[Widgets]: [WIP]: Implement Pagination in ActiveAppWidget based on user interaction

AltStore.xcodeproj/project.pbxproj

@@ -55,6 +55,8 @@
 		A809F69F2D04D7B300F0F0F3 /* libem_proxy_static.a in Frameworks */ = {isa = PBXBuildFile; fileRef = A809F6942D04D71200F0F0F3 /* libem_proxy_static.a */; };
 		A809F6A82D04DA1900F0F0F3 /* minimuxer.swift in Sources */ = {isa = PBXBuildFile; fileRef = A809F6A32D04DA1900F0F0F3 /* minimuxer.swift */; };
 		A809F6A92D04DA1900F0F0F3 /* SwiftBridgeCore.swift in Sources */ = {isa = PBXBuildFile; fileRef = A809F6A72D04DA1900F0F0F3 /* SwiftBridgeCore.swift */; };
+		A80D790D2D2F20AF00A40F40 /* PaginationIntent.swift in Sources */ = {isa = PBXBuildFile; fileRef = A80D790C2D2F20AF00A40F40 /* PaginationIntent.swift */; };
+		A80D790F2D2F217000A40F40 /* PaginationViewModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = A80D790E2D2F217000A40F40 /* PaginationViewModel.swift */; };
 		A82067842D03DC0600645C0D /* OperatingSystemVersion+Comparable.swift in Sources */ = {isa = PBXBuildFile; fileRef = D5708416292448DA00D42D34 /* OperatingSystemVersion+Comparable.swift */; };
 		A82067C42D03E0DE00645C0D /* SemanticVersion in Frameworks */ = {isa = PBXBuildFile; productRef = A82067C32D03E0DE00645C0D /* SemanticVersion */; };
 		A859ED5C2D1EE827003DCC58 /* OpenSSL.xcframework in Frameworks */ = {isa = PBXBuildFile; fileRef = A859ED5B2D1EE80D003DCC58 /* OpenSSL.xcframework */; };
@@ -624,6 +626,8 @@
 		A809F6A52D04DA1900F0F0F3 /* minimuxer-helpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "minimuxer-helpers.swift"; sourceTree = "<group>"; };
 		A809F6A62D04DA1900F0F0F3 /* SwiftBridgeCore.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = SwiftBridgeCore.h; sourceTree = "<group>"; };
 		A809F6A72D04DA1900F0F0F3 /* SwiftBridgeCore.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SwiftBridgeCore.swift; sourceTree = "<group>"; };
+		A80D790C2D2F20AF00A40F40 /* PaginationIntent.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PaginationIntent.swift; sourceTree = "<group>"; };
+		A80D790E2D2F217000A40F40 /* PaginationViewModel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PaginationViewModel.swift; sourceTree = "<group>"; };
 		A859ED5B2D1EE80D003DCC58 /* OpenSSL.xcframework */ = {isa = PBXFileReference; expectedSignature = "AppleDeveloperProgram:67RAULRX93:Marcin Krzyzanowski"; lastKnownFileType = wrapper.xcframework; name = OpenSSL.xcframework; path = SideStore/AltSign/Dependencies/OpenSSL/Frameworks/OpenSSL.xcframework; sourceTree = "<group>"; };
 		A85ACB8E2D1F31C400AA3DE7 /* AltBackup.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; path = AltBackup.xcconfig; sourceTree = "<group>"; };
 		A85ACB8F2D1F31C400AA3DE7 /* AltStore.debug.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; path = AltStore.debug.xcconfig; sourceTree = "<group>"; };
@@ -1161,6 +1165,14 @@
 			name = Products;
 			sourceTree = "<group>";
 		};
+		A80D790B2D2F209700A40F40 /* Intents */ = {
+			isa = PBXGroup;
+			children = (
+				A80D790C2D2F20AF00A40F40 /* PaginationIntent.swift */,
+			);
+			path = Intents;
+			sourceTree = "<group>";
+		};
 		A85ACB942D1F31C400AA3DE7 /* xcconfigs */ = {
 			isa = PBXGroup;
 			children = (
@@ -1693,6 +1705,7 @@
 		BF98916C250AABF3002ACF50 /* AltWidget */ = {
 			isa = PBXGroup;
 			children = (
+				A80D790B2D2F209700A40F40 /* Intents */,
 				A800F6FE2CE28DE300208744 /* Extensions */,
 				BF8B17F0250AC62400F8157F /* AltWidgetExtension.entitlements */,
 				D5FD4EC42A952EAD0097BEE8 /* AltWidgetBundle.swift */,
@@ -2067,6 +2080,7 @@
 		D50C29F22A8ECD71009AB488 /* Widgets */ = {
 			isa = PBXGroup;
 			children = (
+				A80D790E2D2F217000A40F40 /* PaginationViewModel.swift */,
 				D577AB7E2A96878A007FE952 /* AppDetailWidget.swift */,
 				D55467C42A8D72C300F4CE90 /* ActiveAppsWidget.swift */,
 				BF98917D250AAC4F002ACF50 /* LockScreenWidget.swift */,
@@ -2898,12 +2912,14 @@
 				D577AB7F2A96878A007FE952 /* AppDetailWidget.swift in Sources */,
 				BF98917E250AAC4F002ACF50 /* Countdown.swift in Sources */,
 				D5151BE22A90363300C96F28 /* RefreshAllAppsWidgetIntent.swift in Sources */,
+				A80D790D2D2F20AF00A40F40 /* PaginationIntent.swift in Sources */,
 				D5FD4EC92A9530C00097BEE8 /* AppSnapshot.swift in Sources */,
 				D5151BE72A90395400C96F28 /* View+AltWidget.swift in Sources */,
 				BF98917F250AAC4F002ACF50 /* LockScreenWidget.swift in Sources */,
 				A800F7042CE28E3800208744 /* View+AltWidget.swift in Sources */,
 				BF98917F250AAC4F002ACF50 /* LockScreenWidget.swift in Sources */,
 				D5FD4EC52A952EAD0097BEE8 /* AltWidgetBundle.swift in Sources */,
+				A80D790F2D2F217000A40F40 /* PaginationViewModel.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

