Feature: user-selectable theme (#460)

* Fix #457 - Persist entry sorting preferences across app launches
Changed sorting state from @State to @AppStorage in EntriesView to ensure user preferences are saved to UserDefaults. Also made sorting criteria mutually exclusive for a better UX.

* Add option to pick theme (light/dark/auto).
Moved language files and other resources into a sub-folder to clean up the structure a little.

* use #EnvironmentObject

Author: benrhughes

App/Features/Setting/AppSetting.swift

@@ -4,18 +4,28 @@ import SharedLib
 
 final class AppSetting: ObservableObject {
     @Published var webFontSizePercent: Double
+    @Published var theme: Theme
 
     private var cancellable = Set<AnyCancellable>()
 
     init() {
         webFontSizePercent = WallabagUserDefaults.webFontSizePercent
+        theme = Theme(rawValue: WallabagUserDefaults.theme) ?? .auto
 
         $webFontSizePercent
             .sink(receiveValue: updateWebFontSizePercent)
             .store(in: &cancellable)
+
+        $theme
+            .sink(receiveValue: updateTheme)
+            .store(in: &cancellable)
     }
 
     private func updateWebFontSizePercent(_ value: Double) {
         WallabagUserDefaults.webFontSizePercent = value
     }
+
+    private func updateTheme(_ value: Theme) {
+        WallabagUserDefaults.theme = value.rawValue
+    }
 }

App/Features/Setting/SettingView.swift

@@ -1,3 +1,4 @@
+import Factory
 import SharedLib
 import SwiftUI
 
@@ -7,9 +8,17 @@ struct SettingView: View {
     @AppStorage("badge") var badge: Bool = true
     @AppStorage("defaultMode") var defaultMode: String = RetrieveMode.allArticles.rawValue
     @AppStorage("itemPerPageDuringSync") var itemPerPageDuringSync: Int = 50
+    @EnvironmentObject var appSetting: AppSetting
 
     var body: some View {
         Form {
+            Section("Appearance") {
+                Picker("Theme", selection: $appSetting.theme) {
+                    ForEach(Theme.allCases) { theme in
+                        Text(theme.name).tag(theme)
+                    }
+                }
+            }
             Section("Entries list") {
                 Toggle("Show image in list", isOn: $showImageInList)
                 Picker("Default mode", selection: $defaultMode) {
@@ -35,5 +44,6 @@ struct SettingView: View {
 struct SettingView_Previews: PreviewProvider {
     static var previews: some View {
         SettingView()
+            .environmentObject(AppSetting())
     }
 }

App/Lib/Theme.swift

@@ -0,0 +1,25 @@
+import SwiftUI
+
+enum Theme: String, CaseIterable, Identifiable {
+    case auto
+    case light
+    case dark
+
+    var id: String { rawValue }
+
+    var colorScheme: ColorScheme? {
+        switch self {
+        case .auto: return nil
+        case .light: return .light
+        case .dark: return .dark
+        }
+    }
+
+    var name: LocalizedStringKey {
+        switch self {
+        case .auto: return "Auto"
+        case .light: return "Light"
+        case .dark: return "Dark"
+        }
+    }
+}