingSignInAlert = false
@@ -161,15 +163,17 @@ class AppState: ObservableObject {
     // MARK: - Load Xcode Versions
     
     func update() {
-        update()
+        guard !isUpdating else { return }
+        updatePublisher = update()
             .sink(
-                receiveCompletion: { _ in },
+                receiveCompletion: { [unowned self] _ in
+                    self.updatePublisher = nil
+                },
                 receiveValue: { _ in }
             )
-            .store(in: &cancellables)     
     }
     
-    public func update() -> AnyPublisher<[Xcode], Never> {
+    private func update() -> AnyPublisher<[Xcode], Never> {
         signInIfNeeded()
             .flatMap {
                 self.list.update()
diff --git a/Xcodes/Frontend/View+IsHidden.swift b/Xcodes/Frontend/View+IsHidden.swift
new file mode 100644
index 0000000..4da6da0
--- /dev/null
+++ b/Xcodes/Frontend/View+IsHidden.swift
@@ -0,0 +1,24 @@
+import SwiftUI
+
+extension View {
+    @ViewBuilder
+    func isHidden(_ isHidden: Bool) -> some View {
+        if isHidden {
+            self.hidden()
+        } else {
+            self
+        }
+    }
+}
+
+struct View_IsHidden_Previews: PreviewProvider {
+    static var previews: some View {
+        Group {
+            Text("Not Hidden")
+                .isHidden(false)
+            
+            Text("Hidden")
+                .isHidden(true)
+        }
+    }
+}
diff --git a/Xcodes/Frontend/XcodeList/XcodeListView.swift b/Xcodes/Frontend/XcodeList/XcodeListView.swift
index 7a2d0e5..7b70958 100644
--- a/Xcodes/Frontend/XcodeList/XcodeListView.swift
+++ b/Xcodes/Frontend/XcodeList/XcodeListView.swift
@@ -79,9 +79,16 @@ struct XcodeListView: View {
         .toolbar {
             ToolbarItemGroup(placement: .primaryAction) {
                 Button(action: appState.update) {
-                    Image(systemName: "arrow.clockwise")
+                    Label("Refresh", systemImage: "arrow.clockwise")
                 }
                 .keyboardShortcut(KeyEquivalent("r"))
+                .disabled(appState.isUpdating)
+                .isHidden(appState.isUpdating)
+                .overlay(
+                    ProgressView()
+                        .scaleEffect(0.5, anchor: .center)
+                        .isHidden(!appState.isUpdating)
+                )
             }
             ToolbarItem(placement: .principal) {
                 Picker("", selection: $category) {
diff --git a/Xcodes/XcodesApp.swift b/Xcodes/XcodesApp.swift
index 88645fa..0a46137 100644
--- a/Xcodes/XcodesApp.swift
+++ b/Xcodes/XcodesApp.swift
@@ -17,6 +17,13 @@ struct XcodesApp: App {
                     appDelegate.showAboutWindow()
                 }
             }
+            CommandGroup(after: CommandGroupPlacement.newItem) {
+                Button("Refresh") {
+                    appState.update()
+                }
+                .keyboardShortcut(KeyEquivalent("r"))
+                .disabled(appState.isUpdating)
+            }
         }
 
         Settings {

From b342baff02a699a300a09609de1c697fe3b6daf5 Mon Sep 17 00:00:00 2001
From: Brandon Evans <brandon@brandonevans.ca>
Date: Thu, 24 Dec 2020 11:54:55 -0700
Subject: [PATCH 3/9] Update when the app launches or becomes active and it's
 been a day since last update

---
 Xcodes/Backend/AppState.swift                 | 10 ++++++++++
 Xcodes/Backend/Environment.swift              | 11 +++++++++++
 Xcodes/Frontend/XcodeList/XcodeListView.swift |  1 -
 Xcodes/XcodesApp.swift                        |  9 +++++++++
 4 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/Xcodes/Backend/AppState.swift b/Xcodes/Backend/AppState.swift
index 68dec29..0f62038 100644
--- a/Xcodes/Backend/AppState.swift
+++ b/Xcodes/Backend/AppState.swift
@@ -167,12 +167,22 @@ class AppState: ObservableObject {
         updatePublisher = update()
             .sink(
                 receiveCompletion: { [unowned self] _ in
+                    Current.defaults.setDate(Current.date(), forKey: "lastUpdated")
                     self.updatePublisher = nil
                 },
                 receiveValue: { _ in }
             )
     }
     
+    func updateIfNeeded() {
+        guard
+            let lastUpdated = Current.defaults.date(forKey: "lastUpdated"),
+            // This is bad date math but for this use case it doesn't need to be exact
+            lastUpdated < Current.date().addingTimeInterval(-60 * 60 * 24) 
+        else { return }
+        update() as Void
+    }
+    
     private func update() -> AnyPublisher<[Xcode], Never> {
         signInIfNeeded()
             .flatMap {
diff --git a/Xcodes/Backend/Environment.swift b/Xcodes/Backend/Environment.swift
index c0c6c73..fa3be9d 100644
--- a/Xcodes/Backend/Environment.swift
+++ b/Xcodes/Backend/Environment.swift
@@ -19,6 +19,7 @@ public struct Environment {
     public var logging = Logging()
     public var keychain = Keychain()
     public var defaults = Defaults()
+    public var date: () -> Date = Date.init
 }
 
 public var Current = Environment()
@@ -153,6 +154,16 @@ public struct Defaults {
         string(key)
     }
     
+    public var date: (String) -> Date? = { Date(timeIntervalSince1970: UserDefaults.standard.double(forKey: $0)) }
+    public func date(forKey key: String) -> Date? {
+        date(key)
+    }
+    
+    public var setDate: (Date?, String) -> Void = { UserDefaults.standard.set($0?.timeIntervalSince1970, forKey: $1) }
+    public func setDate(_ value: Date?, forKey key: String) {
+        setDate(value, key)
+    }
+    
     public var set: (Any?, String) -> Void = { UserDefaults.standard.set($0, forKey: $1) }
     public func set(_ value: Any?, forKey key: String) {
         set(value, key)
diff --git a/Xcodes/Frontend/XcodeList/XcodeListView.swift b/Xcodes/Frontend/XcodeList/XcodeListView.swift
index 7b70958..cb5523a 100644
--- a/Xcodes/Frontend/XcodeList/XcodeListView.swift
+++ b/Xcodes/Frontend/XcodeList/XcodeListView.swift
@@ -106,7 +106,6 @@ struct XcodeListView: View {
         }
         .navigationSubtitle(Text("Updated \(Date().addingTimeInterval(-600), style: .relative) ago"))
         .frame(minWidth: 200, maxWidth: .infinity, minHeight: 300, maxHeight: .infinity)
-        .onAppear(perform: appState.update)
         .alert(item: $appState.error) { error in
             Alert(title: Text(error.title), 
                   message: Text(verbatim: error.message), 
diff --git a/Xcodes/XcodesApp.swift b/Xcodes/XcodesApp.swift
index 0a46137..18cfdea 100644
--- a/Xcodes/XcodesApp.swift
+++ b/Xcodes/XcodesApp.swift
@@ -4,12 +4,21 @@ import AppKit
 @main
 struct XcodesApp: App {
     @NSApplicationDelegateAdaptor(AppDelegate.self) var appDelegate: AppDelegate
+    @SwiftUI.Environment(\.scenePhase) private var scenePhase: ScenePhase
     @StateObject private var appState = AppState()
     
     var body: some Scene {
         WindowGroup("Xcodes") {
             XcodeListView()
                 .environmentObject(appState)
+                // This is intentionally used on a View, and not on a WindowGroup, 
+                // so that it's triggered when an individual window's phase changes instead of all window phases.
+                // When used on a View it's also invoked on launch, which doesn't occur with a WindowGroup. 
+                .onChange(of: scenePhase) { newScenePhase in
+                    if case .active = newScenePhase {
+                        appState.updateIfNeeded()
+                    }
+                }
         }
         .commands {
             CommandGroup(replacing: .appInfo) {

From 293aef80e3303078a20a6a7b6f05c00bb2675c83 Mon Sep 17 00:00:00 2001
From: Brandon Evans <brandon@brandonevans.ca>
Date: Thu, 24 Dec 2020 16:09:00 -0700
Subject: [PATCH 4/9] Add Xcode Releases data source

