Anki/rslib/src/scheduler/states/steps.rs
2021-02-23 17:35:20 +10:00

82 lines
2.4 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;
#[derive(Clone, Copy, Debug, PartialEq)]
pub(crate) struct LearningSteps<'a> {
steps: &'a [f32],
}
fn to_secs(v: f32) -> u32 {
(v * 60.0) as u32
}
impl<'a> LearningSteps<'a> {
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)
}
// fixme: the logic here is not ideal, but tries to match
// the current python code
pub(crate) fn hard_delay_secs(self, remaining: u32) -> Option<u32> {
let idx = self.get_index(remaining);
if let Some(current) = self
.secs_at_index(idx)
// if current is invalid, try first step
.or_else(|| self.steps.first().copied().map(to_secs))
{
let next = if self.steps.len() > 1 {
self.secs_at_index(idx + 1).unwrap_or(60)
} else {
current * 2
}
.max(current);
Some((current + next) / 2)
} else {
None
}
}
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
}
}