try add example

.github/workflows/CI.yml

@@ -51,5 +51,5 @@ jobs:
       - name: Flutter pub get
         run: flutter pub get
 
-      # - name: Flutter analyze
-      #   run: flutter analyze
+      - name: Flutter analyze
+        run: flutter analyze

lib/example.dart

@@ -0,0 +1,30 @@
+import 'src/rust/frb_generated.dart';
+import 'src/rust/api/fsrs_api.dart';
+
+Future<void> example() async {
+  // Initialize the Rust bridge
+  await RustLib.init();
+
+  // Create a new FSRS instance with default parameters
+  final fsrs = await Fsrs.newInstance(
+    parameters: List<double>.from([
+      0.4, 0.6, 2.4, 5.8, 4.93, 0.94, 0.86, 0.01, 1.49, 0.14, 0.94,
+      2.18, 0.05, 0.34, 1.26, 0.29, 2.61, 0.05, 0.4
+    ]),
+  );
+
+  // Example: Calculate next states for a new item
+  // Initial review with no prior memory state
+  final nextStates = fsrs.nextStates(
+    currentMemoryState: null, // No prior state for new items
+    desiredRetention: 0.9, // 90% retention target
+    daysElapsed: 0, // First review
+  );
+
+  // Print the results
+  print('Next states calculated:');
+  print('Again state: ${(nextStates.again).interval} days');
+  print('Hard  state: ${(nextStates.hard).interval} days');
+  print('Good  state: ${(nextStates.good).interval} days');
+  print('Easy  state: ${(nextStates.easy).interval} days');
+}

rust/src/api/fsrs_api.rs

@@ -6,11 +6,13 @@ pub fn init_app() {
 }
 
 #[derive(Debug, Clone)]
+#[frb(opaque)]
 pub struct FSRS(fsrs::FSRS);
 impl FSRS {
     pub fn new(parameters: Vec<f32>) -> Self {
         Self(fsrs::FSRS::new(Some(&parameters)).unwrap())
     }
+    #[frb(sync)]
     pub fn next_states(
         &self,
         current_memory_state: Option<MemoryState>,
@@ -57,6 +59,7 @@ impl FSRS {
     }
 }
 #[derive(Debug, Clone)]
+#[frb(opaque)]
 pub struct MemoryState(fsrs::MemoryState);
 
 impl MemoryState {
@@ -69,29 +72,37 @@ impl MemoryState {
 }
 
 #[derive(Debug, Clone)]
+#[frb(opaque)]
 pub struct NextStates(fsrs::NextStates);
 impl NextStates {
+    #[frb(sync, getter)]
     pub fn hard(&self) -> ItemState {
         ItemState(self.0.hard.clone())
     }
+    #[frb(sync, getter)]
     pub fn good(&self) -> ItemState {
         ItemState(self.0.good.clone())
     }
+    #[frb(sync, getter)]
     pub fn easy(&self) -> ItemState {
         ItemState(self.0.easy.clone())
     }
+    #[frb(sync, getter)]
     pub fn again(&self) -> ItemState {
         ItemState(self.0.again.clone())
     }
 }
 
 #[derive(Debug, Clone)]
+#[frb(opaque)]
 pub struct ItemState(fsrs::ItemState);
 
 impl ItemState {
+    #[frb(sync, getter)]
     pub fn memory(&self) -> MemoryState {
         MemoryState(self.0.memory.clone())
     }
+    #[frb(sync, getter)]
     pub fn interval(&self) -> f32 {
         self.0.interval
     }
@@ -101,9 +112,11 @@ impl ItemState {
 }
 
 #[derive(Debug, Clone)]
+#[frb(opaque)]
 pub struct FSRSItem(fsrs::FSRSItem);
 
 impl FSRSItem {
+    #[frb(sync)]
     pub fn new(reviews: Vec<FSRSReview>) -> Self {
         Self(fsrs::FSRSItem {
             reviews: reviews.iter().map(|x| x.0).collect(),
@@ -133,9 +146,11 @@ impl FSRSItem {
 }
 
 #[derive(Debug, Clone)]
+#[frb(opaque)]
 pub struct FSRSReview(fsrs::FSRSReview);
 
 impl FSRSReview {
+    #[frb(sync)]
     pub fn new(rating: u32, delta_t: u32) -> Self {
         Self(fsrs::FSRSReview { rating, delta_t })
     }