move answer_button_time to the backend, split sched into separate module

proto/backend.proto

@@ -44,6 +44,7 @@ message BackendInput {
         Empty check_media = 28;
         TrashMediaFilesIn trash_media_files = 29;
         TranslateStringIn translate_string = 30;
+        FormatTimeSpanIn format_time_span = 31;
     }
 }
 
@@ -64,6 +65,7 @@ message BackendOutput {
         MediaCheckOut check_media = 28;
         Empty trash_media_files = 29;
         string translate_string = 30;
+        string format_time_span = 31;
 
         BackendError error = 2047;
     }
@@ -303,3 +305,12 @@ message TranslateArgValue {
         double number = 2;
     }
 }
+
+message FormatTimeSpanIn {
+    enum Context {
+        ANSWER_BUTTONS = 0;
+    }
+
+    float seconds = 1;
+    Context context = 2;
+}

pylib/anki/rsbackend.py

@@ -134,6 +134,8 @@ MediaCheckOutput = pb.MediaCheckOut
 
 StringsGroup = pb.StringsGroup
 
+FormatTimeSpanContext = pb.FormatTimeSpanIn.Context
+
 
 @dataclass
 class ExtractedLatex:
@@ -342,3 +344,10 @@ class RustBackend:
                 translate_string=pb.TranslateStringIn(group=group, key=key, args=args)
             )
         ).translate_string
+
+    def format_time_span(self, seconds: float, context: FormatTimeSpanContext) -> str:
+        return self._run_command(
+            pb.BackendInput(
+                format_time_span=pb.FormatTimeSpanIn(seconds=seconds, context=context)
+            )
+        ).format_time_span

pylib/anki/sched.py

@@ -1,6 +1,8 @@
 # Copyright: Ankitects Pty Ltd and contributors
 # License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 
+from __future__ import annotations
+
 import itertools
 import random
 import time
@@ -8,11 +10,13 @@ from heapq import *
 from operator import itemgetter
 from typing import List, Optional, Set
 
+import anki
 from anki import hooks
 from anki.cards import Card
 from anki.consts import *
 from anki.lang import _
-from anki.utils import answer_button_time, ids2str, intTime
+from anki.rsbackend import FormatTimeSpanContext
+from anki.utils import ids2str, intTime
 
 # queue types: 0=new/cram, 1=lrn, 2=rev, 3=day lrn, -1=suspended, -2=buried
 # revlog types: 0=lrn, 1=rev, 2=relrn, 3=cram
@@ -25,7 +29,7 @@ class Scheduler:
     _spreadRev = True
     _burySiblingsOnAnswer = True
 
-    def __init__(self, col):
+    def __init__(self, col: anki.storage._Collection) -> None:
         self.col = col
         self.queueLimit = 50
         self.reportLimit = 1000
@@ -33,7 +37,7 @@ class Scheduler:
         self.lrnCount = 0
         self.revCount = 0
         self.newCount = 0
-        self.today = None
+        self.today: Optional[int] = None
         self._haveQueues = False
         self._updateCutoff()
 
@@ -1354,7 +1358,9 @@ To study outside of the normal schedule, click the Custom Study button below."""
         ivl_secs = self.nextIvl(card, ease)
         if not ivl_secs:
             return _("(end)")
-        s = answer_button_time(self.col, ivl_secs)
+        s = self.col.backend.format_time_span(
+            ivl_secs, FormatTimeSpanContext.ANSWER_BUTTONS
+        )
         if ivl_secs < self.col.conf["collapseTime"]:
             s = "<" + s
         return s

pylib/anki/schedv2.py

@@ -18,8 +18,8 @@ from anki import hooks
 from anki.cards import Card
 from anki.consts import *
 from anki.lang import _
-from anki.rsbackend import SchedTimingToday
-from anki.utils import answer_button_time, ids2str, intTime
+from anki.rsbackend import FormatTimeSpanContext, SchedTimingToday
+from anki.utils import ids2str, intTime
 
