Fix cards showing up due in the past in a filtered deck

Caused by using due instead of original_due when card was in learning.
I think the original goal of that code was to ignore the learning timestamp
and show the next review date instead, but it's both simpler and more
intuitive to show the learning date instead.

rslib/src/card/mod.rs

@@ -213,6 +213,9 @@ impl Card {
         (self.ease_factor as f32) / 1000.0
     }
 
+    /// Don't use this in situations where you may be using original_due, since
+    /// it only applies to the current due date. You may want to use
+    /// is_unix_epoch_timestap() instead.
     pub fn is_intraday_learning(&self) -> bool {
         matches!(self.queue, CardQueue::Learn | CardQueue::PreviewRepeat)
     }

rslib/src/scheduler/filtered/card.rs

@@ -5,12 +5,13 @@ use super::DeckFilterContext;
 use crate::card::CardQueue;
 use crate::card::CardType;
 use crate::prelude::*;
+use crate::scheduler::timing::is_unix_epoch_timestamp;
 
 impl Card {
     pub(crate) fn restore_queue_from_type(&mut self) {
         self.queue = match self.ctype {
             CardType::Learn | CardType::Relearn => {
-                if self.due > 1_000_000_000 {
+                if is_unix_epoch_timestamp(self.due) {
                     // unix timestamp
                     CardQueue::Learn
                 } else {

rslib/src/scheduler/timing.rs

@@ -178,6 +178,11 @@ pub(crate) fn sched_timing_today(
     }
 }
 
+/// True if provided due number looks like a seconds-based timestamp.
+pub fn is_unix_epoch_timestamp(due: i32) -> bool {
+    due > 1_000_000_000
+}
+
 #[cfg(test)]
 mod test {
     use chrono::FixedOffset;

rslib/src/stats/card.rs

@@ -7,6 +7,7 @@ use crate::card::CardQueue;
 use crate::card::CardType;
 use crate::prelude::*;
 use crate::revlog::RevlogEntry;
+use crate::scheduler::timing::is_unix_epoch_timestamp;
 
 impl Collection {
     pub fn card_stats(&mut self, cid: CardId) -> Result<anki_proto::stats::CardStatsResponse> {
@@ -81,7 +82,7 @@ impl Collection {
             }
             CardType::Review | CardType::Learn | CardType::Relearn => (
                 {
-                    if due <= 1_000_000_000 {
+                    if !is_unix_epoch_timestamp(due) {
                         let days_remaining = due - (self.timing_today()?.days_elapsed as i32);
                         let mut due = TimestampSecs::now();
                         due.0 += (days_remaining as i64) * 86_400;

rslib/src/stats/graphs/future_due.rs

@@ -6,6 +6,7 @@ use std::collections::HashMap;
 use anki_proto::stats::graphs_response::FutureDue;
 
 use super::GraphsContext;
+use crate::scheduler::timing::is_unix_epoch_timestamp;
 
 impl GraphsContext {
     pub(super) fn future_due(&self) -> FutureDue {
@@ -15,15 +16,8 @@ impl GraphsContext {
             if c.queue as i8 <= 0 {
                 continue;
             }
-            // The extra original_due check covers lapsed cards, which have their due date
-            // updated on graduation.
-            let intraday = c.is_intraday_learning();
-            let due = if c.is_filtered() && c.original_due != 0 && !intraday {
-                c.original_due
-            } else {
-                c.due
-            };
-            let due_day = if c.is_intraday_learning() {
+            let due = c.original_or_current_due();
+            let due_day = if is_unix_epoch_timestamp(due) {
                 let offset = due as i64 - self.next_day_start.0;
                 (offset / 86_400) as i32
             } else {