Refactor: Full architectural rework

README.md

@@ -124,13 +124,13 @@ print(retrievabilityValue) // 0.9
 ### Custom Parameters
 
 ```swift
-let params = PartialFSRSParameters(
+let config = FSRSConfiguration(
     requestRetention: 0.9,
     maximumInterval: 36500,
     enableFuzz: true,
     enableShortTerm: true
 )
-let f = fsrs<Flashcard>(params: params)
+let f = FSRS<Flashcard>(configuration: config)
 ```
 
 ### Reschedule with History

Sources/Examples/Flashcard.swift

@@ -119,7 +119,7 @@ var card = Flashcard(
 )
 
 // Preview all possible scheduling outcomes
-let scheduling = try fsrs.repeat(card: card, now: Date())
+let scheduling = try fsrs.schedule(card: card, at: Date())
 
 print("If you rate it 'Again':", scheduling[.again]!.card.due)
 print("If you rate it 'Hard':", scheduling[.hard]!.card.due)
@@ -143,4 +143,4 @@ try jsonData.write(to: fileURL)
 
 // Load and continue scheduling
 let loaded = try JSONDecoder().decode(Flashcard.self, from: jsonData)
-let nextReview = try fsrs.next(card: loaded, now: Date(), rating: .good)
+let nextReview = try fsrs.schedule(card: loaded, at: Date(), rating: .good)

Sources/Examples/LoggerExample.swift

@@ -86,7 +86,7 @@ func exampleBasicLogging() {
     // All operations will now be logged
     let card = MyCard()
     do {
-        let result = try fsrs.next(card: card, now: Date(), rating: .good)
+        let result = try fsrs.schedule(card: card, at: Date(), rating: .good)
         print("Next due: \(result.card.due)")
     } catch {
         print("Error: \(error)")
@@ -101,7 +101,7 @@ func exampleFilteredLogging() {
     // Only warnings and errors will be logged
     let card = MyCard()
     do {
-        _ = try fsrs.forget(card: card, now: Date()) // This will log a warning
+        _ = try fsrs.forget(card: card, at: Date()) // This will log a warning
     } catch {
         print("Error: \(error)")
     }
@@ -118,7 +118,7 @@ func exampleFileLogging() {
     // All logs will be written to file
     let card = MyCard()
     do {
-        let recordLog = try fsrs.repeat(card: card, now: Date())
+        let recordLog = try fsrs.schedule(card: card, at: Date())
         print("Logged \(recordLog.count) scenarios to \(logFileURL.path)")
     } catch {
         print("Error: \(error)")
@@ -151,7 +151,7 @@ func exampleCompositeLogging() {
     // Logs will go to both console and file
     let card = MyCard()
     do {
-        _ = try fsrs.next(card: card, now: Date(), rating: .good)
+        _ = try fsrs.schedule(card: card, at: Date(), rating: .good)
     } catch {
         print("Error: \(error)")
     }
@@ -216,7 +216,7 @@ func exampleLogAnalysis() {
 
     for rating in ratings {
         do {
-            let result = try fsrs.next(card: card, now: Date(), rating: rating)
+            let result = try fsrs.schedule(card: card, at: Date(), rating: rating)
             card = result.card
 
             // You'll see detailed logs showing:
@@ -277,7 +277,7 @@ func examplePerformanceMonitoring() {
     // Run multiple operations
     for _ in 0..<10 {
         do {
-            let result = try fsrs.next(card: card, now: Date(), rating: .good)
+            let result = try fsrs.schedule(card: card, at: Date(), rating: .good)
             card = result.card
         } catch {
             print("Error: \(error)")

Sources/FSRS/Core/FSRSAlgorithm.swift → Sources/FSRS/Algorithm/FSRSAlgorithm.swift

@@ -14,25 +14,25 @@
     /// Optional logger for debugging and monitoring
     public var logger: (any FSRSLogger)?
 
-    /// Initialize FSRS algorithm with parameters
+    /// Initialize FSRS algorithm with configuration
     /// - Parameters:
-    ///   - params: Partial FSRS parameters (missing values use defaults)
+    ///   - configuration: FSRS configuration (missing values use defaults)
     ///   - randomProvider: Random provider (optional, uses system random if not provided)
     ///   - logger: Optional logger for debugging and monitoring
     public init(
-        params: PartialFSRSParameters = PartialFSRSParameters(),
+        configuration: FSRSConfiguration = FSRSConfiguration(),
         randomProvider: RandomProvider? = nil,
         logger: (any FSRSLogger)? = nil
     ) {
         self.randomProvider = randomProvider
         self.logger = logger
-        self.parameters = FSRSParametersGenerator.generate(from: params)
+        self.parameters = FSRSParametersGenerator.generate(from: configuration)
         do {
             self.intervalModifier = try FSRSAlgorithm.calculateIntervalModifier(
                 requestRetention: parameters.requestRetention,
                 weights: parameters.weights
             )
             logger?.debug("Algorithm initialized: requestRetention=\(parameters.requestRetention), maximumInterval=\(parameters.maximumInterval), enableFuzz=\(parameters.enableFuzz), enableShortTerm=\(parameters.enableShortTerm)")
         } catch {
             // This should never happen with valid parameters, but handle gracefully
             logger?.error("Failed to calculate interval modifier: \(error)")
@@ -46,7 +46,7 @@
     ///   - stability: Current stability
     /// - Returns: Retrievability (probability of recall)
     public func forgettingCurve(_ elapsedDays: Double, _ stability: Double) -> Double {
-        let calculator = StabilityCalculator(parameters: parameters, logger: logger)
+        let calculator = MemoryStateCalculator(parameters: parameters, logger: logger)
         let result = try? calculator.forgettingCurve(
             elapsedDays: ElapsedDays(unchecked: elapsedDays),
             stability: Stability(unchecked: stability)
@@ -69,20 +69,14 @@
         guard requestRetention > 0 && requestRetention <= 1 else {
             throw FSRSError.invalidRequestRetention(requestRetention)
         }
-        let (decay, factor) = StabilityCalculator.computeDecayFactor(weights)
+        let (decay, factor) = MemoryStateCalculator.computeDecayFactor(weights)
         let result = (pow(requestRetention, 1 / decay) - 1) / factor
         return roundToFixed(result)
     }
 
 
-    // Note: All calculation methods have been extracted to dedicated calculator classes:
-    // - StabilityCalculator: stability-related formulas
-    // - DifficultyCalculator: difficulty-related formulas
+    // Note: All calculation methods live in Algorithm/ directory:
+    // - MemoryStateCalculator: stability + difficulty formulas (unified)
     // - IntervalCalculator: interval calculation and fuzzing
-    //
-    // The old nextState(), initStability(), nextDifficulty(), nextRecallStability(),
-    // nextForgetStability(), nextShortTermStability(), nextInterval(), and applyFuzz()
-    // methods have been removed as they are now implemented in the calculator classes.
-    //
-    // Schedulers now use these calculators directly via BaseScheduler.
+    // - IntervalConstraintApplier: interval ordering constraints
 }