Shades of green / red on DA blocks

Allow OP_0 in multisig scripts

backend/src/api/blocks.ts

@@ -219,10 +219,10 @@ class Blocks {
     };
   }
 
-  public summarizeBlockTransactions(hash: string, transactions: TransactionExtended[]): BlockSummary {
+  public summarizeBlockTransactions(hash: string, height: number, transactions: TransactionExtended[]): BlockSummary {
     return {
       id: hash,
-      transactions: Common.classifyTransactions(transactions),
+      transactions: Common.classifyTransactions(transactions, height),
     };
   }
 
@@ -616,7 +616,7 @@ class Blocks {
           // add CPFP
           const cpfpSummary = calculateGoodBlockCpfp(height, txs, []);
           // classify
-          const { transactions: classifiedTxs } = this.summarizeBlockTransactions(blockHash, cpfpSummary.transactions);
+          const { transactions: classifiedTxs } = this.summarizeBlockTransactions(blockHash, height, cpfpSummary.transactions);
           await BlocksSummariesRepository.$saveTransactions(height, blockHash, classifiedTxs, 2);
           if (unclassifiedBlocks[height].version < 2 && targetSummaryVersion === 2) {
             const cpfpClusters = await CpfpRepository.$getClustersAt(height);
@@ -653,7 +653,7 @@ class Blocks {
             }
             const cpfpSummary = calculateGoodBlockCpfp(height, templateTxs?.filter(tx => tx['effectiveFeePerVsize'] != null) as MempoolTransactionExtended[], []);
             // classify
-            const { transactions: classifiedTxs } = this.summarizeBlockTransactions(blockHash, cpfpSummary.transactions);
+            const { transactions: classifiedTxs } = this.summarizeBlockTransactions(blockHash, height, cpfpSummary.transactions);
             const classifiedTxMap: { [txid: string]: TransactionClassified } = {};
             for (const tx of classifiedTxs) {
               classifiedTxMap[tx.txid] = tx;
@@ -912,7 +912,7 @@ class Blocks {
       }
       const cpfpSummary: CpfpSummary = calculateGoodBlockCpfp(block.height, transactions, accelerations.map(a => ({ txid: a.txid, max_bid: a.feeDelta })));
       const blockExtended: BlockExtended = await this.$getBlockExtended(block, cpfpSummary.transactions);
-      const blockSummary: BlockSummary = this.summarizeBlockTransactions(block.id, cpfpSummary.transactions);
+      const blockSummary: BlockSummary = this.summarizeBlockTransactions(block.id, block.height, cpfpSummary.transactions);
       this.updateTimerProgress(timer, `got block data for ${this.currentBlockHeight}`);
 
       if (Common.indexingEnabled()) {
@@ -1169,7 +1169,7 @@ class Blocks {
         transactions: cpfpSummary.transactions.map(tx => {
           let flags: number = 0;
           try {
-            flags = Common.getTransactionFlags(tx);
+            flags = Common.getTransactionFlags(tx, height);
           } catch (e) {
             logger.warn('Failed to classify transaction: ' + (e instanceof Error ? e.message : e));
           }
@@ -1188,7 +1188,7 @@ class Blocks {
     } else {
       if (config.MEMPOOL.BACKEND === 'esplora') {
         const txs = (await bitcoinApi.$getTxsForBlock(hash)).map(tx => transactionUtils.extendTransaction(tx));
-        summary = this.summarizeBlockTransactions(hash, txs);
+        summary = this.summarizeBlockTransactions(hash, height || 0, txs);
         summaryVersion = 1;
       } else {
         // Call Core RPC
@@ -1324,7 +1324,7 @@ class Blocks {
           let summaryVersion = 0;
           if (config.MEMPOOL.BACKEND === 'esplora') {
             const txs = (await bitcoinApi.$getTxsForBlock(cleanBlock.hash)).map(tx => transactionUtils.extendTransaction(tx));
-            summary = this.summarizeBlockTransactions(cleanBlock.hash, txs);
+            summary = this.summarizeBlockTransactions(cleanBlock.hash, cleanBlock.height, txs);
             summaryVersion = 1;
           } else {
             // Call Core RPC

backend/src/api/common.ts

@@ -10,7 +10,6 @@ import logger from '../logger';
 import { getVarIntLength, opcodes, parseMultisigScript } from '../utils/bitcoin-script';
 
 // Bitcoin Core default policy settings
-const TX_MAX_STANDARD_VERSION = 2;
 const MAX_STANDARD_TX_WEIGHT = 400_000;
 const MAX_BLOCK_SIGOPS_COST = 80_000;
 const MAX_STANDARD_TX_SIGOPS_COST = (MAX_BLOCK_SIGOPS_COST / 5);
@@ -200,10 +199,13 @@ export class Common {
    *
    * returns true early if any standardness rule is violated, otherwise false
    * (except for non-mandatory-script-verify-flag and p2sh script evaluation rules which are *not* enforced)
+   *
+   * As standardness rules change, we'll need to apply the rules in force *at the time* to older blocks.
+   * For now, just pull out individual rules into versioned functions where necessary.
    */
-  static isNonStandard(tx: TransactionExtended): boolean {
+  static isNonStandard(tx: TransactionExtended, height?: number): boolean {
     // version
-    if (tx.version > TX_MAX_STANDARD_VERSION) {
+    if (this.isNonStandardVersion(tx, height)) {
       return true;
     }
 
