R8 the Mastodon API made real in decePub: featured tags, notify, languages, recommendations, notes, suggestions, the direct stream

A profile shows the hashtags an account features as chips opening their feed; under another account's header is what the
persona keeps of it for itself alone: for one it follows, a bell (follow with notify), the languages of its posts that
reach the home feed (follow with languages[]) and Recommend (endorsements, private here), and for any account a private
note saved on blur or with Save. Settings edits the persona's featured hashtags (added by name or from those used lately,
10 at most) and its reading preferences (/clientapi/avatar/private/preferences), which CascadingState keeps per persona
and the card applies to sensitive media and content warnings. A hashtag's tab features it on the profile. Explore has Who
to follow (/api/v2/suggestions, dismissed for good after asking); Administration has Staff picks. The Direct tab follows
the direct stream's conversation events; status notifications show the post. The follows CSV carries notify and languages.

Verified: Release build, 0 errors (the 3 warnings were there before). Not run against PrivaPub or in the pasture.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WpVCoDeM1qUTRp4fXQdfof

Services/DiscoveryService.cs

@@ -18,9 +18,11 @@ namespace decePubClient.Services
 	}
 
 	/// <summary>
-	/// What there is to find on PrivaPub: hashtags (their week, following them), what is trending there (hashtags, posts
-	/// and links, from public posts it already holds) and the directory of accounts that let themselves be discovered.
-	/// Lists come back empty and values null on failure; nothing throws.
+	/// What there is to find on PrivaPub: hashtags (their week, following them, featuring them on the persona's profile),
+	/// what is trending there (hashtags, posts and links, from public posts it already holds), the directory of accounts that
+	/// let themselves be discovered, and who to follow (PrivaPub's suggestions: the staff's picks, past interactions, popular
+	/// accounts here; never the persona itself nor a sibling persona of its login). Lists come back empty and values null on
+	/// failure; nothing throws.
 	/// </summary>
 	public class DiscoveryService(IHttpService httpService, ILoggingService logger, CoalescingStringLocalizer localizer)
 	{
@@ -44,6 +46,77 @@ namespace decePubClient.Services
 			return new WebResult { Data = await response.MastodonReadFromJsonAsync<Tag>(cancellationToken) };
 		}
 
+		/// <summary>Features a hashtag on the persona's profile, or stops (Mastodon 4.4's tags/:name/feature); its followers are
+		/// told, as featured tags are public. PrivaPub refuses (422) one past its limit. Data is the Tag, its Featuring set.</summary>
+		public async Task<WebResult> FeatureTag(string name, bool feature, CancellationToken cancellationToken = default)
+		{
+			using var response = await httpService.Post(APIs.Mastodon.POST_M_TagAction(name, feature ? "feature" : "unfeature"), cancellationToken: cancellationToken);
+			if (!response.IsSuccessStatusCode)
+				return await response.Content.ReadWebResult(response.StatusCode, localizer, cancellationToken);
+
+			return new WebResult { Data = await response.MastodonReadFromJsonAsync<Tag>(cancellationToken) };
+		}
+
+		/// <summary>The hashtags the persona features on its profile, with how often it used them.</summary>
+		public async Task<List<FeaturedTag>> FeaturedTags(CancellationToken cancellationToken = default)
+		{
+			using var response = await httpService.Get(APIs.Mastodon.GET_FeaturedTags, cancellationToken: cancellationToken);
+			if (response.IsSuccessStatusCode)
+				return await response.MastodonReadFromJsonAsync<List<FeaturedTag>>(cancellationToken) ?? [];
+
+			await LogFailure(response, nameof(FeaturedTags), cancellationToken);
+			return [];
+		}
+
+		/// <summary>Features a hashtag by its name (a # before it is fine); one featured already is answered as it is. PrivaPub
+		/// refuses (422) a name that is no hashtag and one past its limit. Data is the FeaturedTag.</summary>
+		public async Task<WebResult> AddFeaturedTag(string name, CancellationToken cancellationToken = default)
+		{
+			using var response = await httpService.Post(APIs.Mastodon.POST_FeaturedTag,
+				new[] { new KeyValuePair<string, string>("name", name?.Trim().TrimStart('#')) }, cancellationToken: cancellationToken);
+			if (!response.IsSuccessStatusCode)
+				return await response.Content.ReadWebResult(response.StatusCode, localizer, cancellationToken);
+
+			return new WebResult { Data = await response.MastodonReadFromJsonAsync<FeaturedTag>(cancellationToken) };
+		}
+
+		/// <summary>Stops featuring a hashtag, by the featured tag's id; its followers are told.</summary>
+		public async Task<WebResult> RemoveFeaturedTag(string featuredTagId, CancellationToken cancellationToken = default)
+		{
+			using var response = await httpService.Delete(APIs.Mastodon.DELETE_M_FeaturedTag(featuredTagId), cancellationToken: cancellationToken);
+			return response.IsSuccessStatusCode ? new WebResult() : await response.Content.ReadWebResult(response.StatusCode, localizer, cancellationToken);
+		}
+
+		/// <summary>Hashtags the persona used lately and does not feature, the most used first.</summary>
+		public async Task<List<Tag>> FeaturedTagSuggestions(CancellationToken cancellationToken = default)
+		{
+			using var response = await httpService.Get(APIs.Mastodon.GET_FeaturedTagSuggestions, cancellationToken: cancellationToken);
+			if (response.IsSuccessStatusCode)
+				return await response.MastodonReadFromJsonAsync<List<Tag>>(cancellationToken) ?? [];
+
+			await LogFailure(response, nameof(FeaturedTagSuggestions), cancellationToken);
+			return [];
+		}
+
+		/// <summary>Accounts to follow, best first, each with why (/api/v2/suggestions).</summary>
+		public async Task<List<Suggestion>> Suggestions(CancellationToken cancellationToken = default)
+		{
+			using var response = await httpService.Get(APIs.Mastodon.GET_Suggestions, ["limit=40"], cancellationToken: cancellationToken);
+			if (response.IsSuccessStatusCode)
+				return await response.MastodonReadFromJsonAsync<List<Suggestion>>(cancellationToken) ?? [];
+
+			await LogFailure(response, nameof(Suggestions), cancellationToken);
+			return [];
+		}
+
+		/// <summary>Never suggests the account to this persona again; there is no undoing it, but the account can still be
+		/// followed from its profile.</summary>
+		public async Task<WebResult> DismissSuggestion(string accountId, CancellationToken cancellationToken = default)
+		{
+			using var response = await httpService.Delete(APIs.Mastodon.DELETE_M_Suggestion(accountId), cancellationToken: cancellationToken);
+			return response.IsSuccessStatusCode ? new WebResult() : await response.Content.ReadWebResult(response.StatusCode, localizer, cancellationToken);
+		}
+
 		public Task<List<Tag>> FollowedTags(CancellationToken cancellationToken = default) =>
 			List<Tag>(APIs.Mastodon.GET_FollowedTags, ["limit=200"], nameof(FollowedTags), cancellationToken);