Feature: Reflect difficulty estimation into mempool blocks. (#637)

* Add time until to mempool blocks.
Reflect difficulty estimate time.

* Fix estimate calculation.
Turn off the auto refresh.

* Change Math.floor to Math.round.

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

@@ -1,5 +1,5 @@
 import { Component, OnInit, OnDestroy, ChangeDetectionStrategy, ChangeDetectorRef, Input } from '@angular/core';
-import { Subscription, Observable, fromEvent, merge, of } from 'rxjs';
+import { Subscription, Observable, fromEvent, merge, of, combineLatest, timer } from 'rxjs';
 import { MempoolBlock } from 'src/app/interfaces/websocket.interface';
 import { StateService } from 'src/app/services/state.service';
 import { Router } from '@angular/router';
@@ -17,6 +17,7 @@ export class MempoolBlocksComponent implements OnInit, OnDestroy {
 
   mempoolBlocks: MempoolBlock[] = this.mountEmptyBlocks();
   mempoolBlocks$: Observable<MempoolBlock[]>;
+  timeAvg$: Observable<number>;
 
   mempoolBlocksFull: MempoolBlock[] = this.mountEmptyBlocks();
   mempoolBlockStyles = [];
@@ -24,6 +25,7 @@ export class MempoolBlocksComponent implements OnInit, OnDestroy {
   blockSubscription: Subscription;
   networkSubscription: Subscription;
   network = '';
+  now = new Date().getTime();
 
   blockWidth = 125;
   blockPadding = 30;
@@ -75,10 +77,39 @@ export class MempoolBlocksComponent implements OnInit, OnDestroy {
         this.mempoolBlocks = this.reduceMempoolBlocksToFitScreen(JSON.parse(stringifiedBlocks));
         this.updateMempoolBlockStyles();
         this.calculateTransactionPosition();
+        this.now = new Date().getTime();
         return this.mempoolBlocks;
       })
     );
 
+
+    this.timeAvg$ = timer(0, 1000)
+      .pipe(
+        switchMap(() => combineLatest([
+          this.stateService.blocks$.pipe(map(([block]) => block)),
+          this.stateService.lastDifficultyAdjustment$
+        ])),
+        map(([block, DATime]) => {
+          const now = new Date().getTime() / 1000;
+          const diff = now - DATime;
+          const blocksInEpoch = block.height % 2016;
+          let difficultyChange = 0;
+          if (blocksInEpoch > 0) {
+            difficultyChange = (600 / (diff / blocksInEpoch ) - 1) * 100;
+          }
+          const timeAvgDiff = difficultyChange * 0.1;
+
+          let timeAvgMins = 10;
+          if (timeAvgDiff > 0 ){
+            timeAvgMins -= Math.abs(timeAvgDiff);
+          } else {
+            timeAvgMins += Math.abs(timeAvgDiff);
+          }
+
+          return timeAvgMins * 60 * 1000;
+        })
+      );
+
     this.markBlocksSubscription = this.stateService.markBlock$
       .subscribe((state) => {
         this.markIndex = undefined;