feat: add Duration humanize

src/pkg.generated.mbti

@@ -154,6 +154,7 @@ pub fn Duration::days(Int64) -> Self
 pub fn Duration::divide(Self, Int64) -> Self raise TempoError
 pub fn Duration::format_iso(Self) -> String
 pub fn Duration::hours(Int64) -> Self
+pub fn Duration::humanize(Self) -> String
 pub fn Duration::is_negative(Self) -> Bool
 pub fn Duration::is_positive(Self) -> Bool
 pub fn Duration::is_zero(Self) -> Bool

src/tempo.mbt

@@ -2492,6 +2492,56 @@ pub fn Duration::format_iso(self : Duration) -> String {
   }
 }
 
+///|
+/// Format this duration as English elapsed time using day/hour/minute/second
+/// units. Sub-second remainder is dropped.
+pub fn Duration::humanize(self : Duration) -> String {
+  let total_seconds = self.abs().as_seconds()
+  if total_seconds == 0L {
+    "0 seconds"
+  } else {
+    let days = total_seconds / 86_400L
+    let rem = total_seconds - days * 86_400L
+    let hours = rem / 3_600L
+    let rem = rem - hours * 3_600L
+    let minutes = rem / 60L
+    let seconds = rem - minutes * 60L
+    let buf = StringBuilder()
+    if self.is_negative() {
+      buf.write_string("-")
+    }
+    let wrote = write_humanized_duration_component(buf, false, days, "day")
+    let wrote = write_humanized_duration_component(buf, wrote, hours, "hour")
+    let wrote = write_humanized_duration_component(
+      buf, wrote, minutes, "minute",
+    )
+    let _ = write_humanized_duration_component(buf, wrote, seconds, "second")
+    buf.to_string()
+  }
+}
+
+///|
+fn write_humanized_duration_component(
+  buf : StringBuilder,
+  wrote : Bool,
+  value : Int64,
+  unit : String,
+) -> Bool {
+  if value == 0L {
+    wrote
+  } else {
+    if wrote {
+      buf.write_string(" ")
+    }
+    buf.write_string("\{value} ")
+    buf.write_string(unit)
+    if value != 1L {
+      buf.write_string("s")
+    }
+    true
+  }
+}
+
 ///|
 fn[T] json_decode_error(
   path : @json.JsonPath,

src/tempo_test.mbt

@@ -1895,6 +1895,30 @@ test "Duration::format_iso canonical components" {
   assert_eq(@tempo.Duration::hours(-1L).format_iso(), "-PT1H")
 }
 
+///|
+test "Duration::humanize formats elapsed components" {
+  assert_eq(
+    (@tempo.Duration::hours(2L) + @tempo.Duration::minutes(30L)).humanize(),
+    "2 hours 30 minutes",
+  )
+  assert_eq(@tempo.Duration::seconds(1L).humanize(), "1 second")
+  assert_eq(
+    (@tempo.Duration::days(1L) +
+    @tempo.Duration::hours(1L) +
+    @tempo.Duration::minutes(1L) +
+    @tempo.Duration::seconds(1L)).humanize(),
+    "1 day 1 hour 1 minute 1 second",
+  )
+  assert_eq(@tempo.Duration::seconds(0L).humanize(), "0 seconds")
+  assert_eq(@tempo.Duration::milliseconds(500L).humanize(), "0 seconds")
+  assert_eq(@tempo.Duration::seconds(-5L).humanize(), "-5 seconds")
+  assert_eq(@tempo.Duration::minutes(-90L).humanize(), "-1 hour 30 minutes")
+  assert_eq(
+    @tempo.Duration::nanoseconds(-9_223_372_036_854_775_808L).humanize(),
+    "-106751 days 23 hours 47 minutes 16 seconds",
+  )
+}
+
 ///|
 test "Duration::parse_iso fixed-unit components" {
   assert_eq(