---
 Xcodes.xcodeproj/project.pbxproj              | 25 ++++++
 .../xcshareddata/swiftpm/Package.resolved     |  9 ++
 Xcodes/Backend/AppState.swift                 |  9 +-
 Xcodes/Backend/DataSource.swift               | 17 ++++
 Xcodes/Backend/Version+.swift                 |  4 +-
 Xcodes/Backend/Version+XcodeReleases.swift    | 51 +++++++++++
 Xcodes/Backend/XcodeList.swift                | 86 ++++++++++++++-----
 Xcodes/Resources/Licenses.rtf                 | 27 ++++++
 Xcodes/SettingsView.swift                     | 34 ++++++++
 9 files changed, 237 insertions(+), 25 deletions(-)
 create mode 100644 Xcodes/Backend/DataSource.swift
 create mode 100644 Xcodes/Backend/Version+XcodeReleases.swift

diff --git a/Xcodes.xcodeproj/project.pbxproj b/Xcodes.xcodeproj/project.pbxproj
index cdada1e..1dae143 100644
--- a/Xcodes.xcodeproj/project.pbxproj
+++ b/Xcodes.xcodeproj/project.pbxproj
@@ -18,6 +18,9 @@
 		CA9FF84E2595079F00E47BAF /* ScrollingTextView.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA9FF84D2595079F00E47BAF /* ScrollingTextView.swift */; };
 		CA9FF8522595080100E47BAF /* AcknowledgementsView.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA9FF8512595080100E47BAF /* AcknowledgementsView.swift */; };
 		CA9FF8662595130600E47BAF /* View+IsHidden.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA9FF8652595130600E47BAF /* View+IsHidden.swift */; };
+		CA9FF86D25951C6E00E47BAF /* XCModel in Frameworks */ = {isa = PBXBuildFile; productRef = CA9FF86C25951C6E00E47BAF /* XCModel */; };
+		CA9FF877259528CC00E47BAF /* Version+XcodeReleases.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA9FF876259528CC00E47BAF /* Version+XcodeReleases.swift */; };
+		CA9FF87B2595293E00E47BAF /* DataSource.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA9FF87A2595293E00E47BAF /* DataSource.swift */; };
 		CAA1CB2D255A5262003FD669 /* AppleAPI in Frameworks */ = {isa = PBXBuildFile; productRef = CAA1CB2C255A5262003FD669 /* AppleAPI */; };
 		CAA1CB35255A5AD5003FD669 /* SignInCredentialsView.swift in Sources */ = {isa = PBXBuildFile; fileRef = CAA1CB34255A5AD5003FD669 /* SignInCredentialsView.swift */; };
 		CAA1CB45255A5B60003FD669 /* SignIn2FAView.swift in Sources */ = {isa = PBXBuildFile; fileRef = CAA1CB44255A5B60003FD669 /* SignIn2FAView.swift */; };
@@ -82,6 +85,8 @@
 		CA9FF84D2595079F00E47BAF /* ScrollingTextView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ScrollingTextView.swift; sourceTree = "<group>"; };
 		CA9FF8512595080100E47BAF /* AcknowledgementsView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AcknowledgementsView.swift; sourceTree = "<group>"; };
 		CA9FF8652595130600E47BAF /* View+IsHidden.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "View+IsHidden.swift"; sourceTree = "<group>"; };
+		CA9FF876259528CC00E47BAF /* Version+XcodeReleases.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Version+XcodeReleases.swift"; sourceTree = "<group>"; };
+		CA9FF87A2595293E00E47BAF /* DataSource.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DataSource.swift; sourceTree = "<group>"; };
 		CAA1CB34255A5AD5003FD669 /* SignInCredentialsView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SignInCredentialsView.swift; sourceTree = "<group>"; };
 		CAA1CB44255A5B60003FD669 /* SignIn2FAView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SignIn2FAView.swift; sourceTree = "<group>"; };
 		CAA1CB48255A5C97003FD669 /* SignInSMSView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SignInSMSView.swift; sourceTree = "<group>"; };
@@ -128,6 +133,7 @@
 				CABFA9E42592F08E00380FEE /* Version in Frameworks */,
 				CABFA9E92592F0B400380FEE /* PromiseKit in Frameworks */,
 				CABFA9FD2592F13300380FEE /* LegibleError in Frameworks */,
+				CA9FF86D25951C6E00E47BAF /* XCModel in Frameworks */,
 				CABFA9F82592F0F900380FEE /* KeychainAccess in Frameworks */,
 				CABFA9F32592F0E400380FEE /* PMKFoundation in Frameworks */,
 				CAA1CB2D255A5262003FD669 /* AppleAPI in Frameworks */,
@@ -201,6 +207,7 @@
 				CA378F982466567600A58CE0 /* AppState.swift */,
 				CABFAA2B2592FBFC00380FEE /* Configure.swift */,
 				CABFAA482593162500380FEE /* Bundle+InfoPlistValues.swift */,
+				CA9FF87A2595293E00E47BAF /* DataSource.swift */,
 				CABFA9BA2592EEEA00380FEE /* DateFormatter+.swift */,
 				CABFA9B22592EEEA00380FEE /* Entry+.swift */,
 				CABFA9A92592EEE900380FEE /* Environment.swift */,
@@ -213,6 +220,7 @@
 				CABFA9AB2592EEE900380FEE /* URLRequest+Apple.swift */,
 				CABFA9B32592EEEA00380FEE /* URLSession+Promise.swift */,
 				CABFA9A82592EEE900380FEE /* Version+.swift */,
+				CA9FF876259528CC00E47BAF /* Version+XcodeReleases.swift */,
 				CABFA9A62592EEE900380FEE /* Version+Xcode.swift */,
 				CABFA9A72592EEE900380FEE /* XcodeList.swift */,
 			);
@@ -326,6 +334,7 @@
 				CABFA9F22592F0E400380FEE /* PMKFoundation */,
 				CABFA9F72592F0F900380FEE /* KeychainAccess */,
 				CABFA9FC2592F13300380FEE /* LegibleError */,
+				CA9FF86C25951C6E00E47BAF /* XCModel */,
 			);
 			productName = XcodesMac;
 			productReference = CAD2E79E2449574E00113D76 /* Xcodes.app */;
@@ -385,6 +394,7 @@
 				CABFA9F12592F0E400380FEE /* XCRemoteSwiftPackageReference "Foundation" */,
 				CABFA9F62592F0F900380FEE /* XCRemoteSwiftPackageReference "KeychainAccess" */,
 				CABFA9FB2592F13300380FEE /* XCRemoteSwiftPackageReference "LegibleError" */,
+				CA9FF86B25951C6E00E47BAF /* XCRemoteSwiftPackageReference "data" */,
 			);
 			productRefGroup = CAD2E79F2449574E00113D76 /* Products */;
 			projectDirPath = "";
@@ -462,6 +472,7 @@
 				CABFA9CE2592EEEA00380FEE /* Version+Xcode.swift in Sources */,
 				CAA1CB49255A5C97003FD669 /* SignInSMSView.swift in Sources */,
 				CAA1CB35255A5AD5003FD669 /* SignInCredentialsView.swift in Sources */,
+				CA9FF877259528CC00E47BAF /* Version+XcodeReleases.swift in Sources */,
 				CABFAA2D2592FBFC00380FEE /* Configure.swift in Sources */,
 				CA73510D257BFCEF00EA9CF8 /* NSAttributedString+.swift in Sources */,
 				CABFA9C22592EEEA00380FEE /* Promise+.swift in Sources */,
@@ -469,6 +480,7 @@
 				CABFA9CF2592EEEA00380FEE /* Process.swift in Sources */,
 				CABFA9C72592EEEA00380FEE /* Entry+.swift in Sources */,
 				CABFAA2C2592FBFC00380FEE /* SettingsView.swift in Sources */,
+				CA9FF87B2595293E00E47BAF /* DataSource.swift in Sources */,
 				CABFA9C92592EEEA00380FEE /* URLRequest+Apple.swift in Sources */,
 				CABFAA432593104F00380FEE /* AboutView.swift in Sources */,
 				CABFA9CC2592EEEA00380FEE /* Path+.swift in Sources */,
@@ -840,6 +852,14 @@
 /* End XCConfigurationList section */
 
 /* Begin XCRemoteSwiftPackageReference section */
+		CA9FF86B25951C6E00E47BAF /* XCRemoteSwiftPackageReference "data" */ = {
+			isa = XCRemoteSwiftPackageReference;
+			repositoryURL = "https://github.com/xcodereleases/data";
+			requirement = {
+				kind = revision;
+				revision = b47228c688b608e34b3b84079ab6052a24c7a981;
+			};
+		};
 		CABFA9DD2592F07A00380FEE /* XCRemoteSwiftPackageReference "Path" */ = {
 			isa = XCRemoteSwiftPackageReference;
 			repositoryURL = "https://github.com/mxcl/Path.swift";
@@ -899,6 +919,11 @@
 /* End XCRemoteSwiftPackageReference section */
 
