implement clock face & dial

frontend/src/app/components/clock-face/clock-face.component.ts

@@ -1,15 +1,55 @@
-import { Component, Input, OnChanges } from '@angular/core';
+import { ChangeDetectionStrategy, ChangeDetectorRef, Component, Input, OnChanges, OnDestroy, OnInit } from '@angular/core';
+import { Subscription, tap, timer } from 'rxjs';
+import { WebsocketService } from '../../services/websocket.service';
+import { StateService } from '../../services/state.service';
 
 @Component({
   selector: 'app-clock-face',
   templateUrl: './clock-face.component.html',
   styleUrls: ['./clock-face.component.scss'],
+  changeDetection: ChangeDetectionStrategy.OnPush,
 })
-export class ClockFaceComponent implements OnChanges {
+export class ClockFaceComponent implements OnInit, OnChanges, OnDestroy {
   @Input() size: number = 300;
-  faceStyle;
 
-  constructor() {}
+  blocksSubscription: Subscription;
+  timeSubscription: Subscription;
+
+  faceStyle;
+  dialPath;
+  blockTimes = [];
+  segments = [];
+  hours: number = 0;
+  minutes: number = 0;
+  minorTicks: number[] = [];
+  majorTicks: number[] = [];
+
+  constructor(
+    public stateService: StateService,
+    private websocketService: WebsocketService,
+    private cd: ChangeDetectorRef
+  ) {
+    this.updateTime();
+    this.makeTicks();
+  }
+
+  ngOnInit(): void {
+    this.timeSubscription = timer(0, 250).pipe(
+      tap(() => {
+        this.updateTime();
+      })
+    ).subscribe();
+    this.websocketService.want(['blocks']);
+    this.blocksSubscription = this.stateService.blocks$
+      .subscribe(([block]) => {
+        if (block) {
+          this.blockTimes.push([block.height, new Date(block.timestamp * 1000)]);
+          // using block-reported times, so ensure they are sorted chronologically
+          this.blockTimes = this.blockTimes.sort((a, b) => a[1].getTime() - b[1].getTime());
+          this.updateSegments();
+        }
+      });
+  }
 
   ngOnChanges(): void {
     this.faceStyle = {
@@ -17,4 +57,93 @@ export class ClockFaceComponent implements OnChanges {
       height: `${this.size}px`,
     };
   }
+
+  ngOnDestroy(): void {
+    this.timeSubscription.unsubscribe();
+  }
+
+  updateTime(): void {
+    const now = new Date();
+    const seconds = now.getSeconds() + (now.getMilliseconds() / 1000);
+    this.minutes = (now.getMinutes() + (seconds / 60)) % 60;
+    this.hours = now.getHours() + (this.minutes / 60);
+    this.updateSegments();
+  }
+
+  updateSegments(): void {
+    const now = new Date();
+    this.blockTimes = this.blockTimes.filter(time => (now.getTime() - time[1].getTime()) <= 3600000);
+    const tail = new Date(now.getTime() - 3600000);
+    const hourStart = new Date(now.getFullYear(), now.getMonth(), now.getDate(), now.getHours());
+
+    const times = [
+      ['start', tail],
+      ...this.blockTimes,
+      ['end', now],
+    ];
+    const minuteTimes = times.map(time => {
+      return [time[0], (time[1].getTime() - hourStart.getTime()) / 60000];
+    });
+    this.segments = [];
+    const r = 174;
+    const cx = 192;
+    const cy = cx;
+    for (let i = 1; i < minuteTimes.length; i++) {
+      const arc = this.getArc(minuteTimes[i-1][1], minuteTimes[i][1], r, cx, cy);
+      if (arc) {
+        arc.id = minuteTimes[i][0];
+        this.segments.push(arc);
+      }
+    }
+    const arc = this.getArc(minuteTimes[0][1], minuteTimes[1][1], r, cx, cy);
+    if (arc) {
+      this.dialPath = arc.path;
+    }
+
+    this.cd.markForCheck();
+  }
+
+  getArc(startTime, endTime, r, cx, cy): any {
+    const startDegrees = (startTime + 0.2) * 6;
+      const endDegrees = (endTime - 0.2) * 6;
+      const start = this.getPointOnCircle(startDegrees, r, cx, cy);
+      const end = this.getPointOnCircle(endDegrees, r, cx, cy);
+      const arcLength = endDegrees - startDegrees;
+      // merge gaps and omit lines shorter than 1 degree
+      if (arcLength >= 1) {
+        const path = `M ${start.x} ${start.y} A ${r} ${r} 0 ${arcLength > 180 ? 1 : 0} 1 ${end.x} ${end.y}`;
+        return {
+          path,
+          start,
+          end
+        };
+      } else {
+        return null;
+      }
+  }
+
+  getPointOnCircle(deg, r, cx, cy) {
+    const modDeg = ((deg % 360) + 360) % 360;
+    const rad = (modDeg * Math.PI) / 180;
+    return {
+      x: cx + (r * Math.sin(rad)),
+      y: cy - (r * Math.cos(rad)),
+    };
+  }
+
+  makeTicks() {
+    this.minorTicks = [];
+    this.majorTicks = [];
+    for (let i = 1; i < 60; i++) {
+      if (i % 5 === 0) {
+        this.majorTicks.push(i * 6);
+      } else {
+        this.minorTicks.push(i * 6);
+      }
+    }
+  }
+
+  trackBySegment(index: number, segment) {
+    return segment.id;
+  }
 }