Integrating Decide into FoodTruck app

App/App.swift

@@ -7,6 +7,7 @@ The single entry point for the Food Truck app on iOS and macOS.
 
 import SwiftUI
 import FoodTruckKit
+import Decide
 
 /// The app's entry point.
 ///
@@ -18,7 +19,11 @@ struct FoodTruckApp: App {
     @StateObject private var model = FoodTruckModel()
     /// The in-app purchase store's state.
     @StateObject private var accountStore = AccountStore()
-
+
+    init() {
+        ApplicationEnvironment.bootstrap(donuts: model.donuts)
+    }
+
     /// The app's body function.
     ///
     /// This app uses a [`WindowGroup`](https://developer.apple.com/documentation/swiftui/windowgroup) scene, which contains the root view of the app, ``ContentView``.

App/Donut/DonutEditor.swift

@@ -7,10 +7,16 @@ The donut editor view.
 
 import SwiftUI
 import FoodTruckKit
+import Decide
 
 struct DonutEditor: View {
-    @Binding var donut: Donut
-
+    @Observe(\FoodTruckState.$selectedDonut) var id
+    @BindKeyed(\FoodTruckState.Data.$donut) var donuts
+
+    var donut: Donut {
+        donuts[id]
+    }
+
     var body: some View {
         ZStack {
             #if os(macOS)
@@ -76,7 +82,7 @@ struct DonutEditor: View {
     @ViewBuilder
     var editorContent: some View {
         Section("Donut") {
-            TextField("Name", text: $donut.name, prompt: Text("Donut Name"))
+            TextField("Name", text: donuts[id].name, prompt: Text("Donut Name"))
         }
 
         Section("Flavor Profile") {
@@ -108,14 +114,14 @@ struct DonutEditor: View {
         }
 
         Section("Ingredients") {
-            Picker("Dough", selection: $donut.dough) {
+            Picker("Dough", selection: donuts[id].dough) {
                 ForEach(Donut.Dough.all) { dough in
                     Text(dough.name)
                         .tag(dough)
                 }
             }
 
-            Picker("Glaze", selection: $donut.glaze) {
+            Picker("Glaze", selection: donuts[id].glaze) {
                 Section {
                     Text("None")
                         .tag(nil as Donut.Glaze?)
@@ -126,7 +132,7 @@ struct DonutEditor: View {
                 }
             }
 
-            Picker("Topping", selection: $donut.topping) {
+            Picker("Topping", selection: donuts[id].topping) {
                 Section {
                     Text("None")
                         .tag(nil as Donut.Topping?)
@@ -165,7 +171,7 @@ struct DonutEditor_Previews: PreviewProvider {
         @State private var donut = Donut.preview
 
         var body: some View {
-            DonutEditor(donut: $donut)
+            DonutEditor()
         }
     }
 

App/Donut/DonutGallery.swift

@@ -7,9 +7,14 @@ The donut gallery view.
 
 import SwiftUI
 import FoodTruckKit
+import Decide
 
 struct DonutGallery: View {
     @ObservedObject var model: FoodTruckModel
+
+    @Bind(\FoodTruckState.$selectedDonut) var selectedDonut
+    @Bind(\FoodTruckState.Index.$donut) var donutsIndex
+    @ObserveKeyed(\FoodTruckState.Data.$donut) var donutsData
 
     @State private var layout = BrowserLayout.grid
     @State private var sort = DonutSortOrder.popularity(.week)
@@ -19,8 +24,8 @@ struct DonutGallery: View {
     @State private var selection = Set<Donut.ID>()
     @State private var searchText = ""
 
-    var filteredDonuts: [Donut] {
-        model.donuts(sortedBy: sort).filter { $0.matches(searchText: searchText) }
+    var filteredDonuts: [Donut.ID] {
+        donutsIndex.filter { donutsData[$0].matches(searchText: searchText) }
     }
 
     var tableImageSize: Double {
@@ -61,10 +66,18 @@ struct DonutGallery: View {
         .searchable(text: $searchText)
         .navigationTitle("Donuts")
         .navigationDestination(for: Donut.ID.self) { donutID in
-            DonutEditor(donut: model.donutBinding(id: donutID))
+            DonutEditor()
+                .onAppear()  {
+                    selectedDonut = donutID
+                }
         }
         .navigationDestination(for: String.self) { _ in
-            DonutEditor(donut: $model.newDonut)
+            DonutEditor()
+                .onAppear() {
+                    let newID = donutsIndex.count
+                    selectedDonut = newID
+                    donutsIndex.append(newID)
+                }
         }
     }
 
@@ -78,13 +91,13 @@ struct DonutGallery: View {
 
     var table: some View {
         Table(filteredDonuts, selection: $selection) {
-            TableColumn("Name") { donut in
-                NavigationLink(value: donut.id) {
+            TableColumn("Name") { donutId in
+                NavigationLink(value: donutId) {
                     HStack {
-                        DonutView(donut: donut)
+                        DonutView(donut: donutsData[donutId])
                             .frame(width: tableImageSize, height: tableImageSize)
 
-                        Text(donut.name)
+                        Text(donutsData[donutId].name)
                     }
                 }
             }
@@ -180,5 +193,6 @@ struct DonutBakery_Previews: PreviewProvider {
         NavigationStack {
             Preview()
         }
+        .appEnvironment(.preview)
     }
 }