 /* Begin XCSwiftPackageProductDependency section */
+		CA9FF86C25951C6E00E47BAF /* XCModel */ = {
+			isa = XCSwiftPackageProductDependency;
+			package = CA9FF86B25951C6E00E47BAF /* XCRemoteSwiftPackageReference "data" */;
+			productName = XCModel;
+		};
 		CAA1CB2C255A5262003FD669 /* AppleAPI */ = {
 			isa = XCSwiftPackageProductDependency;
 			productName = AppleAPI;
diff --git a/Xcodes.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved b/Xcodes.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved
index 0ee46f5..fba9785 100644
--- a/Xcodes.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved
+++ b/Xcodes.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved
@@ -1,6 +1,15 @@
 {
   "object": {
     "pins": [
+      {
+        "package": "XcodeReleases",
+        "repositoryURL": "https://github.com/xcodereleases/data",
+        "state": {
+          "branch": null,
+          "revision": "b47228c688b608e34b3b84079ab6052a24c7a981",
+          "version": null
+        }
+      },
       {
         "package": "PMKFoundation",
         "repositoryURL": "https://github.com/PromiseKit/Foundation",
diff --git a/Xcodes/Backend/AppState.swift b/Xcodes/Backend/AppState.swift
index 0f62038..e9e36bd 100644
--- a/Xcodes/Backend/AppState.swift
+++ b/Xcodes/Backend/AppState.swift
@@ -4,6 +4,7 @@ import Combine
 import Path
 import LegibleError
 import KeychainAccess
+import SwiftUI
 
 class AppState: ObservableObject {
     private let list = XcodeList()
@@ -20,6 +21,10 @@ class AppState: ObservableObject {
     @Published var isProcessingAuthRequest = false
     @Published var secondFactorData: SecondFactorData?
     
+    private var dataSource: DataSource {
+        Current.defaults.string(forKey: "dataSource").flatMap(DataSource.init(rawValue:)) ?? .default
+    }
+    
     // MARK: - Authentication
     
     func validateSession() -> AnyPublisher<Void, Error> {
@@ -185,8 +190,8 @@ class AppState: ObservableObject {
     
     private func update() -> AnyPublisher<[Xcode], Never> {
         signInIfNeeded()
-            .flatMap {
-                self.list.update()
+            .flatMap { [unowned self] in
+                self.list.update(dataSource: self.dataSource)
             }
             .handleEvents(
                 receiveCompletion: { completion in
diff --git a/Xcodes/Backend/DataSource.swift b/Xcodes/Backend/DataSource.swift
new file mode 100644
index 0000000..69363ae
--- /dev/null
+++ b/Xcodes/Backend/DataSource.swift
@@ -0,0 +1,17 @@
+import Foundation
+
+public enum DataSource: String, CaseIterable, Identifiable, CustomStringConvertible {
+    case apple
+    case xcodeReleases
+    
+    public var id: Self { self }
+    
+    public static var `default` = DataSource.xcodeReleases
+    
+    public var description: String {
+        switch self {
+        case .apple: return "Apple"
+        case .xcodeReleases: return "Xcode Releases"
+        }
+    }
+}
diff --git a/Xcodes/Backend/Version+.swift b/Xcodes/Backend/Version+.swift
index c4ecec3..5fed036 100644
--- a/Xcodes/Backend/Version+.swift
+++ b/Xcodes/Backend/Version+.swift
@@ -19,13 +19,13 @@ public extension Version {
                 return major == installed.major &&
                        minor == installed.minor &&
                        patch == installed.patch &&
-                       prereleaseIdentifiers == installed.prereleaseIdentifiers
+                       prereleaseIdentifiers.map { $0.lowercased() } == installed.prereleaseIdentifiers.map { $0.lowercased() }
             }
             else {
                 return major == installed.major &&
                        minor == installed.minor &&
                        patch == installed.patch &&
-                       prereleaseIdentifiers == installed.prereleaseIdentifiers &&
+                       prereleaseIdentifiers.map { $0.lowercased() } == installed.prereleaseIdentifiers.map { $0.lowercased() } &&
                        buildMetadataIdentifiers.map { $0.lowercased() } == installed.buildMetadataIdentifiers.map { $0.lowercased() }
             }
         }
diff --git a/Xcodes/Backend/Version+XcodeReleases.swift b/Xcodes/Backend/Version+XcodeReleases.swift
new file mode 100644
index 0000000..e13661f
--- /dev/null
+++ b/Xcodes/Backend/Version+XcodeReleases.swift
@@ -0,0 +1,51 @@
+import Version
+import struct XCModel.Xcode
+
+extension Version {
+    /// Initialize a Version from an XcodeReleases' XCModel.Xcode
+    ///
+    /// This is kinda quick-and-dirty, and it would probably be better for us to adopt something closer to XCModel.Xcode under the hood and map the scraped data to it instead.
+    init?(xcReleasesXcode: XCModel.Xcode) {
+        var versionString = xcReleasesXcode.version.number ?? ""
+        
+        // Append trailing ".0" in order to get a fully-specified version string
+        let components = versionString.components(separatedBy: ".")
+        versionString += Array(repeating: ".0", count: 3 - components.count).joined()
+        
+        // Append prerelease identifier
+        switch xcReleasesXcode.version.release {
+        case let .beta(beta):
+            versionString += "-Beta"
+            if beta > 1 {
+                versionString += ".\(beta)"
+            }
+        case let .dp(dp):
+            versionString += "-DP"
+            if dp > 1 {
+                versionString += ".\(dp)"
+            }
+        case .gm:
+            versionString += "-GM"
+        case let .gmSeed(gmSeed):
+            versionString += "-GM.Seed"
+            if gmSeed > 1 {
+                versionString += ".\(gmSeed)"
+            }
+        case let .rc(rc):
+            versionString += "-Release.Candidate"
+            if rc > 1 {
+                versionString += ".\(rc)"
+            }
+        case .release:
+            break
+        }
+        
+        // Append build identifier
+        if let buildNumber = xcReleasesXcode.version.build {
+            versionString += "+\(buildNumber)"
+        }
+        
+        self.init(versionString)
+    }
+}
+
diff --git a/Xcodes/Backend/XcodeList.swift b/Xcodes/Backend/XcodeList.swift
index 25967d6..317b5c1 100644
--- a/Xcodes/Backend/XcodeList.swift
+++ b/Xcodes/Backend/XcodeList.swift
@@ -3,6 +3,7 @@ import Foundation
 import Path
 import Version
 import SwiftSoup
+import struct XCModel.Xcode
 
 /// Provides lists of available Xcodes
 public final class XcodeList {
@@ -12,26 +13,34 @@ public final class XcodeList {
 
     public private(set) var availableXcodes: [Xcode] = []
 
-    public var shouldUpdate: Bool {
-        return availableXcodes.isEmpty
-    }
-
-    public func update() -> AnyPublisher<[Xcode], Error> {
-        releasedXcodes().combineLatest(prereleaseXcodes())
-            .receive(on: DispatchQueue.main)
-            .map { releasedXcodes, prereleaseXcodes in
-                // Starting with Xcode 11 beta 6, developer.apple.com/download and developer.apple.com/download/more both list some pre-release versions of Xcode.
-                // Previously pre-release versions only appeared on developer.apple.com/download.
-                // /download/more doesn't include build numbers, so we trust that if the version number and prerelease identifiers are the same that they're the same build.
-                // If an Xcode version is listed on both sites then prefer the one on /download because the build metadata is used to compare against installed Xcodes.
-                let xcodes = releasedXcodes.filter { releasedXcode in
-                    prereleaseXcodes.contains { $0.version.isEqualWithoutBuildMetadataIdentifiers(to: releasedXcode.version) } == false
-                } + prereleaseXcodes
-                self.availableXcodes = xcodes
-                try? self.cacheAvailableXcodes(xcodes)
-                return xcodes
-            }
-            .eraseToAnyPublisher()
+    public func update(dataSource: DataSource) -> AnyPublisher<[Xcode], Error> {
+        switch dataSource {
+        case .apple:
+            return releasedXcodes().combineLatest(prereleaseXcodes())
+                .receive(on: DispatchQueue.main)
+                .map { releasedXcodes, prereleaseXcodes in
+                    // Starting with Xcode 11 beta 6, developer.apple.com/download and developer.apple.com/download/more both list some pre-release versions of Xcode.
+                    // Previously pre-release versions only appeared on developer.apple.com/download.
+                    // /download/more doesn't include build numbers, so we trust that if the version number and prerelease identifiers are the same that they're the same build.
+                    // If an Xcode version is listed on both sites then prefer the one on /download because the build metadata is used to compare against installed Xcodes.
+                    let xcodes = releasedXcodes.filter { releasedXcode in
+                        prereleaseXcodes.contains { $0.version.isEqualWithoutBuildMetadataIdentifiers(to: releasedXcode.version) } == false
+                    } + prereleaseXcodes
+                    self.availableXcodes = xcodes
+                    try? self.cacheAvailableXcodes(xcodes)
+                    return xcodes
+                }
+                .eraseToAnyPublisher()
+        case .xcodeReleases:
+            return xcodeReleases()
+                .receive(on: DispatchQueue.main)
+                .handleEvents(
+                    receiveOutput: { xcodes in
+                        try? self.cacheAvailableXcodes(xcodes)    
+                    }
+                )
+                .eraseToAnyPublisher()
+        }
     }
 }
 
