Hook up Damus Purple translation service

This commit integrates the Damus Purple translation service:
- Automatically handles translation settings change after purchase
- Asks for permission to override translation settings if the user already has translation setup
- Translation settings can be changed with Damus Purple, if desired
- Translation requests working with the Damus API server

Testing
--------

PASS

Device: iPhone 15 simulator
iOS: 17.2
Damus: This commit
Damus Purple API server: `9397201d7d55ddcec4c18fcd337f759b61dce697` running on Ubuntu 22.04 LTS VM (npm run dev)
iOS setting: English set as the only preferred language.
Steps:
1. Enable Damus Purple feature flag on developer settings, set purple localhost mode, and restart app
2. Set translation setting to something other than none (e.g. DeepL)
3. Simulate Damus Purple purchase
4. Check that when dismissing welcome view, a confirmation prompt will ask the user whether they want to switch translator to Damus Purple. PASS
5. Click "Yes".
6. Go to translation settings. Check that translation settings are set to "Purple". PASS
7. Go to a non-English profile. Check that translations appear with "Mock translation" (Which is the translation text provided by the mock translation server). PASS
8. Reinstall app
9. Repeat the test, but this time starting with no translation settings. Make sure that translation settings will automatically switch to Damus Purple. PASS

Feature flag testing
--------------------

PASS

Preconditions: Same as above
Steps:
1. Turn off translation
2. Turn off Damus Purple feature flag
3. Go to translation settings. Make sure that Damus Purple is not an option. PASS

Closes: https://github.com/damus-io/damus/issues/1836
Signed-off-by: Daniel D’Aquino <daniel@daquino.me>
Reviewed-by: William Casarin <jb55@jb55.com>
Signed-off-by: William Casarin <jb55@jb55.com>

damus/Views/Purple/DamusPurpleView.swift

@@ -42,7 +42,7 @@ struct PurchasedProduct {
 }
 
 struct DamusPurpleView: View {
-    let purple_api: DamusPurple
+    let damus_state: DamusState
     let keypair: Keypair
     
     @State var products: ProductState
@@ -50,13 +50,14 @@ struct DamusPurpleView: View {
     @State var selection: DamusPurpleType = .yearly
     @State var show_welcome_sheet: Bool = false
     @State var show_manage_subscriptions = false
+    @State var show_settings_change_confirmation_dialog = false
     
     @Environment(\.dismiss) var dismiss
     
-    init(purple: DamusPurple, keypair: Keypair) {
+    init(damus_state: DamusState) {
         self._products = State(wrappedValue: .loading)
-        self.purple_api = purple
-        self.keypair = keypair
+        self.damus_state = damus_state
+        self.keypair = damus_state.keypair
     }
     
     var body: some View {
@@ -94,12 +95,38 @@ struct DamusPurpleView: View {
             await load_products()
         }
         .ignoresSafeArea(.all)
-        .sheet(isPresented: $show_welcome_sheet, content: {
+        .sheet(isPresented: $show_welcome_sheet, onDismiss: {
+            update_user_settings_to_purple()
+        }, content: {
             DamusPurpleWelcomeView()
         })
+        .confirmationDialog(
+            NSLocalizedString("It seems that you already have a translation service configured. Would you like to switch to Damus Purple as your translator?", comment: "Confirmation dialog question asking users if they want their translation settings to be automatically switched to the Damus Purple translation service"),
+            isPresented: $show_settings_change_confirmation_dialog,
+            titleVisibility: .visible
+        ) {
+            Button("Yes") {
+                set_translation_settings_to_purple()
+            }.keyboardShortcut(.defaultAction)
+            Button("No", role: .cancel) {}
+        }
         .manageSubscriptionsSheet(isPresented: $show_manage_subscriptions)
     }
     
+    func update_user_settings_to_purple() {
+        if damus_state.settings.translation_service == .none {
+            set_translation_settings_to_purple()
+        }
+        else {
+            show_settings_change_confirmation_dialog = true
+        }
+    }
+    
+    func set_translation_settings_to_purple() {
+        damus_state.settings.translation_service = .purple
+        damus_state.settings.auto_translate = true
+    }
+    
     func handle_transactions(products: [Product]) async {
         for await update in StoreKit.Transaction.updates {
             switch update {
@@ -203,9 +230,9 @@ struct DamusPurpleView: View {
         
         switch result {
             case .success:
-                self.purple_api.starred_profiles_cache[keypair.pubkey] = nil
+                self.damus_state.purple.starred_profiles_cache[keypair.pubkey] = nil
                 Task {
-                    await self.purple_api.send_receipt()
+                    await self.damus_state.purple.send_receipt()
                 }
             default:
                 break
@@ -423,6 +450,6 @@ struct DamusPurpleView_Previews: PreviewProvider {
         ])
          */
         
-        DamusPurpleView(purple: test_damus_state.purple, keypair: test_damus_state.keypair)
+        DamusPurpleView(damus_state: test_damus_state)
     }
 }

damus/Views/Settings/TranslationSettingsView.swift

@@ -9,6 +9,7 @@ import SwiftUI
 
 struct TranslationSettingsView: View {
     @ObservedObject var settings: UserSettingsStore
+    var damus_state: DamusState
     
     @Environment(\.dismiss) var dismiss
     
@@ -19,11 +20,17 @@ struct TranslationSettingsView: View {
                     .toggleStyle(.switch)
 
                 Picker(NSLocalizedString("Service", comment: "Prompt selection of translation service provider."), selection: $settings.translation_service) {
-                    ForEach(TranslationService.allCases, id: \.self) { server in
+                    ForEach(TranslationService.allCases.filter({ settings.enable_experimental_purple_api ? true : $0 != .purple }), id: \.self) { server in
                         Text(server.model.displayName)
                             .tag(server.model.tag)
                     }
                 }
+                
+                if settings.translation_service == .purple && settings.enable_experimental_purple_api {
+                    NavigationLink(destination: DamusPurpleView(damus_state: damus_state)) {
+                        Text(NSLocalizedString("Configure Damus Purple", comment: "Button to allow Damus Purple to be configured"))
+                    }
+                }
 
                 if settings.translation_service == .libretranslate {
                     Picker(NSLocalizedString("Server", comment: "Prompt selection of LibreTranslate server to perform machine translations on notes"), selection: $settings.libretranslate_server) {
@@ -103,6 +110,6 @@ struct TranslationSettingsView: View {
 
 struct TranslationSettingsView_Previews: PreviewProvider {
     static var previews: some View {
-        TranslationSettingsView(settings: UserSettingsStore())
+        TranslationSettingsView(settings: UserSettingsStore(), damus_state: test_damus_state)
     }
 }

damus/Views/SideMenuView.swift

@@ -55,7 +55,7 @@ struct SideMenuView: View {
             }
 
             if damus_state.settings.enable_experimental_purple_api {
-                NavigationLink(destination: DamusPurpleView(purple: damus_state.purple, keypair: damus_state.keypair)) {
+                NavigationLink(destination: DamusPurpleView(damus_state: damus_state)) {
                     HStack(spacing: 13) {
                         Image("nostr-hashtag")
                         Text("Purple")