import { isPlatformBrowser } from '@angular/common';
import { ChangeDetectionStrategy, Component, DestroyRef, PLATFORM_ID, computed, inject, input, signal } from '@angular/core';

@Component({
  selector: 'app-counter-to',
  templateUrl: './counter-to.component.html',
  styleUrl: './counter-to.component.scss',
  changeDetection: ChangeDetectionStrategy.OnPush,
})
export class CounterToComponent {
  readonly startsAt = input<string | null | undefined>(null);

  private readonly now = signal(Date.now());

  protected readonly countdown = computed(() => {
    const startsAt = this.startsAt();
    const instant = startsAt ? Date.parse(startsAt) : NaN;
    if (!Number.isFinite(instant)) return null;

    const remaining = Math.max(0, instant - this.now());
    const seconds = Math.floor(remaining / 1000);
    return {
      finished: remaining === 0,
      days: Math.floor(seconds / 86400),
      hours: Math.floor((seconds % 86400) / 3600),
      minutes: Math.floor((seconds % 3600) / 60),
      seconds: seconds % 60,
    };
  });

  constructor() {
    if (isPlatformBrowser(inject(PLATFORM_ID))) {
      const timer = setInterval(() => this.now.set(Date.now()), 1000);
      inject(DestroyRef).onDestroy(() => clearInterval(timer));
    }
  }
}