AltWidget/AppsTimelineProvider.swift

@@ -24,6 +24,29 @@ struct AppsTimelineProvider
 {
     typealias Entry = AppsEntry
     
+    private var viewModel: PaginationViewModel?
+    private let widgetID: String?
+    
+    init(_ viewModel: PaginationViewModel? = nil){
+        self.viewModel = viewModel
+        self.widgetID = viewModel?.widgetID
+    }
+    
+    private func reloadEntries(apps: [AppSnapshot]){
+        guard let viewModel = self.viewModel else { return }
+        
+        let entries     = Set(viewModel.backup_entries.map{ (app: AppSnapshot) in app.bundleIdentifier })
+        let app_entries = Set(apps.map{ (app: AppSnapshot) in app.bundleIdentifier })
+        
+        // this updates the in-memory entries
+        if entries.isEmpty || entries != app_entries{
+            self.viewModel?.setEntries(apps)
+            // initialize the view
+            self.viewModel?.handlePagination(.up)
+        }
+    }
+    
+    
     func placeholder(in context: TimelineProviderContext) -> AppsEntry
     {
         return AppsEntry(date: Date(), apps: [], isPlaceholder: true)
@@ -37,6 +60,9 @@ struct AppsTimelineProvider
             
             let apps = try await self.fetchApps(withBundleIDs: appBundleIDs)
             
+            // send this for pagination
+            reloadEntries(apps: apps)
+            
             let entry = AppsEntry(date: Date(), apps: apps)
             return entry
         }
@@ -57,6 +83,9 @@ struct AppsTimelineProvider
             
             let apps = try await self.fetchApps(withBundleIDs: appBundleIDs)
 
+            // send this for pagination
+            reloadEntries(apps: apps)
+
             let entries = self.makeEntries(for: apps)
             let timeline = Timeline(entries: entries, policy: .atEnd)
             return timeline
@@ -203,6 +232,7 @@ extension AppsTimelineProvider: TimelineProvider
 
 extension AppsTimelineProvider: IntentTimelineProvider
 {
+
     typealias Intent = ViewAppIntent
     
     func getSnapshot(for intent: Intent, in context: Context, completion: @escaping (AppsEntry) -> Void)

AltWidget/Extensions/View+AltWidget.swift

@@ -53,4 +53,29 @@ extension View
             self
         }
     }
+
+    @ViewBuilder
+    func pageUpButton(widgetID: String) -> some View {
+        if #available(iOSApplicationExtension 17, *) {
+            Button(intent: PaginationIntent(.up, widgetID)){
+                self
+            }
+            .buttonStyle(.plain)
+        } else {
+            self
+        }
+    }
+
+    @ViewBuilder
+    func pageDownButton(widgetID: String) -> some View {
+        if #available(iOSApplicationExtension 17, *) {
+            Button(intent: PaginationIntent(.down, widgetID)){
+                self
+            }
+            .buttonStyle(.plain)
+        } else {
+            self
+        }
+    }
+
 }