 # card types: 0=new, 1=lrn, 2=rev, 3=relrn
 # queue types: 0=new, 1=(re)lrn, 2=rev, 3=day (re)lrn,
@@ -1548,7 +1548,9 @@ To study outside of the normal schedule, click the Custom Study button below."""
         ivl_secs = self.nextIvl(card, ease)
         if not ivl_secs:
             return _("(end)")
-        s = answer_button_time(self.col, ivl_secs)
+        s = self.col.backend.format_time_span(
+            ivl_secs, FormatTimeSpanContext.ANSWER_BUTTONS
+        )
         if ivl_secs < self.col.conf["collapseTime"]:
             s = "<" + s
         return s

pylib/anki/utils.py

@@ -23,8 +23,6 @@ from hashlib import sha1
 from html.entities import name2codepoint
 from typing import Iterable, Iterator, List, Optional, Tuple, Union
 
-import anki
-from anki.backend_pb2 import StringsGroup
 from anki.db import DB
 from anki.lang import _, ngettext
 
@@ -39,22 +37,6 @@ def intTime(scale: int = 1) -> int:
     return int(time.time() * scale)
 
 
-# eg 70 seconds -> (1.16, "minutes")
-def seconds_to_appropriate_unit(seconds: int) -> Tuple[float, str]:
-    unit, _ = optimalPeriod(seconds, 0, 99)
-    amount = convertSecondsTo(seconds, unit)
-    return (amount, unit)
-
-
-def answer_button_time(col: anki.storage._Collection, seconds: int) -> str:
-    (amount, unit) = seconds_to_appropriate_unit(seconds)
-    if unit not in ("months", "years"):
-        amount = int(amount)
-    return col.backend.translate(
-        StringsGroup.SCHEDULING, f"answer-button-time-{unit}", amount=amount
-    )
-
-
 timeTable = {
     "years": lambda n: ngettext("%s year", "%s years", n),
     "months": lambda n: ngettext("%s month", "%s months", n),

rslib/src/backend.rs

@@ -10,7 +10,8 @@ use crate::latex::{extract_latex, ExtractedLatex};
 use crate::media::check::MediaChecker;
 use crate::media::sync::MediaSyncProgress;
 use crate::media::MediaManager;
-use crate::sched::{local_minutes_west_for_stamp, sched_timing_today};
+use crate::sched::cutoff::{local_minutes_west_for_stamp, sched_timing_today};
+use crate::sched::timespan::answer_button_time;
 use crate::template::{
     render_card, without_legacy_template_directives, FieldMap, FieldRequirements, ParsedTemplate,
     RenderedNode,
@@ -200,6 +201,7 @@ impl Backend {
                 OValue::TrashMediaFiles(Empty {})
             }
             Value::TranslateString(input) => OValue::TranslateString(self.translate_string(input)),
+            Value::FormatTimeSpan(input) => OValue::FormatTimeSpan(self.format_time_span(input)),
         })
     }
 
@@ -397,6 +399,18 @@ impl Backend {
 
         self.i18n.get(group).trn(&input.key, map)
     }
+
+    fn format_time_span(&self, input: pb::FormatTimeSpanIn) -> String {
+        let context = match pb::format_time_span_in::Context::from_i32(input.context) {
+            Some(context) => context,
+            None => return "".to_string(),
+        };
+        match context {
+            pb::format_time_span_in::Context::AnswerButtons => {
+                answer_button_time(input.seconds, &self.i18n)
+            }
+        }
+    }
 }
 
 fn translate_arg_to_fluent_val(arg: &pb::TranslateArgValue) -> FluentValue {

rslib/src/sched/cutoff.rs

@@ -92,7 +92,7 @@ pub fn local_minutes_west_for_stamp(stamp: i64) -> i32 {
 
 #[cfg(test)]
 mod test {
-    use crate::sched::{
+    use crate::sched::cutoff::{
         fixed_offset_from_minutes, local_minutes_west_for_stamp, normalized_rollover_hour,
         sched_timing_today,
     };

