Adopt b2b.next's client patterns: services, page state, feedback

Ported from the owner's b2b.next and adapted from MudBlazor to the daisyUI
components:
- LocalizableComponentBase provides CascadingState, Navigation, Toast,
  IsLoading/IsDefaultDisabled, WhenOnline/StartOnlinePolling, and after-render
  jobs that actually run.
- CascadingState starts with initialised state and polls the online status
  with a PeriodicTimer. It reports errors through ILoggingService plus a toast,
  and disposes what it holds.
- New pieces:
  - ToastService + ToastHost, the snackbar, with AddResponseError/Success/
    Warning/Exception in SUtility;
  - ErrorViewer, which shows the validation messages plus AdditionalError(s);
  - LoggingService, which writes to the console and the IndexedDB client log.
- HttpService is rebuilt and registered:
  - auth levels Get/Post/Delete, *Anon and *TotallyAnon;
  - retry with backoff;
  - classified failures (FailureCodes) instead of exceptions;
  - HTTP 410 on cancel;
  - the "default" client.
  ReadWebResult and DefaultReadFromJsonAsync read its responses.
- ClientJsonContext is source-generated, and SUtility.DefaultSerializer and
  Blazored.LocalStorage use it.
- WebResult gains a C# 14 IsInvalid extension property.

The code follows the imported rules:
- Every service and async helper takes a CancellationToken last.
- Primary constructors replace constructor-plus-fields.
- MessagesService and IStorage return Task<WebResult> / Task<List<T>>.
  MessagesService is still mock, building its results in memory; the seed
  feed and thread moved to Faker.
- Index and ExpandMessage follow the page pattern: an offline guard with
  WhenOnline, LoadData, and early returns with toasts on the results they used
  to ignore. ExpandMessage reloads on route change and shows "not found"
  instead of a null message.
- Model and state collections are [], and the fake identity defaults moved
  out of the models.
- Components:
  - no ?. chains over initialised state;
  - [Inject] instead of @inject;
  - IsDefaultDisabled on the actions;
  - autocomplete on every text input;
  - Localizer[key, args] instead of string.Format;
  - the localizer no longer leaks its inner _pLocalizer.
- Settings → General gains a language picker (English/Italiano), and
  SetDefaultCulture limits the culture to those two.

Bugs fixed along the way:
- A compose with untouched (null) content passed the empty check.
- File errors were joined with <br/> and rendered as markup.
- ClientLogs.ErrorMessage() threw on warnings.
- CoalescingStringLocalizer[key, args] showed a raw "{0}" for missing keys.
- AppStatusService exposed a call to a JS function that doesn't exist.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsXgEaXee4GCU1hwYgPJXw

Components/ActionBar.razor

@@ -65,33 +65,38 @@
 </section>
 
 @code {
-	[CascadingParameter] CascadingState CascadingState { get; set; }
 	[Parameter] public EventCallback<MessageForm> OnMessageSubmit { get; set; }
 	[Parameter] public EventCallback<TimelineType> OnTimelineChanged { get; set; }
 	[Parameter] public EventCallback<TimeSortingType> OnTimeSortingChanged { get; set; }
 	[Inject] ILocalStorageService LocalStorage { get; set; }
-	bool isPosting { get; set; } = false;
+	bool isPosting;
 	ActionBarFilter Filters { get; set; } = new();
 
 	protected override async Task OnInitializedAsync()
 	{
 		var filters = await LocalStorage.GetItemAsync<ActionBarFilter>(nameof(ActionBarFilter));
-		if (filters == default)
-			await LocalStorage.SetItemAsync(nameof(ActionBarFilter), Filters);
-		else
+		IsLoading = false;
+		if (filters is not null)
+		{
 			Filters = filters;
+			return;
+		}
+
+		await LocalStorage.SetItemAsync(nameof(ActionBarFilter), Filters);
 	}
 
 	void OpenCloseMessageForm()
 	{
 		isPosting = !isPosting;
 	}
+
 	async Task OnTimelineChange(TimelineType timelineType)
 	{
 		Filters.TimelineType = timelineType;
 		await LocalStorage.SetItemAsync(nameof(ActionBarFilter), Filters);
 		await OnTimelineChanged.InvokeAsync(Filters.TimelineType);
 	}
+
 	async Task OnTimeSortChange(TimeSortingType timeSorting)
 	{
 		Filters.TimeSortingType = timeSorting;

Components/Content.razor

@@ -3,7 +3,7 @@
 <div class="flex gap-3 w-full rounded-xl neo-raised @(Highlighted ? "neo-sm" : "neo-2xs") @CssContainer">
 
 	<div class="flex flex-col py-3 pl-3 md:py-4 md:pl-4 flex-none rounded-l-xl bg-cover bg-no-repeat bg-center"
-			 style="background-image:linear-gradient(to left, var(--color-base-100), transparent), url('@(Message.User?.BackgroundUrl)');">
+			 style="background-image:linear-gradient(to left, var(--color-base-100), transparent), url('@(Message.User.BackgroundUrl)');">
 
