Address & script parsing refactor

frontend/src/app/components/address-labels/address-labels.component.ts

@@ -1,7 +1,7 @@
 import { Component, ChangeDetectionStrategy, Input, OnChanges } from '@angular/core';
 import { Vin, Vout } from '../../interfaces/electrs.interface';
 import { StateService } from '../../services/state.service';
-import { parseMultisigScript } from '../../bitcoin.utils';
+import { AddressType, AddressTypeInfo } from '../../shared/address-utils';
 
 @Component({
   selector: 'app-address-labels',
@@ -12,6 +12,7 @@ import { parseMultisigScript } from '../../bitcoin.utils';
 export class AddressLabelsComponent implements OnChanges {
   network = '';
 
+  @Input() address: AddressTypeInfo;
   @Input() vin: Vin;
   @Input() vout: Vout;
   @Input() channel: any;
@@ -28,10 +29,10 @@ export class AddressLabelsComponent implements OnChanges {
   ngOnChanges() {
     if (this.channel) {
       this.handleChannel();
+    } else if (this.address) {
+      this.handleAddress();
     } else if (this.vin) {
       this.handleVin();
-    } else if (this.vout) {
-      this.handleVout();
     }
   }
 
@@ -42,74 +43,22 @@ export class AddressLabelsComponent implements OnChanges {
     this.label = `Channel ${type}: ${leftNodeName} <> ${rightNodeName}`;
   }
 
+  handleAddress() {
+    if (this.address?.scripts.size) {
+      const script = this.address?.scripts.values().next().value;
+      if (script.template?.label) {
+        this.label = script.template.label;
+      }
+    }
+  }
+
   handleVin() {
-    if (this.vin.inner_witnessscript_asm) {
+    const address = new AddressTypeInfo(this.network || 'mainnet', this.vin.prevout?.scriptpubkey_address, this.vin.prevout?.scriptpubkey_type as AddressType, [this.vin])
-      if (this.vin.inner_witnessscript_asm.indexOf('OP_DEPTH OP_PUSHNUM_12 OP_EQUAL OP_IF OP_PUSHNUM_11') === 0 || this.vin.inner_witnessscript_asm.indexOf('OP_PUSHNUM_15 OP_CHECKMULTISIG OP_IFDUP OP_NOTIF OP_PUSHBYTES_2') === 1259) {
+    if (address?.scripts.size) {
-        if (this.vin.witness.length > 11) {
+      const script = address?.scripts.values().next().value;
-          this.label = 'Liquid Peg Out';
+      if (script.template?.label) {
-        } else {
+        this.label = script.template.label;
-          this.label = 'Emergency Liquid Peg Out';
-        }
-        return;
       }
-
-      const topElement = this.vin.witness[this.vin.witness.length - 2];
-      if (/^OP_IF OP_PUSHBYTES_33 \w{66} OP_ELSE OP_PUSH(NUM_\d+|BYTES_(1 \w{2}|2 \w{4})) OP_CSV OP_DROP OP_PUSHBYTES_33 \w{66} OP_ENDIF OP_CHECKSIG$/.test(this.vin.inner_witnessscript_asm)) {
-        // https://github.com/lightning/bolts/blob/master/03-transactions.md#commitment-transaction-outputs
-        if (topElement === '01') {
