import { ChangeDetectorRef, NgZone, OnDestroy, Pipe, PipeTransform, inject } from '@angular/core'
@Pipe({
	standalone: true,
	name: 'timeAgo',
	pure: false,
})
export class TimeAgoPipe implements PipeTransform, OnDestroy {
	private changeDetectorRef = inject(ChangeDetectorRef)
	private ngZone = inject(NgZone)

	private timer: number | null = null
	transform(date: Date) {
		this.removeTimer()
		const now = new Date()
		const seconds = Math.round(Math.abs((now.getTime() - date.getTime()) / 1000))
		const timeToUpdate = Number.isNaN(seconds) ? 1000 : this.getSecondsUntilUpdate(seconds) * 1000
		this.timer = this.ngZone.runOutsideAngular(() => {
			if (typeof window !== 'undefined') {
				return window.setTimeout(() => {
					this.ngZone.run(() => this.changeDetectorRef.markForCheck())
				}, timeToUpdate)
			}
			return null
		})
		const minutes = Math.round(Math.abs(seconds / 60))
		const hours = Math.round(Math.abs(minutes / 60))
		const days = Math.round(Math.abs(hours / 24))
		const months = Math.round(Math.abs(days / 30.416))
		const years = Math.round(Math.abs(days / 365))
		if (Number.isNaN(seconds)) {
			return ''
		} else if (seconds <= 45) {
			return 'just now'
		} else if (seconds <= 90) {
			return 'a minute ago'
		} else if (minutes <= 45) {
			return minutes + ' minutes ago'
		} else if (minutes <= 90) {
			return 'an hour ago'
		} else if (hours <= 22) {
			return hours + ' hours ago'
		} else if (hours <= 36) {
			return 'a day ago'
		} else if (days <= 25) {
			return days + ' days ago'
		} else if (days <= 45) {
			return 'a month ago'
		} else if (days <= 345) {
			return months + ' months ago'
		} else if (days <= 545) {
			return 'a year ago'
		} else {
			// (days > 545)
			return years + ' years ago'
		}
	}

	ngOnDestroy(): void {
		this.removeTimer()
	}

	private removeTimer() {
		if (this.timer) {
			window.clearTimeout(this.timer)
			this.timer = null
		}
	}

	private getSecondsUntilUpdate(seconds: number) {
		const min = 60
		const hour = min * 60
		const day = hour * 24
		if (seconds < min) {
			// less than 1 min, update every 2 secs
			return 2
		} else if (seconds < hour) {
			// less than an hour, update every 30 secs
			return 30
		} else if (seconds < day) {
			// less then a day, update every 5 mins
			return 300
		} else {
			// update every hour
			return 3600
		}
	}
}