no chart

lib/data/default_deck.dart

@@ -156,42 +156,43 @@ class DefaultDeck {
     final now = DateTime.now();
     
     // Create mock attempt history (4 previous attempts)
+    // Unknown percentage decreases over time as more questions become known
     final attemptHistory = [
-      // First attempt - 6/10 correct (60%)
+      // First attempt - 6/10 correct (60%), ~85% unknown (17/20 questions)
       AttemptHistoryEntry(
         timestamp: now.subtract(const Duration(days: 7)).millisecondsSinceEpoch,
         totalQuestions: 10,
-        correctAnswers: 6,
-        incorrectAnswers: 4,
-        skippedAnswers: 0,
-        timeSpentSeconds: 245,
+        correctCount: 6,
+        percentageCorrect: 60.0,
+        timeSpent: 245000, // milliseconds
+        unknownPercentage: 85.0, // 17 out of 20 questions unknown
       ),
-      // Second attempt - 7/10 correct (70%)
+      // Second attempt - 7/10 correct (70%), ~70% unknown (14/20 questions)
       AttemptHistoryEntry(
         timestamp: now.subtract(const Duration(days: 5)).millisecondsSinceEpoch,
         totalQuestions: 10,
-        correctAnswers: 7,
-        incorrectAnswers: 3,
-        skippedAnswers: 0,
-        timeSpentSeconds: 198,
+        correctCount: 7,
+        percentageCorrect: 70.0,
+        timeSpent: 198000, // milliseconds
+        unknownPercentage: 70.0, // 14 out of 20 questions unknown
       ),
-      // Third attempt - 8/10 correct (80%)
+      // Third attempt - 8/10 correct (80%), ~55% unknown (11/20 questions)
       AttemptHistoryEntry(
         timestamp: now.subtract(const Duration(days: 3)).millisecondsSinceEpoch,
         totalQuestions: 10,
-        correctAnswers: 8,
-        incorrectAnswers: 2,
-        skippedAnswers: 0,
-        timeSpentSeconds: 187,
+        correctCount: 8,
+        percentageCorrect: 80.0,
+        timeSpent: 187000, // milliseconds
+        unknownPercentage: 55.0, // 11 out of 20 questions unknown
       ),
-      // Fourth attempt - 9/10 correct (90%)
+      // Fourth attempt - 9/10 correct (90%), ~45% unknown (9/20 questions)
       AttemptHistoryEntry(
         timestamp: now.subtract(const Duration(days: 1)).millisecondsSinceEpoch,
         totalQuestions: 10,
-        correctAnswers: 9,
-        incorrectAnswers: 1,
-        skippedAnswers: 0,
-        timeSpentSeconds: 165,
+        correctCount: 9,
+        percentageCorrect: 90.0,
+        timeSpent: 165000, // milliseconds
+        unknownPercentage: 45.0, // 9 out of 20 questions unknown
       ),
     ];