-          // top element is '01' to get in the revocation path
-          this.label = 'Revoked Lightning Force Close';
-        } else {
-          // top element is '', this is a delayed to_local output
-          this.label = 'Lightning Force Close';
-        }
-        return;
-      } else if (
-        /^OP_DUP OP_HASH160 OP_PUSHBYTES_20 \w{40} OP_EQUAL OP_IF OP_CHECKSIG OP_ELSE OP_PUSHBYTES_33 \w{66} OP_SWAP OP_SIZE OP_PUSHBYTES_1 20 OP_EQUAL OP_NOTIF OP_DROP OP_PUSHNUM_2 OP_SWAP OP_PUSHBYTES_33 \w{66} OP_PUSHNUM_2 OP_CHECKMULTISIG OP_ELSE OP_HASH160 OP_PUSHBYTES_20 \w{40} OP_EQUALVERIFY OP_CHECKSIG OP_ENDIF (OP_PUSHNUM_1 OP_CSV OP_DROP |)OP_ENDIF$/.test(this.vin.inner_witnessscript_asm) ||
-        /^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_IF OP_HASH160 OP_PUSHBYTES_20 \w{40} OP_EQUALVERIFY OP_PUSHNUM_2 OP_SWAP OP_PUSHBYTES_33 \w{66} OP_PUSHNUM_2 OP_CHECKMULTISIG OP_ELSE OP_DROP OP_PUSHBYTES_3 \w{6} OP_CLTV OP_DROP OP_CHECKSIG OP_ENDIF (OP_PUSHNUM_1 OP_CSV OP_DROP |)OP_ENDIF$/.test(this.vin.inner_witnessscript_asm)
-      ) {
-        // https://github.com/lightning/bolts/blob/master/03-transactions.md#offered-htlc-outputs
-        // https://github.com/lightning/bolts/blob/master/03-transactions.md#received-htlc-outputs
-        if (topElement.length === 66) {
-          // top element is a public key
-          this.label = 'Revoked Lightning HTLC';
-        } else if (topElement) {
-          // top element is a preimage
-          this.label = 'Lightning HTLC';
-        } else {
-          // top element is '' to get in the expiry of the script
-          this.label = 'Expired Lightning HTLC';
-        }
-        return;
-      } else if (/^OP_PUSHBYTES_33 \w{66} OP_CHECKSIG OP_IFDUP OP_NOTIF OP_PUSHNUM_16 OP_CSV OP_ENDIF$/.test(this.vin.inner_witnessscript_asm)) {
-        // https://github.com/lightning/bolts/blob/master/03-transactions.md#to_local_anchor-and-to_remote_anchor-output-option_anchors
-        if (topElement) {
-          // top element is a signature
-          this.label = 'Lightning Anchor';
-        } else {
-          // top element is '', it has been swept after 16 blocks
-          this.label = 'Swept Lightning Anchor';
-        }
-        return;
-      }
-
-      this.detectMultisig(this.vin.inner_witnessscript_asm);
     }
-
-    this.detectMultisig(this.vin.inner_redeemscript_asm);
-
-    this.detectMultisig(this.vin.prevout.scriptpubkey_asm);
-  }
-
-  detectMultisig(script: string) {
-    const ms = parseMultisigScript(script);
-
-    if (ms) {
-      this.label = $localize`:@@address-label.multisig:Multisig ${ms.m}:multisigM: of ${ms.n}:multisigN:`;
-    }
-  }
-
-  handleVout() {
-    this.detectMultisig(this.vout.scriptpubkey_asm);
   }
 }

