init

actionBlocks_server/src/ActionBlocks.Game/Items/ItemRegistry.cs

@@ -0,0 +1,54 @@
+namespace ActionBlocks.Game.Items;
+
+/// <summary>All items that exist in the game. Register new items here.</summary>
+public sealed class ItemRegistry
+{
+    private readonly Dictionary<string, IItem> _items;
+
+    public ItemRegistry(IEnumerable<IItem> items)
+    {
+        _items = items.ToDictionary(i => i.Id);
+    }
+
+    public static ItemRegistry Default { get; } = new(
+    [
+        new AddGarbageLineItem(),
+        new ClearBottomLineItem(),
+        new ClearBoardItem(),
+        new SwapBoardItem(),
+        new InvisibilityItem(),
+    ]);
+
+    public IReadOnlyCollection<IItem> All => _items.Values;
+
+    public IItem? Get(string id) => _items.GetValueOrDefault(id);
+
+    public IItem PickRandom(Random random)
+    {
+        var total = _items.Values.Sum(i => i.SpawnWeight);
+        var roll = random.Next(total);
+        foreach (var item in _items.Values)
+        {
+            roll -= item.SpawnWeight;
+            if (roll < 0)
+            {
+                return item;
+            }
+        }
+        return _items.Values.First();
+    }
+}
+
+/// <summary>Decides whether a new piece carries an item and in which of its minos.</summary>
+public sealed class ItemSpawner(ItemRegistry registry, double chance, Random random)
+{
+    public Core.PieceSpec Decorate(Core.PieceType type)
+    {
+        if (registry.All.Count == 0 || random.NextDouble() >= chance)
+        {
+            return new Core.PieceSpec(type);
+        }
+        var item = registry.PickRandom(random);
+        return new Core.PieceSpec(type, item.Id, random.Next(4));
+    }
+}