From 5d94ba88ee3c83a920e080eaa0913a48b3eb00c1 Mon Sep 17 00:00:00 2001
From: liamcottle <liam@liamcottle.com>
Date: Sun, 9 Mar 2025 17:15:12 +1300
Subject: [PATCH] parse packet types

---
 examples/parse_packet.js |  1 +
 src/advert.js            | 71 +++++++++++++++++++++++++++++++++-------
 src/packet.js            | 43 ++++++++++++++++++++++++
 3 files changed, 104 insertions(+), 11 deletions(-)

diff --git a/examples/parse_packet.js b/examples/parse_packet.js
index d4569b9..04750f3 100644
--- a/examples/parse_packet.js
+++ b/examples/parse_packet.js
@@ -4,3 +4,4 @@ const bytes = Buffer.from("0200B401DF6528CC9778A56F36FE9399A5CF6B0C7EDE", "hex")
 const packet = Packet.fromBytes(bytes);
 
 console.log(packet);
+console.log(packet.parsePayload());
\ No newline at end of file
diff --git a/src/advert.js b/src/advert.js
index bc03568..f4c1525 100644
--- a/src/advert.js
+++ b/src/advert.js
@@ -1,15 +1,51 @@
 import {ed25519} from "@noble/curves/ed25519";
 import BufferReader from "./buffer_reader.js";
 import BufferWriter from "./buffer_writer.js";
-import Packet from "./packet.js";
 
 class Advert {
 
+    static ADV_TYPE_NONE = 0;
+    static ADV_TYPE_CHAT = 1;
+    static ADV_TYPE_REPEATER = 2;
+    static ADV_TYPE_ROOM = 3;
+
+    static ADV_LATLON_MASK = 0x10;
+    static ADV_BATTERY_MASK = 0x20;
+    static ADV_TEMPERATURE_MASK = 0x40;
+    static ADV_NAME_MASK = 0x80;
+
     constructor(publicKey, timestamp, signature, appData) {
         this.publicKey = publicKey;
         this.timestamp = timestamp;
         this.signature = signature;
         this.appData = appData;
+        this.parsed = this.parseAppData();
+    }
+
+    static fromBytes(bytes) {
+
+        // read bytes
+        const bufferReader = new BufferReader(bytes);
+        const publicKey = bufferReader.readBytes(32);
+        const timestamp = bufferReader.readUInt32LE();
+        const signature = bufferReader.readBytes(64);
+        const appData = bufferReader.readRemainingBytes();
+
+        return new Advert(publicKey, timestamp, signature, appData);
+
+    }
+
+    getFlags() {
+        return this.appData[0];
+    }
+
+    getTypeString() {
+        const flags = this.getFlags();
+        if(flags & Advert.ADV_TYPE_NONE) return "ADV_TYPE_NONE";
+        if(flags & Advert.ADV_TYPE_CHAT) return "ADV_TYPE_CHAT";
+        if(flags & Advert.ADV_TYPE_REPEATER) return "ADV_TYPE_REPEATER";
+        if(flags & Advert.ADV_TYPE_ROOM) return "ADV_TYPE_ROOM";
+        return null;
     }
 
     isVerified() {
@@ -25,19 +61,32 @@ class Advert {
 
     }
 
-    static fromPacketBytes(bytes) {
+    parseAppData() {
 
-        // parse packet from bytes
-        const packet = Packet.fromBytes(bytes);
+        // read app data
+        const bufferReader = new BufferReader(this.appData);
+        const flags = bufferReader.readByte();
 
-        // read packet payload
-        const bufferReader = new BufferReader(packet.payload);
-        const publicKey = bufferReader.readBytes(32);
-        const timestamp = bufferReader.readUInt32LE();
-        const signature = bufferReader.readBytes(64);
-        const appData = bufferReader.readRemainingBytes();
+        // parse lat lon
+        var lat = null;
+        var lon = null;
+        if(flags & Advert.ADV_LATLON_MASK){
+            lat = bufferReader.readInt32LE();
+            lon = bufferReader.readInt32LE();
+        }
 
-        return new Advert(publicKey, timestamp, signature, appData);
+        // parse name (remainder of app data)
+        var name = null;
+        if(flags & Advert.ADV_NAME_MASK){
+            name = bufferReader.readString();
+        }
+
+        return {
+            type: this.getTypeString(),
+            lat: lat,
+            lon: lon,
+            name: name,
+        };
 
     }
 
diff --git a/src/packet.js b/src/packet.js
index 3de8b2b..d7f6753 100644
--- a/src/packet.js
+++ b/src/packet.js
@@ -1,4 +1,5 @@
 import BufferReader from "./buffer_reader.js";
+import Advert from "./advert.js";
 
 class Packet {
 
@@ -103,6 +104,48 @@ class Packet {
         return this.header === 0xFF;
     }
 
+    parsePayload() {
+        switch(this.getPayloadType()){
+            case Packet.PAYLOAD_TYPE_REQ: return this.parsePayloadTypeReq();
+            case Packet.PAYLOAD_TYPE_ACK: return this.parsePayloadTypeAck();
+            case Packet.PAYLOAD_TYPE_ADVERT: return this.parsePayloadTypeAdvert();
+            default: return null;
+        }
+    }
+
+    parsePayloadTypeReq() {
+
+        // parse bytes
+        const bufferReader = new BufferReader(this.payload);
+        const dest = bufferReader.readByte();
+        const src = bufferReader.readByte();
+        const encrypted = bufferReader.readRemainingBytes();
+
+        // convert to hex
+        const destHex = dest.toString(16);
+        const srcHex = src.toString(16);
+        const encryptedHex = Buffer.from(encrypted).toString("hex");
+
+        return {
+            src: srcHex,
+            dest: destHex,
+            encrypted: encryptedHex,
+        };
+
+    }
+
+    parsePayloadTypeAck() {
+        return {
+            ack_code: Buffer.from(this.payload).toString("hex"),
+        };
+    }
+
+    parsePayloadTypeAdvert() {
+        return {
+            advert: Advert.fromBytes(this.payload),
+        };
+    }
+
 }
 
 export default Packet;