frontend/src/app/components/address/address.component.html

@@ -220,14 +220,14 @@
 <ng-template #volumeRow>
   <tr>
     <td i18n="address.volume">Volume</td>
-    <td><app-amount [satoshis]="chainStats.volume + mempoolStats.volume"></app-amount></td>
+    <td *ngIf="chainStats.funded_txo_sum !== undefined; else confidentialTd"><app-amount [satoshis]="chainStats.volume + mempoolStats.volume"></app-amount></td>
   </tr>
 </ng-template>
 
 <ng-template #typeRow>
   <tr>
     <td i18n="address.type">Type</td>
-    <td><app-address-type [vout]="exampleVout || exampleVin?.prevout || null"></app-address-type><app-address-labels [channel]="exampleChannel" [vin]="exampleVin" [vout]="exampleVout" class="ml-1"></app-address-labels></td>
+    <td><app-address-type [address]="addressTypeInfo"></app-address-type><app-address-labels [channel]="exampleChannel" [address]="addressTypeInfo" class="ml-1"></app-address-labels></td>
   </tr>
 </ng-template>
 

frontend/src/app/components/address/address.component.ts

@@ -2,7 +2,7 @@ import { Component, OnInit, OnDestroy, HostListener } from '@angular/core';
 import { ActivatedRoute, ParamMap } from '@angular/router';
 import { ElectrsApiService } from '../../services/electrs-api.service';
 import { switchMap, filter, catchError, map, tap } from 'rxjs/operators';
-import { Address, ChainStats, Transaction, Vin, Vout } from '../../interfaces/electrs.interface';
+import { Address, ChainStats, Transaction, Vin } from '../../interfaces/electrs.interface';
 import { WebsocketService } from '../../services/websocket.service';
 import { StateService } from '../../services/state.service';
 import { AudioService } from '../../services/audio.service';
@@ -11,6 +11,7 @@ import { of, merge, Subscription, Observable } from 'rxjs';
 import { SeoService } from '../../services/seo.service';
 import { seoDescriptionNetwork } from '../../shared/common.utils';
 import { AddressInformation } from '../../interfaces/node-api.interface';
+import { AddressTypeInfo } from '../../shared/address-utils';
 
 class AddressStats implements ChainStats {
   address: string;
@@ -112,14 +113,13 @@ export class AddressComponent implements OnInit, OnDestroy {
   blockTxSubscription: Subscription;
   addressLoadingStatus$: Observable<number>;
   addressInfo: null | AddressInformation = null;
+  addressTypeInfo: null | AddressTypeInfo;
 
   fullyLoaded = false;
   chainStats: AddressStats;
   mempoolStats: AddressStats;
 
   exampleChannel?: any;
-  exampleVin?: Vin;
-  exampleVout?: Vout;
 
   now = Date.now() / 1000;
   balancePeriod: 'all' | '1m' = 'all';
@@ -161,8 +161,6 @@ export class AddressComponent implements OnInit, OnDestroy {
           this.transactions = null;
           this.addressInfo = null;
           this.exampleChannel = null;
-          this.exampleVin = null;
-          this.exampleVout = null;
           document.body.scrollTo(0, 0);
           this.addressString = params.get('id') || '';
           if (/^[A-Z]{2,5}1[AC-HJ-NP-Z02-9]{8,100}|04[a-fA-F0-9]{128}|(02|03)[a-fA-F0-9]{64}$/.test(this.addressString)) {
@@ -171,6 +169,8 @@ export class AddressComponent implements OnInit, OnDestroy {
           this.seoService.setTitle($localize`:@@address.component.browser-title:Address: ${this.addressString}:INTERPOLATION:`);
           this.seoService.setDescription($localize`:@@meta.description.bitcoin.address:See mempool transactions, confirmed transactions, balance, and more for ${this.stateService.network==='liquid'||this.stateService.network==='liquidtestnet'?'Liquid':'Bitcoin'}${seoDescriptionNetwork(this.stateService.network)} address ${this.addressString}:INTERPOLATION:.`);
 
+          this.addressTypeInfo = new AddressTypeInfo(this.stateService.network || 'mainnet', this.addressString);
+
           return merge(
             of(true),
             this.stateService.connectionState$
@@ -268,17 +268,13 @@ export class AddressComponent implements OnInit, OnDestroy {
         }
         this.isLoadingTransactions = false;
 
+        let addressVin: Vin[] = [];
         for (const tx of this.transactions) {
-          if (!this.exampleVin) {
+          addressVin = addressVin.concat(tx.vin.filter(v => v.prevout?.scriptpubkey_address === this.address.address));
-            this.exampleVin = tx.vin.find(v => v.prevout?.scriptpubkey_address === this.address.address);
-          }
-          if (!this.exampleVout) {
-            this.exampleVout = tx.vout.find(v => v.scriptpubkey_address === this.address.address);
-          }
-          if (this.exampleVin && this.exampleVout) {
-            break;
-          }
         }
+        this.addressTypeInfo.processInputs(addressVin);
+        // hack to trigger change detection
+        this.addressTypeInfo = this.addressTypeInfo.clone();
 
         if (!this.showBalancePeriod()) {
           this.setBalancePeriod('all');

frontend/src/app/components/transactions-list/transactions-list.component.html

@@ -75,7 +75,7 @@
                           {{ vin.prevout.scriptpubkey_type?.toUpperCase() }}
                         </ng-template>
                         <div>
-                          <app-address-labels [vin]="vin" [channel]="tx._channels && tx._channels.inputs[vindex] ? tx._channels.inputs[vindex] : null"></app-address-labels>
+                          <app-address-labels  [vin]="vin" [channel]="tx._channels && tx._channels.inputs[vindex] ? tx._channels.inputs[vindex] : null"></app-address-labels>
                         </div>
                       </ng-template>
                     </ng-container>

