feat: initial CMagicGem reimplementation

src/main/java/cn/infstar/cMagicGem/reward/RewardContext.java

@@ -0,0 +1,48 @@
+package cn.infstar.cmagicgem.reward;
+
+import cn.infstar.cmagicgem.gem.GemDefinition;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.ItemStack;
+
+import java.util.IdentityHashMap;
+import java.util.Map;
+import java.util.function.DoubleSupplier;
+
+public final class RewardContext {
+    private final Player player;
+    private final GemDefinition gem;
+    private ItemStack item;
+    private final boolean removal;
+    private final Map<Object, Double> evaluatedNumbers = new IdentityHashMap<>();
+
+    public RewardContext(Player player, GemDefinition gem, ItemStack item, boolean removal) {
+        this.player = player;
+        this.gem = gem;
+        this.item = item;
+        this.removal = removal;
+    }
+
+    public Player player() {
+        return player;
+    }
+
+    public GemDefinition gem() {
+        return gem;
+    }
+
+    public ItemStack item() {
+        return item;
+    }
+
+    public void item(ItemStack item) {
+        this.item = item;
+    }
+
+    public boolean removal() {
+        return removal;
+    }
+
+    public double evaluatedNumber(Object key, DoubleSupplier supplier) {
+        return evaluatedNumbers.computeIfAbsent(key, ignored -> supplier.getAsDouble());
+    }
+}