Replacing footer and latest blocks with a stats dashboard.

backend/src/api/blocks.ts

@@ -7,6 +7,7 @@ import { Common } from './common';
 class Blocks {
   private blocks: Block[] = [];
   private currentBlockHeight = 0;
+  private lastDifficultyAdjustmentTime = 0;
   private newBlockCallback: ((block: Block, txIds: string[], transactions: TransactionExtended[]) => void) | undefined;
 
   constructor() { }
@@ -38,6 +39,13 @@ class Blocks {
         this.currentBlockHeight = blockHeightTip - config.INITIAL_BLOCK_AMOUNT;
       }
 
+      if (!this.lastDifficultyAdjustmentTime) {
+        const heightDiff = blockHeightTip % 2016;
+        const blockHash = await bitcoinApi.getBlockHash(blockHeightTip - heightDiff);
+        const block = await bitcoinApi.getBlock(blockHash);
+        this.lastDifficultyAdjustmentTime = block.timestamp;
+      }
+
       while (this.currentBlockHeight < blockHeightTip) {
         if (this.currentBlockHeight === 0) {
           this.currentBlockHeight = blockHeightTip;
@@ -78,6 +86,10 @@ class Blocks {
         block.medianFee = transactions.length > 1 ? Common.median(transactions.map((tx) => tx.feePerVsize)) : 0;
         block.feeRange = transactions.length > 1 ? Common.getFeesInRange(transactions.slice(0, transactions.length - 1), 8) : [0, 0];
 
+        if (block.height % 2016 === 0) {
+          this.lastDifficultyAdjustmentTime = block.timestamp;
+        }
+
         this.blocks.push(block);
         if (this.blocks.length > config.KEEP_BLOCK_AMOUNT) {
           this.blocks.shift();
@@ -93,6 +105,10 @@ class Blocks {
     }
   }
 
+  public getLastDifficultyAdjustmentTime(): number {
+    return this.lastDifficultyAdjustmentTime;
+  }
+
   private stripCoinbaseTransaction(tx: TransactionExtended): TransactionMinerInfo {
     return {
       vin: [{

backend/src/api/websocket-handler.ts

@@ -84,6 +84,7 @@ class WebsocketHandler {
             client.send(JSON.stringify({
               'mempoolInfo': memPool.getMempoolInfo(),
               'vBytesPerSecond': memPool.getVBytesPerSecond(),
+              'lastDifficultyAdjustment': blocks.getLastDifficultyAdjustmentTime(),
               'blocks': _blocks.slice(Math.max(_blocks.length - config.INITIAL_BLOCK_AMOUNT, 0)),
               'conversions': fiatConversion.getTickers()['BTCUSD'],
               'mempool-blocks': mempoolBlocks.getMempoolBlocks(),
@@ -270,6 +271,7 @@ class WebsocketHandler {
       const response = {
         'block': block,
         'mempoolInfo': memPool.getMempoolInfo(),
+        'lastDifficultyAdjustment': blocks.getLastDifficultyAdjustmentTime(),
       };
 
       if (mBlocks && client['want-mempool-blocks']) {