frontend/src/app/shared/address-utils.ts

@@ -0,0 +1,193 @@
+import '@angular/localize/init';
+import { ScriptInfo } from './script.utils';
+import { Vin } from '../interfaces/electrs.interface';
+import { BECH32_CHARS_LW, BASE58_CHARS, HEX_CHARS } from './regex.utils';
+
+export type AddressType = 'fee'
+  | 'empty'
+  | 'provably_unspendable'
+  | 'op_return'
+  | 'multisig'
+  | 'p2pk'
+  | 'p2pkh'
+  | 'p2sh'
+  | 'p2sh-p2wpkh'
+  | 'p2sh-p2wsh'
+  | 'v0_p2wpkh'
+  | 'v0_p2wsh'
+  | 'v1_p2tr'
+  | 'confidential'
+  | 'unknown'
+
+const ADDRESS_PREFIXES = {
+  mainnet: {
+    base58: {
+      pubkey: ['1'],
+      script: ['3'],
+    },
+    bech32: 'bc1',
+  },
+  testnet: {
+    base58: {
+      pubkey: ['m', 'n'],
+      script: '2',
+    },
+    bech32: 'tb1',
+  },
+  testnet4: {
+    base58: {
+      pubkey: ['m', 'n'],
+      script: '2',
+    },
+    bech32: 'tb1',
+  },
+  signet: {
+    base58: {
+      pubkey: ['m', 'n'],
+      script: '2',
+    },
+    bech32: 'tb1',
+  },
+  liquid: {
+    base58: {
+      pubkey: ['P','Q'],
+      script: ['G','H'],
+      confidential: ['V'],
+    },
+    bech32: 'ex1',
+    confidential: 'lq1',
+  },
+  liquidtestnet: {
+    base58: {
+      pubkey: ['F'],
+      script: ['8','9'],
+      confidential: ['V'], // TODO: check if this is actually correct
+    },
+    bech32: 'tex1',
+    confidential: 'tlq1',
+  },
+};
+
+// precompiled regexes for common address types (excluding prefixes)
+const base58Regex = RegExp('^' + BASE58_CHARS + '{26,34}$');
+const confidentialb58Regex = RegExp('^[TJ]' + BASE58_CHARS + '{78}$');
+const p2wpkhRegex = RegExp('^q' + BECH32_CHARS_LW + '{38}$');
+const p2wshRegex = RegExp('^q' + BECH32_CHARS_LW + '{58}$');
+const p2trRegex = RegExp('^p' + BECH32_CHARS_LW + '{58}$');
+const pubkeyRegex = RegExp('^' + `(04${HEX_CHARS}{128})|(0[23]${HEX_CHARS}{64})$`);
+
+export function detectAddressType(address: string, network: string): AddressType {
+  // normal address types
+  const firstChar = address.substring(0, 1);
+  if (ADDRESS_PREFIXES[network].base58.pubkey.includes(firstChar) && base58Regex.test(address.slice(1))) {
+    return 'p2pkh';
+  } else if (ADDRESS_PREFIXES[network].base58.script.includes(firstChar) && base58Regex.test(address.slice(1))) {
+    return 'p2sh';
+  } else if (address.startsWith(ADDRESS_PREFIXES[network].bech32)) {
+    const suffix = address.slice(ADDRESS_PREFIXES[network].bech32.length);
+    if (p2wpkhRegex.test(suffix)) {
+      return 'v0_p2wpkh';
+    } else if (p2wshRegex.test(suffix)) {
+      return 'v0_p2wsh';
+    } else if (p2trRegex.test(suffix)) {
+      return 'v1_p2tr';
+    }
+  }
+
+  // p2pk
+  if (pubkeyRegex.test(address)) {
+    return 'p2pk';
+  }
+
+  // liquid-specific types
+  if (network.startsWith('liquid')) {
+    if (ADDRESS_PREFIXES[network].base58.confidential.includes(firstChar) && confidentialb58Regex.test(address.slice(1))) {
+      return 'confidential';
+    } else if (address.startsWith(ADDRESS_PREFIXES[network].confidential)) {
+      return 'confidential';
+    }
+  }
+
+  return 'unknown';
+}
+
+/**