@@ -51,6 +60,8 @@ extension XcodeList {
 }
 
 extension XcodeList {
+    // MARK: Apple
+    
     private func releasedXcodes() -> AnyPublisher<[Xcode], Error> {
         Current.network.dataTask(with: URLRequest.downloads)
             .map(\.data)
@@ -84,7 +95,7 @@ extension XcodeList {
             .eraseToAnyPublisher()
     }
 
-    func parsePrereleaseXcodes(from data: Data) throws -> [Xcode] {
+    private func parsePrereleaseXcodes(from data: Data) throws -> [Xcode] {
         let body = String(data: data, encoding: .utf8)!
         let document = try SwiftSoup.parse(body)
 
@@ -102,3 +113,36 @@ extension XcodeList {
         return [Xcode(version: version, url: url, filename: filename, releaseDate: DateFormatter.downloadsReleaseDate.date(from: releaseDateString))]
     }
 }
+
+extension XcodeList {
+    // MARK: XcodeReleases
+    
+    private func xcodeReleases() -> AnyPublisher<[Xcode], Error> {
+        Current.network.dataTask(with: URLRequest(url: URL(string: "https://xcodereleases.com/data.json")!))
+            .map(\.data)
+            .decode(type: [XCModel.Xcode].self, decoder: JSONDecoder())
+            .map { xcReleasesXcodes in  
+                let xcodes = xcReleasesXcodes.compactMap { xcReleasesXcode -> Xcode? in
+                    guard
+                        let downloadURL = xcReleasesXcode.links?.download?.url,
+                        let version = Version(xcReleasesXcode: xcReleasesXcode)
+                    else { return nil }
+                    
+                    let releaseDate = Calendar(identifier: .gregorian).date(from: DateComponents(
+                        year: xcReleasesXcode.date.year,
+                        month: xcReleasesXcode.date.month,
+                        day: xcReleasesXcode.date.day
+                    ))
+                    
+                    return Xcode(
+                        version: version,
+                        url: downloadURL,
+                        filename: String(downloadURL.path.suffix(fromLast: "/")),
+                        releaseDate: releaseDate
+                    )
+                }
+                return xcodes
+            }
+            .eraseToAnyPublisher()
+    }
+}
diff --git a/Xcodes/Resources/Licenses.rtf b/Xcodes/Resources/Licenses.rtf
index f9dca46..f140dc0 100644
--- a/Xcodes/Resources/Licenses.rtf
+++ b/Xcodes/Resources/Licenses.rtf
@@ -360,6 +360,33 @@ SOFTWARE.\
 \
 \
 
+\fs34 data\
+\
+
+\fs26 MIT License\
+\
+Copyright (c) 2018 \
+\
+Permission is hereby granted, free of charge, to any person obtaining a copy\
+of this software and associated documentation files (the "Software"), to deal\
+in the Software without restriction, including without limitation the rights\
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell\
+copies of the Software, and to permit persons to whom the Software is\
+furnished to do so, subject to the following conditions:\
+\
+The above copyright notice and this permission notice shall be included in all\
+copies or substantial portions of the Software.\
+\
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR\
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,\
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE\
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER\
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,\
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE\
+SOFTWARE.\
+\
+\
+
 \fs34 LegibleError\
 \
 
diff --git a/Xcodes/SettingsView.swift b/Xcodes/SettingsView.swift
index 373561f..5ff2646 100644
--- a/Xcodes/SettingsView.swift
+++ b/Xcodes/SettingsView.swift
@@ -3,6 +3,7 @@ import SwiftUI
 
 struct SettingsView: View {
     @EnvironmentObject var appState: AppState
+    @AppStorage("dataSource") var dataSource: DataSource = .xcodeReleases
     
     var body: some View {
         VStack(alignment: .leading) {
@@ -21,6 +22,22 @@ struct SettingsView: View {
                 }
                 .frame(maxWidth: .infinity, alignment: .leading)
             }
+            
+            GroupBox(label: Text("Data Source")) {
+                VStack(alignment: .leading) {
+                    Picker("Data Source", selection: $dataSource) {
+                        ForEach(DataSource.allCases) { dataSource in
+                            Text(dataSource.description)
+                                .tag(dataSource)
+                        }
+                    }
+                    .labelsHidden()
+                    
+                    AttributedText(dataSourceFootnote)
+                        .font(.footnote)
+                }
+                .frame(maxWidth: .infinity, alignment: .leading)
+            }
             Spacer()
         }
         .padding()
@@ -28,6 +45,23 @@ struct SettingsView: View {
         .frame(width: 300)
         .frame(minHeight: 300)
     }
+    
+    private var dataSourceFootnote: NSAttributedString {
+        let string = """
+        The Apple data source scrapes the Apple Developer website. It will always show the latest releases that are available, but is more fragile.
+
+        Xcode Releases is an unofficial list of Xcode releases. It's provided as well-formed data, contains extra information that is not readily available from Apple, and is less likely to break if Apple redesigns their developer website.
+        """
+        let attributedString = NSMutableAttributedString(
+            string: string, 
+            attributes: [
+                .font: NSFont.preferredFont(forTextStyle: .footnote, options: [:]),
+                .foregroundColor: NSColor.labelColor
+            ]
+        )
+        attributedString.addAttribute(.link, value: URL(string: "https://xcodereleases.com")!, range: NSRange(string.range(of: "Xcode Releases")!, in: string))
+        return attributedString
+    }
 }
 
 struct SettingsView_Previews: PreviewProvider {

From f06d72f3eb372b427591d09c3963094e7ea2e0fc Mon Sep 17 00:00:00 2001
From: Brandon Evans <brandon@brandonevans.ca>
Date: Thu, 24 Dec 2020 16:51:20 -0700
Subject: [PATCH 5/9] Split up Models.swift

---
 Xcodes.xcodeproj/project.pbxproj              | 16 +++++++---
 Xcodes/Backend/AvailableXcode.swift           | 17 ++++++++++
 Xcodes/Backend/Downloads.swift                | 17 ++++++++++
 .../{Models.swift => InstalledXcode.swift}    | 32 ++-----------------
 4 files changed, 48 insertions(+), 34 deletions(-)
 create mode 100644 Xcodes/Backend/AvailableXcode.swift
 create mode 100644 Xcodes/Backend/Downloads.swift
 rename Xcodes/Backend/{Models.swift => InstalledXcode.swift} (79%)