AltWidget/Intents/PaginationIntent.swift

@@ -0,0 +1,46 @@
+//
+//  PaginationIntent.swift
+//  AltStore
+//
+//  Created by Magesh K on 08/01/25.
+//  Copyright © 2025 SideStore. All rights reserved.
+//
+
+import AppIntents
+import WidgetKit
+
+public enum Direction: String{
+    case up = "up"
+    case down = "down"
+}
+
+@available(iOS 17, *)
+struct PaginationIntent: AppIntent, @unchecked Sendable {
+    static var title: LocalizedStringResource { "Scroll up or down in Active Apps Widget" }
+    static var isDiscoverable: Bool { false }
+
+    @Parameter(title: "Direction")
+    var direction: String
+
+    @Parameter(title: "Widget Identifier")
+    var widgetID: String
+        
+    init(){}
+    
+    init(_ direction: Direction, _ widgetID: String){
+        self.direction = direction.rawValue
+        self.widgetID = widgetID
+    }
+
+    func perform() async throws -> some IntentResult {
+        let direction = Direction(rawValue: direction)!
+        guard let viewModel = PaginationViewModel.instance(widgetID) else{
+            print("viewModel for widgetID: \(widgetID) not found, ignoring request")
+            return .result()
+        }
+        viewModel.handlePagination(direction)
+        WidgetCenter.shared.reloadTimelines(ofKind: viewModel.widgetID)
+        return .result()
+    }
+}
+

AltWidget/Widgets/ActiveAppsWidget.swift

@@ -24,17 +24,25 @@ private extension Color
 //@available(iOS 17, *)
 struct ActiveAppsWidget: Widget
 {
-    private let kind: String = "ActiveApps"
+    private var viewModel = PaginationViewModel.getNewInstance(
+        "ActiveApps" + UUID().uuidString
+    )
     
     public var body: some WidgetConfiguration {
         if #available(iOS 17, *)
         {
-            return StaticConfiguration(kind: kind, provider: AppsTimelineProvider()) { entry in
+            let staticConfig =  StaticConfiguration(
-                ActiveAppsWidgetView(entry: entry)
+                kind: viewModel.widgetID,
+                provider: AppsTimelineProvider(viewModel)
+            ) { entry in
+                ActiveAppsWidgetView(entry: entry, viewModel: viewModel)
             }
             .supportedFamilies([.systemMedium])
             .configurationDisplayName("Active Apps")
             .description("View remaining days until your active apps expire. Tap the countdown timers to refresh them in the background.")
+            
+            // this widgetConfiguration is requested/drawn once per widget per process lifecycle
+            return staticConfig
         }
         else
         {
@@ -50,9 +58,16 @@ private struct ActiveAppsWidgetView: View
 {
     var entry: AppsEntry
     
+    @ObservedObject private var viewModel: PaginationViewModel
+    
     @Environment(\.colorScheme)
     private var colorScheme
     
+    init(entry: AppsEntry, viewModel: PaginationViewModel){
+        self.entry = entry
+        self.viewModel = viewModel
+    }
+    
     var body: some View {
         Group {
             if entry.apps.isEmpty
@@ -80,15 +95,19 @@ private struct ActiveAppsWidgetView: View
     private var content: some View {
         GeometryReader { (geometry) in
             
-            let numberOfApps = max(entry.apps.count, 1) // Ensure we don't divide by 0
+            let MAX_ROWS_PER_PAGE = PaginationViewModel.MAX_ROWS_PER_PAGE
-            let preferredRowHeight = (geometry.size.height / Double(numberOfApps)) - 8
+            
+            let preferredRowHeight = (geometry.size.height / Double(MAX_ROWS_PER_PAGE)) - 8
             let rowHeight = min(preferredRowHeight, geometry.size.height / 2)
             
-            ZStack(alignment: .center) {
+            HStack(alignment: .center) {
-                VStack(spacing: 12) {
-                    ForEach(entry.apps, id: \.bundleIdentifier) { app in
                 
-                        let icon = app.icon ?? UIImage(named: "SideStore")!
+//                VStack(spacing: 12) {
+                LazyVStack(spacing: 12) {
+                    ForEach($viewModel.sliding_window, id: \.bundleIdentifier) { app in
+                        let app = app.wrappedValue      // remove the binding
+                        
+                        let icon: UIImage = app.icon ?? UIImage(named: "SideStore")!
                         
