Part six

src/flashcards/ActionsLogger.java

@@ -0,0 +1,25 @@
+package flashcards;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class ActionsLogger {
+
+  private List<String> logs;
+
+  public ActionsLogger() {
+    this.logs = new ArrayList<>();
+  }
+
+  public List<String> getLogs() {
+    return logs;
+  }
+
+  public void log(String action) {
+    logs.add(action);
+  }
+
+  public void clear() {
+    logs.clear();
+  }
+}

src/flashcards/Flashcards.java

@@ -0,0 +1,77 @@
+package flashcards;
+
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+public class Flashcards {
+
+  private Map<String, String> cardToDefinition;
+  private Map<String, String> definitionToCard;
+
+  private Map<String, Integer> stats;
+
+  private boolean terminated;
+
+  public Flashcards() {
+    this.cardToDefinition = new LinkedHashMap<>();
+    this.definitionToCard = new LinkedHashMap<>();
+    this.stats = new HashMap<>();
+    this.terminated = false;
+  }
+
+  public void addCard(String card, String definition) {
+    cardToDefinition.put(card, definition);
+    definitionToCard.put(definition, card);
+  }
+
+  public void removeCard(String card) {
+    String def = cardToDefinition.get(card);
+    definitionToCard.remove(def);
+    cardToDefinition.remove(card);
+  }
+
+  public boolean existsCard(String card) {
+    return cardToDefinition.containsKey(card);
+  }
+
+  public boolean existsDefinition(String definition) {
+    return definitionToCard.containsKey(definition);
+  }
+
+  public Map<String, Integer> getStats() {
+    return stats;
+  }
+
+  public void resetStats() {
+    stats.clear();
+  }
+
+  public boolean isTerminated() {
+    return terminated;
+  }
+
+  public void setTerminated(boolean terminated) {
+    this.terminated = terminated;
+  }
+
+  public Map<String, String> getCards() {
+    return cardToDefinition;
+  }
+
+  public void incStats(String answer) {
+    stats.merge(answer, 1, (x, y) -> x + y);
+  }
+
+  public boolean isGuessed(String card, String guess) {
+    return definitionToCard.containsKey(guess) && cardToDefinition.get(card).equals(guess);
+  }
+
+  public String getDefinition(String card) {
+    return cardToDefinition.get(card);
+  }
+
+  public String getCard(String definition) {
+    return definitionToCard.get(definition);
+  }
+}

src/flashcards/Main.java

@@ -1,7 +1,38 @@
 package flashcards;
 
+import flashcards.command.Command;
+import flashcards.command.factory.CommandFactory;
+import java.util.Scanner;
+
 public class Main {
-    public static void main(String[] args) {
-        System.out.print("Hello world!");
+
+  private Flashcards flashcards;
+  private CommandFactory commandFactory;
+
+  public Main(Flashcards flashcards, CommandFactory commandFactory) {
+    this.flashcards = flashcards;
+    this.commandFactory = commandFactory;
+  }
+
+  public void actionLoop(Scanner scanner) {
+    while (!flashcards.isTerminated()) {
+
+      System.out.println(
+          "Input the action (add, remove, import, export, ask, exit, log, hardest card, reset stats):");
+
+      String action = scanner.nextLine();
+
+      Command command = commandFactory.getCommand(action, scanner);
+      command.execute();
+    }
+  }
+
+  public static void main(String[] args) {
+    ActionsLogger actionsLogger = new ActionsLogger();
+    Flashcards flashcards = new Flashcards();
+    Main main = new Main(flashcards, CommandFactory.getDefault(flashcards,actionsLogger));
+    try (Scanner scanner = new Scanner(System.in)) {
+      main.actionLoop(scanner);
     }
+  }
 }

src/flashcards/command/AddCard.java

@@ -0,0 +1,28 @@
+package flashcards.command;
+
+import flashcards.Flashcards;
+import java.util.Scanner;
+
+public class AddCard implements Command {
+
+  private Flashcards flashcards;
+  private Scanner scanner;
+
+  public AddCard(Flashcards flashcards, Scanner scanner) {
+    this.flashcards = flashcards;
+    this.scanner = scanner;
+  }
+
+  @Override
+  public void execute() {
+    System.out.println("The card:");
+    String card = scanner.nextLine();
+
+    System.out.println("The definition of the card:");
+    String definition = scanner.nextLine();
+
+    flashcards.addCard(card, definition);
+
+    System.out.printf("The pair (\"%s\":\"%s\") is added.\n\n", card, definition);
+  }
+}

