feat: expose block state properties through MCP

MinecraftClient/Mapping/BlockPalettes/BlockStateDefinition.cs

@@ -0,0 +1,71 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+
+namespace MinecraftClient.Mapping.BlockPalettes
+{
+    /// <summary>
+    /// Compact description of the property combinations in a contiguous block-state range.
+    /// </summary>
+    public sealed class BlockStateDefinition
+    {
+        private static readonly IReadOnlyDictionary<string, string> s_emptyProperties =
+            new ReadOnlyDictionary<string, string>(new Dictionary<string, string>());
+
+        private readonly BlockStatePropertyDefinition[] _properties;
+        public int FirstStateId { get; }
+        public int LastStateId { get; }
+        public static IReadOnlyDictionary<string, string> EmptyProperties => s_emptyProperties;
+
+        public BlockStateDefinition(int firstStateId, int stateCount, BlockStatePropertyDefinition[] properties)
+        {
+            ArgumentOutOfRangeException.ThrowIfNegative(firstStateId);
+            ArgumentOutOfRangeException.ThrowIfNegativeOrZero(stateCount);
+            ArgumentNullException.ThrowIfNull(properties);
+
+            FirstStateId = firstStateId;
+            LastStateId = checked(firstStateId + stateCount - 1);
+            _properties = properties;
+        }
+
+        public IReadOnlyDictionary<string, string> GetProperties(int stateId)
+        {
+            if (stateId < FirstStateId || stateId > LastStateId)
+                return EmptyProperties;
+
+            int offset = stateId - FirstStateId;
+            Dictionary<string, string> result = new(_properties.Length, StringComparer.Ordinal);
+            for (int i = 0; i < _properties.Length; i++)
+            {
+                BlockStatePropertyDefinition property = _properties[i];
+                int valueIndex = (offset / property.Stride) % property.Values.Length;
+                result[property.Name] = property.Values[valueIndex];
+            }
+
+            return result;
+        }
+    }
+
+    /// <summary>
+    /// Property name and its values in Minecraft's block-state iteration order.
+    /// </summary>
+    public sealed class BlockStatePropertyDefinition
+    {
+        public string Name { get; }
+        public string[] Values { get; }
+        public int Stride { get; }
+
+        public BlockStatePropertyDefinition(string name, string[] values, int stride)
+        {
+            ArgumentException.ThrowIfNullOrEmpty(name);
+            ArgumentNullException.ThrowIfNull(values);
+            if (values.Length == 0)
+                throw new ArgumentException("A block-state property must define at least one value.", nameof(values));
+            ArgumentOutOfRangeException.ThrowIfNegativeOrZero(stride);
+
+            Name = name;
+            Values = values;
+            Stride = stride;
+        }
+    }
+}