+ * Parses & classifies address types + properties from address strings
+ *
+ * can optionally augment this data with examples of spends from the address,
+ * e.g. to classify revealed scripts for scripthash-type addresses.
+ */
+export class AddressTypeInfo {
+  network: string;
+  address: string;
+  type: AddressType;
+  // script data
+  scripts: Map<string, ScriptInfo>; // raw script
+  // flags
+  isMultisig?: { m: number, n: number };
+  tapscript?: boolean;
+
+  constructor (network: string, address: string, type?: AddressType, vin?: Vin[]) {
+    this.network = network;
+    this.address = address;
+    this.scripts = new Map();
+    if (type) {
+      this.type = type;
+    } else {
+      this.type = detectAddressType(address, network);
+    }
+    this.processInputs(vin);
+  }
+
+  public clone(): AddressTypeInfo {
+    const cloned = new AddressTypeInfo(this.network, this.address, this.type);
+    cloned.scripts = new Map(Array.from(this.scripts, ([key, value]) => [key, value?.clone()]));
+    cloned.isMultisig = this.isMultisig;
+    cloned.tapscript = this.tapscript;
+    return cloned;
+  }
+
+  public processInputs(vin: Vin[] = []): void {
+    // taproot can have multiple script paths
+    if (this.type === 'v1_p2tr') {
+      for (const v of vin) {
+        if (v.inner_witnessscript_asm) {
+          this.tapscript = true;
+          const controlBlock = v.witness[v.witness.length - 1].startsWith('50') ? v.witness[v.witness.length - 2] : v.witness[v.witness.length - 1];
+          this.processScript(new ScriptInfo('inner_witnessscript', undefined, v.inner_witnessscript_asm, v.witness, controlBlock));
+        }
+      }
+    // for single-script types, if we've seen one input we've seen them all
+    } else if (['p2sh', 'v0_p2wsh'].includes(this.type)) {
+      if (!this.scripts.size && vin.length) {
+        const v = vin[0];
+        // wrapped segwit
+        if (this.type === 'p2sh' && v.witness?.length) {
+          if (v.scriptsig.startsWith('160014')) {
+            this.type = 'p2sh-p2wpkh';
+          } else if (v.scriptsig.startsWith('220020')) {
+            this.type = 'p2sh-p2wsh';
+          }
+        }
+        // real script
+        if (this.type !== 'p2sh-p2wpkh') {
+          if (v.inner_witnessscript_asm) {
+            this.processScript(new ScriptInfo('inner_witnessscript', undefined, v.inner_witnessscript_asm, v.witness));
+          } else if (v.inner_redeemscript_asm) {
+            this.processScript(new ScriptInfo('inner_redeemscript', undefined, v.inner_redeemscript_asm, v.witness));
+          } else if (v.scriptsig || v.scriptsig_asm) {
+            this.processScript(new ScriptInfo('scriptsig', v.scriptsig, v.scriptsig_asm, v.witness));
+          }
+        }
+      }
+    }
+    // and there's nothing more to learn from processing inputs for non-scripthash types
+  }
+
+  private processScript(script: ScriptInfo): void {
+    this.scripts.set(script.key, script);
+    if (script.template?.type === 'multisig') {
+      this.isMultisig = { m: script.template['m'], n: script.template['n'] };
+    }
+  }
+}