 		<a class="block h-12 w-12 md:h-16 md:w-16" href="@Message.User.ProfileUrl" title="@Message.User.UserName">
 			<img alt="@Message.User.UserName" class="h-12 w-12 md:h-16 md:w-16 object-cover rounded-full neo-raised neo-2xs" src="@(Message.User.PictureUrl ?? "/imgs/icon-192.png")" />
@@ -32,8 +32,8 @@
 					</a>
 				</span>
 				<span class="flex-none inline-flex gap-1 items-center">
-					<span title="@Message.CreatedAt.ToLocalTime().ToString("📅dd/MM/yy 🕒HH:mm")">
-						@Message.CreatedAt.GetPassedTime(Localizer._pLocalizer)
+					<span title="@Message.CreatedAt.ToLocalTime().ToString(SUtility.dateTimeFormatExt)">
+						@Message.CreatedAt.GetPassedTime(Localizer)
 					</span>
 					<i aria-hidden="true" class="@Message.MessageType.GetMessageTypeIcon() text-base"
 						 title="@Localizer[Message.MessageType.ToString()]">
@@ -104,13 +104,13 @@
 			<div class="flex gap-3">
 				@if (OnMessageReply.HasDelegate)
 				{
-					<DButton Size="DSize.Sm" Active="isAnswering" OnClick="Reply" title="@Localizer[isAnswering ? "Close" : "Reply"]">
+					<DButton Size="DSize.Sm" Active="isAnswering" Disabled="IsDefaultDisabled" OnClick="Reply" title="@Localizer[isAnswering ? "Close" : "Reply"]">
 						<i aria-hidden="true" class="@SUtility.IfTrueThen(isAnswering, "ion-md-close-circle", "ion-md-text") text-lg text-success"></i>
 					</DButton>
 				}
 				@if (OnMessageBoost.HasDelegate)
 				{
-					<DButton Size="DSize.Sm" Active="Message.IsBoostedByCurrentUser" OnClick="() => OnMessageBoost.InvokeAsync(Message)"
+					<DButton Size="DSize.Sm" Active="Message.IsBoostedByCurrentUser" Disabled="IsDefaultDisabled" OnClick="() => OnMessageBoost.InvokeAsync(Message)"
 							 title="@Localizer["Boost"]">
 						<i aria-hidden="true" class="ion-md-repeat @SUtility.IfTrueThen(Message.BoostsCounter != 0, null, "text-lg") text-info"></i>
 						@if (Message.BoostsCounter != 0)
@@ -121,7 +121,7 @@
 				}
 				@if (OnMessageFavourite.HasDelegate)
 				{
-					<DButton Size="DSize.Sm" Active="Message.IsFavourite" OnClick="() => OnMessageFavourite.InvokeAsync(Message)"
+					<DButton Size="DSize.Sm" Active="Message.IsFavourite" Disabled="IsDefaultDisabled" OnClick="() => OnMessageFavourite.InvokeAsync(Message)"
 							 title="@Localizer["Favourite"]">
 						<i aria-hidden="true" class="@SUtility.IfTrueThen(Message.IsFavourite, "ion-md-heart-dislike", "ion-md-heart") text-lg text-pink-300"></i>
 					</DButton>
@@ -138,28 +138,29 @@
 					<ChildContent>
 						@if (OnUserDirectMessage.HasDelegate)
 						{
-							<DButton Size="DSize.Sm" class="justify-start whitespace-nowrap" OnClick="() => OnUserDirectMessage.InvokeAsync(Message)">
+							<DButton Size="DSize.Sm" class="justify-start whitespace-nowrap" Disabled="IsDefaultDisabled" OnClick="() => OnUserDirectMessage.InvokeAsync(Message)">
 								<i aria-hidden="true" class="ion-md-paper-plane text-base text-success"></i>
 								<span>@Localizer["Direct message"]</span>
 							</DButton>
 						}
 						@if (OnUserSilence.HasDelegate)
 						{
-							<DButton Size="DSize.Sm" class="justify-start whitespace-nowrap" OnClick="() => OnUserSilence.InvokeAsync(Message.User)">
+							<DButton Size="DSize.Sm" class="justify-start whitespace-nowrap" Disabled="IsDefaultDisabled" OnClick="() => OnUserSilence.InvokeAsync(Message.User)">
 								<i aria-hidden="true" class="ion-md-eye-off text-base drop-shadow-sm text-warning"></i>
 								<span>@Localizer["Mute"]</span>
 							</DButton>
 						}
 						@if (OnUserBlock.HasDelegate)
 						{
-							<DButton Size="DSize.Sm" class="justify-start whitespace-nowrap" OnClick="() => OnUserBlock.InvokeAsync(Message.User)">
+							<DButton Size="DSize.Sm" class="justify-start whitespace-nowrap" Disabled="IsDefaultDisabled" OnClick="() => OnUserBlock.InvokeAsync(Message.User)">
 								<i aria-hidden="true" class="ion-md-remove-circle text-base text-error"></i>
 								<span>@Localizer["Block"]</span>
 							</DButton>
 						}
-						@if (@*Message.User.UserName == CurrentUserName &&*@ OnMessageDelete.HasDelegate)
+						@* Once signed in for real: only for the author's own messages (Message.User.UserId == CascadingState.User.Id). *@
+						@if (OnMessageDelete.HasDelegate)
 						{
-							<DButton Size="DSize.Sm" class="justify-start whitespace-nowrap" OnClick="DeleteMessage" title="@Localizer["Delete"]">
+							<DButton Size="DSize.Sm" class="justify-start whitespace-nowrap" Disabled="IsDefaultDisabled" OnClick="DeleteMessage" title="@Localizer["Delete"]">
 								<i aria-hidden="true" class="ion-md-trash text-lg text-error"></i>
 								<span>@Localizer["Delete"]</span>
 							</DButton>
@@ -184,8 +185,6 @@
 </div>
 
 @code {
-	[CascadingParameter] Task<AuthenticationState> AuthState { get; set; }
-	[CascadingParameter] CascadingState CascadingState { get; set; }
 	[Parameter] public Message Message { get; set; } = new();
 	[Parameter] public EventCallback<MessageForm> OnMessageReply { get; set; }
 	[Parameter] public EventCallback<Message> OnMessageBoost { get; set; }
@@ -200,15 +199,9 @@
 	[Parameter] public bool Highlighted { get; set; }
 	[Parameter] public bool IncludeExpand { get; set; } = true;
 
