Anki/rslib/src/scheduler/states/steps.rs
RumovZ 79ebded211 Round calculated Hard days (#1661)
* Round calculated Hard days

* clarify docstring (dae)
2022-02-13 13:37:52 +10:00

124 lines
4.1 KiB
Rust

// Copyright: Ankitects Pty Ltd and contributors
// License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
const DEFAULT_SECS_IF_MISSING: u32 = 60;
const DAY: u32 = 60 * 60 * 24;
#[derive(Clone, Copy, Debug, PartialEq)]
pub(crate) struct LearningSteps<'a> {
/// The steps in minutes.
steps: &'a [f32],
}
fn to_secs(v: f32) -> u32 {
(v * 60.0) as u32
}
impl<'a> LearningSteps<'a> {
/// Takes `steps` as minutes.
pub(crate) fn new(steps: &[f32]) -> LearningSteps<'_> {
LearningSteps { steps }
}
/// Strip off 'learning today', and ensure index is in bounds.
fn get_index(self, remaining: u32) -> usize {
let total = self.steps.len();
total
.saturating_sub((remaining % 1000) as usize)
.min(total.saturating_sub(1))
}
fn secs_at_index(&self, index: usize) -> Option<u32> {
self.steps.get(index).copied().map(to_secs)
}
/// Cards in learning must always have at least one learning step.
pub(crate) fn again_delay_secs_learn(&self) -> u32 {
self.secs_at_index(0).unwrap_or(DEFAULT_SECS_IF_MISSING)
}
pub(crate) fn again_delay_secs_relearn(&self) -> Option<u32> {
self.secs_at_index(0)
}
pub(crate) fn hard_delay_secs(self, remaining: u32) -> Option<u32> {
let idx = self.get_index(remaining);
self.secs_at_index(idx)
// if current is invalid, try first step
.or_else(|| self.steps.first().copied().map(to_secs))
.map(|current| {
// special case to avoid Hard and Again showing same interval
if idx == 0 {
// if there is no next step, simulate one with twice the interval of `current`
let next = self
.secs_at_index(idx + 1)
.unwrap_or_else(|| current.saturating_mul(2));
maybe_round_in_days(current.saturating_add(next) / 2)
} else {
current
}
})
}
pub(crate) fn good_delay_secs(self, remaining: u32) -> Option<u32> {
let idx = self.get_index(remaining);
self.secs_at_index(idx + 1)
}
pub(crate) fn current_delay_secs(self, remaining: u32) -> u32 {
let idx = self.get_index(remaining);
self.secs_at_index(idx).unwrap_or_default()
}
pub(crate) fn remaining_for_good(self, remaining: u32) -> u32 {
let idx = self.get_index(remaining);
self.steps.len().saturating_sub(idx + 1) as u32
}
pub(crate) fn remaining_for_failed(self) -> u32 {
self.steps.len() as u32
}
}
/// If the given interval in seconds surpasses 1 day, rounds it to a whole number of days.
/// Ensures that the user gets the same results earlier and later in the day.
/// Returns seconds.
fn maybe_round_in_days(secs: u32) -> u32 {
if secs > DAY {
((secs as f32 / DAY as f32).round() as u32).saturating_mul(DAY)
} else {
secs
}
}
#[cfg(test)]
mod test {
use super::*;
macro_rules! assert_delay_secs {
($steps:expr, $remaining:expr, $again_delay:expr, $hard_delay:expr, $good_delay:expr) => {
let steps = LearningSteps::new(&$steps);
assert_eq!(steps.again_delay_secs_learn(), $again_delay);
assert_eq!(steps.hard_delay_secs($remaining), $hard_delay);
assert_eq!(steps.good_delay_secs($remaining), $good_delay);
};
}
#[test]
fn delay_secs() {
assert_delay_secs!([10.0], 1, 600, Some(900), None);
assert_delay_secs!([1.0, 10.0], 2, 60, Some(330), Some(600));
assert_delay_secs!([1.0, 10.0], 1, 60, Some(600), None);
assert_delay_secs!([1.0, 10.0, 100.0], 3, 60, Some(330), Some(600));
assert_delay_secs!([1.0, 10.0, 100.0], 2, 60, Some(600), Some(6000));
assert_delay_secs!([1.0, 10.0, 100.0], 1, 60, Some(6000), None);
}
#[test]
fn rounding_days() {
assert_eq!(maybe_round_in_days(DAY - 1), DAY - 1);
assert_eq!(maybe_round_in_days((1.5 * DAY as f32) as u32), 2 * DAY);
}
}