frontend/src/app/shared/components/address-type/address-type.component.html

@@ -1,4 +1,4 @@
-@switch (vout?.scriptpubkey_type || null) {
+@switch (address.type || null) {
   @case ('fee') {
     <span i18n="address.fee">fee</span>
   }
@@ -24,6 +24,6 @@
     <span>unknown</span>
   }
   @default {
-    <span>{{ vout.scriptpubkey_type.toUpperCase() }}</span>
+    <span>{{ address.type.toUpperCase() }}</span>
   }
 }

frontend/src/app/shared/components/address-type/address-type.component.ts

@@ -1,5 +1,5 @@
 import { Component, Input } from '@angular/core';
-import { Vout } from '../../../interfaces/electrs.interface';
+import { AddressTypeInfo } from '../../address-utils';
 
 @Component({
   selector: 'app-address-type',
@@ -7,5 +7,5 @@ import { Vout } from '../../../interfaces/electrs.interface';
   styleUrls: []
 })
 export class AddressTypeComponent {
-  @Input() vout: Vout;
+  @Input() address: AddressTypeInfo;
 }

frontend/src/app/shared/regex.utils.ts

@@ -1,14 +1,14 @@
 import { Env } from '../services/state.service';
 
 // all base58 characters
-const BASE58_CHARS = `[a-km-zA-HJ-NP-Z1-9]`;
+export const BASE58_CHARS = `[a-km-zA-HJ-NP-Z1-9]`;
 
 // all bech32 characters (after the separator)
-const BECH32_CHARS_LW = `[ac-hj-np-z02-9]`;
+export const BECH32_CHARS_LW = `[ac-hj-np-z02-9]`;
 const BECH32_CHARS_UP = `[AC-HJ-NP-Z02-9]`;
 
 // Hex characters
-const HEX_CHARS = `[a-fA-F0-9]`;
+export const HEX_CHARS = `[a-fA-F0-9]`;
 
 // A regex to say "A single 0 OR any number with no leading zeroes"
 // Capped at 9 digits so as to not be confused with lightning channel IDs (which are around 17 digits)

frontend/src/app/shared/script.utils.ts

@@ -145,8 +145,116 @@ for (let i = 187; i <= 255; i++) {
 
 export { opcodes };
 
