From 24b37e03a01d0df5d53775f2519523fa7b23333b Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Sat, 6 Jul 2024 06:47:42 +0000
Subject: [PATCH] add pretty time util

Signed-off-by: Jason Volk <jason@zemos.net>
---
 src/admin/server/commands.rs | 17 +++-----
 src/core/utils/time.rs       | 79 +++++++++++++++++++++++++++++++++++-
 2 files changed, 83 insertions(+), 13 deletions(-)

diff --git a/src/admin/server/commands.rs b/src/admin/server/commands.rs
index 2ab71033..06007fb8 100644
--- a/src/admin/server/commands.rs
+++ b/src/admin/server/commands.rs
@@ -1,24 +1,17 @@
-use conduit::{warn, Error, Result};
+use conduit::{utils::time, warn, Error, Result};
 use ruma::events::room::message::RoomMessageEventContent;
 
 use crate::services;
 
 pub(super) async fn uptime(_body: Vec<&str>) -> Result<RoomMessageEventContent> {
-	let seconds = services()
+	let elapsed = services()
 		.server
 		.started
 		.elapsed()
-		.expect("standard duration")
-		.as_secs();
-	let result = format!(
-		"up {} days, {} hours, {} minutes, {} seconds.",
-		seconds / 86400,
-		(seconds % 86400) / 60 / 60,
-		(seconds % 3600) / 60,
-		seconds % 60,
-	);
+		.expect("standard duration");
 
-	Ok(RoomMessageEventContent::notice_plain(result))
+	let result = time::pretty(elapsed);
+	Ok(RoomMessageEventContent::notice_plain(format!("{result}.")))
 }
 
 pub(super) async fn show_config(_body: Vec<&str>) -> Result<RoomMessageEventContent> {
diff --git a/src/core/utils/time.rs b/src/core/utils/time.rs
index 7de00e9e..39ceb3c3 100644
--- a/src/core/utils/time.rs
+++ b/src/core/utils/time.rs
@@ -1,4 +1,6 @@
-use std::time::{SystemTime, UNIX_EPOCH};
+#![allow(clippy::enum_glob_use)]
+
+use std::time::{Duration, SystemTime, UNIX_EPOCH};
 
 #[inline]
 #[must_use]
@@ -26,3 +28,78 @@ pub fn format(ts: SystemTime, str: &str) -> String {
 	let dt: DateTime<Utc> = ts.into();
 	dt.format(str).to_string()
 }
+
+#[must_use]
+pub fn pretty(d: Duration) -> String {
+	use Unit::*;
+
+	let fmt = |w, f, u| format!("{w}.{f} {u}");
+	let gen64 = |w, f, u| fmt(w, (f * 100.0) as u64, u);
+	let gen128 = |w, f, u| gen64(u64::try_from(w).expect("u128 to u64"), f, u);
+	match whole_and_frac(d) {
+		(Days(whole), frac) => gen64(whole, frac, "days"),
+		(Hours(whole), frac) => gen64(whole, frac, "hours"),
+		(Mins(whole), frac) => gen64(whole, frac, "minutes"),
+		(Secs(whole), frac) => gen64(whole, frac, "seconds"),
+		(Millis(whole), frac) => gen128(whole, frac, "milliseconds"),
+		(Micros(whole), frac) => gen128(whole, frac, "microseconds"),
+		(Nanos(whole), frac) => gen128(whole, frac, "nanoseconds"),
+	}
+}
+
+/// Return a pair of (whole part, frac part) from a duration where. The whole
+/// part is the largest Unit containing a non-zero value, the frac part is a
+/// rational remainder left over.
+#[must_use]
+pub fn whole_and_frac(d: Duration) -> (Unit, f64) {
+	use Unit::*;
+
+	let whole = whole_unit(d);
+	(
+		whole,
+		match whole {
+			Days(_) => (d.as_secs() % 86_400) as f64 / 86_400.0,
+			Hours(_) => (d.as_secs() % 3_600) as f64 / 3_600.0,
+			Mins(_) => (d.as_secs() % 60) as f64 / 60.0,
+			Secs(_) => f64::from(d.subsec_millis()) / 1000.0,
+			Millis(_) => f64::from(d.subsec_micros()) / 1000.0,
+			Micros(_) => f64::from(d.subsec_nanos()) / 1000.0,
+			Nanos(_) => 0.0,
+		},
+	)
+}
+
+/// Return the largest Unit which represents the duration. The value is
+/// rounded-down, but never zero.
+#[must_use]
+pub fn whole_unit(d: Duration) -> Unit {
+	use Unit::*;
+
+	match d.as_secs() {
+		86_400.. => Days(d.as_secs() / 86_400),
+		3_600..=86_399 => Hours(d.as_secs() / 3_600),
+		60..=3_599 => Mins(d.as_secs() / 60),
+
+		_ => match d.as_micros() {
+			1_000_000.. => Secs(d.as_secs()),
+			1_000..=999_999 => Millis(d.subsec_millis().into()),
+
+			_ => match d.as_nanos() {
+				1_000.. => Micros(d.subsec_micros().into()),
+
+				_ => Nanos(d.subsec_nanos().into()),
+			},
+		},
+	}
+}
+
+#[derive(Eq, PartialEq, Clone, Copy, Debug)]
+pub enum Unit {
+	Days(u64),
+	Hours(u64),
+	Mins(u64),
+	Secs(u64),
+	Millis(u128),
+	Micros(u128),
+	Nanos(u128),
+}