rslib/src/sched/mod.rs

@@ -0,0 +1,2 @@
+pub mod cutoff;
+pub mod timespan;

rslib/src/sched/timespan.rs

@@ -0,0 +1,118 @@
+// Copyright: Ankitects Pty Ltd and contributors
+// License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
+
+use crate::i18n::{tr_args, I18n, StringsGroup};
+
+pub fn answer_button_time(seconds: f32, i18n: &I18n) -> String {
+    let span = Timespan::from_secs(seconds).natural_span();
+    let amount = match span.unit() {
+        TimespanUnit::Months | TimespanUnit::Years => span.as_unit(),
+        // we don't show fractional value except for months/years
+        _ => span.as_unit().round(),
+    };
+    let unit = span.unit().as_str();
+    let args = tr_args!["amount" => amount];
+    i18n.get(StringsGroup::Scheduling)
+        .trn(&format!("answer-button-time-{}", unit), args)
+}
+
+const SECOND: f32 = 1.0;
+const MINUTE: f32 = 60.0 * SECOND;
+const HOUR: f32 = 60.0 * MINUTE;
+const DAY: f32 = 24.0 * HOUR;
+const MONTH: f32 = 30.0 * DAY;
+const YEAR: f32 = 365.0 * MONTH;
+
+#[derive(Clone, Copy)]
+enum TimespanUnit {
+    Seconds,
+    Minutes,
+    Hours,
+    Days,
+    Months,
+    Years,
+}
+
+impl TimespanUnit {
+    fn as_str(self) -> &'static str {
+        match self {
+            TimespanUnit::Seconds => "seconds",
+            TimespanUnit::Minutes => "minutes",
+            TimespanUnit::Hours => "hours",
+            TimespanUnit::Days => "days",
+            TimespanUnit::Months => "months",
+            TimespanUnit::Years => "years",
+        }
+    }
+}
+
+#[derive(Clone, Copy)]
+struct Timespan {
+    seconds: f32,
+    unit: TimespanUnit,
+}
+
+impl Timespan {
+    fn from_secs(seconds: f32) -> Self {
+        Timespan {
+            seconds,
+            unit: TimespanUnit::Seconds,
+        }
+    }
+
+    /// Return the value as the configured unit, eg seconds=70/unit=Minutes
+    /// returns 1.17
+    fn as_unit(self) -> f32 {
+        let s = self.seconds;
+        match self.unit {
+            TimespanUnit::Seconds => s,
+            TimespanUnit::Minutes => s / MINUTE,
+            TimespanUnit::Hours => s / HOUR,
+            TimespanUnit::Days => s / DAY,
+            TimespanUnit::Months => s / MONTH,
+            TimespanUnit::Years => s / YEAR,
+        }
+    }
+
+    fn unit(self) -> TimespanUnit {
+        self.unit
+    }
+
+    /// Return a new timespan in the most appropriate unit, eg
+    /// 70 secs -> timespan in minutes
+    fn natural_span(self) -> Timespan {
+        let secs = self.seconds.abs();
+        let unit = if secs < MINUTE {
+            TimespanUnit::Seconds
+        } else if secs < HOUR {
+            TimespanUnit::Minutes
+        } else if secs < DAY {
+            TimespanUnit::Hours
+        } else if secs < MONTH {
+            TimespanUnit::Days
+        } else if secs < YEAR {
+            TimespanUnit::Months
+        } else {
+            TimespanUnit::Years
+        };
+
+        Timespan {
+            seconds: self.seconds,
+            unit,
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::i18n::I18n;
+    use crate::sched::timespan::{answer_button_time, MONTH};
+
+    #[test]
+    fn answer_buttons() {
+        let i18n = I18n::new(&["zz"], "");
+        assert_eq!(answer_button_time(30.0, &i18n), "30s");
+        assert_eq!(answer_button_time(70.0, &i18n), "1m");
+        assert_eq!(answer_button_time(1.1 * MONTH, &i18n), "1.10mo");
+    }
+}