From 56656839b3ef6f04530ffdf938e0ebbd2cf9939c Mon Sep 17 00:00:00 2001
From: Antoni Spaanderman <56turtle56@gmail.com>
Date: Sun, 27 Mar 2022 16:13:48 +0200
Subject: [PATCH] Detect more lightning scripts:

- expired htlc
- anchor
- swept anchor

Fix indentation what i messed up in 7565aa7

Add explanation
---
 .../address-labels.component.ts               | 41 +++++++++++++------
 1 file changed, 29 insertions(+), 12 deletions(-)

diff --git a/frontend/src/app/components/address-labels/address-labels.component.ts b/frontend/src/app/components/address-labels/address-labels.component.ts
index 75bbe7cba..2ce0ae5a3 100644
--- a/frontend/src/app/components/address-labels/address-labels.component.ts
+++ b/frontend/src/app/components/address-labels/address-labels.component.ts
@@ -46,19 +46,36 @@ export class AddressLabelsComponent implements OnInit {
         return;
       }
 
+      const topElement = this.vin.witness[this.vin.witness.length - 2];
       // https://github.com/lightning/bolts/blob/master/03-transactions.md#commitment-transaction-outputs
       if (/^OP_IF OP_PUSHBYTES_33 \w{66} OP_ELSE OP_PUSHBYTES_(1 \w{2}|2 \w{4}) OP_CSV OP_DROP OP_PUSHBYTES_33 \w{66} OP_ENDIF OP_CHECKSIG$/.test(this.vin.inner_witnessscript_asm)) {
-          if (this.vin.witness[this.vin.witness.length - 2] == '01') {
-              this.lightning = 'Revoked Force Close';
-          } else {
-              this.lightning = 'Force Close';
-          }
+        if (topElement === '01') {
+          // top element is '01' to get in the revocation path
+          this.lightning = 'Revoked Force Close';
+        } else {
+          // top element is '', this is a delayed to_local output
+          this.lightning = 'Force Close';
+        }
       // https://github.com/lightning/bolts/blob/master/03-transactions.md#offered-htlc-outputs
       } else if (/^OP_DUP OP_HASH160 OP_PUSHBYTES_20 \w{40} OP_EQUAL OP_IF OP_CHECKSIG OP_ELSE OP_PUSHBYTES_33 \w{66} OP_SWAP OP_SIZE OP_PUSHBYTES_1 20 OP_EQUAL OP_NOTIF OP_DROP OP_PUSHNUM_2 OP_SWAP OP_PUSHBYTES_33 \w{66} OP_PUSHNUM_2 OP_CHECKMULTISIG OP_ELSE OP_HASH160 OP_PUSHBYTES_20 \w{40} OP_EQUALVERIFY OP_CHECKSIG OP_ENDIF (OP_PUSHNUM_1 OP_CHECKSEQUENCEVERIFY OP_DROP |)OP_ENDIF$/.test(this.vin.inner_witnessscript_asm)) {
-        if (this.vin.witness[this.vin.witness.length - 2].length == 66) {
-            this.lightning = 'Revoked HTLC';
+        if (topElement.length === 66) {
+          // top element is a public key
+          this.lightning = 'Revoked HTLC';
+        } else if (topElement) {
+          // top element is a preimage
+          this.lightning = 'HTLC';
         } else {
-            this.lightning = 'HTLC';
+          // top element is '' to get in the multisig path of the script
+          this.lightning = 'Expired HTLC';
+        }
+      // https://github.com/lightning/bolts/blob/master/03-transactions.md#to_local_anchor-and-to_remote_anchor-output-option_anchors
+      } else if (/^OP_PUSHBYTES_33 \w{66} OP_CHECKSIG OP_IFDUP OP_NOTIF OP_PUSHNUM_16 OP_CSV OP_ENDIF$/.test(this.vin.inner_witnessscript_asm)) {
+        if (topElement) {
+          // top element is a signature
+          this.lightning = 'Anchor';
+        } else {
+          // top element is '', it has been swept after 16 blocks
+          this.lightning = 'Swept Anchor';
         }
       }
 
@@ -77,19 +94,19 @@ export class AddressLabelsComponent implements OnInit {
       return;
     }
     const ops = script.split(' ');
-    if (ops.length < 3 || ops.pop() != 'OP_CHECKMULTISIG') {
+    if (ops.length < 3 || ops.pop() !== 'OP_CHECKMULTISIG') {
       return;
     }
     const opN = ops.pop();
     if (!opN.startsWith('OP_PUSHNUM_')) {
       return;
     }
-    const n = parseInt(opN.match(/[0-9]+/)[0]);
+    const n = parseInt(opN.match(/[0-9]+/)[0], 10);
     if (ops.length < n * 2 + 1) {
       return;
     }
     // pop n public keys
-    for (var i = 0; i < n; i++) {
+    for (let i = 0; i < n; i++) {
       if (!/^0((2|3)\w{64}|4\w{128})$/.test(ops.pop())) {
         return;
       }
@@ -101,7 +118,7 @@ export class AddressLabelsComponent implements OnInit {
     if (!opM.startsWith('OP_PUSHNUM_')) {
       return;
     }
-    const m = parseInt(opM.match(/[0-9]+/)[0]);
+    const m = parseInt(opM.match(/[0-9]+/)[0], 10);
 
     this.multisig = true;
     this.multisigM = m;