App/Donut/DonutGalleryGrid.swift

@@ -7,10 +7,13 @@ The grid view used in the DonutGallery.
 
 import SwiftUI
 import FoodTruckKit
+import Decide
 
 struct DonutGalleryGrid: View {
-    var donuts: [Donut]
+    var donuts: [Donut.ID]
     var width: Double
+
+    @ObserveKeyed(\FoodTruckState.Data.$donut) var donutsData
 
     #if os(iOS)
     @Environment(\.horizontalSizeClass) private var sizeClass
@@ -58,15 +61,15 @@ struct DonutGalleryGrid: View {
 
     var body: some View {
         LazyVGrid(columns: gridItems, spacing: 20) {
-            ForEach(donuts) { donut in
-                NavigationLink(value: donut.id) {
+            ForEach(donuts, id: \.self) { donutId in
+                NavigationLink(value: donutId) {
                     VStack {
-                        DonutView(donut: donut)
+                        DonutView(donut: donutsData[donutId])
                             .frame(width: thumbnailSize, height: thumbnailSize)
 
                         VStack {
-                            let flavor = donut.flavors.mostPotentFlavor
-                            Text(donut.name)
+                            let flavor = donutsData[donutId].flavors.mostPotentFlavor
+                            Text(donutsData[donutId].name)
                             HStack(spacing: 4) {
                                 flavor.image
                                 Text(flavor.name)
@@ -86,18 +89,22 @@ struct DonutGalleryGrid: View {
 
 struct DonutGalleryGrid_Previews: PreviewProvider {
     struct Preview: View {
-        @State private var donuts = Donut.all
-        
+        @State private var donuts = Donut.all.map { $0.id }
+
         var body: some View {
             GeometryReader { geometryProxy in
                 ScrollView {
-                    DonutGalleryGrid(donuts: donuts, width: geometryProxy.size.width)
+                    DonutGalleryGrid(
+                        donuts: donuts,
+                        width: geometryProxy.size.width
+                    )
                 }
             }
         }
     }
 
     static var previews: some View {
         Preview()
+            .appEnvironment(.preview)
     }
 }

App/General/ApplicationEnvironment+Preview.swift

@@ -0,0 +1,49 @@
+//
+//  ApplicationEnvironment+Preview.swift
+//
+//
+//  Created by Anton Kolchunov on 21.08.23.
+//
+
+import Foundation
+import FoodTruckKit
+@testable import Decide
+
+extension ApplicationEnvironment {
+    static var preview: ApplicationEnvironment {
+        bootstrap()
+        return `default`
+    }
+
+    static func bootstrap(donuts: [Donut] = Donut.all) {
+        bootstrap(donuts.map { $0.id }, for: \FoodTruckState.Index.$donut)
+        for donut in donuts {
+            bootstrap(donut, for: \FoodTruckState.Data.$donut, at: donut.id)
+        }
+        bootstrap(0, for: \FoodTruckState.$selectedDonut)
+    }
+
+    // TODO: Move to Decide framework
+    static func bootstrap<S: AtomicState, Value>(
+        _ newValue: Value,
+        for keyPath: KeyPath<S, Mutable<Value>>
+    ) {
+        `default`.setValue(
+            newValue,
+            keyPath.appending(path: \.wrappedValue)
+        )
+    }
+
+    // TODO: Move to Decide framework
+    static func bootstrap<I:Hashable, S: KeyedState<I>, Value>(
+        _ newValue: Value,
+        for keyPath: KeyPath<S, Mutable<Value>>,
+        at identifier: I
+    ) {
+        `default`.setValue(
+            newValue,
+            keyPath.appending(path: \.wrappedValue),
+            at: identifier)
+    }
+}
+

App/General/Int+Identifiable.swift

@@ -0,0 +1,13 @@
+//
+//  Int+Identifiable.swift
+//  Food Truck
+//
+//  Created by Anton Kolchunov on 21.08.23.
+//  Copyright © 2023 Apple. All rights reserved.
+//
+
+import Foundation
+
+extension Int: Identifiable {
+    public var id: Int { self }
+}

App/Navigation/DetailColumn.swift

@@ -42,7 +42,7 @@ struct DetailColumn: View {
         case .donuts:
             DonutGallery(model: model)
         case .donutEditor:
-            DonutEditor(donut: $model.newDonut)
+            DonutEditor()
         case .topFive:
             TopFiveDonutsView(model: model)
         case .city(let id):

App/Truck/FoodTruckState.swift

@@ -0,0 +1,32 @@
+//
+//  FoodTruckState.swift
+//  Food Truck
+//
+//  Created by Anton Kolchunov on 21.08.23.
+//  Copyright © 2023 Apple. All rights reserved.
+//
+
+import Decide
+import FoodTruckKit
+
+final class FoodTruckState: AtomicState {
+    @Mutable @Property public var selectedDonut: Donut.ID = -1
+
+    final class Index: AtomicState {
+        @Mutable @Property public var donut = [Donut.ID]()
+    }
+
+    final class Data: KeyedState<Donut.ID> {
+        @Mutable @Property public var donut: Donut = Donut.newDonut
+    }
+}
+
+extension Donut {
+    static var newDonut = Donut(
+        id: Donut.all.count,
+        name: String(localized: "New Donut", comment: "New donut-placeholder name."),
+        dough: .plain,
+        glaze: .none,
+        topping: .none
+    )
+}