diff --git a/Xcodes.xcodeproj/project.pbxproj b/Xcodes.xcodeproj/project.pbxproj
index 1dae143..54a1f30 100644
--- a/Xcodes.xcodeproj/project.pbxproj
+++ b/Xcodes.xcodeproj/project.pbxproj
@@ -21,6 +21,8 @@
 		CA9FF86D25951C6E00E47BAF /* XCModel in Frameworks */ = {isa = PBXBuildFile; productRef = CA9FF86C25951C6E00E47BAF /* XCModel */; };
 		CA9FF877259528CC00E47BAF /* Version+XcodeReleases.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA9FF876259528CC00E47BAF /* Version+XcodeReleases.swift */; };
 		CA9FF87B2595293E00E47BAF /* DataSource.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA9FF87A2595293E00E47BAF /* DataSource.swift */; };
+		CA9FF88125955C7000E47BAF /* AvailableXcode.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA9FF88025955C7000E47BAF /* AvailableXcode.swift */; };
+		CA9FF8872595607900E47BAF /* InstalledXcode.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA9FF8862595607900E47BAF /* InstalledXcode.swift */; };
 		CAA1CB2D255A5262003FD669 /* AppleAPI in Frameworks */ = {isa = PBXBuildFile; productRef = CAA1CB2C255A5262003FD669 /* AppleAPI */; };
 		CAA1CB35255A5AD5003FD669 /* SignInCredentialsView.swift in Sources */ = {isa = PBXBuildFile; fileRef = CAA1CB34255A5AD5003FD669 /* SignInCredentialsView.swift */; };
 		CAA1CB45255A5B60003FD669 /* SignIn2FAView.swift in Sources */ = {isa = PBXBuildFile; fileRef = CAA1CB44255A5B60003FD669 /* SignIn2FAView.swift */; };
@@ -31,7 +33,7 @@
 		CABFA9BF2592EEEA00380FEE /* URLSession+Promise.swift in Sources */ = {isa = PBXBuildFile; fileRef = CABFA9B32592EEEA00380FEE /* URLSession+Promise.swift */; };
 		CABFA9C12592EEEA00380FEE /* Version+.swift in Sources */ = {isa = PBXBuildFile; fileRef = CABFA9A82592EEE900380FEE /* Version+.swift */; };
 		CABFA9C22592EEEA00380FEE /* Promise+.swift in Sources */ = {isa = PBXBuildFile; fileRef = CABFA9B02592EEEA00380FEE /* Promise+.swift */; };
-		CABFA9C32592EEEA00380FEE /* Models.swift in Sources */ = {isa = PBXBuildFile; fileRef = CABFA9B92592EEEA00380FEE /* Models.swift */; };
+		CABFA9C32592EEEA00380FEE /* Downloads.swift in Sources */ = {isa = PBXBuildFile; fileRef = CABFA9B92592EEEA00380FEE /* Downloads.swift */; };
 		CABFA9C52592EEEA00380FEE /* FileManager+.swift in Sources */ = {isa = PBXBuildFile; fileRef = CABFA9B82592EEEA00380FEE /* FileManager+.swift */; };
 		CABFA9C72592EEEA00380FEE /* Entry+.swift in Sources */ = {isa = PBXBuildFile; fileRef = CABFA9B22592EEEA00380FEE /* Entry+.swift */; };
 		CABFA9C92592EEEA00380FEE /* URLRequest+Apple.swift in Sources */ = {isa = PBXBuildFile; fileRef = CABFA9AB2592EEE900380FEE /* URLRequest+Apple.swift */; };
@@ -87,6 +89,8 @@
 		CA9FF8652595130600E47BAF /* View+IsHidden.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "View+IsHidden.swift"; sourceTree = "<group>"; };
 		CA9FF876259528CC00E47BAF /* Version+XcodeReleases.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Version+XcodeReleases.swift"; sourceTree = "<group>"; };
 		CA9FF87A2595293E00E47BAF /* DataSource.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DataSource.swift; sourceTree = "<group>"; };
+		CA9FF88025955C7000E47BAF /* AvailableXcode.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AvailableXcode.swift; sourceTree = "<group>"; };
+		CA9FF8862595607900E47BAF /* InstalledXcode.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = InstalledXcode.swift; sourceTree = "<group>"; };
 		CAA1CB34255A5AD5003FD669 /* SignInCredentialsView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SignInCredentialsView.swift; sourceTree = "<group>"; };
 		CAA1CB44255A5B60003FD669 /* SignIn2FAView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SignIn2FAView.swift; sourceTree = "<group>"; };
 		CAA1CB48255A5C97003FD669 /* SignInSMSView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SignInSMSView.swift; sourceTree = "<group>"; };
@@ -106,7 +110,7 @@
 		CABFA9B32592EEEA00380FEE /* URLSession+Promise.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "URLSession+Promise.swift"; sourceTree = "<group>"; };
 		CABFA9B42592EEEA00380FEE /* Process.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Process.swift; sourceTree = "<group>"; };
 		CABFA9B82592EEEA00380FEE /* FileManager+.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "FileManager+.swift"; sourceTree = "<group>"; };
-		CABFA9B92592EEEA00380FEE /* Models.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Models.swift; sourceTree = "<group>"; };
+		CABFA9B92592EEEA00380FEE /* Downloads.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Downloads.swift; sourceTree = "<group>"; };
 		CABFA9BA2592EEEA00380FEE /* DateFormatter+.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "DateFormatter+.swift"; sourceTree = "<group>"; };
 		CABFA9D42592EF6300380FEE /* DECISIONS.md */ = {isa = PBXFileReference; lastKnownFileType = net.daringfireball.markdown; path = DECISIONS.md; sourceTree = "<group>"; };
 		CABFAA2A2592FBFC00380FEE /* SettingsView.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = SettingsView.swift; path = Xcodes/SettingsView.swift; sourceTree = SOURCE_ROOT; };
@@ -205,15 +209,17 @@
 			isa = PBXGroup;
 			children = (
 				CA378F982466567600A58CE0 /* AppState.swift */,
+				CA9FF88025955C7000E47BAF /* AvailableXcode.swift */,
 				CABFAA2B2592FBFC00380FEE /* Configure.swift */,
 				CABFAA482593162500380FEE /* Bundle+InfoPlistValues.swift */,
 				CA9FF87A2595293E00E47BAF /* DataSource.swift */,
 				CABFA9BA2592EEEA00380FEE /* DateFormatter+.swift */,
+				CABFA9B92592EEEA00380FEE /* Downloads.swift */,
 				CABFA9B22592EEEA00380FEE /* Entry+.swift */,
 				CABFA9A92592EEE900380FEE /* Environment.swift */,
 				CABFA9B82592EEEA00380FEE /* FileManager+.swift */,
 				CABFA9AC2592EEE900380FEE /* Foundation.swift */,
-				CABFA9B92592EEEA00380FEE /* Models.swift */,
+				CA9FF8862595607900E47BAF /* InstalledXcode.swift */,
 				CABFA9AE2592EEE900380FEE /* Path+.swift */,
 				CABFA9B42592EEEA00380FEE /* Process.swift */,
 				CABFA9B02592EEEA00380FEE /* Promise+.swift */,
@@ -460,12 +466,13 @@
 				CABFA9BF2592EEEA00380FEE /* URLSession+Promise.swift in Sources */,
 				CABFA9BB2592EEEA00380FEE /* DateFormatter+.swift in Sources */,
 				CABFA9BD2592EEEA00380FEE /* Environment.swift in Sources */,
-				CABFA9C32592EEEA00380FEE /* Models.swift in Sources */,
+				CABFA9C32592EEEA00380FEE /* Downloads.swift in Sources */,
 				CA378F992466567600A58CE0 /* AppState.swift in Sources */,
 				CAD2E7A42449574E00113D76 /* XcodeListView.swift in Sources */,
 				CAA1CB45255A5B60003FD669 /* SignIn2FAView.swift in Sources */,
 				CABFA9C52592EEEA00380FEE /* FileManager+.swift in Sources */,
 				CABFA9CD2592EEEA00380FEE /* Foundation.swift in Sources */,
+				CA9FF8872595607900E47BAF /* InstalledXcode.swift in Sources */,
 				CA9FF84E2595079F00E47BAF /* ScrollingTextView.swift in Sources */,
 				CABFA9C12592EEEA00380FEE /* Version+.swift in Sources */,
 				CA9FF8522595080100E47BAF /* AcknowledgementsView.swift in Sources */,
@@ -488,6 +495,7 @@
 				63EAA4EB259944450046AB8F /* ProgressButton.swift in Sources */,
 				CA5D781E257365D6008EDE9D /* PinCodeTextView.swift in Sources */,
 				CA39711924495F0E00AFFB77 /* AppStoreButtonStyle.swift in Sources */,
+				CA9FF88125955C7000E47BAF /* AvailableXcode.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/Xcodes/Backend/AvailableXcode.swift b/Xcodes/Backend/AvailableXcode.swift
new file mode 100644
index 0000000..f1c0c0a
--- /dev/null
+++ b/Xcodes/Backend/AvailableXcode.swift
@@ -0,0 +1,17 @@
+import Foundation
+import Version
+
+/// A version of Xcode that's available for installation
+public struct AvailableXcode: Codable {
+    public let version: Version
+    public let url: URL
+    public let filename: String
+    public let releaseDate: Date?
+
+    public init(version: Version, url: URL, filename: String, releaseDate: Date?) {
+        self.version =  version
+        self.url = url
+        self.filename = filename
+        self.releaseDate = releaseDate
+    }
+}
diff --git a/Xcodes/Backend/Downloads.swift b/Xcodes/Backend/Downloads.swift
new file mode 100644
index 0000000..45e2bb7
--- /dev/null
+++ b/Xcodes/Backend/Downloads.swift
@@ -0,0 +1,17 @@
+import Foundation
+import Path
+import Version
+
+struct Downloads: Codable {
+    let downloads: [Download]
+}
+
+public struct Download: Codable {
+    public let name: String
+    public let files: [File]
+    public let dateModified: Date
+
+    public struct File: Codable {
+        public let remotePath: String
+    }
+}
diff --git a/Xcodes/Backend/Models.swift b/Xcodes/Backend/InstalledXcode.swift
similarity index 79%
rename from Xcodes/Backend/Models.swift
rename to Xcodes/Backend/InstalledXcode.swift
index fe0fbb8..aa3d716 100644
--- a/Xcodes/Backend/Models.swift
+++ b/Xcodes/Backend/InstalledXcode.swift
@@ -1,7 +1,8 @@
 import Foundation
-import Path
 import Version
+import Path
 