-	bool isAnswering { get; set; } = false;
+	bool isAnswering;
 
-	string CurrentUserName
-	{
-		get
-		{
-			return AuthState.Result.User.Identity?.Name;
-		}
-	}
+	protected override void OnInitialized() => IsLoading = false;
 
 	async Task DeleteMessage()
 	{
@@ -222,11 +215,8 @@
 		await OnMessageReply.InvokeAsync(messageForm);
 	}
 
-	async Task Reply()
+	void Reply()
 	{
-		await Task.Run(() =>
-		{
-		});
 		isAnswering = !isAnswering;
 	}
-}
+}

Components/Daisy/DataDisplay/DAccordion.razor

@@ -1,4 +1,4 @@
-@inherits DComponentBase
+@inherits DComponentBase
 
 @* daisyUI Accordion: https://daisyui.com/components/accordion/ . Instead of daisyUI's radio group, the open item is an
    index in C# (@bind-Active, -1 = none). Each DAccordionItem registers itself through the cascading value and renders a
@@ -19,7 +19,7 @@
 	/// <summary>Join the items into one block (join join-vertical, join-item).</summary>
 	[Parameter] public bool Joined { get; set; }
 
-	readonly List<DAccordionItem> items = new();
+	readonly List<DAccordionItem> items = [];
 
 	string CssClass => Cx(Joined ? "join join-vertical rounded-box neo-raised" : "flex flex-col gap-2", Class);
 

Components/Daisy/DataDisplay/DAvatar.razor

@@ -18,6 +18,7 @@
 
 @code {
 	[Parameter] public string Src { get; set; }
+	// "" on purpose (the documented exception to "no string defaults"): an empty alt marks a decorative image.
 	[Parameter] public string Alt { get; set; } = "";
 	/// <summary>Shown in the frame when there is no Src, e.g. initials with Placeholder.</summary>
 	[Parameter] public RenderFragment ChildContent { get; set; }

Components/Daisy/DataDisplay/DCarousel.razor

@@ -1,5 +1,4 @@
-@inherits DComponentBase
-@inject NavigationManager NavigationManager
+@inherits DComponentBase
 
 @* daisyUI Carousel: https://daisyui.com/components/carousel/ . A scroll-snap strip of DCarouselItem children; the
    user scrolls or swipes it. Give each item w-full for one slide at a time. ShowNavigation (previous/next on every
@@ -25,6 +24,7 @@
 </CascadingValue>
 
 @code {
+	[Inject] NavigationManager NavigationManager { get; set; }
 	[Parameter] public RenderFragment ChildContent { get; set; }
 	[Parameter] public DCarouselSnap Snap { get; set; }
 	[Parameter] public DDirection Direction { get; set; }
@@ -36,7 +36,7 @@
 	[Parameter] public string NextText { get; set; } = "Next slide";
 	[Parameter] public string SlideText { get; set; } = "Slide";
 
-	readonly List<DCarouselItem> items = new();
+	readonly List<DCarouselItem> items = [];
 	readonly string uid = "d" + Guid.NewGuid().ToString("N")[..8];
 
 	RenderFragment Strip => @<div @attributes="AdditionalAttributes" class="@CssClass">@ChildContent</div>;

Components/Daisy/DataDisplay/DHoverGallery.razor

@@ -16,6 +16,7 @@
 
 @code {
 	[Parameter] public IEnumerable<string> Images { get; set; }
+	// "" on purpose (the documented exception to "no string defaults"): an empty alt marks a decorative image.
 	[Parameter] public string Alt { get; set; } = "";
 	[Parameter] public RenderFragment ChildContent { get; set; }
 }

Components/Daisy/Navigation/DTabs.razor

@@ -1,4 +1,4 @@
-@inherits DComponentBase
+@inherits DComponentBase
 
 @* daisyUI Tab: https://daisyui.com/components/tab/ . Each DTab child registers itself through the cascading value;
    DTabs renders the tab buttons and the active tab's content. The active tab is an index (@bind-Active). *@
@@ -35,7 +35,7 @@
 	[Parameter] public bool Bottom { get; set; }
 	[Parameter] public string ContentClass { get; set; } = "pt-4";
 
-	readonly List<DTab> tabs = new();
+	readonly List<DTab> tabs = [];
 
 	string CssClass => Cx("tabs", VariantClass, SizeClass, Bottom ? "tabs-bottom" : null, Class);
 

