Re-expose legacy RMSE calculations

Closes #4143

proto/anki/scheduler.proto

@@ -56,6 +56,8 @@ service SchedulerService {
   rpc SimulateFsrsReview(SimulateFsrsReviewRequest)
       returns (SimulateFsrsReviewResponse);
   rpc EvaluateParams(EvaluateParamsRequest) returns (EvaluateParamsResponse);
+  rpc EvaluateParamsLegacy(EvaluateParamsLegacyRequest)
+      returns (EvaluateParamsResponse);
   rpc ComputeMemoryState(cards.CardId) returns (ComputeMemoryStateResponse);
   // The number of days the calculated interval was fuzzed by on the previous
   // review (if any). Utilized by the FSRS add-on.
@@ -442,6 +444,12 @@ message EvaluateParamsRequest {
   uint32 num_of_relearning_steps = 3;
 }
 
+message EvaluateParamsLegacyRequest {
+  repeated float params = 1;
+  string search = 2;
+  int64 ignore_revlogs_before_ms = 3;
+}
+
 message EvaluateParamsResponse {
   float log_loss = 1;
   float rmse_bins = 2;

rslib/src/scheduler/fsrs/params.rs

@@ -299,6 +299,33 @@ impl Collection {
                 .is_ok()
         })?)
     }
+
+    pub fn evaluate_params_legacy(
+        &mut self,
+        params: &Params,
+        search: &str,
+        ignore_revlogs_before: TimestampMillis,
+    ) -> Result<ModelEvaluation> {
+        let timing = self.timing_today()?;
+        let mut anki_progress = self.new_progress_handler::<ComputeParamsProgress>();
+        let guard = self.search_cards_into_table(search, SortMode::NoOrder)?;
+        let revlogs: Vec<RevlogEntry> = guard
+            .col
+            .storage
+            .get_revlog_entries_for_searched_cards_in_card_order()?;
+        let (items, review_count) =
+            fsrs_items_for_training(revlogs, timing.next_day_at, ignore_revlogs_before);
+        anki_progress.state.reviews = review_count as u32;
+        let fsrs = FSRS::new(Some(params))?;
+        Ok(fsrs.evaluate(items, |ip| {
+            anki_progress
+                .update(false, |p| {
+                    p.total_iterations = ip.total as u32;
+                    p.current_iteration = ip.current as u32;
+                })
+                .is_ok()
+        })?)
+    }
 }
 
 #[derive(Default, Clone, Copy, Debug)]

rslib/src/scheduler/service/mod.rs

@@ -307,6 +307,21 @@ impl crate::services::SchedulerService for Collection {
         })
     }
 
+    fn evaluate_params_legacy(
+        &mut self,
+        input: scheduler::EvaluateParamsLegacyRequest,
+    ) -> Result<scheduler::EvaluateParamsResponse> {
+        let ret = self.evaluate_params_legacy(
+            &input.params,
+            &input.search,
+            input.ignore_revlogs_before_ms.into(),
+        )?;
+        Ok(scheduler::EvaluateParamsResponse {
+            log_loss: ret.log_loss,
+            rmse_bins: ret.rmse_bins,
+        })
+    }
+
     fn get_optimal_retention_parameters(
         &mut self,
         input: scheduler::GetOptimalRetentionParametersRequest,