feat(render): implement Campaign AR and terrain fidelity

src/AcDream.Core/Plugins/PluginManifest.cs

@@ -2,6 +2,13 @@ using System.Text.Json;
 
 namespace AcDream.Core.Plugins;
 
+/// <summary>Host facility an entry assembly declares in <c>plugin.json</c>.</summary>
+public enum PluginKind
+{
+    Gameplay,
+    RenderPack,
+}
+
 public sealed record PluginManifest(
     string Id,
     string DisplayName,
@@ -10,6 +17,32 @@ public sealed record PluginManifest(
     int ApiVersion,
     IReadOnlyList<string> Dependencies)
 {
+    /// <summary>
+    /// Declared entry-point kinds. Old manifests omit <c>kinds</c> and remain
+    /// gameplay plugins, preserving the pre-render-pack loading contract.
+    /// </summary>
+    public IReadOnlyList<PluginKind> Kinds { get; init; } = [PluginKind.Gameplay];
+
+    public PluginManifest(
+        string Id,
+        string DisplayName,
+        string Version,
+        string EntryDll,
+        int ApiVersion,
+        IReadOnlyList<string> Dependencies,
+        IReadOnlyList<PluginKind> Kinds)
+        : this(Id, DisplayName, Version, EntryDll, ApiVersion, Dependencies)
+    {
+        ArgumentNullException.ThrowIfNull(Kinds);
+        if (Kinds.Count == 0)
+            throw new ArgumentException("At least one plugin kind is required.", nameof(Kinds));
+        this.Kinds = Kinds
+            .Distinct()
+            .ToArray();
+    }
+
+    public bool Declares(PluginKind kind) => Kinds.Contains(kind);
+
     public static PluginManifest Parse(string json)
     {
         PluginManifestDto? dto;
@@ -32,13 +65,40 @@ public sealed record PluginManifest(
         if (dto.ApiVersion <= 0)
             throw new PluginManifestException("apiVersion must be >= 1");
 
+        IReadOnlyList<PluginKind> kinds = ParseKinds(dto.Kinds);
+
         return new PluginManifest(
             dto.Id!,
             dto.DisplayName!,
             dto.Version!,
             dto.EntryDll!,
             dto.ApiVersion,
-            dto.Dependencies ?? Array.Empty<string>());
+            dto.Dependencies ?? Array.Empty<string>(),
+            kinds);
+    }
+
+    private static IReadOnlyList<PluginKind> ParseKinds(IReadOnlyList<string>? values)
+    {
+        if (values is null)
+            return [PluginKind.Gameplay];
+        if (values.Count == 0)
+            throw new PluginManifestException("kinds must contain at least one entry");
+
+        var kinds = new List<PluginKind>(values.Count);
+        foreach (string? value in values)
+        {
+            if (string.IsNullOrWhiteSpace(value)
+                || !Enum.TryParse(value, ignoreCase: true, out PluginKind kind)
+                || !Enum.IsDefined(kind))
+            {
+                throw new PluginManifestException(
+                    $"unknown plugin kind: {value ?? "<null>"}");
+            }
+
+            if (!kinds.Contains(kind))
+                kinds.Add(kind);
+        }
+        return kinds;
     }
 
     private static void Require(string? value, string jsonFieldName)
@@ -61,6 +121,7 @@ public sealed record PluginManifest(
         public string? EntryDll { get; set; }
         public int ApiVersion { get; set; }
         public IReadOnlyList<string>? Dependencies { get; set; }
+        public IReadOnlyList<string>? Kinds { get; set; }
     }
 }