@@ -250,6 +252,8 @@ export class Common {
         }
       } else if (['unknown', 'provably_unspendable', 'empty'].includes(vin.prevout?.scriptpubkey_type || '')) {
         return true;
+      } else if (this.isNonStandardAnchor(tx, height)) {
+        return true;
       }
       // TODO: bad-witness-nonstandard
     }
@@ -335,6 +339,49 @@ export class Common {
     return false;
   }
 
+  // Individual versioned standardness rules
+
+  static V3_STANDARDNESS_ACTIVATION_HEIGHT = {
+    'testnet4': 42_000,
+    'testnet': 2_900_000,
+    'signet': 211_000,
+    '': 863_500,
+  };
+  static isNonStandardVersion(tx: TransactionExtended, height?: number): boolean {
+    let TX_MAX_STANDARD_VERSION = 3;
+    if (
+      height != null
+      && this.V3_STANDARDNESS_ACTIVATION_HEIGHT[config.MEMPOOL.NETWORK]
+      && height <= this.V3_STANDARDNESS_ACTIVATION_HEIGHT[config.MEMPOOL.NETWORK]
+    ) {
+      // V3 transactions were non-standard to spend before v28.x (scheduled for 2024/09/30 https://github.com/bitcoin/bitcoin/issues/29891)
+      TX_MAX_STANDARD_VERSION = 2;
+    }
+
+    if (tx.version > TX_MAX_STANDARD_VERSION) {
+      return true;
+    }
+    return false;
+  }
+
+  static ANCHOR_STANDARDNESS_ACTIVATION_HEIGHT = {
+    'testnet4': 42_000,
+    'testnet': 2_900_000,
+    'signet': 211_000,
+    '': 863_500,
+  };
+  static isNonStandardAnchor(tx: TransactionExtended, height?: number): boolean {
+    if (
+      height != null
+      && this.ANCHOR_STANDARDNESS_ACTIVATION_HEIGHT[config.MEMPOOL.NETWORK]
+      && height <= this.ANCHOR_STANDARDNESS_ACTIVATION_HEIGHT[config.MEMPOOL.NETWORK]
+    ) {
+      // anchor outputs were non-standard to spend before v28.x (scheduled for 2024/09/30 https://github.com/bitcoin/bitcoin/issues/29891)
+      return true;
+    }
+    return false;
+  }
+
   static getNonWitnessSize(tx: TransactionExtended): number {
     let weight = tx.weight;
     let hasWitness = false;
@@ -415,7 +462,7 @@ export class Common {
     return flags;
   }
 
-  static getTransactionFlags(tx: TransactionExtended): number {
+  static getTransactionFlags(tx: TransactionExtended, height?: number): number {
     let flags = tx.flags ? BigInt(tx.flags) : 0n;
 
     // Update variable flags (CPFP, RBF)
@@ -548,7 +595,7 @@ export class Common {
     if (hasFakePubkey) {
       flags |= TransactionFlags.fake_pubkey;
     }
-    
+
     // fast but bad heuristic to detect possible coinjoins
     // (at least 5 inputs and 5 outputs, less than half of which are unique amounts, with no address reuse)
     const addressReuse = Object.keys(reusedOutputAddresses).reduce((acc, key) => Math.max(acc, (reusedInputAddresses[key] || 0) + (reusedOutputAddresses[key] || 0)), 0) > 1;
@@ -564,17 +611,17 @@ export class Common {
       flags |= TransactionFlags.batch_payout;
     }
 
-    if (this.isNonStandard(tx)) {
+    if (this.isNonStandard(tx, height)) {
       flags |= TransactionFlags.nonstandard;
     }
 
     return Number(flags);
   }
 
-  static classifyTransaction(tx: TransactionExtended): TransactionClassified {
+  static classifyTransaction(tx: TransactionExtended, height?: number): TransactionClassified {
     let flags = 0;
     try {
-      flags = Common.getTransactionFlags(tx);
+      flags = Common.getTransactionFlags(tx, height);
     } catch (e) {
       logger.warn('Failed to add classification flags to transaction: ' + (e instanceof Error ? e.message : e));
     }
@@ -585,8 +632,8 @@ export class Common {
     };
   }
 
