From 80588c1ce4b50960414f3d8ec2bec2f36a65fc6f Mon Sep 17 00:00:00 2001
From: Joel Wetzell <jwetzell@yahoo.com>
Date: Sat, 15 Mar 2025 09:54:58 -0500
Subject: [PATCH] add decoder for zone collision detection submodule

---
 src/decoders/index.ts                         |  4 +++
 .../motion/zone-collision-detection.ts        | 32 +++++++++++++++++
 src/decoders/motion/zone-object.ts            | 21 +++++++++++
 src/models.ts                                 | 13 +++++++
 tests/decode.test.js                          | 35 +++++++++++++++++++
 5 files changed, 105 insertions(+)
 create mode 100644 src/decoders/motion/zone-collision-detection.ts
 create mode 100644 src/decoders/motion/zone-object.ts

diff --git a/src/decoders/index.ts b/src/decoders/index.ts
index 90416bf..c96275a 100644
--- a/src/decoders/index.ts
+++ b/src/decoders/index.ts
@@ -4,6 +4,8 @@ import OrientationEuler from './motion/orientation-euler';
 import OrientationQuaternion from './motion/orientation-quaternion';
 import TrackedPointAccelVelocity from './motion/tracked-point-accel-velocity';
 import TrackedPointPosition from './motion/tracked-point-position';
+import ZoneCollisionDetection from './motion/zone-collision-detection';
+import ZoneObject from './motion/zone-object';
 import RTTrPHeader from './rttrp';
 
 export const Decoders = {
@@ -14,4 +16,6 @@ export const Decoders = {
   TrackedPointAccelVelocity,
   OrientationQuaternion,
   OrientationEuler,
+  ZoneCollisionDetection,
+  ZoneObject,
 };
diff --git a/src/decoders/motion/zone-collision-detection.ts b/src/decoders/motion/zone-collision-detection.ts
new file mode 100644
index 0000000..4d01700
--- /dev/null
+++ b/src/decoders/motion/zone-collision-detection.ts
@@ -0,0 +1,32 @@
+import { Decoders } from '..';
+import { ZoneCollisionDetection, ZoneObject } from '../../models';
+
+export default (bytes: Uint8Array, isLittleEndian: boolean = false): ZoneCollisionDetection => {
+  const view = new DataView(bytes.buffer, bytes.byteOffset, bytes.byteLength);
+
+  const type = view.getUint8(0);
+  if (type !== 0x22) {
+    throw new Error('Zone Collision Detection module must have a type of 0x22');
+  }
+
+  const size = view.getUint16(1, isLittleEndian);
+  if (size !== bytes.byteLength) {
+    throw new Error('Zone Collision Detection module size mismatch');
+  }
+  const numberOfZones = view.getUint8(3);
+
+  const zones: ZoneObject[] = [];
+  let zoneObjectOffset = 4;
+
+  for (let index = 0; index < numberOfZones; index++) {
+    const zone = Decoders.ZoneObject(bytes.subarray(zoneObjectOffset));
+    zones.push(zone);
+    zoneObjectOffset += zone.size;
+  }
+  return {
+    type,
+    size,
+    numberOfZones,
+    zones,
+  };
+};
diff --git a/src/decoders/motion/zone-object.ts b/src/decoders/motion/zone-object.ts
new file mode 100644
index 0000000..19b57c2
--- /dev/null
+++ b/src/decoders/motion/zone-object.ts
@@ -0,0 +1,21 @@
+import { ZoneObject } from '../../models';
+const textDecoder = new TextDecoder('utf-8');
+export default (bytes: Uint8Array): ZoneObject => {
+  const size = bytes[0];
+  if (bytes.byteLength < size) {
+    throw new Error('Zone Object size does not have enough actual bytes');
+  }
+
+  const moduleBytes = bytes.subarray(0, size);
+
+  const nameLength = moduleBytes[1];
+  if (moduleBytes.byteLength - 2 !== nameLength) {
+    throw new Error('Zone Object name length does not match actual moduleBytes length');
+  }
+  const name = textDecoder.decode(moduleBytes.subarray(2));
+  return {
+    size,
+    nameLength,
+    name,
+  };
+};
diff --git a/src/models.ts b/src/models.ts
index 7cccc4e..83a5883 100644
--- a/src/models.ts
+++ b/src/models.ts
@@ -76,3 +76,16 @@ export type OrientationEuler = {
   r2: number;
   r3: number;
 };
+
+export type ZoneCollisionDetection = {
+  type: number;
+  size: number;
+  numberOfZones: number;
+  zones: ZoneObject[];
+};
+
+export type ZoneObject = {
+  size: number;
+  nameLength: number;
+  name: string;
+};
diff --git a/tests/decode.test.js b/tests/decode.test.js
index ebb4f95..3061d14 100644
--- a/tests/decode.test.js
+++ b/tests/decode.test.js
@@ -131,6 +131,41 @@ const goodTests = [
     },
     decoder: Decoders.TrackedPointAccelVelocity,
   },
+  {
+    description: 'Zone Collision Detection',
+    bytes: new Uint8Array([
+      0x22, 0x00, 0x14, 0x02, 0x08, 0x06, 0x7a, 0x6f, 0x6e, 0x65, 0x20, 0x31, 0x08, 0x06, 0x7a, 0x6f, 0x6e, 0x65, 0x20,
+      0x32,
+    ]),
+    expected: {
+      type: 0x22,
+      size: 20,
+      numberOfZones: 2,
+      zones: [
+        {
+          size: 0x08,
+          nameLength: 0x06,
+          name: 'zone 1',
+        },
+        {
+          size: 0x08,
+          nameLength: 0x06,
+          name: 'zone 2',
+        },
+      ],
+    },
+    decoder: Decoders.ZoneCollisionDetection,
+  },
+  {
+    description: 'Zone Object',
+    bytes: new Uint8Array([0x08, 0x06, 0x7a, 0x6f, 0x6e, 0x65, 0x20, 0x31]),
+    expected: {
+      size: 0x08,
+      nameLength: 0x06,
+      name: 'zone 1',
+    },
+    decoder: Decoders.ZoneObject,
+  },
 ];
 
 describe('RTTrP Bytes Decoding', () => {