Add spaced repetition flashcard mode

Author: wendelinwemhoener

META-INF/MANIFEST.MF

@@ -0,0 +1,3 @@
+Manifest-Version: 1.0
+Main-Class: seedu.duke.Duke
+

data/flashcards/flashcard.txt

@@ -0,0 +1 @@
+3 | Hello | Duke | - | - | -

src/main/java/seedu/duke/flashcard/Flashcard.java

@@ -2,26 +2,21 @@
 
 package seedu.duke.flashcard;
 
-import seedu.duke.flashcard.review.FlashcardReview;
-
 import java.time.LocalDateTime;
 import java.util.ArrayList;
 
 public class Flashcard {
     private static int globalMaxId = 1;
     private String frontText;
     private String backText;
-    private ArrayList<FlashcardReview> reviews;
-    private LocalDateTime lastReviewOn;
     private int id;
+    private int difficulty;
 
     public Flashcard(String frontText, String backText) {
         this.frontText = frontText;
         this.backText = backText;
 
-        reviews = new ArrayList<>();
-
-        lastReviewOn = null;
+        difficulty = 5;  // initial difficulty of a flashcard
 
         globalMaxId += 1;
         id = globalMaxId;
@@ -39,10 +34,6 @@ public static void calculateAndUpdateGlobalMaxId(FlashcardList flashcardList) {
         globalMaxId = currentMax + 1;
     }
 
-    public void setLastReviewOn(LocalDateTime lastReviewOn) {
-        this.lastReviewOn = lastReviewOn;
-    }
-
     public String getFrontText() {
         return frontText;
     }
@@ -56,25 +47,23 @@ public String getBackText() {
     }
 
     //@@author junhyeong0411
-
-    public ArrayList<FlashcardReview> getReviews(){
-        return reviews;
-    }
-
     public void setId (int id) {
         this.id = id;
     }
 
 
-    //@@author WenderlinWemhoener
+    //@@author wendelinwemhoener
     public String toString() {
         return "front text: " + frontText + System.lineSeparator()
                 + "back text: " + backText + System.lineSeparator()
-                + "next review due on: " + lastReviewOn + System.lineSeparator()
                 + "id: " + id + System.lineSeparator();
     }
 
-    public void addReview(FlashcardReview flashcardReview) {
-        reviews.add(flashcardReview);
+    public void applyDifficultyChange(int difficultyChange) {
+        difficulty += difficultyChange;
+    }
+
+    public int getDifficulty() {
+        return difficulty;
     }
 }

src/main/java/seedu/duke/flashcard/FlashcardStorage.java

@@ -1,7 +1,5 @@
 package seedu.duke.flashcard;
 
-import seedu.duke.flashcard.review.FlashcardReview;
-
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.FileWriter;

src/main/java/seedu/duke/flashcard/FlashcardStorageParser.java

@@ -1,8 +1,5 @@
 package seedu.duke.flashcard;
 
-import seedu.duke.flashcard.review.FlashcardReview;
-import seedu.duke.flashcard.review.ReviewDifficulty;
-
 import java.time.LocalDateTime;
 import java.util.ArrayList;
 

src/main/java/seedu/duke/flashcard/command/StartReviewCommand.java

@@ -4,7 +4,6 @@
 
 import seedu.duke.flashcard.FlashcardList;
 import seedu.duke.flashcard.review.RandomReviewMode;
-import seedu.duke.flashcard.review.ReviewByTagMode;
 import seedu.duke.flashcard.review.ReviewMode;
 import seedu.duke.flashcard.review.SpacedRepetitionReviewMode;
 
@@ -14,7 +13,7 @@
 
 public class StartReviewCommand extends DualFlashcardCommand {
     private final ArrayList<String> choices = new ArrayList<>(Arrays.asList(
-            "a", "b", "c"));
+            "a", "b"));
 
     public StartReviewCommand(String input) {
         this.input = input;
@@ -27,7 +26,6 @@ private String getUserChoiceReviewMode(Scanner scanner) {
         System.out.println("    How do you want to review your flashcards?");
         System.out.println("        a) random mode");
         System.out.println("        b) spaced repetition mode");
-        System.out.println("        c) review by tag mode");
 
         return scanner.nextLine();
     }
@@ -37,8 +35,8 @@ protected void executeBeginnerMode(Scanner scanner,
         String choice = getUserChoiceReviewMode(scanner);
 