-  static classifyTransactions(txs: TransactionExtended[]): TransactionClassified[] {
-    return txs.map(Common.classifyTransaction);
+  static classifyTransactions(txs: TransactionExtended[], height?: number): TransactionClassified[] {
+    return txs.map(tx => Common.classifyTransaction(tx, height));
   }
 
   static stripTransaction(tx: TransactionExtended): TransactionStripped {

backend/src/api/mining/mining-routes.ts

@@ -30,6 +30,7 @@ class MiningRoutes {
       .get(config.MEMPOOL.API_URL_PREFIX + 'mining/blocks/fee-rates/:interval', this.$getHistoricalBlockFeeRates)
       .get(config.MEMPOOL.API_URL_PREFIX + 'mining/blocks/sizes-weights/:interval', this.$getHistoricalBlockSizeAndWeight)
       .get(config.MEMPOOL.API_URL_PREFIX + 'mining/difficulty-adjustments/:interval', this.$getDifficultyAdjustments)
+      .get(config.MEMPOOL.API_URL_PREFIX + 'mining/difficulty-adjustment/:height', this.$getDifficultyAdjustment)
       .get(config.MEMPOOL.API_URL_PREFIX + 'mining/blocks/predictions/:interval', this.$getHistoricalBlocksHealth)
       .get(config.MEMPOOL.API_URL_PREFIX + 'mining/blocks/audit/scores', this.$getBlockAuditScores)
       .get(config.MEMPOOL.API_URL_PREFIX + 'mining/blocks/audit/scores/:height', this.$getBlockAuditScores)
@@ -297,6 +298,18 @@ class MiningRoutes {
     }
   }
 
+  private async $getDifficultyAdjustment(req: Request, res: Response) {
+    try {
+      const adjustment = await DifficultyAdjustmentsRepository.$getAdjustmentAtHeight(parseInt(req.params.height, 10));
+      res.header('Pragma', 'public');
+      res.header('Cache-control', 'public');
+      res.setHeader('Expires', new Date(Date.now() + 1000 * 300).toUTCString());
+      res.json(adjustment);
+    } catch (e) {
+      res.status(e instanceof Error && e.message === 'not found' ? 204 : 500).send(e instanceof Error ? e.message : e);
+    }
+  }
+
   private async $getRewardStats(req: Request, res: Response) {
     try {
       const response = await mining.$getRewardStats(parseInt(req.params.blockCount, 10));

backend/src/repositories/BlocksRepository.ts

@@ -1106,7 +1106,7 @@ class BlocksRepository {
         let summaryVersion = 0;
         if (config.MEMPOOL.BACKEND === 'esplora') {
           const txs = (await bitcoinApi.$getTxsForBlock(dbBlk.id)).map(tx => transactionUtils.extendTransaction(tx));
-          summary = blocks.summarizeBlockTransactions(dbBlk.id, txs);
+          summary = blocks.summarizeBlockTransactions(dbBlk.id, dbBlk.height, txs);
           summaryVersion = 1;
         } else {
           // Call Core RPC

backend/src/repositories/DifficultyAdjustmentsRepository.ts

@@ -88,6 +88,22 @@ class DifficultyAdjustmentsRepository {
     }
   }
 
+  public async $getAdjustmentAtHeight(height: number): Promise<IndexedDifficultyAdjustment> {
+    try {
+      if (isNaN(height)) {
+        throw new Error(`argument must be a number`);
+      }
+      const [rows] = await DB.query(`SELECT * FROM difficulty_adjustments WHERE height = ?`, [height]);
+      if (!rows[0]) {
+        throw new Error(`not found`);
+      }
+      return rows[0] as IndexedDifficultyAdjustment;
+    } catch (e: any) {
+      logger.err(`Cannot get difficulty adjustment from the database. Reason: ${e instanceof Error ? e.message : e}`, logger.tags.mining);
+      throw e;
+    }
+  }
+
   public async $getAdjustmentsHeights(): Promise<number[]> {
     try {
       const [rows]: any[] = await DB.query(`SELECT height FROM difficulty_adjustments`);

backend/src/utils/bitcoin-script.ts

@@ -158,7 +158,7 @@ export function parseMultisigScript(script: string): void | { m: number, n: numb
   if (!opN) {
     return;
   }
-  if (!opN.startsWith('OP_PUSHNUM_')) {
+  if (opN !== 'OP_0' && !opN.startsWith('OP_PUSHNUM_')) {
     return;
   }
   const n = parseInt(opN.match(/[0-9]+/)?.[0] || '', 10);
@@ -178,7 +178,7 @@ export function parseMultisigScript(script: string): void | { m: number, n: numb
   if (!opM) {
     return;
   }
-  if (!opM.startsWith('OP_PUSHNUM_')) {
+  if (opM !== 'OP_0' && !opM.startsWith('OP_PUSHNUM_')) {
     return;
   }
   const m = parseInt(opM.match(/[0-9]+/)?.[0] || '', 10);

frontend/src/app/bitcoin.utils.ts

@@ -135,7 +135,7 @@ export function parseMultisigScript(script: string): void | { m: number, n: numb
     return;
   }
   const opN = ops.pop();
-  if (!opN.startsWith('OP_PUSHNUM_')) {
+  if (opN !== 'OP_0' && !opN.startsWith('OP_PUSHNUM_')) {
     return;
   }
   const n = parseInt(opN.match(/[0-9]+/)[0], 10);
@@ -152,7 +152,7 @@ export function parseMultisigScript(script: string): void | { m: number, n: numb
     }
   }
   const opM = ops.pop();
-  if (!opM.startsWith('OP_PUSHNUM_')) {
+  if (opM !== 'OP_0' && !opM.startsWith('OP_PUSHNUM_')) {
     return;
   }
   const m = parseInt(opM.match(/[0-9]+/)[0], 10);

