Entity metadata (#37)

* add example generated metadata.rs

* metadata.rs codegen

* add the files

* add comment to top of metadata.rs

* avoid clone

* metadata

* defaults

* defaults

* fix metadata readers and writers

* fix bad bitmasks and ignore some clippy warnings in generated code

* add set_index function to entity metadatas

* applying metadata

1 files changed, 28 insertions, 2 deletions

diff --git a/azalea-world/src/entity/mod.rs b/azalea-world/src/entity/mod.rs
index 37474d1d..e537e7e0 100644
--- a/azalea-world/src/entity/mod.rs
+++ b/azalea-world/src/entity/mod.rs
@@ -1,6 +1,8 @@
 mod data;
 mod dimensions;
+pub mod metadata;
 
+pub use self::metadata::EntityMetadata;
 use crate::Dimension;
 use azalea_block::BlockState;
 use azalea_core::{BlockPos, Vec3, AABB};
@@ -142,6 +144,18 @@ impl<'d> EntityMut<'d> {
             z: acceleration.z * (x_rot as f64) + acceleration.x * (y_rot as f64),
         }
     }
+
+    /// Apply the given metadata items to the entity. Everything that isn't
+    /// included in items will be left unchanged. If an error occured, None
+    /// will be returned.
+    ///
+    /// TODO: this should be changed to have a proper error.
+    pub fn apply_metadata(&mut self, items: &Vec<EntityDataItem>) -> Option<()> {
+        for item in items {
+            self.metadata.set_index(item.index, item.value.clone())?;
+        }
+        Some(())
+    }
 }
 
 impl<'d> EntityMut<'d> {
@@ -264,10 +278,13 @@ pub struct EntityData {
     /// Whether the entity will try to jump every tick
     /// (equivalent to the space key being held down in vanilla).
     pub jumping: bool,
+
+    /// Stores some extra data about the entity, including the entity type.
+    pub metadata: EntityMetadata,
 }
 
 impl EntityData {
-    pub fn new(uuid: Uuid, pos: Vec3) -> Self {
+    pub fn new(uuid: Uuid, pos: Vec3, metadata: EntityMetadata) -> Self {
         let dimensions = EntityDimensions {
             width: 0.6,
             height: 1.8,
@@ -297,6 +314,8 @@ impl EntityData {
             dimensions,
 
             jumping: false,
+
+            metadata,
         }
     }
 
@@ -318,7 +337,14 @@ mod tests {
     fn from_mut_entity_to_ref_entity() {
         let mut dim = Dimension::default();
         let uuid = Uuid::from_u128(100);
-        dim.add_entity(0, EntityData::new(uuid, Vec3::default()));
+        dim.add_entity(
+            0,
+            EntityData::new(
+                uuid,
+                Vec3::default(),
+                EntityMetadata::Player(metadata::Player::default()),
+            ),
+        );
         let entity: EntityMut = dim.entity_mut(0).unwrap();
         let entity_ref: EntityRef = entity.into();
         assert_eq!(entity_ref.uuid, uuid);