+export type ScriptType = 'scriptpubkey'
+  | 'scriptsig'
+  | 'inner_witnessscript'
+  | 'inner_redeemscript'
+
+export interface ScriptTemplate {
+  type: string;
+  label: string;
+}
+
+export const ScriptTemplates: { [type: string]: (...args: any) => ScriptTemplate } = {
+  liquid_peg_out: () => ({ type: 'liquid_peg_out', label: 'Liquid Peg Out' }),
+  liquid_peg_out_emergency: () => ({ type: 'liquid_peg_out_emergency', label: 'Emergency Liquid Peg Out' }),
+  ln_force_close: () => ({ type: 'ln_force_close', label: 'Lightning Force Close' }),
+  ln_force_close_revoked: () => ({ type: 'ln_force_close_revoked', label: 'Revoked Lightning Force Close' }),
+  ln_htlc: () => ({ type: 'ln_htlc', label: 'Lightning HTLC' }),
+  ln_htlc_revoked: () => ({ type: 'ln_htlc_revoked', label: 'Revoked Lightning HTLC' }),
+  ln_htlc_expired: () => ({ type: 'ln_htlc_expired', label: 'Expired Lightning HTLC' }),
+  ln_anchor: () => ({ type: 'ln_anchor', label: 'Lightning Anchor' }),
+  ln_anchor_swept: () => ({ type: 'ln_anchor_swept', label: 'Swept Lightning Anchor' }),
+  multisig: (m: number, n: number) => ({ type: 'multisig', m, n, label: $localize`:@@address-label.multisig:Multisig ${m}:multisigM: of ${n}:multisigN:` }),
+};
+
+export class ScriptInfo {
+  type: ScriptType;
+  scriptPath?: string;
+  hex?: string;
+  asm?: string;
+  template: ScriptTemplate;
+
+  constructor(type: ScriptType, hex?: string, asm?: string, witness?: string[], scriptPath?: string) {
+    this.type = type;
+    this.hex = hex;
+    this.asm = asm;
+    if (scriptPath) {
+      this.scriptPath = scriptPath;
+    }
+    if (this.asm) {
+      this.template = detectScriptTemplate(this.type, this.asm, witness);
+    }
+  }
+
+  public clone(): ScriptInfo {
+    return { ...this };
+  }
+
+  get key(): string {
+    return this.type + (this.scriptPath || '');
+  }
+}
+
+/** parses an inner_witnessscript + witness stack, and detects named script types */
+export function detectScriptTemplate(type: ScriptType, script_asm: string, witness?: string[]): ScriptTemplate | undefined {
+  if (type === 'inner_witnessscript' && witness?.length) {
+    if (script_asm.indexOf('OP_DEPTH OP_PUSHNUM_12 OP_EQUAL OP_IF OP_PUSHNUM_11') === 0 || script_asm.indexOf('OP_PUSHNUM_15 OP_CHECKMULTISIG OP_IFDUP OP_NOTIF OP_PUSHBYTES_2') === 1259) {
+      if (witness.length > 11) {
+        return ScriptTemplates.liquid_peg_out();
+      } else {
+        return ScriptTemplates.liquid_peg_out_emergency();
+      }
+    }
+
+    const topElement = witness[witness.length - 2];
+    if (/^OP_IF OP_PUSHBYTES_33 \w{66} OP_ELSE OP_PUSH(NUM_\d+|BYTES_(1 \w{2}|2 \w{4})) OP_CSV OP_DROP OP_PUSHBYTES_33 \w{66} OP_ENDIF OP_CHECKSIG$/.test(script_asm)) {
+      // https://github.com/lightning/bolts/blob/master/03-transactions.md#commitment-transaction-outputs
+      if (topElement === '01') {
+        // top element is '01' to get in the revocation path
+        return ScriptTemplates.ln_force_close_revoked();
+      } else {
+        // top element is '', this is a delayed to_local output
+        return ScriptTemplates.ln_force_close();
+      }
+    } 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_CSV OP_DROP |)OP_ENDIF$/.test(script_asm) ||
+      /^OP_DUP OP_HASH160 OP_PUSHBYTES_20 \w{40} OP_EQUAL OP_IF OP_CHECKSIG OP_ELSE OP_PUSHBYTES_33 \w{66} OP_SWAP OP_SIZE OP_PUSHBYTES_1 20 OP_EQUAL OP_IF OP_HASH160 OP_PUSHBYTES_20 \w{40} OP_EQUALVERIFY OP_PUSHNUM_2 OP_SWAP OP_PUSHBYTES_33 \w{66} OP_PUSHNUM_2 OP_CHECKMULTISIG OP_ELSE OP_DROP OP_PUSHBYTES_3 \w{6} OP_CLTV OP_DROP OP_CHECKSIG OP_ENDIF (OP_PUSHNUM_1 OP_CSV OP_DROP |)OP_ENDIF$/.test(script_asm)
+    ) {
+      // https://github.com/lightning/bolts/blob/master/03-transactions.md#offered-htlc-outputs
+      // https://github.com/lightning/bolts/blob/master/03-transactions.md#received-htlc-outputs
+      if (topElement.length === 66) {
+        // top element is a public key
+        return ScriptTemplates.ln_htlc_revoked();
+      } else if (topElement) {
+        // top element is a preimage
+        return ScriptTemplates.ln_htlc();
+      } else {
+        // top element is '' to get in the expiry of the script
+        return ScriptTemplates.ln_htlc_expired();
+      }
+    } else if (/^OP_PUSHBYTES_33 \w{66} OP_CHECKSIG OP_IFDUP OP_NOTIF OP_PUSHNUM_16 OP_CSV OP_ENDIF$/.test(script_asm)) {
+      // https://github.com/lightning/bolts/blob/master/03-transactions.md#to_local_anchor-and-to_remote_anchor-output-option_anchors
+      if (topElement) {
+        // top element is a signature
+        return ScriptTemplates.ln_anchor();
+      } else {
+        // top element is '', it has been swept after 16 blocks
+        return ScriptTemplates.ln_anchor_swept();
+      }
+    }
+  }
+
+  const multisig = parseMultisigScript(script_asm);
+  if (multisig) {
+    return ScriptTemplates.multisig(multisig.m, multisig.n);
+  }
+
+  return;
+}
+
 /** extracts m and n from a multisig script (asm), returns nothing if it is not a multisig script */
-export function parseMultisigScript(script: string): void | { m: number, n: number } {
+export function parseMultisigScript(script: string): undefined | { m: number, n: number } {
   if (!script) {
     return;
   }