src/flashcards/command/AskCard.java

@@ -0,0 +1,51 @@
+package flashcards.command;
+
+import flashcards.ActionsLogger;
+import flashcards.Flashcards;
+import java.util.Scanner;
+
+public class AskCard implements Command {
+
+  private Flashcards flashcards;
+  private Scanner scanner;
+  private ActionsLogger logger;
+
+  public AskCard(Flashcards flashcards, Scanner scanner, ActionsLogger logger) {
+    this.flashcards = flashcards;
+    this.scanner = scanner;
+    this.logger = logger;
+  }
+
+  @Override
+  public void execute() {
+    System.out.println("How many times to ask?");
+    String num = scanner.nextLine();
+    logger.log(num);
+    int n = Integer.parseInt(num);
+    for (String card : flashcards.getCards().keySet()) {
+      if (n <= 0) {
+        break;
+      }
+      System.out.printf("Print the definition of \"%s\":\n", card);
+      String guess = scanner.nextLine();
+      logger.log(guess);
+      if (flashcards.isGuessed(card, guess)) {
+        System.out.printf("Correct answer.\n");
+      } else if (flashcards.existsDefinition(guess)) {
+        String correctDefinition = flashcards.getDefinition(card);
+        String youMeanCard = flashcards.getCard(guess);
+        System.out.printf(
+            "Wrong answer (the correct one is \"%s\", you've just written a definition of \"%s\" card).\n",
+            correctDefinition, youMeanCard);
+        flashcards.incStats(card);
+      } else {
+        String correctCard = flashcards.getDefinition(card);
+        flashcards.incStats(card);
+        System.out
+            .printf("Wrong answer (the correct one is \"%s\").\n", correctCard);
+      }
+      n--;
+    }
+    System.out.printf("\n");
+  }
+}

src/flashcards/command/Command.java

@@ -0,0 +1,6 @@
+package flashcards.command;
+
+public interface Command {
+
+  void execute();
+}

src/flashcards/command/ExitCommand.java

@@ -0,0 +1,18 @@
+package flashcards.command;
+
+import flashcards.Flashcards;
+
+public class ExitCommand implements Command {
+
+  private Flashcards flashcards;
+
+  public ExitCommand(Flashcards flashcards) {
+    this.flashcards = flashcards;
+  }
+
+  @Override
+  public void execute() {
+    System.out.println("Bye bye!");
+    flashcards.setTerminated(true);
+  }
+}

src/flashcards/command/ExportCard.java

@@ -0,0 +1,41 @@
+package flashcards.command;
+
+import flashcards.ActionsLogger;
+import flashcards.Flashcards;
+import java.io.BufferedWriter;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.Map.Entry;
+import java.util.Scanner;
+
+public class ExportCard implements Command {
+
+  private Flashcards flashcards;
+  private Scanner scanner;
+  private ActionsLogger logger;
+
+  public ExportCard(Flashcards flashcards, Scanner scanner, ActionsLogger logger) {
+    this.flashcards = flashcards;
+    this.scanner = scanner;
+    this.logger = logger;
+  }
+
+  @Override
+  public void execute() {
+    System.out.println("File name:");
+    String fileName = scanner.nextLine();
+    logger.log(fileName);
+    try (BufferedWriter writer = Files.newBufferedWriter(Paths.get(fileName));
+        PrintWriter print = new PrintWriter(writer)) {
+      for (Entry<String, String> entry : flashcards.getCards().entrySet()) {
+        print.printf("%s\n%s\n", entry.getKey(), entry.getValue());
+      }
+    } catch (IOException e) {
+      System.out.printf("0 cards have been saved.\n\n");
+      return;
+    }
+    System.out.printf("%d cards have been saved.\n\n", flashcards.getCards().size());
+  }
+}

src/flashcards/command/HardestCard.java

@@ -0,0 +1,32 @@
+package flashcards.command;
+
+import flashcards.Flashcards;
+import java.util.Iterator;
+import java.util.Map.Entry;
+
+public class HardestCard implements Command {
+
+  private Flashcards flashcards;
+
+  public HardestCard(Flashcards flashcards) {
+    this.flashcards = flashcards;
+  }
+
+  @Override
+  public void execute() {
+    Iterator<Entry<String, Integer>> iterator = flashcards.getStats().entrySet().iterator();
+    Entry<String, Integer> maxErrors = iterator.hasNext() ? iterator.next() : null;
+    if (maxErrors == null) {
+      System.out.printf("No stats\n\n");
+      return;
+    }
+    while (iterator.hasNext()) {
+      Entry<String, Integer> cur = iterator.next();
+      if (cur.getValue() > maxErrors.getValue()) {
+        maxErrors = cur;
+      }
+    }
+    System.out.printf("The hardest card is \"%s\". You have %d errors answering it.\n\n",
+        maxErrors.getKey(), maxErrors.getValue());
+  }
+}

src/flashcards/command/ImportCard.java

@@ -0,0 +1,45 @@
+package flashcards.command;
+
+import flashcards.ActionsLogger;
+import flashcards.Flashcards;
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.Scanner;
+
+public class ImportCard implements Command {
+
+  private Flashcards flashcards;
+  private Scanner scanner;
+  private ActionsLogger logger;
+
+  public ImportCard(Flashcards flashcards, Scanner scanner, ActionsLogger logger) {
+    this.flashcards = flashcards;
+    this.scanner = scanner;
+    this.logger = logger;
+  }
+
+  @Override
+  public void execute() {
+    System.out.println("File name:");
+    String fileName = scanner.nextLine();
+    logger.log(fileName);
+    int count = 0;
+    try (BufferedReader reader = Files.newBufferedReader(Paths.get(fileName))) {
+      String card;
+      while ((card = reader.readLine()) != null) {
+        String def = reader.readLine();
+        if (def == null) {
+          break;
+        }
+        flashcards.addCard(card, def);
+        count++;
+      }
+    } catch (IOException e) {
+      System.out.printf("0 cards have been saved.\n\n");
+      return;
+    }
+    System.out.printf("%d cards have been saved.\n\n", count);
+  }
+}