use chrono::{DateTime, Utc};
use std::fmt;
use yew::prelude::*;

pub fn now() -> DateTime<Utc> {
	let now = stdweb::web::Date::now() / 1000.0;
	let now_floor = now.floor();
	let secs = now_floor as i64;
	let nanosecs = ((now - now_floor) * 1e9).round() as u32;
	DateTime::from_utc(chrono::NaiveDateTime::from_timestamp(secs, nanosecs), Utc)
}

struct PrettyFormatDuration(chrono::Duration);

impl fmt::Display for PrettyFormatDuration {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
		if self.0 == chrono::Duration::zero() {
			return write!(f, "now");
		}

		let (abs_duration, future) = if self.0 < chrono::Duration::zero() {
			(-self.0, true)
		} else {
			(self.0, false)
		};
		if future {
			write!(f, "in ")?;
		}

		if abs_duration.num_seconds() < 2 {
			// write!(f, "{}ms", abs_duration.num_milliseconds())?;
			write!(f, "now")?;
		} else if abs_duration.num_seconds() < 120 {
			write!(f, "{}s", abs_duration.num_seconds())?;
		} else if abs_duration.num_minutes() < 120 {
			write!(f, "{}m", abs_duration.num_minutes())?;
		} else if abs_duration.num_hours() < 48 {
			write!(f, "{}h", abs_duration.num_hours())?;
		} else {
			write!(f, "{}d", abs_duration.num_days())?;
		}

		if !future {
			write!(f, " ago")?;
		}

		Ok(())
	}
}

pub fn ago<COMP>(dt: DateTime<Utc>) -> Html<COMP>
where
	COMP: Component,
{
	let duration = now().signed_duration_since(dt);
	let dt_s = format!("{}", dt);
	html! {
		<time datetime=&dt_s title=&dt_s>{ PrettyFormatDuration(duration) }</time>
	}
}