add 'studied-today' to Fluent

The string has been constructed in parts so the old translations
could be preserved

rslib/src/i18n/scheduling.ftl

@@ -11,29 +11,76 @@ answer-button-time-months = {$amount}mo
 answer-button-time-years = {$amount}y
 
 ## A span of time, such as the delay until a card is shown again, the
-## amount of time taken to answer a card, and so on.
+## amount of time taken to answer a card, and so on. It is used by itself,
+## such as in the Interval column of the browse screen,
+## and labels like "Total Time" in the card info screen.
 
 time-span-seconds = { $amount ->
    [one]   {$amount} second
   *[other] {$amount} seconds
   }
+
 time-span-minutes = { $amount ->
    [one]   {$amount} minute
   *[other] {$amount} minutes
   }
+
 time-span-hours = { $amount ->
    [one]   {$amount} hour
   *[other] {$amount} hours
   }
+
 time-span-days = { $amount ->
    [one]   {$amount} day
   *[other] {$amount} days
   }
+
 time-span-months = { $amount ->
    [one]   {$amount} month
   *[other] {$amount} months
   }
+
 time-span-years = { $amount ->
    [one]   {$amount} year
   *[other] {$amount} years
   }
+
+## A span of time studying took place in, for example
+## "(studied 30 cards) in 3 minutes". In English the text
+## just adds "in" to the start of time-span-*, but other
+## languages may need to use different words here instead
+## of reusing the time-span-* text.
+## See the 'studied-today' context for where this is used,
+## and the Polish translation for an example of different
+## wordings used here.
+
+in-time-span-seconds = in { time-span-seconds }
+in-time-span-minutes = in { time-span-minutes }
+in-time-span-hours = in { time-span-hours }
+in-time-span-days = in { time-span-days }
+in-time-span-months = in { time-span-months }
+in-time-span-years = in { time-span-years }
+
+##
+
+cards = { $cards ->
+   [one] {$cards} card
+  *[other] {$cards} cards
+  }
+
+# Shown at the bottom of the deck list, and in the statistics screen.
+# eg "Studied 3 cards in 13 seconds today (4.33s/card)."
+# The { in-time-span-seconds } part should be pasted in from the English
+# version unmodified.
+
+studied-today =
+  Studied { cards }
+  { $unit ->
+     [seconds] { in-time-span-seconds }
+     [minutes] { in-time-span-minutes }
+     [hours]   { in-time-span-hours }
+     [days]    { in-time-span-days }
+     [months]  { in-time-span-months }
+    *[years]   { in-time-span-years }
+  } today
+  ({$secs-per-card}s/card).

rslib/src/sched/timespan.rs

@@ -28,6 +28,23 @@ pub fn time_span(seconds: f32, i18n: &I18n) -> String {
         .trn(&format!("time-span-{}", unit), args)
 }
 
+// fixme: this doesn't belong here
+#[allow(dead_code)]
+fn studied_today(cards: usize, secs: f32, i18n: &I18n) -> String {
+    let span = Timespan::from_secs(secs).natural_span();
+    let amount = span.as_unit();
+    let unit = span.unit().as_str();
+    let secs_per = if cards > 0 {
+        secs / (cards as f32)
+    } else {
+        0.0
+    };
+    let args = tr_args!["amount" => amount, "unit" => unit,
+        "cards" => cards, "secs-per-card" => secs_per];
+    i18n.get(StringsGroup::Scheduling)
+        .trn("studied-today", args)
+}
+
 const SECOND: f32 = 1.0;
 const MINUTE: f32 = 60.0 * SECOND;
 const HOUR: f32 = 60.0 * MINUTE;
@@ -117,8 +134,8 @@ impl Timespan {
 
 #[cfg(test)]
 mod test {
-    use crate::i18n::I18n;
-    use crate::sched::timespan::{answer_button_time, MONTH};
+    use crate::i18n::{I18n, StringsGroup};
+    use crate::sched::timespan::{answer_button_time, studied_today, time_span, MONTH};
 
     #[test]
     fn answer_buttons() {
@@ -127,4 +144,22 @@ mod test {
         assert_eq!(answer_button_time(70.0, &i18n), "1m");
         assert_eq!(answer_button_time(1.1 * MONTH, &i18n), "1.10mo");
     }
+
+    #[test]
+    fn time_spans() {
+        let i18n = I18n::new(&["zz"], "");
+        assert_eq!(time_span(1.0, &i18n), "1 second");
+        assert_eq!(time_span(30.0, &i18n), "30 seconds");
+        assert_eq!(time_span(90.0, &i18n), "1.50 minutes");
+    }
+
+    #[test]
+    fn combo() {
+        // temporary test of fluent term handling
+        let i18n = I18n::new(&["zz"], "");
+        assert_eq!(
+            &studied_today(3, 13.0, &i18n).replace("\n", " "),
+            "Studied 3 cards in 13 seconds today (4.33s/card)."
+        );
+    }
 }