                         // 1024x1024 images are not supported by previews but supported by device
                         // so we scale the image to 97% so as to reduce its actual size but not too much
@@ -142,12 +161,33 @@ private struct ActiveAppsWidgetView: View
                             }
                             .font(.system(size: 16, weight: .semibold, design: .rounded))
                             .invalidatableContent()
-                            .padding(.horizontal, 8)
                             .activatesRefreshAllAppsIntent()
                         }
                         .frame(height: rowHeight)
                     }
                 }
+                
+                Spacer(minLength: 16)
+                
+                let buttonWidth: CGFloat = 16
+                VStack {
+                    Image(systemName: "arrow.up")
+                        .resizable()
+                        .frame(width: buttonWidth, height: buttonWidth)
+                        .mask(Capsule())
+                        .opacity(0.3)
+                        .pageUpButton(widgetID: viewModel.widgetID)
+                    
+                    Spacer()
+                    
+                    Image(systemName: "arrow.down")
+                        .resizable()
+                        .frame(width: buttonWidth, height: buttonWidth)
+                        .opacity(0.3)
+                        .mask(Capsule())
+                        .pageDownButton(widgetID: viewModel.widgetID)
+                }
+                .padding(.vertical)
             }
             .frame(maxWidth: .infinity, maxHeight: .infinity)
         }

AltWidget/Widgets/LockScreenWidget.swift

@@ -82,6 +82,7 @@ private struct ComplicationView: View
         
         let progress = Double(daysRemaining) / Double(totalDays)
         
+        // TODO: Gauge initialized with an out-of-bounds progress amount. The amount will be clamped to the nearest bound.
         Gauge(value: progress) {
             if daysRemaining < 0
             {

AltWidget/Widgets/PaginationViewModel.swift

@@ -0,0 +1,105 @@
+//
+//  PaginationViewModel.swift
+//  AltStore
+//
+//  Created by Magesh K on 09/01/25.
+//  Copyright © 2025 SideStore. All rights reserved.
+//
+
+import Foundation
+import Combine
+
+class PaginationViewModel: ObservableObject {
+    
+    private static var instances: [String:PaginationViewModel] = [:]
+    
+    public static let MAX_ROWS_PER_PAGE = 3
+    
+    @Published public var sliding_window: [AppSnapshot] = []
+    @Published public var refreshed: Bool = false
+    
+    private init(){}
+    
+    private var _widgetID: String?
+    public lazy var widgetID: String = {
+        return _widgetID!
+    }()
+    
+    public static func getNewInstance(_ widgetID: String) -> PaginationViewModel {
+        let instance = PaginationViewModel()
+        PaginationViewModel.instances[widgetID] = instance
+        instance._widgetID = widgetID
+        return instance
+    }
+
+    public static func instance(_ widgetID: String) -> PaginationViewModel? {
+        return PaginationViewModel.instances[widgetID]
+    }
+    
+    public private(set) var backup_entries: [AppSnapshot] = []
+    
+    private var r_queue: [AppSnapshot] = []
+    private var l_queue: [AppSnapshot] = []
+    
+    private var lastIndex: Int { r_queue.count - 1 }
+
+    public func setEntries(_ entries: [AppSnapshot]) {
+        r_queue = entries
+        backup_entries = entries
+    }
+    
+    public func handlePagination(_ direction: Direction) {
+        
+        var sliding_window = Array(sliding_window)
+        var l_queue = Array(l_queue)
+        var r_queue = Array(r_queue)
+        
+        // If entries is empty, do nothing
+        guard !backup_entries.isEmpty else {
+            sliding_window.removeAll()
+            return
+        }
+        
+        switch direction {
+        case .up:
+            // move window contents to left-q since we are moving right side
+            if !sliding_window.isEmpty {
+                // take the window as-is and put it to right of l_queue
+                l_queue.append(contentsOf: sliding_window)
+            }
+            
+            // clear the window
+            sliding_window.removeAll()
+        
+            let size = min(r_queue.count, Self.MAX_ROWS_PER_PAGE)
+            for _ in 0..<size {
+                if !r_queue.isEmpty {
+                    sliding_window.append(r_queue.removeFirst())
+                }
+            }
+            
+        case .down:
+            // move window contents to right-q since we are moving left side
+            if !sliding_window.isEmpty {
+                // take the window as-is and put it to left of r_queue
+                r_queue.insert(contentsOf: sliding_window, at: 0)
+            }
+            
+            // clear the window
+            sliding_window.removeAll()
+            
+            let size = min(l_queue.count, Self.MAX_ROWS_PER_PAGE)
+            for _ in 0..<size {
+                sliding_window.insert(l_queue.removeLast(), at: 0)
+            }
+        }
+        
+        if !sliding_window.isEmpty {
+            // commit
+            self.sliding_window = sliding_window
+            self.l_queue = l_queue
+            self.r_queue = r_queue
+            self.refreshed = true
+        }
+    }
+}