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

@@ -78,6 +78,25 @@
                   </ng-template>
                 </td>
               </tr>
+              <tr *ngIf="this.stateService.network === '' && block.height % 2016 === 0">
+                <td i18n="mining.difficulty-adjustment">Adjustment</td>
+                <td>
+                  <ng-container *ngIf="cacheService.daCache[block.height]?.adjustment > 0; else loadingAdjustment">
+                    <div [style.color]="cacheService.daCache[block.height].adjustment > 1 ? 'var(--green)' : (cacheService.daCache[block.height].adjustment < 1 ? 'var(--red)' : '')">
+                      @if (cacheService.daCache[block.height].adjustment > 1) {
+                        <fa-icon class="retarget-sign up" [icon]="['fas', 'caret-up']" [fixedWidth]="true"></fa-icon>
+                      } @else if (cacheService.daCache[block.height].adjustment < 1) {
+                        <fa-icon class="retarget-sign" [icon]="['fas', 'caret-down']" [fixedWidth]="true"></fa-icon>
+                      }
+                      {{ (cacheService.daCache[block.height].adjustment - 1) * 100 | absolute | number: '1.2-2' }}
+                      <span class="symbol">%</span>
+                    </div>
+                  </ng-container>
+                  <ng-template #loadingAdjustment>
+                    <span class="skeleton-loader" style="max-width: 60px"></span>
+                  </ng-template>
+                </td>
+              </tr>
             </ng-container>
             <ng-template #skeletonRows>
               <tr>
@@ -193,6 +212,10 @@
         </span>
         </td>
       </tr>
+      <tr *ngIf="this.stateService.network === '' && block.height % 2016 === 0">
+        <td i18n="block.difficulty">Difficulty</td>
+        <td>{{ block.difficulty | amountShortener: 2 }}</td>
+      </tr>
     </ng-container>
     <ng-template #loadingRest>
       <tr>

frontend/src/app/components/block/block.component.scss

@@ -280,3 +280,11 @@ h1 {
   top: -1px;
   margin-right: 2px;
 }
+
+.retarget-sign {
+  margin-right: -3px;
+  &.up {
+    position: relative;
+    top: 2px;
+  }
+}

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

@@ -99,7 +99,7 @@ export class BlockComponent implements OnInit, OnDestroy {
     private relativeUrlPipe: RelativeUrlPipe,
     private apiService: ApiService,
     private priceService: PriceService,
-    private cacheService: CacheService,
+    public cacheService: CacheService,
     private servicesApiService: ServicesApiServices,
     private cd: ChangeDetectorRef,
     private preloadService: PreloadService,

frontend/src/app/components/blockchain-blocks/blockchain-blocks.component.ts

@@ -1,10 +1,12 @@
 import { Component, OnInit, OnDestroy, ChangeDetectionStrategy, ChangeDetectorRef, Input, OnChanges, SimpleChanges } from '@angular/core';
-import { Observable, Subscription, delay, filter, tap } from 'rxjs';
+import { Observable, Subscription, delay, filter, of, retryWhen, switchMap, take, tap, throwError } from 'rxjs';
 import { StateService } from '../../services/state.service';
 import { specialBlocks } from '../../app.constants';
 import { BlockExtended } from '../../interfaces/node-api.interface';
 import { Location } from '@angular/common';
 import { CacheService } from '../../services/cache.service';
+import { ApiService } from '../../services/api.service';
+import { colorFromRetarget } from '../../shared/common.utils';
 
 interface BlockchainBlock extends BlockExtended {
   placeholder?: boolean;
@@ -77,6 +79,7 @@ export class BlockchainBlocksComponent implements OnInit, OnChanges, OnDestroy {
   constructor(
     public stateService: StateService,
     public cacheService: CacheService,
+    public apiService: ApiService,
     private cd: ChangeDetectorRef,
     private location: Location,
   ) {
@@ -334,6 +337,31 @@ export class BlockchainBlocksComponent implements OnInit, OnChanges, OnDestroy {
     return this.specialBlocks[height]?.networks.includes(this.stateService.network || 'mainnet') ? true : false;
   }
 
+  isDA(height: number): boolean {
+    const isDA = height % 2016 === 0 && this.stateService.network === '';
+    if (isDA && !this.cacheService.daCache[height]?.exact) {
+      const estimatedAdjustment = this.cacheService.daCache[height]?.adjustment || 0;
+      this.cacheService.daCache[height] = { adjustment: estimatedAdjustment, exact: true };
+      this.apiService.getDifficultyAdjustmentByHeight$(height).pipe(
+        switchMap(da => {
+          const blocksAvailable = (this.height || this.chainTip) && this.blockStyles[(this.height || this.chainTip) - height];
+          return blocksAvailable ? of(da) : throwError(() => new Error());
+        }),
+        retryWhen(errors =>
+          errors.pipe(
+            delay(1000),
+            take(3)
+          )
+        ),
+        tap((da) => {
+          this.cacheService.daCache[height] = { adjustment: da?.adjustment || 1, exact: true };
+          this.blockStyles[(this.height || this.chainTip) - height].background = colorFromRetarget(da?.adjustment);
+        })
+      ).subscribe();
+    }
+    return isDA;
+  }
+
   getStyleForBlock(block: BlockchainBlock, index: number, animateEnterFrom: number = 0) {
     if (!block || block.placeholder) {
       return this.getStyleForPlaceholderBlock(index, animateEnterFrom);
@@ -349,7 +377,8 @@ export class BlockchainBlocksComponent implements OnInit, OnChanges, OnDestroy {
 
