added a shitty ecs that I'm confident is way worse than just looping … (#4)

* added a shitty ecs that I'm confident is way worse than just looping objects lol

* mader a rendering system based on ecs

core/ecs/ecs.ts

@@ -0,0 +1,110 @@
+type ComponentMap<CT> = {
+  uid: (number | null)[];
+} & {
+  [K in keyof CT]?: Array<CT[K] | null>;
+};
+
+namespace ECS {
+  export type System<ComponentsType extends Record<string | number, any>> = (
+    arg: ComponentsType & { uid: (number | null)[] },
+  ) => Partial<ComponentsType> | null;
+}
+
+class ECS<ComponentsType extends Record<string | number, any>> {
+  private components: ComponentMap<ComponentsType> = { uid: [] };
+  private componentDefaults: Record<
+    string,
+    null | ComponentsType[keyof ComponentsType]
+  > = { uid: null };
+  private systems: Record<string, ECS.System<ComponentsType>> = {};
+
+  /**
+   * System
+   */
+  runSystems() {
+    const limit = this.components.uid.length;
+    for (let i = 0; i < limit; i++) {
+      const obj = {} as Record<string, unknown>;
+
+      for (const key in this.components) {
+        obj[key] = this.components[key]![i];
+      }
+
+      const systems = Object.values(this.systems);
+      for (let j = 0; j < systems.length; j++) {
+        const res = systems[j](
+          obj as ComponentsType & { uid: (number | null)[] },
+        );
+        if (!res) continue;
+
+        for (const key in res) {
+          if (!this.components[key]) continue;
+          this.components[key][i] = res[key]!;
+        }
+      }
+    }
+  }
+
+  addSystem(system: ECS.System<ComponentsType>) {
+    const id = crypto.randomUUID();
+    this.systems[id] = system;
+    return id;
+  }
+
+  removeSystem(id: string) {
+    delete this.systems[id];
+  }
+
+  getById(uid: number) {
+    if (this.components.uid.length <= uid) return {};
+
+    const obj = {} as Record<string, unknown>;
+
+    for (const key in this.components) {
+      obj[key] = this.components[key]![uid];
+    }
+
+    return obj;
+  }
+
+  /**
+   * Entity
+   */
+  addEntity(components: ComponentsType) {
+    for (const key in this.components) {
+      if (key === "uid") {
+        this.components[key].push(this.components[key].length);
+        continue;
+      }
+
+      this.components[key]!.push(
+        components[key] ?? this.componentDefaults[key],
+      );
+    }
+
+    return this.components.uid.length - 1;
+  }
+
+  /**
+   * Component
+   */
+  addComponent(
+    name: keyof ComponentsType,
+    fillValue = null as null | ComponentsType[keyof ComponentsType],
+    defaultValue = null as null | ComponentsType[keyof ComponentsType],
+  ) {
+    if (this.components[name]) throw new Error("Component already exists");
+
+    this.components[name] = new Array(this.components.uid.length).fill(
+      fillValue,
+    ) as ComponentMap<ComponentsType>[keyof ComponentsType];
+
+    this.componentDefaults[name as string] = defaultValue;
+  }
+
+  removeComponent(name: keyof ComponentsType) {
+    delete this.components[name];
+  }
+}
+
+export { ECS };