         while (!choices.contains(choice.toLowerCase())) {
-            System.out.println("    Invalid choice! Your choice must be a, b " +
-                    "or c! Please try again.");
+            System.out.println("    Invalid choice! Your choice must be a or " +
+                    "b! Please try again.");
 
             choice = getUserChoiceReviewMode(scanner);
         }
@@ -54,8 +52,8 @@ protected void executeExpertMode(Scanner scanner,
             String choice = commandParts[2].toLowerCase();
 
             if (!choices.contains(choice)) {
-                System.out.println("    Invalid choice! Your choice must be a, b " +
-                        "or c! Please try again.");
+                System.out.println("    Invalid choice! Your choice must be a" +
+                        " or b! Please try again.");
                 return;
             }
 
@@ -65,21 +63,15 @@ protected void executeExpertMode(Scanner scanner,
                     "flashcards REVIEW_MODE'");
             System.out.println("    Please try again.");
         }
-
-
     }
 
     private void startReview(Scanner scanner,
                              FlashcardList flashcardList,
                              String choice) {
         ReviewMode reviewMode = createReviewMode(choice.toLowerCase(), flashcardList);
 
-        if (reviewMode instanceof RandomReviewMode) {
-            reviewMode.startReviewSession(scanner);
-        } else {
-            System.out.println("    This review mode hasn't yet been " +
-                    "implemented. Sorry!");
-        }
+        reviewMode.startReviewSession(scanner);
+
     }
 
     private ReviewMode createReviewMode(String choice, FlashcardList flashcardList) {
@@ -89,8 +81,6 @@ private ReviewMode createReviewMode(String choice, FlashcardList flashcardList)
             reviewMode = new RandomReviewMode(flashcardList);
         } else if (choice.equals("b")) {
             reviewMode = new SpacedRepetitionReviewMode(flashcardList);
-        } else if (choice.equals("c")) {
-            reviewMode = new ReviewByTagMode(flashcardList);
         }
 
         assert reviewMode != null;

src/main/java/seedu/duke/flashcard/review/FlashcardReview.java

@@ -5,7 +5,6 @@
 import seedu.duke.flashcard.Flashcard;
 import seedu.duke.flashcard.FlashcardList;
 
-import java.time.LocalDateTime;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Scanner;
@@ -21,8 +20,13 @@ public ReviewMode(FlashcardList flashcardList) {
 
     public void startReviewSession(Scanner scanner) {
         System.out.println("    You have started a review session in "
-                + getReviewModeName());
-        System.out.println();
+                + getReviewModeName() + System.lineSeparator());
+
+        if (flashcardList.isEmpty()) {
+            System.out.println("    You have no flashcards to review!");
+            System.out.println("    Add some flashcards and try again.");
+            return;
+        }
 
         while (true) {
             Flashcard flashcardToReview = pickFlashcard();
@@ -38,9 +42,9 @@ public void startReviewSession(Scanner scanner) {
             System.out.println("    The actual back text is: " + flashcardToReview.getBackText());
             System.out.println();
 
-            letUserRateReviewDifficulty(scanner, flashcardToReview);
-
-            flashcardToReview.setLastReviewOn(LocalDateTime.now());
+            if (getReviewModeName().equals("spaced repetition mode")) {
+                letUserRateReviewDifficulty(scanner, flashcardToReview);
+            }
         }
 
         System.out.println("    Success! You have ended this review session.");
@@ -78,21 +82,19 @@ protected void letUserRateReviewDifficulty(Scanner scanner,
             choice = scanner.nextLine();
         }
 
-        ReviewDifficulty reviewDifficulty;
+        int difficultyChange;
         switch (choice.toLowerCase()) {
         case "e":
-            reviewDifficulty = ReviewDifficulty.EASY;
+            difficultyChange = -1;
             break;
         case "m":
-            reviewDifficulty = ReviewDifficulty.MODERATE;
+            difficultyChange = 0;
             break;
         default:
-            reviewDifficulty = ReviewDifficulty.HARD;
+            difficultyChange = +1;
             break;
         }
 
-        FlashcardReview flashcardReview =
-                new FlashcardReview(LocalDateTime.now(), reviewDifficulty);
-        flashcard.addReview(flashcardReview);
+        flashcard.applyDifficultyChange(difficultyChange);
     }
 }