     return {
       left: addLeft + this.blockOffset * index + 'px',
-      background: `repeating-linear-gradient(
+      background: this.isDA(block.height) ? colorFromRetarget(this.cacheService.daCache[block.height]?.adjustment || 1) :
+      `repeating-linear-gradient(
         var(--secondary),
         var(--secondary) ${greenBackgroundHeight}%,
         ${this.gradientColors[this.network][0]} ${Math.max(greenBackgroundHeight, 0)}%,

frontend/src/app/components/difficulty-adjustments-table/difficulty-adjustments-table.components.ts

@@ -5,6 +5,7 @@ import { ApiService } from '../../services/api.service';
 import { formatNumber } from '@angular/common';
 import { selectPowerOfTen } from '../../bitcoin.utils';
 import { StateService } from '../../services/state.service';
+import { CacheService } from '../../services/cache.service';
 
 @Component({
   selector: 'app-difficulty-adjustments-table',
@@ -27,7 +28,8 @@ export class DifficultyAdjustmentsTable implements OnInit {
   constructor(
     @Inject(LOCALE_ID) public locale: string,
     private apiService: ApiService,
-    public stateService: StateService
+    public stateService: StateService,
+    private cacheService: CacheService,
   ) {
   }
 
@@ -52,6 +54,7 @@ export class DifficultyAdjustmentsTable implements OnInit {
                 adjustment[2] / selectedPowerOfTen.divider,
                 this.locale, `1.${decimals}-${decimals}`) + selectedPowerOfTen.unit
             });
+            this.cacheService.daCache[adjustment[1]] = { adjustment: adjustment[3], exact: true };
           }
           this.isLoading = false;
           return tableData.slice(0, 6);

frontend/src/app/components/mempool-block/mempool-block.component.html

@@ -41,6 +41,25 @@
                 </div>
               </td>
             </tr>
+            <tr *ngIf="this.stateService.network === '' && mempoolBlock.height % 2016 === 0">
+              <td i18n="mining.difficulty-adjustment">Adjustment</td>
+              <td>
+                <ng-container *ngIf="cacheService.daCache[mempoolBlock.height]?.adjustment > 0; else loadingAdjustment">
+                  <div [style.color]="cacheService.daCache[mempoolBlock.height].adjustment > 1 ? 'var(--green)' : (cacheService.daCache[mempoolBlock.height].adjustment < 1 ? 'var(--red)' : '')">
+                    @if (cacheService.daCache[mempoolBlock.height].adjustment > 1) {
+                      <fa-icon class="retarget-sign up" [icon]="['fas', 'caret-up']" [fixedWidth]="true"></fa-icon>
+                    } @else if (cacheService.daCache[mempoolBlock.height].adjustment < 1) {
+                      <fa-icon class="retarget-sign" [icon]="['fas', 'caret-down']" [fixedWidth]="true"></fa-icon>
+                    }
+                    {{ (cacheService.daCache[mempoolBlock.height].adjustment - 1) * 100 | absolute | number: '1.2-2' }}
+                    <span class="symbol">%</span>
+                  </div>
+                </ng-container>
+                <ng-template #loadingAdjustment>
+                  <span class="skeleton-loader" style="max-width: 60px"></span>
+                </ng-template>
+              </td>
+            </tr>
           </tbody>
         </table>
         <app-fee-distribution-graph *ngIf="webGlEnabled" [transactions]="mempoolBlockTransactions$ | async" [feeRange]="mempoolBlock.isStack ? mempoolBlock.feeRange : []" [vsize]="mempoolBlock.blockVSize" ></app-fee-distribution-graph>

frontend/src/app/components/mempool-block/mempool-block.component.scss

@@ -36,3 +36,11 @@ h1 {
     margin: auto;
   }
 }
+
+.retarget-sign {
+  margin-right: -3px;
+  &.up {
+    position: relative;
+    top: 2px;
+  }
+}

frontend/src/app/components/mempool-block/mempool-block.component.ts

@@ -9,6 +9,7 @@ import { Observable, BehaviorSubject } from 'rxjs';
 import { SeoService } from '../../services/seo.service';
 import { seoDescriptionNetwork } from '../../shared/common.utils';
 import { WebsocketService } from '../../services/websocket.service';
+import { CacheService } from '../../services/cache.service';
 