Components/ErrorViewer.razor

@@ -0,0 +1,58 @@
+@implements IDisposable
+
+@* In-page errors (b2b.next's WidmannErrorViewer): the validation messages of the cascading EditContext, then
+   AdditionalError (one message) and AdditionalErrors (a list; never join a list into one string), one <li> each.
+   Renders nothing when there is nothing to show. Messages are text, not markup: they can contain file names. *@
+@if (HasContent)
+{
+	<DAlert Color="@(Severity is ErrorViewerSeverity.Warning ? DAlertColor.Warning : DAlertColor.Error)" Variant="DAlertVariant.Soft"
+			class="@Cx("text-sm", ContainerClass)">
+		<ul class="list-inside list-disc">
+			@foreach (var message in Messages)
+			{
+				<li>@message</li>
+			}
+		</ul>
+	</DAlert>
+}
+
+@code {
+	[CascadingParameter] EditContext EditContext { get; set; }
+	[Parameter] public string ContainerClass { get; set; }
+	[Parameter] public ErrorViewerSeverity Severity { get; set; }
+	[Parameter] public string AdditionalError { get; set; }
+	[Parameter] public IEnumerable<string> AdditionalErrors { get; set; } = [];
+
+	EditContext subscribedEditContext;
+
+	IEnumerable<string> Messages =>
+		(EditContext?.GetValidationMessages() ?? [])
+		.Append(AdditionalError)
+		.Concat(AdditionalErrors)
+		.Where(message => !string.IsNullOrEmpty(message));
+
+	bool HasContent => Messages.Any();
+
+	static string Cx(params string[] classes) => DCx.Join(classes);
+
+	protected override void OnParametersSet()
+	{
+		if (EditContext == subscribedEditContext)
+			return;
+
+		Unsubscribe();
+		subscribedEditContext = EditContext;
+		if (subscribedEditContext is not null)
+			subscribedEditContext.OnValidationStateChanged += OnValidationStateChanged;
+	}
+
+	void OnValidationStateChanged(object sender, ValidationStateChangedEventArgs e) => _ = InvokeAsync(StateHasChanged);
+
+	void Unsubscribe()
+	{
+		if (subscribedEditContext is not null)
+			subscribedEditContext.OnValidationStateChanged -= OnValidationStateChanged;
+	}
+
+	public void Dispose() => Unsubscribe();
+}

Components/ErrorViewerSeverity.cs

@@ -0,0 +1,7 @@
+namespace decePubClient.Components;
+
+public enum ErrorViewerSeverity
+{
+	Error,
+	Warning
+}

Components/MessageUpsertForm.razor

@@ -4,15 +4,15 @@
 	<DataAnnotationsValidator />
 
 	<div class="flex flex-col mb-3">
-		<DInput TValue="string" class="w-full rounded-t-[1.4rem] rounded-b-lg" maxlength="64"
+		<DInput TValue="string" class="w-full rounded-t-[1.4rem] rounded-b-lg" maxlength="64" autocomplete="off"
 				placeholder="@Localizer["Title (optional)"]" Value="@MessageForm.Title"
 				ValueChanged="(v) => OnTitleChanged(v)"
 				ValueExpression="() => MessageForm.Title" />
 		<div class="relative mt-1">
 			<DTextarea TValue="string" @bind-Value="MessageForm.Content" Immediate="true"
-					   class="w-full rounded-b-[1.4rem] rounded-t-lg" maxlength="5000"
+					   class="w-full rounded-b-[1.4rem] rounded-t-lg" maxlength="@MaxContentLength" autocomplete="off"
 					   placeholder="@Localizer["oh shit... here we go again"]" rows="3" />
-			<span class="absolute text-xs opacity-50 right-2 bottom-1">@(MessageForm.Content?.Length ?? 0)/5000</span>
+			<span class="absolute text-xs opacity-50 right-2 bottom-1">@ContentLength/@MaxContentLength</span>
 		</div>
 		@if (showPreviewButton && isPreviewOpen && MessageForm.Content is { Length: > 0 })
 		{
@@ -30,10 +30,6 @@
 				</div>
 			</div>
 		}
-		<div class="text-error text-sm">
-			<ValidationMessage For="() => MessageForm.Content" />
-			@contentError
-		</div>
 	</div>
 
 	<div class="flex flex-col gap-3 mb-3 @SUtility.IfTrueThen(MessageForm.Media.Count == 0, "hidden")">
@@ -51,14 +47,14 @@
 										<i class="ion-md-image"></i> <b>@media.FileName</b>
 									</p>
 									<p class="text-xs break-all">
-										<i class="ion-md-code"></i> @media.ContentType <i class="ion-md-fitness"></i> @media.Size.GetFileSize(Localizer._pLocalizer)
+										<i class="ion-md-code"></i> @media.ContentType <i class="ion-md-fitness"></i> @media.Size.GetFileSize(Localizer)
 									</p>
 								</div>
 								<DButton Size="DSize.Sm" class="self-start" OnClick="() => RemoveFile(media)">
 									<i class="ion-md-trash text-base text-red-400"></i>
 								</DButton>
 							</div>
-							<DTextarea TValue="string" @bind-Value="media.AltText" Size="DSize.Sm" class="w-full rounded-lg!"
+							<DTextarea TValue="string" @bind-Value="media.AltText" Size="DSize.Sm" class="w-full rounded-lg!" autocomplete="off"
 									   placeholder="@Localizer["Alternative text"]" rows="1" />
 						</div>
 					</div>
@@ -74,7 +70,7 @@
 								<b>@media.FileName</b>
 							</p>
 							<p class="text-xs break-all">
-								<i class="ion-md-code"></i> @media.ContentType <i class="ion-md-fitness"></i> @media.Size.GetFileSize(Localizer._pLocalizer)
+								<i class="ion-md-code"></i> @media.ContentType <i class="ion-md-fitness"></i> @media.Size.GetFileSize(Localizer)
 							</p>
 						</div>
 						<DButton Size="DSize.Sm" OnClick="() => RemoveFile(media)">
@@ -92,7 +88,7 @@
 								<b>@media.FileName</b>
 							</p>
 							<p class="text-xs break-all">
-								<i class="ion-md-code"></i> @media.ContentType <i class="ion-md-fitness"></i> @media.Size.GetFileSize(Localizer._pLocalizer)
+								<i class="ion-md-code"></i> @media.ContentType <i class="ion-md-fitness"></i> @media.Size.GetFileSize(Localizer)
 							</p>
 							<audio controls="controls" class="w-full max-h-8">
 								<source src="@media.Base64Preview" type="@media.ContentType">
@@ -108,19 +104,14 @@
 
