From 1b83d7f9a7888a2a6131ae920860712dd8bbb9da Mon Sep 17 00:00:00 2001
From: bloeys <bloeys@outlook.com>
Date: Fri, 6 Oct 2023 04:23:42 +0400
Subject: [PATCH] Change Entity->BaseEntity + Add Entity interface

---
 entity/base_comp.go | 10 +++++-----
 entity/comp.go      |  4 ++--
 entity/entity.go    | 17 +++++++++++++++--
 entity/registry.go  | 10 +++++-----
 4 files changed, 27 insertions(+), 14 deletions(-)

diff --git a/entity/base_comp.go b/entity/base_comp.go
index 33abe6c..770906e 100755
--- a/entity/base_comp.go
+++ b/entity/base_comp.go
@@ -5,23 +5,23 @@ import "github.com/bloeys/nmage/assert"
 var _ Comp = &BaseComp{}
 
 type BaseComp struct {
-	Entity *Entity
+	Entity *BaseEntity
 }
 
 func (b BaseComp) baseComp() {
 }
 
-func (b *BaseComp) Init(parent *Entity) {
+func (b *BaseComp) Init(parent *BaseEntity) {
 	assert.T(parent != nil, "Component was initialized with a nil parent. That is not allowed.")
 	b.Entity = parent
 }
 
-func (b *BaseComp) Name() string {
+func (b BaseComp) Name() string {
 	return "Base Component"
 }
 
-func (b *BaseComp) Update() {
+func (b BaseComp) Update() {
 }
 
-func (b *BaseComp) Destroy() {
+func (b BaseComp) Destroy() {
 }
diff --git a/entity/comp.go b/entity/comp.go
index 4a22dc8..efce0ff 100755
--- a/entity/comp.go
+++ b/entity/comp.go
@@ -8,7 +8,7 @@ type Comp interface {
 	baseComp()
 
 	Name() string
-	Init(parent *Entity)
+	Init(parent *BaseEntity)
 	Update()
 	Destroy()
 }
@@ -21,7 +21,7 @@ type CompContainer struct {
 	Comps []Comp
 }
 
-func AddComp[T Comp](e *Entity, cc *CompContainer, c T) {
+func AddComp[T Comp](e *BaseEntity, cc *CompContainer, c T) {
 
 	assert.T(!HasComp[T](cc), "Entity with id '%v' already has component of type '%T'", e.ID, c)
 
diff --git a/entity/entity.go b/entity/entity.go
index f91d02c..e021351 100755
--- a/entity/entity.go
+++ b/entity/entity.go
@@ -13,14 +13,27 @@ const (
 	IndexBitMask        = 0x00_00_FFFF_FFFF_FFFF
 )
 
+type Entity interface {
+	baseEntity()
+	GetHandle() EntityHandle
+}
+
 type EntityHandle uint64
 
-type Entity struct {
+var _ Entity = &BaseEntity{}
+
+type BaseEntity struct {
 	// Byte 1: Generation; Byte 2: Flags; Bytes 3-8: Index
 	ID EntityHandle
 }
 
-func (e *Entity) HasFlag(ef EntityFlag) bool {
+func (be BaseEntity) baseEntity() {}
+
+func (be BaseEntity) GetHandle() EntityHandle {
+	return be.ID
+}
+
+func (e *BaseEntity) HasFlag(ef EntityFlag) bool {
 	return GetFlags(e.ID)&ef > 0
 }
 
diff --git a/entity/registry.go b/entity/registry.go
index bcefaa9..fe0186b 100755
--- a/entity/registry.go
+++ b/entity/registry.go
@@ -17,18 +17,18 @@ type freeListitem struct {
 
 type Registry struct {
 	EntityCount uint64
-	Entities    []Entity
+	Entities    []BaseEntity
 
 	FreeList     *freeListitem
 	FreeListSize uint32
 }
 
-func (r *Registry) NewEntity() *Entity {
+func (r *Registry) NewEntity() *BaseEntity {
 
 	assert.T(r.EntityCount < uint64(len(r.Entities)), "Can not add more entities to registry because it is full")
 
 	entityToUseIndex := uint64(0)
-	var entityToUse *Entity = nil
+	var entityToUse *BaseEntity = nil
 
 	if r.FreeList != nil && r.FreeListSize > FreeListUsageThreshold {
 
@@ -61,7 +61,7 @@ func (r *Registry) NewEntity() *Entity {
 	return entityToUse
 }
 
-func (r *Registry) GetEntity(id EntityHandle) *Entity {
+func (r *Registry) GetEntity(id EntityHandle) *BaseEntity {
 
 	index := GetIndex(id)
 	gen := GetGeneration(id)
@@ -99,6 +99,6 @@ func (r *Registry) FreeEntity(id EntityHandle) {
 func NewRegistry(size uint32) *Registry {
 	assert.T(size > 0, "Registry size must be more than zero")
 	return &Registry{
-		Entities: make([]Entity, size),
+		Entities: make([]BaseEntity, size),
 	}
 }