+/// A version of Xcode that's already installed
 public struct InstalledXcode: Equatable {
     public let path: Path
     /// Composed of the bundle short version from Info.plist and the product build version from version.plist
@@ -39,34 +40,6 @@ public struct InstalledXcode: Equatable {
     }
 }
 
-public struct Xcode: Codable {
-    public let version: Version
-    public let url: URL
-    public let filename: String
-    public let releaseDate: Date?
-
-    public init(version: Version, url: URL, filename: String, releaseDate: Date?) {
-        self.version =  version
-        self.url = url
-        self.filename = filename
-        self.releaseDate = releaseDate
-    }
-}
-
-struct Downloads: Codable {
-    let downloads: [Download]
-}
-
-public struct Download: Codable {
-    public let name: String
-    public let files: [File]
-    public let dateModified: Date
-
-    public struct File: Codable {
-        public let remotePath: String
-    }
-}
-
 public struct InfoPlist: Decodable {
     public let bundleID: String?
     public let bundleShortVersion: String?
@@ -86,4 +59,3 @@ public struct VersionPlist: Decodable {
         case productBuildVersion = "ProductBuildVersion"
     }
 }
-

From 33b5f96ed2be27fc948ea007f4255e877db56f91 Mon Sep 17 00:00:00 2001
From: Brandon Evans <brandon@brandonevans.ca>
Date: Thu, 24 Dec 2020 16:51:57 -0700
Subject: [PATCH 6/9] Merge XcodeList into AppState

---
 Xcodes.xcodeproj/project.pbxproj              |  8 +-
 ...{XcodeList.swift => AppState+Update.swift} | 93 +++++++++++++------
 Xcodes/Backend/AppState.swift                 | 86 +++++------------
 3 files changed, 95 insertions(+), 92 deletions(-)
 rename Xcodes/Backend/{XcodeList.swift => AppState+Update.swift} (64%)

diff --git a/Xcodes.xcodeproj/project.pbxproj b/Xcodes.xcodeproj/project.pbxproj
index 54a1f30..579d372 100644
--- a/Xcodes.xcodeproj/project.pbxproj
+++ b/Xcodes.xcodeproj/project.pbxproj
@@ -37,7 +37,7 @@
 		CABFA9C52592EEEA00380FEE /* FileManager+.swift in Sources */ = {isa = PBXBuildFile; fileRef = CABFA9B82592EEEA00380FEE /* FileManager+.swift */; };
 		CABFA9C72592EEEA00380FEE /* Entry+.swift in Sources */ = {isa = PBXBuildFile; fileRef = CABFA9B22592EEEA00380FEE /* Entry+.swift */; };
 		CABFA9C92592EEEA00380FEE /* URLRequest+Apple.swift in Sources */ = {isa = PBXBuildFile; fileRef = CABFA9AB2592EEE900380FEE /* URLRequest+Apple.swift */; };
-		CABFA9CA2592EEEA00380FEE /* XcodeList.swift in Sources */ = {isa = PBXBuildFile; fileRef = CABFA9A72592EEE900380FEE /* XcodeList.swift */; };
+		CABFA9CA2592EEEA00380FEE /* AppState+Update.swift in Sources */ = {isa = PBXBuildFile; fileRef = CABFA9A72592EEE900380FEE /* AppState+Update.swift */; };
 		CABFA9CC2592EEEA00380FEE /* Path+.swift in Sources */ = {isa = PBXBuildFile; fileRef = CABFA9AE2592EEE900380FEE /* Path+.swift */; };
 		CABFA9CD2592EEEA00380FEE /* Foundation.swift in Sources */ = {isa = PBXBuildFile; fileRef = CABFA9AC2592EEE900380FEE /* Foundation.swift */; };
 		CABFA9CE2592EEEA00380FEE /* Version+Xcode.swift in Sources */ = {isa = PBXBuildFile; fileRef = CABFA9A62592EEE900380FEE /* Version+Xcode.swift */; };
@@ -99,7 +99,7 @@
 		CABFA9A12592EAFB00380FEE /* LICENSE */ = {isa = PBXFileReference; lastKnownFileType = text; path = LICENSE; sourceTree = "<group>"; };
 		CABFA9A32592ED5700380FEE /* Apple.paw */ = {isa = PBXFileReference; lastKnownFileType = file; name = Apple.paw; path = ../xcodes/Apple.paw; sourceTree = "<group>"; };
 		CABFA9A62592EEE900380FEE /* Version+Xcode.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Version+Xcode.swift"; sourceTree = "<group>"; };
-		CABFA9A72592EEE900380FEE /* XcodeList.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = XcodeList.swift; sourceTree = "<group>"; };
+		CABFA9A72592EEE900380FEE /* AppState+Update.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "AppState+Update.swift"; sourceTree = "<group>"; };
 		CABFA9A82592EEE900380FEE /* Version+.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Version+.swift"; sourceTree = "<group>"; };
 		CABFA9A92592EEE900380FEE /* Environment.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Environment.swift; sourceTree = "<group>"; };
 		CABFA9AB2592EEE900380FEE /* URLRequest+Apple.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "URLRequest+Apple.swift"; sourceTree = "<group>"; };
@@ -209,6 +209,7 @@
 			isa = PBXGroup;
 			children = (
 				CA378F982466567600A58CE0 /* AppState.swift */,
+				CABFA9A72592EEE900380FEE /* AppState+Update.swift */,
 				CA9FF88025955C7000E47BAF /* AvailableXcode.swift */,
 				CABFAA2B2592FBFC00380FEE /* Configure.swift */,
 				CABFAA482593162500380FEE /* Bundle+InfoPlistValues.swift */,
@@ -228,7 +229,6 @@
 				CABFA9A82592EEE900380FEE /* Version+.swift */,
 				CA9FF876259528CC00E47BAF /* Version+XcodeReleases.swift */,
 				CABFA9A62592EEE900380FEE /* Version+Xcode.swift */,
-				CABFA9A72592EEE900380FEE /* XcodeList.swift */,
 			);
 			path = Backend;
 			sourceTree = "<group>";
@@ -461,7 +461,7 @@
 				CA735109257BF96D00EA9CF8 /* AttributedText.swift in Sources */,
 				CABFAA492593162500380FEE /* Bundle+InfoPlistValues.swift in Sources */,
 				CA9FF8662595130600E47BAF /* View+IsHidden.swift in Sources */,
-				CABFA9CA2592EEEA00380FEE /* XcodeList.swift in Sources */,
+				CABFA9CA2592EEEA00380FEE /* AppState+Update.swift in Sources */,
 				CA44901F2463AD34003D8213 /* Tag.swift in Sources */,
 				CABFA9BF2592EEEA00380FEE /* URLSession+Promise.swift in Sources */,
 				CABFA9BB2592EEEA00380FEE /* DateFormatter+.swift in Sources */,
diff --git a/Xcodes/Backend/XcodeList.swift b/Xcodes/Backend/AppState+Update.swift
similarity index 64%
rename from Xcodes/Backend/XcodeList.swift
rename to Xcodes/Backend/AppState+Update.swift
index 317b5c1..a6e41aa 100644
--- a/Xcodes/Backend/XcodeList.swift
+++ b/Xcodes/Backend/AppState+Update.swift
@@ -5,15 +5,47 @@ import Version
 import SwiftSoup
 import struct XCModel.Xcode
 
-/// Provides lists of available Xcodes
-public final class XcodeList {
-    public init() {
-        try? loadCachedAvailableXcodes()
+extension AppState {
+    private var dataSource: DataSource {
+        Current.defaults.string(forKey: "dataSource").flatMap(DataSource.init(rawValue:)) ?? .default
+    }
+    
+    func updateIfNeeded() {
+        guard
+            let lastUpdated = Current.defaults.date(forKey: "lastUpdated"),
+            // This is bad date math but for this use case it doesn't need to be exact
+            lastUpdated < Current.date().addingTimeInterval(-60 * 60 * 24) 
+        else { return }
+        update() as Void
     }
 
-    public private(set) var availableXcodes: [Xcode] = []
+    func update() {
+        guard !isUpdating else { return }
+        updatePublisher = update()
+            .sink(
+                receiveCompletion: { [unowned self] completion in
+                    switch completion {
+                    case let .failure(error):
+                        self.error = AlertContent(title: "Update Error", message: error.legibleLocalizedDescription)
+                    case .finished:
+                        Current.defaults.setDate(Current.date(), forKey: "lastUpdated")
+                    }
 