 	</div>
 
-	@if (fileInputErrorMessage is { Length: > 0 })
-	{
-		<div class="text-error text-sm p-1 md:p-2 mb-3 rounded-xl neo-inset neo-2xs">
-			@((MarkupString)fileInputErrorMessage)
-		</div>
-	}
+	<ErrorViewer ContainerClass="mb-3" AdditionalError="@contentError" AdditionalErrors="fileErrors" />
 
 	<div class="flex flex-wrap items-start justify-between gap-3">
 		<div class="flex flex-wrap items-start gap-3">
 			<DDropdown @bind-IsOpen="MessageForm.IsScopeOptionsOpen"
 					   TriggerClass="@(MessageForm.IsScopeOptionsOpen ? "btn btn-sm btn-active" : "btn btn-sm")"
 					   ContentClass="mt-2 flex gap-2 p-2 rounded-box"
-					   title="@string.Format(Localizer["Message scope type: {0}"], Localizer[MessageForm.MessageType.ToString()])">
+					   title="@Localizer["Message scope type: {0}", Localizer[MessageForm.MessageType.ToString()]]">
 				<Trigger>
 					<i class="@MessageForm.MessageType.GetMessageTypeIcon() text-base"></i>
 				</Trigger>
@@ -180,9 +171,6 @@
 						}
 					</ChildContent>
 				</DSelect>
-				<div class="text-error text-sm">
-					<ValidationMessage For="() => MessageForm.ContentType" />
-				</div>
 			</div>
 
 			@if (showPreviewButton)
@@ -194,7 +182,7 @@
 
 		</div>
 
-		<DButton Size="DSize.Sm" Type="submit">
+		<DButton Size="DSize.Sm" Type="submit" Disabled="IsDefaultDisabled">
 			<span>@Localizer["Post"]</span>
 			<i class="ion-md-send"></i>
 		</DButton>
@@ -204,16 +192,46 @@
 </EditForm>
 
 @code {
-	[CascadingParameter] CascadingState CascadingState { get; set; }
+	const int MaxContentLength = 5_000;
+
+	[Inject] ILoggingService Logger { get; set; }
 	[Parameter] public Message AnsweringMessage { get; set; }
 	[Parameter] public EventCallback<MessageForm> OnMessageSubmit { get; set; }
 	MessageForm MessageForm { get; set; } = new();
-	int totalCharacters { get; set; } = 0;
-	string fileInputErrorMessage { get; set; }
-	string contentError { get; set; }
-	string acceptedFilesTypes { get; set; } = ".jpg,.jpeg,.png,.gif";
-	bool showPreviewButton { get; set; } = false;
-	bool isPreviewOpen { get; set; } = false;
+	List<string> fileErrors = [];
+	string contentError;
+	string acceptedFilesTypes = ".jpg,.jpeg,.png,.gif";
+	bool showPreviewButton;
+	bool isPreviewOpen;
+
+	// Content is null until the user types: a form starts without text.
+	int ContentLength => MessageForm.Content?.Length ?? 0;
+
+	int MaximumFileCount => MessageForm.MediaType switch
+	{
+		MediaType.Images => 5,
+		MediaType.Video or MediaType.Audio => 1,
+		MediaType.Documents => 3,
+		_ => 0
+	};
+
+	long MaximumFileSize => MessageForm.MediaType switch
+	{
+		MediaType.Images or MediaType.Documents => 3_145_728,
+		MediaType.Audio => 5_242_880,
+		MediaType.Video => 20_971_520,
+		_ => 0
+	};
+
+	protected override void OnInitialized()
+	{
+		IsLoading = false;
+		if (AnsweringMessage is null)
+			return;
+
+		MessageForm.Title = AnsweringMessage.Title;
+		MessageForm.RootMessageId = AnsweringMessage.RootMessageId ?? AnsweringMessage.MessageId;
+	}
 
 	void UpdateMessageType(MessageType messageType)
 	{
@@ -221,114 +239,68 @@
 		MessageForm.IsScopeOptionsOpen = false;
 	}
 
-	protected override void OnInitialized()
-	{
-		if (AnsweringMessage != default)
-		{
-			MessageForm.Title = AnsweringMessage.Title;
-			MessageForm.RootMessageId = AnsweringMessage.RootMessageId ?? AnsweringMessage.MessageId;
-		}
-	}
+	bool ShouldDisableUpload() => MessageForm.Media.Count >= MaximumFileCount;
 
-	bool ShouldDisableUpload()
-	{
-		switch (MessageForm.MediaType)
-		{
-			case MediaType.Images:
-				return MessageForm.Media.Count == 5;
-			case MediaType.Video:
-			case MediaType.Audio:
-				return MessageForm.Media.Count == 1;
-			case MediaType.Documents:
-				return MessageForm.Media.Count == 3;
-			default:
-				return true;
-		}
-	}
-
-	bool ShouldHaveMultipleUpload()
-	{
-		return MessageForm.MediaType is MediaType.Images or MediaType.Documents;
-	}
+	bool ShouldHaveMultipleUpload() => MessageForm.MediaType is MediaType.Images or MediaType.Documents;
 
