From ad991fcf39acaecc5198eb184a35a43ad3e811af Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bart=C5=82omiej=20Przemys=C5=82aw=20Pluta?=
 <noreply.git@mx.bartlomiejpluta.com>
Date: Sat, 6 Mar 2021 10:18:40 +0100
Subject: [PATCH] Create FollowPathAI and NoopAI artificial intelligence
 strategies

---
 .../base/api/game/ai/FollowPathAI.java        | 142 ++++++++++++++++++
 .../base/api/game/ai/NoopAI.java              |  13 ++
 2 files changed, 155 insertions(+)
 create mode 100644 api/src/main/java/com/bartlomiejpluta/base/api/game/ai/FollowPathAI.java
 create mode 100644 api/src/main/java/com/bartlomiejpluta/base/api/game/ai/NoopAI.java

diff --git a/api/src/main/java/com/bartlomiejpluta/base/api/game/ai/FollowPathAI.java b/api/src/main/java/com/bartlomiejpluta/base/api/game/ai/FollowPathAI.java
new file mode 100644
index 00000000..d5ec4884
--- /dev/null
+++ b/api/src/main/java/com/bartlomiejpluta/base/api/game/ai/FollowPathAI.java
@@ -0,0 +1,142 @@
+package com.bartlomiejpluta.base.api.game.ai;
+
+import com.bartlomiejpluta.base.api.game.entity.Direction;
+import com.bartlomiejpluta.base.api.game.entity.Movement;
+import com.bartlomiejpluta.base.api.game.map.layer.object.ObjectLayer;
+
+import java.util.LinkedList;
+import java.util.List;
+
+public class FollowPathAI implements AI {
+   private final List<PathSegment> path = new LinkedList<>();
+   private final NPC npc;
+   private final boolean repeat;
+
+   private int current = 0;
+
+   public FollowPathAI(NPC npc) {
+      this(npc, true);
+   }
+
+   public FollowPathAI(NPC npc, boolean repeat) {
+      this.npc = npc;
+      this.repeat = repeat;
+   }
+
+   @Override
+   public void nextActivity(ObjectLayer layer, float dt) {
+      if (!repeat && isRetired()) {
+         return;
+      }
+
+      if (!npc.isMoving()) {
+         PathSegment item = (PathSegment) path.get(current % path.size());
+         if (item.perform(npc, layer, dt)) {
+            ++current;
+         }
+      }
+   }
+
+   public boolean isRetired() {
+      return current == path.size() - 1;
+   }
+
+   public FollowPathAI move(Direction direction) {
+      return move(direction, false);
+   }
+
+   public FollowPathAI move(Direction direction, boolean ignore) {
+      path.add(new Move(direction, ignore));
+      return this;
+   }
+
+   public FollowPathAI turn(Direction direction) {
+      path.add(new Turn(direction));
+      return this;
+   }
+
+   public FollowPathAI wait(float seconds) {
+      path.add(new Wait(seconds));
+      return this;
+   }
+
+   public FollowPathAI run(Runnable runnable) {
+      path.add(new Run(runnable));
+      return this;
+   }
+
+   public interface PathSegment {
+      boolean perform(NPC npc, ObjectLayer layer, float dt);
+   }
+
+   private static class Move implements PathSegment {
+      private final Direction direction;
+      private final boolean ignore;
+
+      public Move(Direction direction, boolean ignore) {
+         this.direction = direction;
+         this.ignore = ignore;
+      }
+
+      @Override
+      public boolean perform(NPC npc, ObjectLayer layer, float dt) {
+         Movement movement = npc.prepareMovement(direction);
+
+         if (ignore || layer.isMovementPossible(movement)) {
+            layer.pushMovement(movement);
+            return true;
+         }
+
+         return false;
+      }
+   }
+
+   private static class Turn implements PathSegment {
+      private final Direction direction;
+
+      public Turn(Direction direction) {
+         this.direction = direction;
+      }
+
+      @Override
+      public boolean perform(NPC npc, ObjectLayer layer, float dt) {
+         npc.setFaceDirection(direction);
+         return true;
+      }
+   }
+
+   private static class Wait implements PathSegment {
+      private float accumulator = 0.0f;
+      private final float seconds;
+
+      public Wait(float seconds) {
+         this.seconds = seconds;
+      }
+
+      @Override
+      public boolean perform(NPC npc, ObjectLayer layer, float dt) {
+         accumulator += dt;
+
+         if (accumulator > seconds) {
+            accumulator = 0.0f;
+            return true;
+         }
+
+         return false;
+      }
+   }
+
+   private static class Run implements PathSegment {
+      private final Runnable runnable;
+
+      private Run(Runnable runnable) {
+         this.runnable = runnable;
+      }
+
+      @Override
+      public boolean perform(NPC npc, ObjectLayer layer, float dt) {
+         runnable.run();
+         return true;
+      }
+   }
+}
diff --git a/api/src/main/java/com/bartlomiejpluta/base/api/game/ai/NoopAI.java b/api/src/main/java/com/bartlomiejpluta/base/api/game/ai/NoopAI.java
new file mode 100644
index 00000000..c4881a5c
--- /dev/null
+++ b/api/src/main/java/com/bartlomiejpluta/base/api/game/ai/NoopAI.java
@@ -0,0 +1,13 @@
+package com.bartlomiejpluta.base.api.game.ai;
+
+import com.bartlomiejpluta.base.api.game.map.layer.object.ObjectLayer;
+
+public class NoopAI implements AI {
+
+   @Override
+   public void nextActivity(ObjectLayer layer, float dt) {
+      // do nothing
+   }
+
+   public static AI INSTANCE = new NoopAI();
+}