 @Component({
   selector: 'app-mempool-block',
@@ -30,6 +31,7 @@ export class MempoolBlockComponent implements OnInit, OnDestroy {
     public stateService: StateService,
     private seoService: SeoService,
     private websocketService: WebsocketService,
+    public cacheService: CacheService,
     private cd: ChangeDetectorRef,
     @Inject(PLATFORM_ID) private platformId: Object,
   ) {

frontend/src/app/components/mempool-blocks/mempool-blocks.component.ts

@@ -1,10 +1,10 @@
 import { Component, OnInit, OnDestroy, ChangeDetectionStrategy, ChangeDetectorRef, HostListener, Input, OnChanges, SimpleChanges, Output, EventEmitter, ViewChild, ElementRef } from '@angular/core';
-import { Subscription, Observable, of, combineLatest } from 'rxjs';
+import { Subscription, Observable, of, combineLatest, throwError } from 'rxjs';
 import { MempoolBlock } from '../../interfaces/websocket.interface';
 import { StateService } from '../../services/state.service';
 import { EtaService } from '../../services/eta.service';
 import { Router } from '@angular/router';
-import { delay, filter, map, switchMap, tap } from 'rxjs/operators';
+import { delay, filter, map, retryWhen, switchMap, take, tap } from 'rxjs/operators';
 import { feeLevels } from '../../app.constants';
 import { specialBlocks } from '../../app.constants';
 import { RelativeUrlPipe } from '../../shared/pipes/relative-url/relative-url.pipe';
@@ -12,6 +12,8 @@ import { Location } from '@angular/common';
 import { DifficultyAdjustment, MempoolPosition } from '../../interfaces/node-api.interface';
 import { animate, style, transition, trigger } from '@angular/animations';
 import { ThemeService } from '../../services/theme.service';
+import { CacheService } from '../../services/cache.service';
+import { colorFromRetarget } from '../../shared/common.utils';
 
 @Component({
   selector: 'app-mempool-blocks',
@@ -93,6 +95,7 @@ export class MempoolBlocksComponent implements OnInit, OnChanges, OnDestroy {
   constructor(
     private router: Router,
     public stateService: StateService,
+    public cacheService: CacheService,
     private etaService: EtaService,
     private themeService: ThemeService,
     private cd: ChangeDetectorRef,
@@ -387,6 +390,37 @@ export class MempoolBlocksComponent implements OnInit, OnChanges, OnDestroy {
     this.mempoolBlocksFull.forEach((block, i) => this.mempoolBlockStyles.push(this.getStyleForMempoolBlock(block, i)));
   }
 
+  isDA(height: number): boolean {
+    if (this.chainTip === -1) {
+      return false;
+    }
+    const isDA = height % 2016 === 0 && this.stateService.network === '';
+    if (isDA && !this.cacheService.daCache[height]) {
+      this.cacheService.daCache[height] = { adjustment: 0 };
+      this.difficultyAdjustments$.pipe(
+        filter(da => !!da),
+        switchMap(da => {
+          const mempoolBlocksAvailable = this.chainTip && this.mempoolBlockStyles[height - this.chainTip - 1];
+          return mempoolBlocksAvailable ? of(da) : throwError(() => new Error());
+        }),
+        retryWhen(errors =>
+          errors.pipe(
+            delay(100),
+            take(3)
+          )
+        ),
+        tap(da => {
+          const adjustment = parseFloat((1 + da.difficultyChange / 100).toFixed(4));
+          if (adjustment !== this.cacheService.daCache[height].adjustment) {
+            this.cacheService.daCache[height].adjustment = adjustment;
+            this.mempoolBlockStyles[height - this.chainTip - 1].background = colorFromRetarget(adjustment);
+          }
+        })
+      ).subscribe();
+    }
+    return isDA;
+  }
+
   getStyleForMempoolBlock(mempoolBlock: MempoolBlock, index: number) {
     const emptyBackgroundSpacePercentage = Math.max(100 - mempoolBlock.blockVSize / this.stateService.blockVSize * 100, 0);
     const usedBlockSpace = 100 - emptyBackgroundSpacePercentage;
@@ -410,7 +444,7 @@ export class MempoolBlocksComponent implements OnInit, OnChanges, OnDestroy {
 
     return {
       'right': this.containerOffset + index * this.blockOffset + 'px',
-      'background': backgroundGradients.join(',') + ')'
+      'background': this.isDA(mempoolBlock.height) ? colorFromRetarget(this.cacheService.daCache[mempoolBlock.height]?.adjustment || 1) : backgroundGradients.join(',') + ')'
     };
   }
 

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

@@ -747,7 +747,7 @@ export class TrackerComponent implements OnInit, OnDestroy {
 
   checkAccelerationEligibility() {
     if (this.tx) {
-      this.tx.flags = getTransactionFlags(this.tx);
+      this.tx.flags = getTransactionFlags(this.tx, null, null, this.tx.status?.block_time, this.stateService.network);
       const replaceableInputs = (this.tx.flags & (TransactionFlags.sighash_none | TransactionFlags.sighash_acp)) > 0n;
       const highSigop = (this.tx.sigops * 20) > this.tx.weight;
       this.eligibleForAcceleration = !replaceableInputs && !highSigop;

