milestone 9

README.md

@@ -120,9 +120,9 @@ Implement ALL models exactly as specified in the Prisma schema.
 | 5 | Collections | User collections + global HSK collections | ✅ Complete |
 | 5 | Hanzi Search | Search interface and detail views | ✅ Complete |
 | 6 | SM-2 Algorithm | Core learning algorithm + tests | ✅ Complete |
-| 7-8 | Learning UI | Learning session interface | 🔄 Next |
-| 9 | Dashboard | Progress tracking and visualizations | |
-| 10 | UI Polish | Responsive design, dark mode | |
+| 7-8 | Learning UI | Learning session interface | ✅ Complete |
+| 9 | Dashboard | Progress tracking and visualizations | ✅ Complete |
+| 10 | UI Polish | Responsive design, dark mode | 🔄 Next |
 | 11 | Testing & Docs | Complete test coverage | |
 | 12 | Deployment | Production deployment + data import | |
 
@@ -251,6 +251,120 @@ Implement ALL models exactly as specified in the Prisma schema.
 - `generateWrongAnswers()` - Generate 3 incorrect options from same HSK level
 - `shuffleOptions()` - Fisher-Yates shuffle for randomizing answer positions
 
+### ✅ Milestone 7-8 Completed Features
+
+**Learning Interface:**
+- ✅ Learning session page (`/learn/[collectionId]`) with dynamic routing
+- ✅ Large hanzi display (text-9xl) for easy reading
+- ✅ 4 pinyin answer options in 2x2 grid layout
+- ✅ Auto-submit after answer selection (100ms delay)
+- ✅ Progress bar showing "Card X of Y" with percentage
+- ✅ Green/red feedback overlay with checkmark/X icons
+- ✅ Correct answer display for incorrect responses
+- ✅ English meaning display after answer submission
+- ✅ Session summary screen with statistics:
+  - Total cards, correct/incorrect counts
+  - Accuracy percentage
+  - Session duration in minutes
+- ✅ Keyboard shortcuts:
+  - Press 1-4 to select answer options
+  - Press Space to continue after feedback
+- ✅ Loading and error states
+- ✅ Responsive mobile-first design
+
+**Learning Server Actions:**
+- ✅ `startLearningSession()` - Initialize session with card selection and answer generation
+- ✅ `submitAnswer()` - Record answer and update SM-2 progress
+- ✅ `endSession()` - Mark session complete and return summary
+- ✅ `getDueCards()` - Count cards due today/this week
+- ✅ `updateCardDifficulty()` - Manual difficulty override (EASY/MEDIUM/HARD/SUSPENDED)
+- ✅ `removeFromLearning()` - Suspend card from learning
+
+**SM-2 Integration:**
+- ✅ Automatic progress tracking with SM-2 algorithm
+- ✅ Due card selection with priority sorting
+- ✅ New card introduction when insufficient due cards
+- ✅ Two-stage card randomization:
+  - Random tiebreaker for equal-priority cards during selection
+  - Final shuffle of selected cards for presentation
+- ✅ Wrong answer generation from same HSK level
+- ✅ Session tracking in database (LearningSession, SessionReview)
+
+**Navigation Integration:**
+- ✅ "Start Learning" button on collection detail pages
+- ✅ "Learn All" option on dashboard
+- ✅ Routes: `/learn/all` and `/learn/[collectionId]`
+
+**Files Created:**
+- `src/actions/learning.ts` - Learning session Server Actions (700+ lines)
+- `src/app/(app)/learn/[collectionId]/page.tsx` - Learning session UI (340+ lines)
+
+**Enhancements:**
+- ✅ English meaning display for vocabulary reinforcement
+- ✅ Randomized card presentation to prevent demoralization
+- ✅ All 38 SM-2 algorithm tests passing with 98.92% coverage
+
+### ✅ Milestone 9 Completed Features
+
+**Dashboard Enhancements:**
+- ✅ Real-time statistics widgets replacing hardcoded zeros
+- ✅ Due cards counter (now, today, this week)
+- ✅ Total learned cards count
+- ✅ Daily goal progress tracker (reviewed today / daily goal)
+- ✅ Learning streak calculation (consecutive days with reviews)
+- ✅ Recent activity section showing last 5 learning sessions
+- ✅ Session cards with accuracy percentages and collection names
+- ✅ Navigation link to progress page
+
+**Progress Page:**
+- ✅ Comprehensive progress page at `/progress`
+- ✅ Date range selector (7/30/90/365 days)
+- ✅ Summary statistics cards:
+  - Cards reviewed in selected period
+  - Overall accuracy percentage
+  - Total cards in learning
+  - Average session length (minutes)
+- ✅ Daily Activity bar chart (Recharts):
+  - Stacked correct/incorrect reviews by date
+  - Interactive tooltips with detailed counts
+- ✅ Accuracy Trend line chart:
+  - Daily accuracy percentage over time
+  - Smooth line visualization
+- ✅ Session history table:
+  - Sortable by date
+  - Shows collection, cards reviewed, accuracy, session length
+  - Responsive design
+- ✅ Dark mode compatible color schemes
+
+**Progress Server Actions:**
+- ✅ `getStatistics()` - Returns due cards, total learned, daily goal, streak
+- ✅ `getUserProgress()` - Returns overview stats and daily activity breakdown
+- ✅ `getLearningSessions()` - Returns paginated session history
+- ✅ `getHanziProgress()` - Individual hanzi progress details
+- ✅ `resetHanziProgress()` - Reset card to initial state
+
+**Statistics Calculations:**
+- ✅ Streak calculation algorithm (consecutive days with reviews)
+- ✅ Daily activity aggregation using Map for efficient grouping
+- ✅ Accuracy calculations (correct / total reviews)
+- ✅ Average session length (total duration / session count)
+- ✅ Date range filtering for historical data
+
+**Recharts Integration:**
+- ✅ Installed and configured Recharts library
+- ✅ Line chart component for trends
+- ✅ Bar chart component with stacking for activity
+- ✅ Responsive containers for mobile/desktop
+- ✅ Custom tooltips and legends
+
+**Files Created:**
+- `src/actions/progress.ts` - Progress tracking Server Actions (550+ lines)
+- `src/app/(app)/progress/page.tsx` - Progress visualization page (380+ lines)
+
+**Files Modified:**
+- `src/app/(app)/dashboard/page.tsx` - Added real statistics and recent activity
+- Navigation updated across dashboard and progress pages
+
 ## 🎨 Naming Conventions
 
 **User-Facing:**