Show errors when handling playlists

Model/PlaylistsModel.swift

@@ -52,14 +52,22 @@ final class PlaylistsModel: ObservableObject {
             }
     }
 
-    func addVideo(playlistID: Playlist.ID, videoID: Video.ID, onSuccess: @escaping () -> Void = {}) {
+    func addVideo(
+        playlistID: Playlist.ID,
+        videoID: Video.ID,
+        onSuccess: @escaping () -> Void = {},
+        onFailure: @escaping (RequestError) -> Void = { _ in }
+    ) {
         let resource = accounts.api.playlistVideos(playlistID)
         let body = ["videoId": videoID]
 
-        resource?.request(.post, json: body).onSuccess { _ in
+        resource?
+            .request(.post, json: body)
+            .onSuccess { _ in
                 self.load(force: true)
                 onSuccess()
             }
+            .onFailure(onFailure)
     }
 
     func removeVideo(videoIndexID: String, playlistID: Playlist.ID, onSuccess: @escaping () -> Void = {}) {

Shared/Playlists/AddToPlaylistView.swift

@@ -7,8 +7,12 @@ struct AddToPlaylistView: View {
 
     @State private var selectedPlaylistID: Playlist.ID = ""
 
+    @State private var error = ""
+    @State private var presentingErrorAlert = false
+
     @Environment(\.colorScheme) private var colorScheme
     @Environment(\.presentationMode) private var presentationMode
+
     @EnvironmentObject<PlaylistsModel> private var model
 
     var body: some View {
@@ -120,6 +124,12 @@ struct AddToPlaylistView: View {
             Button("Add to Playlist", action: addToPlaylist)
                 .disabled(selectedPlaylist.isNil)
                 .padding(.top, 30)
+                .alert(isPresented: $presentingErrorAlert) {
+                    Alert(
+                        title: Text("Error when accessing playlist"),
+                        message: Text(error)
+                    )
+                }
             #if !os(tvOS)
                 .keyboardShortcut(.defaultAction)
             #endif
@@ -155,9 +165,17 @@ struct AddToPlaylistView: View {
 
         Defaults[.lastUsedPlaylistID] = id
 
-        model.addVideo(playlistID: id, videoID: video.videoID) {
+        model.addVideo(
+            playlistID: id,
+            videoID: video.videoID,
+            onSuccess: {
                 presentationMode.wrappedValue.dismiss()
+            },
+            onFailure: { requestError in
+                error = "(\(requestError.httpStatusCode ?? -1)) \(requestError.userMessage)"
+                presentingErrorAlert = true
             }
+        )
     }
 
     private var selectedPlaylist: Playlist? {

Shared/Playlists/PlaylistFormView.swift

@@ -8,7 +8,10 @@ struct PlaylistFormView: View {
     @State private var visibility = Playlist.Visibility.public
 
     @State private var valid = false
-    @State private var showingDeleteConfirmation = false
+    @State private var presentingDeleteConfirmation = false
+
+    @State private var formError = ""
+    @State private var presentingErrorAlert = false
 
     @Environment(\.colorScheme) private var colorScheme
     @Environment(\.presentationMode) private var presentationMode
@@ -57,6 +60,12 @@ struct PlaylistFormView: View {
 
                         Button("Save", action: submitForm)
                             .disabled(!valid)
+                            .alert(isPresented: $presentingErrorAlert) {
+                                Alert(
+                                    title: Text("Error when accessing playlist"),
+                                    message: Text(formError)
+                                )
+                            }
                             .keyboardShortcut(.defaultAction)
                     }
                     .frame(minHeight: 35)
@@ -165,7 +174,9 @@ struct PlaylistFormView: View {
 
         let body = ["title": name, "privacy": visibility.rawValue]
 
-        resource?.request(editing ? .patch : .post, json: body).onSuccess { response in
+        resource?
+            .request(editing ? .patch : .post, json: body)
+            .onSuccess { response in
                 if let modifiedPlaylist: Playlist = response.typedContent() {
                     playlist = modifiedPlaylist
                 }
@@ -174,6 +185,10 @@ struct PlaylistFormView: View {
 
                 presentationMode.wrappedValue.dismiss()
             }
+            .onFailure { error in
+                formError = "(\(error.httpStatusCode ?? -1)) \(error.userMessage)"
+                presentingErrorAlert = true
+            }
     }
 
     var resource: Resource? {
@@ -207,9 +222,9 @@ struct PlaylistFormView: View {
 
     var deletePlaylistButton: some View {
         Button("Delete") {
-            showingDeleteConfirmation = true
+            presentingDeleteConfirmation = true
         }
-        .alert(isPresented: $showingDeleteConfirmation) {
+        .alert(isPresented: $presentingDeleteConfirmation) {
             Alert(
                 title: Text("Are you sure you want to delete playlist?"),
                 message: Text("Playlist \"\(playlist.title)\" will be deleted.\nIt cannot be undone."),
@@ -221,11 +236,17 @@ struct PlaylistFormView: View {
     }
 
     func deletePlaylistAndDismiss() {
-        accounts.api.playlist(playlist.id)?.request(.delete).onSuccess { _ in
+        accounts.api.playlist(playlist.id)?
+            .request(.delete)
+            .onSuccess { _ in
                 playlist = nil
                 playlists.load(force: true)
                 presentationMode.wrappedValue.dismiss()
             }
+            .onFailure { error in
+                formError = "(\(error.httpStatusCode ?? -1)) \(error.localizedDescription)"
+                presentingErrorAlert = true
+            }
     }
 }