refactor: Overhaul LayerZero collector implementation

src/collector/layer-zero/layer-zero.utils.ts

@@ -0,0 +1,56 @@
+import { keccak256 } from "ethers6";
+
+
+export interface LayerZeroPacket {
+    nonce: number;
+    srcEid: number;
+    sender: string;
+    dstEid: number;
+    receiver: string;
+    guid: string;
+    message: string;
+}
+
+export interface LayerZeroHeader {
+    version: number;
+    nonce: number;
+    srcEid: number;
+    sender: string;
+    dstEid: number;
+    receiver: string;
+}
+
+
+
+export function decodePacket(encodedPacket: string): LayerZeroPacket {
+    return {
+        nonce: Number('0x' + encodedPacket.slice(2 + 2, 2 + 2 + 16)),
+        srcEid: Number('0x' + encodedPacket.slice(2 + 18, 2 + 18 + 8)),
+        // NOTE: keep only the last 20 bytes of the 'sender' field.
+        sender: ('0x' + encodedPacket.slice(2 + 26 + 24, 2 + 26 + 64)).toLowerCase(),
+        dstEid: Number('0x' + encodedPacket.slice(2 + 90, 2 + 90 + 8)),
+        // NOTE: keep only the last 20 bytes of the 'receiver' field.
+        receiver: ('0x' + encodedPacket.slice(2 + 98 + 24, 2 + 98 + 64)).toLowerCase(),
+        guid: '0x' + encodedPacket.slice(2 + 162, 2 + 162 + 64),
+        message: '0x' + encodedPacket.slice(2 + 226),
+    };
+}
+
+export function decodeHeader(encodedHeader: string): LayerZeroHeader {
+    return {
+        version: Number('0x' + encodedHeader.slice(2, 2 + 2)),
+        nonce: Number('0x' + encodedHeader.slice(2 + 2, 2 + 2 + 16)),
+        srcEid: Number('0x' + encodedHeader.slice(2 + 18, 2 + 18 + 8)),
+        // NOTE: keep only the last 20 bytes of the 'sender' field.
+        sender: '0x' + encodedHeader.slice(2 + 26 + 24, 2 + 26 + 64).toLowerCase(),
+        dstEid: Number('0x' + encodedHeader.slice(2 + 90, 2 + 90 + 8)),
+        // NOTE: keep only the last 20 bytes of the 'receiver' field.
+        receiver: '0x' + encodedHeader.slice(2 + 98 + 24, 2 + 98 + 64).toLowerCase(),
+    }
+}
+
+
+export function calculatePayloadHash(guid: string, message: string): string {
+    const payload = `${guid}${message.slice(2)}`;   // 'slice(2)' used to remove the '0x' from the 'message'
+    return keccak256(payload);
+}