-    public func update(dataSource: DataSource) -> AnyPublisher<[Xcode], Error> {
+                    self.updatePublisher = nil
+                },
+                receiveValue: { _ in }
+            )
+    }
+    
+    private func update() -> AnyPublisher<[AvailableXcode], Error> {
+        signInIfNeeded()
+            .flatMap { [unowned self] in
+                self.updateAvailableXcodes(from: self.dataSource)
+            }
+            .eraseToAnyPublisher()
+    }
+    
+    private func updateAvailableXcodes(from dataSource: DataSource) -> AnyPublisher<[AvailableXcode], Error> {
         switch dataSource {
         case .apple:
             return releasedXcodes().combineLatest(prereleaseXcodes())
@@ -26,16 +58,21 @@ public final class XcodeList {
                     let xcodes = releasedXcodes.filter { releasedXcode in
                         prereleaseXcodes.contains { $0.version.isEqualWithoutBuildMetadataIdentifiers(to: releasedXcode.version) } == false
                     } + prereleaseXcodes
-                    self.availableXcodes = xcodes
-                    try? self.cacheAvailableXcodes(xcodes)
                     return xcodes
                 }
+                .handleEvents(
+                    receiveOutput: { xcodes in
+                        self.availableXcodes = xcodes
+                        try? self.cacheAvailableXcodes(xcodes)
+                    }
+                )
                 .eraseToAnyPublisher()
         case .xcodeReleases:
             return xcodeReleases()
                 .receive(on: DispatchQueue.main)
                 .handleEvents(
                     receiveOutput: { xcodes in
+                        self.availableXcodes = xcodes
                         try? self.cacheAvailableXcodes(xcodes)    
                     }
                 )
@@ -44,14 +81,16 @@ public final class XcodeList {
     }
 }
 
-extension XcodeList {
-    private func loadCachedAvailableXcodes() throws {
+extension AppState {
+    // MARK: - Available Xcode Cache
+
+    func loadCachedAvailableXcodes() throws {
         guard let data = Current.files.contents(atPath: Path.cacheFile.string) else { return }
-        let xcodes = try JSONDecoder().decode([Xcode].self, from: data)
+        let xcodes = try JSONDecoder().decode([AvailableXcode].self, from: data)
         self.availableXcodes = xcodes
     }
 
-    private func cacheAvailableXcodes(_ xcodes: [Xcode]) throws {
+    func cacheAvailableXcodes(_ xcodes: [AvailableXcode]) throws {
         let data = try JSONEncoder().encode(xcodes)
         try FileManager.default.createDirectory(at: Path.cacheFile.url.deletingLastPathComponent(),
                                                 withIntermediateDirectories: true)
@@ -59,20 +98,20 @@ extension XcodeList {
     }
 }
 
-extension XcodeList {
-    // MARK: Apple
+extension AppState {
+    // MARK: - Apple
     
-    private func releasedXcodes() -> AnyPublisher<[Xcode], Error> {
+    private func releasedXcodes() -> AnyPublisher<[AvailableXcode], Error> {
         Current.network.dataTask(with: URLRequest.downloads)
             .map(\.data)
             .decode(type: Downloads.self, decoder: configure(JSONDecoder()) {
                 $0.dateDecodingStrategy = .formatted(.downloadsDateModified)
             })
-            .map { downloads -> [Xcode] in
+            .map { downloads -> [AvailableXcode] in
                 let xcodes = downloads
                     .downloads
                     .filter { $0.name.range(of: "^Xcode [0-9]", options: .regularExpression) != nil }
-                    .compactMap { download -> Xcode? in
+                    .compactMap { download -> AvailableXcode? in
                         let urlPrefix = URL(string: "https://download.developer.apple.com/")!
                         guard 
                             let xcodeFile = download.files.first(where: { $0.remotePath.hasSuffix("dmg") || $0.remotePath.hasSuffix("xip") }),
@@ -80,22 +119,22 @@ extension XcodeList {
                         else { return nil }
 
                         let url = urlPrefix.appendingPathComponent(xcodeFile.remotePath)
-                        return Xcode(version: version, url: url, filename: String(xcodeFile.remotePath.suffix(fromLast: "/")), releaseDate: download.dateModified)
+                        return AvailableXcode(version: version, url: url, filename: String(xcodeFile.remotePath.suffix(fromLast: "/")), releaseDate: download.dateModified)
                     }
                 return xcodes
             }
             .eraseToAnyPublisher()
     }
 
-    private func prereleaseXcodes() -> AnyPublisher<[Xcode], Error> {
+    private func prereleaseXcodes() -> AnyPublisher<[AvailableXcode], Error> {
         Current.network.dataTask(with: URLRequest.download)
-            .tryMap { (data, _) -> [Xcode] in
+            .tryMap { (data, _) -> [AvailableXcode] in
                 try self.parsePrereleaseXcodes(from: data)
             }
             .eraseToAnyPublisher()
     }
 
-    private func parsePrereleaseXcodes(from data: Data) throws -> [Xcode] {
+    private func parsePrereleaseXcodes(from data: Data) throws -> [AvailableXcode] {
         let body = String(data: data, encoding: .utf8)!
         let document = try SwiftSoup.parse(body)
 
@@ -110,19 +149,19 @@ extension XcodeList {
 
         let filename = String(path.suffix(fromLast: "/"))
 
-        return [Xcode(version: version, url: url, filename: filename, releaseDate: DateFormatter.downloadsReleaseDate.date(from: releaseDateString))]
+        return [AvailableXcode(version: version, url: url, filename: filename, releaseDate: DateFormatter.downloadsReleaseDate.date(from: releaseDateString))]
     }
 }
 
-extension XcodeList {
-    // MARK: XcodeReleases
+extension AppState {
+    // MARK: - XcodeReleases
     
-    private func xcodeReleases() -> AnyPublisher<[Xcode], Error> {
+    private func xcodeReleases() -> AnyPublisher<[AvailableXcode], Error> {
         Current.network.dataTask(with: URLRequest(url: URL(string: "https://xcodereleases.com/data.json")!))
             .map(\.data)
             .decode(type: [XCModel.Xcode].self, decoder: JSONDecoder())
             .map { xcReleasesXcodes in  
-                let xcodes = xcReleasesXcodes.compactMap { xcReleasesXcode -> Xcode? in
+                let xcodes = xcReleasesXcodes.compactMap { xcReleasesXcode -> AvailableXcode? in
                     guard
                         let downloadURL = xcReleasesXcode.links?.download?.url,
                         let version = Version(xcReleasesXcode: xcReleasesXcode)
@@ -134,7 +173,7 @@ extension XcodeList {
                         day: xcReleasesXcode.date.day
                     ))
                     
-                    return Xcode(
+                    return AvailableXcode(
                         version: version,
                         url: downloadURL,
                         filename: String(downloadURL.path.suffix(fromLast: "/")),
diff --git a/Xcodes/Backend/AppState.swift b/Xcodes/Backend/AppState.swift
index e9e36bd..e0ec6e2 100644
--- a/Xcodes/Backend/AppState.swift
+++ b/Xcodes/Backend/AppState.swift
@@ -7,12 +7,16 @@ import KeychainAccess
 import SwiftUI
 
 class AppState: ObservableObject {
-    private let list = XcodeList()
     private let client = AppleAPI.Client()
     private var cancellables = Set<AnyCancellable>()
     
     @Published var authenticationState: AuthenticationState = .unauthenticated
-    @Published var allVersions: [XcodeVersion] = []
+    @Published var availableXcodes: [AvailableXcode] = [] {
+        willSet {
+            updateAllVersions(newValue)
+        }
+    }
+    var allVersions: [XcodeVersion] = []
     @Published var updatePublisher: AnyCancellable?
     var isUpdating: Bool { updatePublisher != nil }
     @Published var error: AlertContent?
@@ -21,8 +25,8 @@ class AppState: ObservableObject {
     @Published var isProcessingAuthRequest = false
     @Published var secondFactorData: SecondFactorData?
     