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

@@ -901,7 +901,7 @@ export class TransactionComponent implements OnInit, AfterViewInit, OnDestroy {
       this.segwitEnabled = !this.tx.status.confirmed || isFeatureActive(this.stateService.network, this.tx.status.block_height, 'segwit');
       this.taprootEnabled = !this.tx.status.confirmed || isFeatureActive(this.stateService.network, this.tx.status.block_height, 'taproot');
       this.rbfEnabled = !this.tx.status.confirmed || isFeatureActive(this.stateService.network, this.tx.status.block_height, 'rbf');
-      this.tx.flags = getTransactionFlags(this.tx);
+      this.tx.flags = getTransactionFlags(this.tx, null, null, this.tx.status?.block_time, this.stateService.network);
       this.filters = this.tx.flags ? toFilters(this.tx.flags).filter(f => f.txPage) : [];
       this.checkAccelerationEligibility();
     } else {

frontend/src/app/docs/api-docs/api-docs-data.ts

@@ -3670,6 +3670,39 @@ export const restApiDocsData = [
       }
     }
   },
+  {
+    type: "endpoint",
+    category: "mining",
+    httpRequestMethod: "GET",
+    fragment: "get-difficulty-adjustment-by-height",
+    title: "GET Difficulty Adjustment",
+    description: {
+      default: "<p>Returns difficulty adjustment for the block at the specified <code>:blockHeight</code>. If no adjustment happened at that height, an empty response is returned.</p>"
+    },
+    urlString: "/v1/mining/difficulty-adjustment/:blockHeight",
+    showConditions: [""],
+    showJsExamples: showJsExamplesDefaultFalse,
+    codeExample: {
+      default: {
+        codeTemplate: {
+          curl: `/api/v1/mining/difficulty-adjustment/%{1}`,
+          commonJS: ``,
+          esModule: ``
+        },
+        codeSampleMainnet: {
+          esModule: [],
+          commonJS: [],
+          curl: [`756000`],
+          response: `{
+  "time": "2022-09-28T02:56:34.000Z",
+  "height": 756000,
+  "difficulty": 31360548173144.9,
+  "adjustment": 0.97863
+}`
+        },
+      }
+    }
+  },
   {
     type: "endpoint",
     category: "mining",

frontend/src/app/services/api.service.ts

@@ -315,6 +315,12 @@ export class ApiService {
       );
   }
 
+  getDifficultyAdjustmentByHeight$(height: number): Observable<any> {
+    return this.httpClient.get<any>(
+      this.apiBaseUrl + this.apiBasePath + `/api/v1/mining/difficulty-adjustment/${height}`
+    );
+  }
+
   getHistoricalHashrate$(interval: string | undefined): Observable<any> {
     return this.httpClient.get<any[]>(
         this.apiBaseUrl + this.apiBasePath + `/api/v1/mining/hashrate` +

frontend/src/app/services/cache.service.ts

@@ -23,6 +23,7 @@ export class CacheService {
   blockLoading: { [height: number]: boolean } = {};
   copiesInBlockQueue: { [height: number]: number } = {};
   blockPriorities: number[] = [];
+  daCache: { [height: number]: { adjustment: number, exact?: boolean } } = {};
 
   constructor(
     private stateService: StateService,
@@ -128,6 +129,7 @@ export class CacheService {
     this.blockLoading = {};
     this.copiesInBlockQueue = {};
     this.blockPriorities = [];
+    this.daCache = {};
   }
 
   getCachedBlock(height) {

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

@@ -240,3 +240,25 @@ export function md5(inputString): string {
     }
     return rh(a)+rh(b)+rh(c)+rh(d);
 }
+
+export function colorFromRetarget(da: number): string {
+  const minDA = 0.95;
+  const maxDA = 1.05;
+  const midDA = 1;
+
+  const red = { r: 220, g: 53, b: 69 };
+  const grey = { r: 108, g: 117, b: 125 };
+  const green = { r: 59, g: 204, b: 73 };
+
+  const interpolateColor = (color1, color2, ratio) => {
+    ratio = Math.min(1, Math.max(0, ratio));
+    const r = Math.round(color1.r + ratio * (color2.r - color1.r));
+    const g = Math.round(color1.g + ratio * (color2.g - color1.g));
+    const b = Math.round(color1.b + ratio * (color2.b - color1.b));
+    return `rgba(${r}, ${g}, ${b}, 0.7)`;
+  }
+
+  return da <= midDA ?
+    interpolateColor(red, grey, (da - minDA) / (midDA - minDA)) : 
+    interpolateColor(grey, green, (da - midDA) / (maxDA - midDA));
+}

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

@@ -267,7 +267,7 @@ export function parseMultisigScript(script: string): undefined | { m: number, n:
   if (!opN) {
     return;
   }
-  if (!opN.startsWith('OP_PUSHNUM_')) {
+  if (opN !== 'OP_0' && !opN.startsWith('OP_PUSHNUM_')) {
     return;
   }
   const n = parseInt(opN.match(/[0-9]+/)?.[0] || '', 10);
@@ -287,7 +287,7 @@ export function parseMultisigScript(script: string): undefined | { m: number, n:
   if (!opM) {
     return;
   }
-  if (!opM.startsWith('OP_PUSHNUM_')) {
+  if (opM !== 'OP_0' && !opM.startsWith('OP_PUSHNUM_')) {
     return;
   }
   const m = parseInt(opM.match(/[0-9]+/)?.[0] || '', 10);