 	async Task OnFileChange(InputFileChangeEventArgs eventArgs)
+	{
+		fileErrors = [];
+		var maximumFileCount = MaximumFileCount;
+		if (eventArgs.FileCount + MessageForm.Media.Count > maximumFileCount)
+		{
+			fileErrors.Add(Localizer["The maximum number of files accepted is {0}, but {1} were supplied.", maximumFileCount,
+				MessageForm.Media.Count + eventArgs.FileCount]);
+			return;
+		}
+
+		var maximumFileSize = MaximumFileSize;
+		foreach (var file in eventArgs.GetMultipleFiles(maximumFileCount))
+		{
+			if (file.Name == default || file.ContentType == default || MessageForm.Media.Any(m => m.FileName == file.Name))
+				continue;
+
+			if (file.Size > maximumFileSize)
+			{
+				fileErrors.Add(Localizer["Supplied file \"{0}\" with size {1} exceeds the maximum of {2}.", file.Name,
+					file.Size.GetFileSize(Localizer), maximumFileSize.GetFileSize(Localizer)]);
+				continue;
+			}
+
+			var uploadMedia = await ReadFile(file, maximumFileSize);
+			if (uploadMedia is null)
+			{
+				fileErrors.Add(Localizer["The file \"{0}\" could not be read.", file.Name]);
+				continue;
+			}
+
+			MessageForm.Media.Add(uploadMedia);
+		}
+	}
+
+	/// <summary>Reads a picked file into memory; null when the browser can't read it (logged).</summary>
+	async Task<UploadMedia> ReadFile(IBrowserFile file, long maximumFileSize, CancellationToken cancellationToken = default)
 	{
 		try
 		{
-			fileInputErrorMessage = string.Empty;
-			var maximumFileCount = MessageForm.MediaType switch
+			using var memoryStream = new MemoryStream();
+			await using var fileStream = file.OpenReadStream(maximumFileSize, cancellationToken);
+			await fileStream.CopyToAsync(memoryStream, cancellationToken);
+			var uploadMedia = new UploadMedia
 			{
-				MediaType.Images => 5,
-				MediaType.Audio => 1,
-				MediaType.Video => 1,
-				MediaType.Documents => 3,
-				_ => 0
+				FileName = file.Name,
+				ContentType = file.ContentType,
+				Size = file.Size,
+				Blob = memoryStream.ToArray()
 			};
-			if (eventArgs.FileCount > maximumFileCount)
-			{
-				fileInputErrorMessage = string.Format(Localizer["The maximum number of files accepted is {0}, but {1} were supplied."], maximumFileCount, eventArgs.FileCount);
-				return;
-			}
-			if (eventArgs.FileCount + MessageForm.Media.Count > maximumFileCount)
-			{
-				fileInputErrorMessage = string.Format(Localizer["The maximum number of files accepted is {0}, but {1} were supplied."], maximumFileCount, $"{MessageForm.Media.Count}+{eventArgs.FileCount}");
-				return;
-			}
-			var maxAllowedSize = MessageForm.MediaType switch
-			{
-				MediaType.Images => 3_145_728,
-				MediaType.Audio => 5_242_880,
-				MediaType.Video => 20_971_520,
-				MediaType.Documents => 3_145_728,
-				_ => 0
-			};
-			var uploadMedia = default(UploadMedia);
-			using (var memStream = new MemoryStream())
-				foreach (var file in eventArgs.GetMultipleFiles(maximumFileCount))
-				{
-					if (file.Name == default || file.ContentType == default) continue;
-					if (MessageForm.Media.Any(m => m.FileName == file.Name)) continue;
-					if (file.Size > maxAllowedSize)
-					{
-						fileInputErrorMessage += string.Format(Localizer["Supplied file \"{0}\" with size {1:N0}MBs exceeds the maximum of {2:N0}MBs."], file.Name, file.Size / 1_048_576, maxAllowedSize / 1_048_576) + "<br/>";
-						continue;
-					}
-
-					uploadMedia = new()
-						{
-							FileName = file.Name,
-							ContentType = file.ContentType,
-							Size = file.Size
-						};
-					try
-					{
-						using (var imgStream = file.OpenReadStream(maxAllowedSize))
-						{
-							await imgStream.CopyToAsync(memStream);
-							memStream.Position = 0;
-							uploadMedia.Blob = memStream.ToArray();
-							await memStream.FlushAsync();
-						}
-					}
-					catch (IOException e)
-					{
-						fileInputErrorMessage = e.Message;
-						continue;
-					}
-					catch (Exception e)
-					{
-						fileInputErrorMessage = e.Message;
-						continue;
-					}
-					if (MessageForm.MediaType is MediaType.Images or MediaType.Audio)
-						uploadMedia.Base64Preview = $"data:{uploadMedia.ContentType};base64,{Convert.ToBase64String(uploadMedia.Blob)}";
-
-					MessageForm.Media.Add(uploadMedia);
-				}
+			if (MessageForm.MediaType is MediaType.Images or MediaType.Audio)
+				uploadMedia.Base64Preview = $"data:{uploadMedia.ContentType};base64,{Convert.ToBase64String(uploadMedia.Blob)}";
+			return uploadMedia;
 		}
-		catch (Exception e)
+		catch (Exception ex)
 		{
-			fileInputErrorMessage = e.Message;
+			await Logger.ProcessError(ex, $"{nameof(MessageUpsertForm)}.{nameof(ReadFile)}:{file.Name}", cancellationToken);
+			return default;
 		}
 	}
 
@@ -342,12 +314,6 @@
 		MessageForm.Title = value;
 	}
 
-	void ContentLengthChanged()
-	{
-		totalCharacters = MessageForm.Content?.Length ?? 0;
-		StateHasChanged();
-	}
-
 	void OnContentTypeChanged(ContentType contentType)
 	{
 		MessageForm.ContentType = contentType;
@@ -375,7 +341,7 @@
 	async Task OnValidSubmit()
 	{
 		contentError = default;
-		if ((MessageForm.Content is { Length: 0 } && MessageForm.Media.Count == 0))
+		if (string.IsNullOrWhiteSpace(MessageForm.Content) && MessageForm.Media.Count == 0)
 		{
 			contentError = Localizer["Missing content, either message or media"];
 			return;
@@ -383,4 +349,4 @@
 
