feat: NPC reactions gated by conditions, applying effects

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Semesterprojekt/src/test/java/thb/jeanluc/adventure/command/impl/ReactionEffectsTest.java

@@ -0,0 +1,42 @@
+package thb.jeanluc.adventure.command.impl;
+
+import org.junit.jupiter.api.Test;
+import thb.jeanluc.adventure.game.GameContext;
+import thb.jeanluc.adventure.io.TestIO;
+import thb.jeanluc.adventure.model.Condition;
+import thb.jeanluc.adventure.model.Effect;
+import thb.jeanluc.adventure.model.Npc;
+import thb.jeanluc.adventure.model.NpcReaction;
+import thb.jeanluc.adventure.model.Player;
+import thb.jeanluc.adventure.model.Room;
+import thb.jeanluc.adventure.model.item.PlainItem;
+
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class ReactionEffectsTest {
+    @Test
+    void reactionRequiresFlagAndAppliesEffects() {
+        Room room = new Room("k", "K", "d");
+        Npc man = Npc.shell("man", "Old Man", "stooped", "hi");
+        man.putReaction("fuse", NpcReaction.builder()
+                .requires(List.of(new Condition(Condition.Type.FLAG, "cellar_drained")))
+                .effects(List.of(new Effect(Effect.Type.SET_FLAG, "fuse_installed")))
+                .response("Done.")
+                .build());
+        room.addNpc(man);
+        Player player = new Player(room, 0);
+        player.addItem(PlainItem.builder().id("fuse").name("Fuse").description("d").build());
+        TestIO io = new TestIO();
+        GameContext ctx = new GameContext(null, player, io);
+
+        new GiveCommand().execute(ctx, List.of("fuse", "man"));
+        assertThat(ctx.getState().isSet("fuse_installed")).isFalse(); // requires not met
+
+        ctx.getState().set("cellar_drained");
+        new GiveCommand().execute(ctx, List.of("fuse", "man"));
+        assertThat(ctx.getState().isSet("fuse_installed")).isTrue();
+        assertThat(io.allOutput()).contains("Done.");
+    }
+}