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

@@ -2,9 +2,9 @@ import { TransactionFlags } from './filters.utils';
 import { getVarIntLength, opcodes, parseMultisigScript, isPoint } from './script.utils';
 import { Transaction } from '../interfaces/electrs.interface';
 import { CpfpInfo, RbfInfo, TransactionStripped } from '../interfaces/node-api.interface';
+import { StateService } from '../services/state.service';
 
 // Bitcoin Core default policy settings
-const TX_MAX_STANDARD_VERSION = 2;
 const MAX_STANDARD_TX_WEIGHT = 400_000;
 const MAX_BLOCK_SIGOPS_COST = 80_000;
 const MAX_STANDARD_TX_SIGOPS_COST = (MAX_BLOCK_SIGOPS_COST / 5);
@@ -89,10 +89,13 @@ export function isDERSig(w: string): boolean {
  *
  * returns true early if any standardness rule is violated, otherwise false
  * (except for non-mandatory-script-verify-flag and p2sh script evaluation rules which are *not* enforced)
+ *
+ * As standardness rules change, we'll need to apply the rules in force *at the time* to older blocks.
+ * For now, just pull out individual rules into versioned functions where necessary.
  */
-export function isNonStandard(tx: Transaction): boolean {
+export function isNonStandard(tx: Transaction, height?: number, network?: string): boolean {
   // version
-  if (tx.version > TX_MAX_STANDARD_VERSION) {
+  if (isNonStandardVersion(tx, height, network)) {
     return true;
   }
 
@@ -139,6 +142,8 @@ export function isNonStandard(tx: Transaction): boolean {
       }
     } else if (['unknown', 'provably_unspendable', 'empty'].includes(vin.prevout?.scriptpubkey_type || '')) {
       return true;
+    } else if (isNonStandardAnchor(tx, height, network)) {
+      return true;
     }
     // TODO: bad-witness-nonstandard
   }
@@ -203,6 +208,51 @@ export function isNonStandard(tx: Transaction): boolean {
   return false;
 }
 
+// Individual versioned standardness rules
+
+const V3_STANDARDNESS_ACTIVATION_HEIGHT = {
+  'testnet4': 42_000,
+  'testnet': 2_900_000,
+  'signet': 211_000,
+  '': 863_500,
+};
+function isNonStandardVersion(tx: Transaction, height?: number, network?: string): boolean {
+  let TX_MAX_STANDARD_VERSION = 3;
+  if (
+    height != null
+    && network != null
+    && V3_STANDARDNESS_ACTIVATION_HEIGHT[network]
+    && height <= V3_STANDARDNESS_ACTIVATION_HEIGHT[network]
+  ) {
+    // V3 transactions were non-standard to spend before v28.x (scheduled for 2024/09/30 https://github.com/bitcoin/bitcoin/issues/29891)
+    TX_MAX_STANDARD_VERSION = 2;
+  }
+
+  if (tx.version > TX_MAX_STANDARD_VERSION) {
+    return true;
+  }
+  return false;
+}
+
+const ANCHOR_STANDARDNESS_ACTIVATION_HEIGHT = {
+  'testnet4': 42_000,
+  'testnet': 2_900_000,
+  'signet': 211_000,
+  '': 863_500,
+};
+function isNonStandardAnchor(tx: Transaction, height?: number, network?: string): boolean {
+  if (
+    height != null
+    && network != null
+    && ANCHOR_STANDARDNESS_ACTIVATION_HEIGHT[network]
+    && height <= ANCHOR_STANDARDNESS_ACTIVATION_HEIGHT[network]
+  ) {
+    // anchor outputs were non-standard to spend before v28.x (scheduled for 2024/09/30 https://github.com/bitcoin/bitcoin/issues/29891)
+    return true;
+  }
+  return false;
+}
+
 // A witness program is any valid scriptpubkey that consists of a 1-byte push opcode
 // followed by a data push between 2 and 40 bytes.
 // https://github.com/bitcoin/bitcoin/blob/2c79abc7ad4850e9e3ba32a04c530155cda7f980/src/script/script.cpp#L224-L240
@@ -289,7 +339,7 @@ export function isBurnKey(pubkey: string): boolean {
   ].includes(pubkey);
 }
 
-export function getTransactionFlags(tx: Transaction, cpfpInfo?: CpfpInfo, replacement?: boolean): bigint {
+export function getTransactionFlags(tx: Transaction, cpfpInfo?: CpfpInfo, replacement?: boolean, height?: number, network?: string): bigint {
   let flags = tx.flags ? BigInt(tx.flags) : 0n;
 
   // Update variable flags (CPFP, RBF)
@@ -439,7 +489,7 @@ export function getTransactionFlags(tx: Transaction, cpfpInfo?: CpfpInfo, replac
     flags |= TransactionFlags.batch_payout;
   }
 
-  if (isNonStandard(tx)) {
+  if (isNonStandard(tx, height, network)) {
     flags |= TransactionFlags.nonstandard;
   }