Group FAQs by a topic relation, ordered; drop unused FAQ teaser

Elternbeirat.Contracts/FaqTopic.cs

@@ -0,0 +1,73 @@
+using System.Text.Json.Serialization;
+
+namespace Elternbeirat.Contracts;
+
+/// <summary>
+///     A topic the FAQ entries are grouped under, as stored in PocketBase.
+/// </summary>
+/// <remarks>
+///     A <see cref="Faq"/> points at its topic through a relation, so the FAQ page
+///     groups the questions by topic and shows the groups in <see cref="Order"/>.
+///     Making the topic its own record (rather than a free-text field on each
+///     question) means the heading, its order and its optional <see cref="Intro"/>
+///     are edited in one place and shared by every question in the group.
+/// </remarks>
+public record FaqTopic
+{
+    /// <summary>
+    ///     Gets the PocketBase record id.
+    /// </summary>
+    /// <remarks>
+    ///     <see langword="required"/>: every stored record has an id. Modeling it as
+    ///     required states which fields a record must carry, independent of the store,
+    ///     so a future data source has to supply them too.
+    /// </remarks>
+    [JsonPropertyName("id")]
+    public required string Id { get; init; }
+
+    /// <summary>
+    ///     Gets the heading shown above the group of questions, e.g.
+    ///     <c>"Mensa und Mittagessen"</c>.
+    /// </summary>
+    /// <remarks>
+    ///     Free text; may contain umlauts and spaces. For the URL, see <see cref="Slug"/>.
+    ///     <see langword="required"/>: a topic without a heading has nothing to show, and
+    ///     the field is required in PocketBase.
+    /// </remarks>
+    [JsonPropertyName("title")]
+    public required string Title { get; init; }
+
+    /// <summary>
+    ///     Gets the URL slug of the topic, e.g. <c>"mensa"</c>.
+    /// </summary>
+    /// <value>
+    ///     A URL path segment: lowercase letters, digits and single hyphens as
+    ///     separators, no umlauts. PocketBase enforces this on save via a field
+    ///     pattern (<c>^[a-z0-9]+(-[a-z0-9]+)*$</c>), so every stored slug is already
+    ///     canonical and the app can use it verbatim.
+    /// </value>
+    /// <remarks>
+    ///     <see langword="required"/>: the slug is required in PocketBase and is the
+    ///     stable identifier of a topic, independent of its display title.
+    /// </remarks>
+    [JsonPropertyName("slug")]
+    public required string Slug { get; init; }
+
+    /// <summary>
+    ///     Gets the optional introduction shown below the topic heading, as Markdown.
+    /// </summary>
+    /// <value>
+    ///     The intro Markdown, or an empty string when the topic has none.
+    /// </value>
+    [JsonPropertyName("intro")]
+    public string Intro { get; init; } = string.Empty;
+
+    /// <summary>
+    ///     Gets the sort order of the topic among the FAQ groups.
+    /// </summary>
+    /// <value>
+    ///     The sort key; topics with smaller values appear first.
+    /// </value>
+    [JsonPropertyName("order")]
+    public double Order { get; init; }
+}