 		await OnMessageSubmit.InvokeAsync(MessageForm);
 	}
-}
+}

Components/Styleguide/DataInputSection.razor

@@ -11,31 +11,31 @@
 			<div class="flex flex-wrap items-center gap-2">
 				@foreach (var color in Enum.GetValues<DColor>())
 				{
-					<DInput @bind-Value="text" Color="color" placeholder="@color.ToString()" class="w-36" />
+					<DInput autocomplete="off" @bind-Value="text" Color="color" placeholder="@color.ToString()" class="w-36" />
 				}
 			</div>
 			<div class="flex flex-wrap items-center gap-2">
-				<DInput @bind-Value="text" Size="DSize.Xs" placeholder="Xs" class="w-28" />
-				<DInput @bind-Value="text" Size="DSize.Sm" placeholder="Sm" class="w-28" />
-				<DInput @bind-Value="text" placeholder="Md" class="w-28" />
-				<DInput @bind-Value="text" Size="DSize.Lg" placeholder="Lg" class="w-28" />
-				<DInput @bind-Value="text" Size="DSize.Xl" placeholder="Xl" class="w-28" />
+				<DInput autocomplete="off" @bind-Value="text" Size="DSize.Xs" placeholder="Xs" class="w-28" />
+				<DInput autocomplete="off" @bind-Value="text" Size="DSize.Sm" placeholder="Sm" class="w-28" />
+				<DInput autocomplete="off" @bind-Value="text" placeholder="Md" class="w-28" />
+				<DInput autocomplete="off" @bind-Value="text" Size="DSize.Lg" placeholder="Lg" class="w-28" />
+				<DInput autocomplete="off" @bind-Value="text" Size="DSize.Xl" placeholder="Xl" class="w-28" />
 			</div>
 			<div class="flex flex-wrap items-center gap-2">
-				<DInput @bind-Value="text" Ghost="true" placeholder="Ghost" />
-				<DInput @bind-Value="text" disabled placeholder="Disabled" />
-				<DInput @bind-Value="search" Immediate="true" placeholder="Search">
+				<DInput autocomplete="off" @bind-Value="text" Ghost="true" placeholder="Ghost" />
+				<DInput autocomplete="off" @bind-Value="text" disabled placeholder="Disabled" />
+				<DInput autocomplete="off" @bind-Value="search" Immediate="true" placeholder="Search">
 					<Prefix><i class="ion-md-search opacity-50"></i></Prefix>
 					<Suffix><kbd class="kbd kbd-sm">⌘</kbd><kbd class="kbd kbd-sm">K</kbd></Suffix>
 				</DInput>
-				<DInput @bind-Value="site" Color="DColor.Primary">
+				<DInput autocomplete="off" @bind-Value="site" Color="DColor.Primary">
 					<Prefix><DLabel>https://</DLabel></Prefix>
 					<Suffix><DLabel>.com</DLabel></Suffix>
 				</DInput>
 			</div>
 			<p class="text-sm opacity-60">Immediate search: "@search", text: "@text"</p>
 			<div class="flex flex-col">
-				<DInput @bind-Value="model.Name" Validator="true" placeholder="Name (required)" class="w-full max-w-xs" />
+				<DInput autocomplete="off" @bind-Value="model.Name" Validator="true" placeholder="Name (required)" class="w-full max-w-xs" />
 				<DValidatorHint>Name is required</DValidatorHint>
 			</div>
 		</section>
@@ -82,22 +82,22 @@
 			<div class="grid grid-cols-3 gap-2">
 				@foreach (var color in Enum.GetValues<DColor>())
 				{
-					<DTextarea @bind-Value="bio" Color="color" placeholder="@color.ToString()" class="min-h-0 h-12" />
+					<DTextarea autocomplete="off" @bind-Value="bio" Color="color" placeholder="@color.ToString()" class="min-h-0 h-12" />
 				}
 			</div>
 			<div class="flex flex-wrap items-start gap-2">
-				<DTextarea @bind-Value="bio" Size="DSize.Xs" placeholder="Xs" class="w-24" />
-				<DTextarea @bind-Value="bio" Size="DSize.Sm" placeholder="Sm" class="w-24" />
-				<DTextarea @bind-Value="bio" placeholder="Md" class="w-24" />
-				<DTextarea @bind-Value="bio" Size="DSize.Lg" placeholder="Lg" class="w-24" />
-				<DTextarea @bind-Value="bio" Size="DSize.Xl" placeholder="Xl" class="w-24" />
+				<DTextarea autocomplete="off" @bind-Value="bio" Size="DSize.Xs" placeholder="Xs" class="w-24" />
+				<DTextarea autocomplete="off" @bind-Value="bio" Size="DSize.Sm" placeholder="Sm" class="w-24" />
+				<DTextarea autocomplete="off" @bind-Value="bio" placeholder="Md" class="w-24" />
+				<DTextarea autocomplete="off" @bind-Value="bio" Size="DSize.Lg" placeholder="Lg" class="w-24" />
+				<DTextarea autocomplete="off" @bind-Value="bio" Size="DSize.Xl" placeholder="Xl" class="w-24" />
 			</div>
 			<div class="flex flex-wrap items-start gap-2">
-				<DTextarea @bind-Value="bio" Ghost="true" placeholder="Ghost" />
-				<DTextarea @bind-Value="bio" disabled placeholder="Disabled" />
+				<DTextarea autocomplete="off" @bind-Value="bio" Ghost="true" placeholder="Ghost" />
+				<DTextarea autocomplete="off" @bind-Value="bio" disabled placeholder="Disabled" />
 			</div>
 			<div class="flex flex-col">
-				<DTextarea @bind-Value="model.Bio" Immediate="true" Validator="true" placeholder="Bio, 10 to 140 characters" class="w-full" />
+				<DTextarea autocomplete="off" @bind-Value="model.Bio" Immediate="true" Validator="true" placeholder="Bio, 10 to 140 characters" class="w-full" />
 				<DValidatorHint>Between 10 and 140 characters</DValidatorHint>
 				<span class="text-sm opacity-60">@(model.Bio?.Length ?? 0)/140</span>
 			</div>
@@ -286,21 +286,21 @@
 				<Legend>Page details</Legend>
 				<ChildContent>
 					<DLabel>Title</DLabel>
-					<DInput @bind-Value="text" placeholder="My awesome page" />
+					<DInput autocomplete="off" @bind-Value="text" placeholder="My awesome page" />
 					<DLabel>Slug</DLabel>
-					<DInput @bind-Value="site" placeholder="my-awesome-page" />
+					<DInput autocomplete="off" @bind-Value="site" placeholder="my-awesome-page" />
 				</ChildContent>
 				<Description>You can edit these later</Description>
 			</DFieldset>
 			<DFieldset disabled>
 				<Legend>Disabled fieldset</Legend>
-				<ChildContent><DInput @bind-Value="text" placeholder="Can't type here" /></ChildContent>
+				<ChildContent><DInput autocomplete="off" @bind-Value="text" placeholder="Can't type here" /></ChildContent>
 			</DFieldset>
 			<DLabel Floating="true" Text="Your email">
-				<DInput @bind-Value="email" placeholder="mail@site.com" />
+				<DInput autocomplete="off" @bind-Value="email" placeholder="mail@site.com" />
 			</DLabel>
 			<DLabel Floating="true" Text="Notes">
-				<DTextarea @bind-Value="bio" placeholder="Notes" />
+				<DTextarea autocomplete="off" @bind-Value="bio" placeholder="Notes" />
 			</DLabel>
 		</section>
 
