Refactor rating logic in RevlogEntry and update related scheduling functions

This commit introduces a new `has_rating` method in the `RevlogEntry` struct to encapsulate the logic for checking if an entry has a rating. The scheduling logic in `params.rs` and the calculation of normal answer counts in `card.rs` have been updated to use this new method, enhancing code clarity and maintainability.

rslib/src/revlog/mod.rs

@@ -102,12 +102,16 @@ impl RevlogEntry {
         self.review_kind == RevlogReviewKind::Filtered && self.ease_factor == 0
     }
 
+    pub(crate) fn has_rating(&self) -> bool {
+        self.button_chosen > 0
+    }
+
     /// Returns true if the review entry is not manually rescheduled and not
     /// cramming. Used to filter out entries that shouldn't be considered
     /// for statistics and scheduling.
     pub(crate) fn has_rating_and_affects_scheduling(&self) -> bool {
         // not rescheduled/set due date/reset
-        self.button_chosen > 0
+        self.has_rating()
             // not cramming
             && !self.is_cramming()
     }

rslib/src/scheduler/fsrs/params.rs

@@ -400,7 +400,7 @@ pub(crate) fn reviews_for_fsrs(
         // For incomplete review histories, initial memory state is based on the first
         // user-graded review after the cutoff date with interval >= 1d.
         let within_cutoff = entry.id.0 > ignore_revlogs_before.0;
-        let user_graded = matches!(entry.button_chosen, 1..=4);
+        let user_graded = entry.has_rating();
         let interday = entry.interval >= 1 || entry.interval <= -86400;
         if user_graded && within_cutoff && interday {
             first_user_grade_idx = Some(index);
@@ -469,16 +469,7 @@ pub(crate) fn reviews_for_fsrs(
     }
 
     // Filter out unwanted entries
-    entries.retain(|entry| {
-        !(
-            // set due date, reset or rescheduled
-            (entry.review_kind == RevlogReviewKind::Manual || entry.button_chosen == 0)
-            || // cram
-            entry.is_cramming()
-            || // rescheduled
-            (entry.review_kind == RevlogReviewKind::Rescheduled)
-        )
-    });
+    entries.retain(|entry| entry.has_rating_and_affects_scheduling());
 
     // Compute delta_t for each entry
     let delta_ts = iter::once(0)

rslib/src/stats/card.rs

@@ -187,7 +187,7 @@ impl Collection {
 }
 
 fn average_and_total_secs_strings(revlog: &[RevlogEntry]) -> (f32, f32) {
-    let normal_answer_count = revlog.iter().filter(|r| r.button_chosen > 0).count();
+    let normal_answer_count = revlog.iter().filter(|r| r.has_rating()).count();
     let total_secs: f32 = revlog
         .iter()
         .map(|entry| (entry.taken_millis as f32) / 1000.0)