-    private var dataSource: DataSource {
-        Current.defaults.string(forKey: "dataSource").flatMap(DataSource.init(rawValue:)) ?? .default
+    init() {
+        try? loadCachedAvailableXcodes()
     }
     
     // MARK: - Authentication
@@ -165,53 +169,29 @@ class AppState: ObservableObject {
         authenticationState = .unauthenticated
     }
     
-    // MARK: - Load Xcode Versions
+    // MARK: -
     
-    func update() {
-        guard !isUpdating else { return }
-        updatePublisher = update()
-            .sink(
-                receiveCompletion: { [unowned self] _ in
-                    Current.defaults.setDate(Current.date(), forKey: "lastUpdated")
-                    self.updatePublisher = nil
-                },
-                receiveValue: { _ in }
-            )
+    func install(id: String) {
+        // TODO:
     }
     
-    func updateIfNeeded() {
-        guard
-            let lastUpdated = Current.defaults.date(forKey: "lastUpdated"),
-            // This is bad date math but for this use case it doesn't need to be exact
-            lastUpdated < Current.date().addingTimeInterval(-60 * 60 * 24) 
-        else { return }
-        update() as Void
+    func uninstall(id: String) {
+        // TODO:
     }
     
-    private func update() -> AnyPublisher<[Xcode], Never> {
-        signInIfNeeded()
-            .flatMap { [unowned self] in
-                self.list.update(dataSource: self.dataSource)
-            }
-            .handleEvents(
-                receiveCompletion: { completion in
-                    if case let .failure(error) = completion {
-                        self.error = AlertContent(title: "Update Error", message: error.legibleLocalizedDescription)
-                    }
-                }
-            )
-            .catch { _ in
-                Just(self.list.availableXcodes)
-            }
-            .handleEvents(
-                receiveOutput: { [unowned self] xcodes in
-                    self.updateAllVersions(xcodes)
-                }
-            )
-            .eraseToAnyPublisher()
+    func reveal(id: String) {
+        // TODO: show error if not
+        guard let installedXcode = Current.files.installedXcodes(Path.root/"Applications").first(where: { $0.version.xcodeDescription == id }) else { return }
+        NSWorkspace.shared.activateFileViewerSelecting([installedXcode.path.url])
+    }
+
+    func select(id: String) {
+        // TODO:
     }
     
-    private func updateAllVersions(_ xcodes: [Xcode]) {
+    // MARK: - Private
+    
+    private func updateAllVersions(_ xcodes: [AvailableXcode]) {
         let installedXcodes = Current.files.installedXcodes(Path.root/"Applications")
         var allXcodeVersions = xcodes.map { $0.version }
         for installedXcode in installedXcodes {
@@ -243,26 +223,10 @@ class AppState: ObservableObject {
             }
     }
     
-    func install(id: String) {
-        // TODO:
-    }
-    
-    func uninstall(id: String) {
-        // TODO:
-    }
-    
-    func reveal(id: String) {
-        // TODO: show error if not
-        guard let installedXcode = Current.files.installedXcodes(Path.root/"Applications").first(where: { $0.version.xcodeDescription == id }) else { return }
-        NSWorkspace.shared.activateFileViewerSelecting([installedXcode.path.url])
-    }
-
-    func select(id: String) {
-        // TODO:
-    }
 
     // MARK: - Nested Types
     
+    /// A merging of AvailableXcode and InstalledXcode prepared for display
     struct XcodeVersion: Identifiable {
         let title: String
         let installState: InstallState

From 115de2d3a2bf958ca77257dee2b90001213a986f Mon Sep 17 00:00:00 2001
From: Brandon Evans <brandon@brandonevans.ca>
Date: Sat, 26 Dec 2020 19:30:28 -0700
Subject: [PATCH 7/9] Show last updated date in toolbar

---
 Xcodes/Frontend/XcodeList/XcodeListView.swift | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/Xcodes/Frontend/XcodeList/XcodeListView.swift b/Xcodes/Frontend/XcodeList/XcodeListView.swift
index cb5523a..c97b3b6 100644
--- a/Xcodes/Frontend/XcodeList/XcodeListView.swift
+++ b/Xcodes/Frontend/XcodeList/XcodeListView.swift
@@ -7,6 +7,7 @@ struct XcodeListView: View {
     @State private var selection = Set<String>()
     @State private var rowBeingConfirmedForUninstallation: AppState.XcodeVersion?
     @State private var searchText: String = ""
+    @AppStorage("lastUpdated") private var lastUpdated: Double?
     
     @AppStorage("xcodeListCategory") private var category: Category = .all
     
@@ -104,7 +105,7 @@ struct XcodeListView: View {
                     .frame(width: 200)
             }
         }
-        .navigationSubtitle(Text("Updated \(Date().addingTimeInterval(-600), style: .relative) ago"))
+        .navigationSubtitle(subtitleText)
         .frame(minWidth: 200, maxWidth: .infinity, minHeight: 300, maxHeight: .infinity)
         .alert(item: $appState.error) { error in
             Alert(title: Text(error.title), 
@@ -137,6 +138,14 @@ struct XcodeListView: View {
             SignInPhoneListView(isPresented: $appState.secondFactorData.isNotNil, authOptions: secondFactorData.authOptions, sessionData: secondFactorData.sessionData)
         }
     }
+    
+    private var subtitleText: Text {
+        if let lastUpdated = lastUpdated.map(Date.init(timeIntervalSince1970:)) {
+            return Text("Updated at \(lastUpdated, style: .date) \(lastUpdated, style: .time)")
+        } else {
+            return Text("")
+        }
+    }
 }
 
 struct XcodeListView_Previews: PreviewProvider {

From 8594996b871ed79b3152d5aaeaa6bd84aa76c25a Mon Sep 17 00:00:00 2001
From: Brandon Evans <brandon@brandonevans.ca>
Date: Sun, 27 Dec 2020 16:49:08 -0700
Subject: [PATCH 8/9] Add feedback IDs in comments

---
 Xcodes/XcodesApp.swift | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Xcodes/XcodesApp.swift b/Xcodes/XcodesApp.swift
index 18cfdea..ea66958 100644
--- a/Xcodes/XcodesApp.swift
+++ b/Xcodes/XcodesApp.swift
@@ -14,6 +14,7 @@ struct XcodesApp: App {
                 // This is intentionally used on a View, and not on a WindowGroup, 
                 // so that it's triggered when an individual window's phase changes instead of all window phases.
                 // When used on a View it's also invoked on launch, which doesn't occur with a WindowGroup. 
+                // FB8954581 ScenePhase read from App doesn't return a value on launch
                 .onChange(of: scenePhase) { newScenePhase in
                     if case .active = newScenePhase {
                         appState.updateIfNeeded()
@@ -69,6 +70,7 @@ class AppDelegate: NSObject, NSApplicationDelegate {
     /// WindowGroup lets the user open more than one window right now, which is a little strange for an About window.
     /// (It's also weird that the main Xcode list window can be opened more than once, there should only be one.)
     /// To work around this, an AppDelegate holds onto a single instance of an NSWindow that is shown here.  
+    /// FB8954588 Scene / WindowGroup is missing API to limit the number of windows that can be created
     func showAboutWindow() {
         aboutWindow.center()
         aboutWindow.makeKeyAndOrderFront(nil)

From de54c3d784498542177a9b4e3f45b8b0efad0276 Mon Sep 17 00:00:00 2001
From: Brandon Evans <brandon@brandonevans.ca>
Date: Sun, 27 Dec 2020 18:33:29 -0700
Subject: [PATCH 9/9] Only sign in before refreshing when using Apple data
 source

---
 Xcodes/Backend/AppState+Update.swift | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/Xcodes/Backend/AppState+Update.swift b/Xcodes/Backend/AppState+Update.swift
index a6e41aa..856d49f 100644
--- a/Xcodes/Backend/AppState+Update.swift
+++ b/Xcodes/Backend/AppState+Update.swift
@@ -21,7 +21,7 @@ extension AppState {
 
     func update() {
         guard !isUpdating else { return }
-        updatePublisher = update()
+        updatePublisher = updateAvailableXcodes(from: self.dataSource)
             .sink(
                 receiveCompletion: { [unowned self] completion in
                     switch completion {
@@ -36,19 +36,12 @@ extension AppState {
                 receiveValue: { _ in }
             )
     }
-    
-    private func update() -> AnyPublisher<[AvailableXcode], Error> {
-        signInIfNeeded()
-            .flatMap { [unowned self] in
-                self.updateAvailableXcodes(from: self.dataSource)
-            }
-            .eraseToAnyPublisher()
-    }
-    
+
     private func updateAvailableXcodes(from dataSource: DataSource) -> AnyPublisher<[AvailableXcode], Error> {
         switch dataSource {
         case .apple:
-            return releasedXcodes().combineLatest(prereleaseXcodes())
+            return signInIfNeeded() 
+                .flatMap { [unowned self] in self.releasedXcodes().combineLatest(self.prereleaseXcodes()) }
                 .receive(on: DispatchQueue.main)
                 .map { releasedXcodes, prereleaseXcodes in
                     // Starting with Xcode 11 beta 6, developer.apple.com/download and developer.apple.com/download/more both list some pre-release versions of Xcode.