@@ -308,11 +308,11 @@
 			<h3 class="text-lg font-bold">DValidator / DValidatorHint</h3>
 			<p class="text-sm opacity-60">Native rules, checked by the browser once you've edited the field.</p>
 			<div class="flex flex-col">
-				<DInput @bind-Value="email" Type="email" Validator="true" required="true" placeholder="mail@site.com" />
+				<DInput autocomplete="off" @bind-Value="email" Type="email" Validator="true" required="true" placeholder="mail@site.com" />
 				<DValidatorHint>Enter a valid email address</DValidatorHint>
 			</div>
 			<div class="flex flex-col">
-				<DInput @bind-Value="username" Validator="true" required="true" pattern="[A-Za-z][A-Za-z0-9\-]*" minlength="3"
+				<DInput autocomplete="off" @bind-Value="username" Validator="true" required="true" pattern="[A-Za-z][A-Za-z0-9\-]*" minlength="3"
 						maxlength="30" placeholder="Username" title="Only letters, numbers or dash" />
 				<DValidatorHint Compact="true">Must be 3 to 30 letters, numbers or dashes (Compact: no space while valid)</DValidatorHint>
 			</div>
@@ -375,7 +375,7 @@
 	string framework;
 	DColor? filterColor;
 	string otp;
-	List<string> files = new();
+	List<string> files = [];
 
 	void Submitted(bool valid) => submitResult = valid ? "Valid" : "Invalid: see the messages above";
 

Components/Styleguide/FeedbackSection.razor

@@ -216,7 +216,7 @@
 
 	record Toast(int Id, DAlertColor Color);
 
-	readonly List<Toast> toasts = new();
+	readonly List<Toast> toasts = [];
 	DToastHorizontal toastHorizontal;
 	DToastVertical toastVertical;
 	int toastCount;

Components/Styleguide/LayoutSection.razor

@@ -165,7 +165,7 @@
 			<DButton class="join-item">from lg</DButton>
 		</DJoin>
 		<DJoin>
-			<input class="input join-item" placeholder="Email" />
+			<input autocomplete="off" class="input join-item" placeholder="Email" />
 			<select class="select join-item w-28">
 				<option>Filter</option>
 				<option>Sci-fi</option>

Components/ToastHost.razor

@@ -0,0 +1,41 @@
+@implements IDisposable
+
+@* Shows ToastService's messages at the bottom end of the screen. Placed once, in MainLayout. *@
+@if (Toast.Messages.Count > 0)
+{
+	<DToast class="z-[1000]">
+		@foreach (var message in Toast.Messages)
+		{
+			<DAlert @key="message.Id" Color="ColorOf(message.Severity)" class="max-w-sm">
+				<ChildContent>
+					<span class="break-words">@message.Text</span>
+				</ChildContent>
+				<Actions>
+					<DButton Size="DSize.Xs" Shape="DButtonShape.Circle" Variant="DButtonVariant.Ghost" aria-label="@Localizer["Close"]"
+							 OnClick="() => Toast.Close(message.Id)">
+						<i class="ion-md-close"></i>
+					</DButton>
+				</Actions>
+			</DAlert>
+		}
+	</DToast>
+}
+
+@code {
+	[Inject] ToastService Toast { get; set; }
+	[Inject] CoalescingStringLocalizer Localizer { get; set; }
+
+	protected override void OnInitialized() => Toast.Changed += OnChanged;
+
+	void OnChanged() => _ = InvokeAsync(StateHasChanged);
+
+	static DAlertColor ColorOf(ToastSeverity severity) => severity switch
+	{
+		ToastSeverity.Success => DAlertColor.Success,
+		ToastSeverity.Warning => DAlertColor.Warning,
+		ToastSeverity.Error => DAlertColor.Error,
+		_ => DAlertColor.Info
+	};
+
+	public void Dispose() => Toast.Changed -= OnChanged;
+}