Use FSRS difficulty when sorting by ease

ftl/core/deck-config.ftl

@@ -203,6 +203,8 @@ deck-config-sort-order-ascending-intervals = Ascending intervals
 deck-config-sort-order-descending-intervals = Descending intervals
 deck-config-sort-order-ascending-ease = Ascending ease
 deck-config-sort-order-descending-ease = Descending ease
+deck-config-sort-order-ascending-difficulty = Ascending difficulty
+deck-config-sort-order-descending-difficulty = Descending difficulty
 deck-config-sort-order-relative-overdueness = Relative overdueness
 deck-config-display-order-will-use-current-deck =
     Anki will use the display order from the deck you 

rslib/src/scheduler/queue/builder/gathering.rs

@@ -40,6 +40,7 @@ impl QueueBuilder {
             self.context.timing.days_elapsed,
             self.context.sort_options.review_order,
             kind,
+            self.context.fsrs,
             |card| {
                 if self.limits.root_limit_reached(LimitKind::Review) {
                     return Ok(false);

rslib/src/scheduler/queue/builder/mod.rs

@@ -118,6 +118,7 @@ struct Context {
     sort_options: QueueSortOptions,
     seen_note_ids: HashMap<NoteId, BuryMode>,
     deck_map: HashMap<DeckId, Deck>,
+    fsrs: bool,
 }
 
 impl QueueBuilder {
@@ -150,6 +151,7 @@ impl QueueBuilder {
                 sort_options,
                 seen_note_ids: HashMap::new(),
                 deck_map,
+                fsrs: col.get_config_bool(BoolKey::Fsrs),
             },
         })
     }

rslib/src/storage/card/mod.rs

@@ -253,12 +253,13 @@ impl super::SqliteStorage {
         day_cutoff: u32,
         order: ReviewCardOrder,
         kind: DueCardKind,
+        fsrs: bool,
         mut func: F,
     ) -> Result<()>
     where
         F: FnMut(DueCard) -> Result<bool>,
     {
-        let order_clause = review_order_sql(order, day_cutoff);
+        let order_clause = review_order_sql(order, day_cutoff, fsrs);
         let mut stmt = self.db.prepare_cached(&format!(
             "{} order by {}",
             include_str!("due_cards.sql"),
@@ -693,7 +694,13 @@ enum ReviewOrderSubclause {
     IntervalsDescending,
     EaseAscending,
     EaseDescending,
-    RelativeOverdueness { today: u32 },
+    /// FSRS
+    DifficultyAscending,
+    /// FSRS
+    DifficultyDescending,
+    RelativeOverdueness {
+        today: u32,
+    },
 }
 
 impl fmt::Display for ReviewOrderSubclause {
@@ -707,6 +714,8 @@ impl fmt::Display for ReviewOrderSubclause {
             ReviewOrderSubclause::IntervalsDescending => "ivl desc",
             ReviewOrderSubclause::EaseAscending => "factor asc",
             ReviewOrderSubclause::EaseDescending => "factor desc",
+            ReviewOrderSubclause::DifficultyAscending => "extract_fsrs_variable(data, 'd') asc",
+            ReviewOrderSubclause::DifficultyDescending => "extract_fsrs_variable(data, 'd') desc",
             ReviewOrderSubclause::RelativeOverdueness { today } => {
                 temp_string = format!("ivl / cast({today}-due+0.001 as real)", today = today);
                 &temp_string
@@ -716,15 +725,25 @@ impl fmt::Display for ReviewOrderSubclause {
     }
 }
 
-fn review_order_sql(order: ReviewCardOrder, today: u32) -> String {
+fn review_order_sql(order: ReviewCardOrder, today: u32, fsrs: bool) -> String {
     let mut subclauses = match order {
         ReviewCardOrder::Day => vec![ReviewOrderSubclause::Day],
         ReviewCardOrder::DayThenDeck => vec![ReviewOrderSubclause::Day, ReviewOrderSubclause::Deck],
         ReviewCardOrder::DeckThenDay => vec![ReviewOrderSubclause::Deck, ReviewOrderSubclause::Day],
         ReviewCardOrder::IntervalsAscending => vec![ReviewOrderSubclause::IntervalsAscending],
         ReviewCardOrder::IntervalsDescending => vec![ReviewOrderSubclause::IntervalsDescending],
-        ReviewCardOrder::EaseAscending => vec![ReviewOrderSubclause::EaseAscending],
+        ReviewCardOrder::EaseAscending => {
-        ReviewCardOrder::EaseDescending => vec![ReviewOrderSubclause::EaseDescending],
+            vec![if fsrs {
+                ReviewOrderSubclause::DifficultyDescending
+            } else {
+                ReviewOrderSubclause::EaseAscending
+            }]
+        }
+        ReviewCardOrder::EaseDescending => vec![if fsrs {
+            ReviewOrderSubclause::DifficultyAscending
+        } else {
+            ReviewOrderSubclause::EaseDescending
+        }],
         ReviewCardOrder::RelativeOverdueness => {
             vec![ReviewOrderSubclause::RelativeOverdueness { today }]
         }

ts/deck-options/DisplayOrder.svelte

@@ -32,6 +32,7 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 
     const config = state.currentConfig;
     const defaults = state.defaults;
+    const fsrs = state.fsrs;
 
     const currentDeck = "\n\n" + tr.deckConfigDisplayOrderWillUseCurrentDeck();
 
@@ -191,7 +192,7 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
             <EnumSelectorRow
                 bind:value={$config.reviewOrder}
                 defaultValue={defaults.reviewOrder}
-                choices={reviewOrderChoices()}
+                choices={reviewOrderChoices($fsrs)}
             >
                 <SettingTitle
                     on:click={() =>

ts/deck-options/choices.ts

@@ -62,7 +62,7 @@ export function newSortOrderChoices(): Choice<DeckConfig_Config_NewCardSortOrder
     ];
 }
 
-export function reviewOrderChoices(): Choice<DeckConfig_Config_ReviewCardOrder>[] {
+export function reviewOrderChoices(fsrs: boolean): Choice<DeckConfig_Config_ReviewCardOrder>[] {
     return [
         {
             label: tr.deckConfigSortOrderDueDateThenRandom(),
@@ -85,11 +85,11 @@ export function reviewOrderChoices(): Choice<DeckConfig_Config_ReviewCardOrder>[
             value: DeckConfig_Config_ReviewCardOrder.INTERVALS_DESCENDING,
         },
         {
-            label: tr.deckConfigSortOrderAscendingEase(),
+            label: fsrs ? tr.deckConfigSortOrderDescendingDifficulty() : tr.deckConfigSortOrderAscendingEase(),
             value: DeckConfig_Config_ReviewCardOrder.EASE_ASCENDING,
         },
         {
-            label: tr.deckConfigSortOrderDescendingEase(),
+            label: fsrs ? tr.deckConfigSortOrderAscendingDifficulty() : tr.deckConfigSortOrderDescendingEase(),
             value: DeckConfig_Config_ReviewCardOrder.EASE_DESCENDING,
         },
         {