From 182b6fbe1b2f691170566068ba9064efe2c2d6e0 Mon Sep 17 00:00:00 2001
From: Felix Cravic <themode@outlook.fr>
Date: Tue, 26 May 2020 18:25:35 +0200
Subject: [PATCH] Added Player#facePosition and Player#spectate

---
 .../net/minestom/server/entity/Player.java    | 61 ++++++++++++++++++-
 .../packet/server/play/FacePlayerPacket.java  |  2 +-
 2 files changed, 61 insertions(+), 2 deletions(-)

diff --git a/src/main/java/net/minestom/server/entity/Player.java b/src/main/java/net/minestom/server/entity/Player.java
index 28f8d3cd0..a775e627d 100644
--- a/src/main/java/net/minestom/server/entity/Player.java
+++ b/src/main/java/net/minestom/server/entity/Player.java
@@ -737,7 +737,7 @@ public class Player extends LivingEntity {
      * @param food the new food value
      */
     public void setFood(int food) {
-        Check.argCondition(!MathUtils.isBetween(food, 0, 20), "Food needs to be between 0 and 20");
+        Check.argCondition(!MathUtils.isBetween(food, 0, 20), "Food has to be between 0 and 20");
         this.food = food;
         sendUpdateHealthPacket();
     }
@@ -842,6 +842,60 @@ public class Player extends LivingEntity {
         return !itemDropEvent.isCancelled();
     }
 
+    /**
+     * Rotate the player to face {@code targetPosition}
+     *
+     * @param facePoint      the point from where the player should aim
+     * @param targetPosition the target position to face
+     */
+    public void facePosition(FacePoint facePoint, Position targetPosition) {
+        facePosition(facePoint, targetPosition, null, null);
+    }
+
+    /**
+     * Rotate the player to face {@code entity}
+     *
+     * @param facePoint   the point from where the player should aim
+     * @param entity      the entity to face
+     * @param targetPoint the point to aim at {@code entity} position
+     */
+    public void facePosition(FacePoint facePoint, Entity entity, FacePoint targetPoint) {
+        facePosition(facePoint, entity.getPosition(), entity, targetPoint);
+    }
+
+    private void facePosition(FacePoint facePoint, Position targetPosition, Entity entity, FacePoint targetPoint) {
+        FacePlayerPacket facePlayerPacket = new FacePlayerPacket();
+        facePlayerPacket.entityFacePosition = facePoint == FacePoint.EYE ?
+                FacePlayerPacket.FacePosition.EYES : FacePlayerPacket.FacePosition.FEET;
+        facePlayerPacket.targetX = targetPosition.getX();
+        facePlayerPacket.targetY = targetPosition.getY();
+        facePlayerPacket.targetZ = targetPosition.getZ();
+        if (entity != null) {
+            facePlayerPacket.entityId = entity.getEntityId();
+            facePlayerPacket.entityFacePosition = targetPoint == FacePoint.EYE ?
+                    FacePlayerPacket.FacePosition.EYES : FacePlayerPacket.FacePosition.FEET;
+        }
+        playerConnection.sendPacket(facePlayerPacket);
+    }
+
+    /**
+     * Set the camera at {@code entity} eyes
+     *
+     * @param entity the entity to spectate
+     */
+    public void spectate(Entity entity) {
+        CameraPacket cameraPacket = new CameraPacket();
+        cameraPacket.cameraId = entity.getEntityId();
+        playerConnection.sendPacket(cameraPacket);
+    }
+
+    /**
+     * Reset the camera at the player
+     */
+    public void stopSpectating() {
+        spectate(this);
+    }
+
     /**
      * Used to retrieve the default spawn point
      * can be altered by the {@link PlayerRespawnEvent#setRespawnPosition(Position)}
@@ -1566,6 +1620,11 @@ public class Player extends LivingEntity {
         HIDDEN
     }
 
+    public enum FacePoint {
+        FEET,
+        EYE
+    }
+
     public class PlayerSettings {
 
         private String locale;
diff --git a/src/main/java/net/minestom/server/network/packet/server/play/FacePlayerPacket.java b/src/main/java/net/minestom/server/network/packet/server/play/FacePlayerPacket.java
index 4f48655a1..bd390afe3 100644
--- a/src/main/java/net/minestom/server/network/packet/server/play/FacePlayerPacket.java
+++ b/src/main/java/net/minestom/server/network/packet/server/play/FacePlayerPacket.java
@@ -8,7 +8,6 @@ public class FacePlayerPacket implements ServerPacket {
 
     public FacePosition facePosition;
     public double targetX, targetY, targetZ;
-    public boolean isEntity;
     public int entityId;
     public FacePosition entityFacePosition;
 
@@ -20,6 +19,7 @@ public class FacePlayerPacket implements ServerPacket {
         writer.writeDouble(targetY);
         writer.writeDouble(targetZ);
 
+        final boolean isEntity = entityId > 0;
         writer.writeBoolean(isEntity);
         if (isEntity) {
             writer.writeVarInt(entityId);