feat: rng & commands impl & tests

src/core/region.ts

@@ -5,7 +5,7 @@ import {RNG} from "../utils/rng";
 export type Region = Entity & {
   // aligning axes of the region
   axes: RegionAxis[];
-  
+
   // current children; expect no overlapped positions
   children: EntityAccessor<Part>[];
 }
@@ -27,7 +27,49 @@ export type RegionAxis = {
  */
 export function applyAlign(region: Region){
   for (const axis of region.axes) {
-    // TODO implement this
+    if (region.children.length === 0) continue;
+
+    // 获取当前轴向上的所有位置
+    const positions = region.children.map(accessor => accessor.value.position);
+    
+    // 根据当前轴的位置排序 children
+    region.children.sort((a, b) => {
+      const posA = a.value.position[0] ?? 0;
+      const posB = b.value.position[0] ?? 0;
+      return posA - posB;
+    });
+
+    if (axis.align === 'start' && axis.min !== undefined) {
+      // 从 min 开始紧凑排列
+      region.children.forEach((accessor, index) => {
+        const currentPos = accessor.value.position.slice();
+        currentPos[0] = axis.min! + index;
+        accessor.value.position = currentPos;
+      });
+    } else if (axis.align === 'end' && axis.max !== undefined) {
+      // 从 max 开始向前紧凑排列
+      const count = region.children.length;
+      region.children.forEach((accessor, index) => {
+        const currentPos = accessor.value.position.slice();
+        currentPos[0] = axis.max! - (count - 1 - index);
+        accessor.value.position = currentPos;
+      });
+    } else if (axis.align === 'center') {
+      // 居中排列
+      const count = region.children.length;
+      const min = axis.min ?? 0;
+      const max = axis.max ?? count - 1;
+      const range = max - min;
+      const center = min + range / 2;
+      
+      region.children.forEach((accessor, index) => {
+        const currentPos = accessor.value.position.slice();
+        // 计算相对于中心的偏移
+        const offset = index - (count - 1) / 2;
+        currentPos[0] = center + offset;
+        accessor.value.position = currentPos;
+      });
+    }
   }
 }
 
@@ -37,5 +79,17 @@ export function applyAlign(region: Region){
  * @param rng
  */
 export function shuffle(region: Region, rng: RNG){
-  // TODO implement this
-}
+  if (region.children.length <= 1) return;
+
+  // Fisher-Yates 洗牌算法
+  const children = [...region.children];
+  for (let i = children.length - 1; i > 0; i--) {
+    const j = rng.nextInt(i + 1);
+    // 交换位置
+    const posI = children[i].value.position.slice();
+    const posJ = children[j].value.position.slice();
+    
+    children[i].value.position = posJ;
+    children[j].value.position = posI;
+  }
+}