Added #

• Core Models

  • ReviewCard - Complete card state with phase tracking, statistics, and metadata support
  • ReviewQuality - Type-safe enum with Again, Hard, Good, Easy ratings
  • SRSSettings - 17+ fully configurable parameters (no dead code!)
  • ReviewResult - Immutable review outcome with transition metadata
  • IntervalPreview - Preview intervals for UI button display

• Algorithms

  • SM2Algorithm - Classic SuperMemo 2 implementation
  • SM2PlusAlgorithm - Enhanced SM-2 with overdue bonus calculation
  • CustomAlgorithm - Build your own with interval and ease callbacks
  • SRSAlgorithm - Abstract interface for custom implementations

• Spaced Repetition Engine

  • SpacedRepetitionEngine - Main API for card management
  • Card creation, review processing, batch operations
  • Card suspension, reset, and rescheduling
  • Due card filtering and priority sorting

• Review Scheduler

  • ReviewScheduler - Session management with configurable limits
  • SchedulerConfig - Configure new cards, reviews per session
  • Priority-based card ordering (overdue > learning > new)
  • Multiple scheduling modes (interleaved, new first, review first)

• Statistics

  • CardStatistics - Per-card metrics (success rate, stability, difficulty)
  • DeckStatistics - Aggregate deck analytics
  • MasteryCalculator - Mastery levels from Not Started to Expert
  • Streak tracking, retention analysis, workload estimation

• Utilities

  • IntervalFormatter - Human-readable interval formatting (1m, 10m, 1d, 7d)
  • SRSValidator - Input validation for all parameters
  • SRSSerializer - Full deck import/export support

• Configuration Presets

  • SRSSettings.anki() - Standard Anki defaults
  • SRSSettings.supermemo() - Original SuperMemo settings
  • SRSSettings.aggressive() - Faster learning curve
  • SRSSettings.relaxed() - Lower review burden

• Documentation

  • Comprehensive README with examples
  • Full API documentation
  • Working example application

Technical Highlights #

• Pure Dart - no dependencies, works everywhere (Flutter, CLI, server)
• 138+ unit and integration tests
• All settings are functional (fixed 9 dead code issues from original)
• Zero hardcoded algorithm values
• Full JSON serialization support
• Immutable card updates

Credits #

• Based on the SM-2 algorithm by Piotr Wozniak
• Inspired by Anki and SuperMemo
• Extracted and improved from the Revisable app