Implement rewind command feature

src/main/java/seedu/algobase/commons/core/Messages.java

@@ -15,4 +15,6 @@ public class Messages {
     public static final String MESSAGE_INVALID_TAG_DISPLAYED_INDEX = "The Tag index provided is invalid";
     public static final String MESSAGE_PLANS_LISTED_OVERVIEW = "%1$d plans listed!";
     public static final String MESSAGE_INVALID_COMMAND_NAME = "Command %1$s not found!";
+    public static final String MESSAGE_INVALID_REWIND_NUMBER = "Invalid rewind number! (Is it larger than the "
+        + "number of all successfully executed commands in this launch of AlgoBase?)";
 }

src/main/java/seedu/algobase/logic/LogicManager.java

@@ -9,11 +9,13 @@
 import seedu.algobase.commons.core.LogsCenter;
 import seedu.algobase.logic.commands.Command;
 import seedu.algobase.logic.commands.CommandResult;
+import seedu.algobase.logic.commands.RewindCommand;
 import seedu.algobase.logic.commands.exceptions.CommandException;
 import seedu.algobase.logic.parser.AlgoBaseParser;
 import seedu.algobase.logic.parser.exceptions.ParseException;
 import seedu.algobase.model.Model;
 import seedu.algobase.model.ReadOnlyAlgoBase;
+import seedu.algobase.model.commandhistory.CommandHistory;
 import seedu.algobase.model.gui.GuiState;
 import seedu.algobase.model.plan.Plan;
 import seedu.algobase.model.problem.Problem;
@@ -45,6 +47,10 @@ public CommandResult execute(String commandText) throws CommandException, ParseE
         CommandResult commandResult;
         Command command = algoBaseParser.parseCommand(commandText);
         commandResult = command.execute(model);
+        // We don't consider RewindCommand as a valid candidate to be stored in the command history.
+        if (!(command instanceof RewindCommand)) {
+            model.addCommandHistory(new CommandHistory(commandText)); // Save command text for rewind feature
+        }
 
         try {
             storage.saveAlgoBase(model.getAlgoBase());

src/main/java/seedu/algobase/logic/commands/CommandResult.java

@@ -17,21 +17,24 @@ public class CommandResult {
     /** The application should exit. */
     private final boolean exit;
 
+    private final boolean isRewind;
+
     /**
      * Constructs a {@code CommandResult} with the specified fields.
      */
-    public CommandResult(String feedbackToUser, boolean showHelp, boolean exit) {
+    public CommandResult(String feedbackToUser, boolean showHelp, boolean exit, boolean isRewind) {
         this.feedbackToUser = requireNonNull(feedbackToUser);
         this.showHelp = showHelp;
         this.exit = exit;
+        this.isRewind = isRewind;
     }
 
     /**
      * Constructs a {@code CommandResult} with the specified {@code feedbackToUser},
      * and other fields set to their default value.
      */
     public CommandResult(String feedbackToUser) {
-        this(feedbackToUser, false, false);
+        this(feedbackToUser, false, false, false);
     }
 
     public String getFeedbackToUser() {
@@ -46,6 +49,10 @@ public boolean isExit() {
         return exit;
     }
 
+    public boolean isRewind() {
+        return isRewind;
+    }
+
     @Override
     public boolean equals(Object other) {
         if (other == this) {
@@ -59,13 +66,14 @@ public boolean equals(Object other) {
 
         CommandResult otherCommandResult = (CommandResult) other;
         return feedbackToUser.equals(otherCommandResult.feedbackToUser)
-                && showHelp == otherCommandResult.showHelp
-                && exit == otherCommandResult.exit;
+            && showHelp == otherCommandResult.showHelp
+            && exit == otherCommandResult.exit
+            && isRewind == otherCommandResult.isRewind;
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(feedbackToUser, showHelp, exit);
+        return Objects.hash(feedbackToUser, showHelp, exit, isRewind);
     }
 
     @Override

src/main/java/seedu/algobase/logic/commands/ExitCommand.java

@@ -13,7 +13,7 @@ public class ExitCommand extends Command {
 
     @Override
     public CommandResult execute(Model model) {
-        return new CommandResult(MESSAGE_EXIT_ACKNOWLEDGEMENT, false, true);
+        return new CommandResult(MESSAGE_EXIT_ACKNOWLEDGEMENT, false, true, false);
     }
 
 }

src/main/java/seedu/algobase/logic/commands/HelpCommand.java

@@ -50,10 +50,10 @@ public CommandResult execute(Model model) {
             }
             String commandPrompt = "Available commands are: " + commandWords.toString() + "\n"
                 + "More information can be found in the popup window.";
-            return new CommandResult(commandPrompt, true, false);
+            return new CommandResult(commandPrompt, true, false, false);
         } else {
             String commandUsage = getClassStringField(commandClass, "MESSAGE_USAGE");
-            return new CommandResult(commandUsage, false, false);
+            return new CommandResult(commandUsage);
         }
     }
 

src/main/java/seedu/algobase/logic/commands/RewindCommand.java

@@ -0,0 +1,47 @@
+package seedu.algobase.logic.commands;
+
+import static java.util.Objects.requireNonNull;
+
+import java.util.List;
+
+import seedu.algobase.commons.core.Messages;
+import seedu.algobase.commons.core.index.Index;
+import seedu.algobase.logic.commands.exceptions.CommandException;
+import seedu.algobase.model.Model;
+import seedu.algobase.model.commandhistory.CommandHistory;
+
+/**
+ * Rewinds the content of CommandBox to a previous successfully executed command.
+ */
+public class RewindCommand extends Command {
+
+    public static final String COMMAND_WORD = "rewind";
+
+    public static final String MESSAGE_USAGE = COMMAND_WORD
+        + ": Rewinds the command input to a previous successfully executed command input.\n"
+        + "Parameters: INDEX (must be a positive integer, represents how many commands ago you want to rewind to)\n"
+        + "Example: " + COMMAND_WORD + " 1";
+
+    public static final String MESSAGE_SUCCESS = "Rewind successfully!";
+    public static final String REWIND_TO_LAST_COMMAND_TEXT = COMMAND_WORD + " 1";
+
+    private final Index targetIndex;
+
+    public RewindCommand(Index targetIndex) {
+        this.targetIndex = targetIndex;
+    }
+
+    @Override
+    public CommandResult execute(Model model) throws CommandException {
+        requireNonNull(model);
+        List<CommandHistory> commandHistories = model.getCommandHistoryList();
+
+        if (targetIndex.getOneBased() > commandHistories.size()) {
+            throw new CommandException(Messages.MESSAGE_INVALID_REWIND_NUMBER);
+        }
+
+        CommandHistory commandHistoryToShow = commandHistories.get(
+            commandHistories.size() - targetIndex.getOneBased());
+        return new CommandResult(commandHistoryToShow.getCommandText(), false, false, true);
+    }
+}

src/main/java/seedu/algobase/logic/parser/AlgoBaseParser.java

@@ -28,6 +28,7 @@
 import seedu.algobase.logic.commands.ListPlanCommand;
 import seedu.algobase.logic.commands.ListTagCommand;
 import seedu.algobase.logic.commands.OpenTabCommand;
+import seedu.algobase.logic.commands.RewindCommand;
 import seedu.algobase.logic.commands.SortCommand;
 import seedu.algobase.logic.commands.SwitchTabCommand;
 import seedu.algobase.logic.commands.UndoneTaskCommand;
@@ -108,6 +109,10 @@ public Command parseCommand(String userInput) throws ParseException {
         case UndoneTaskCommand.COMMAND_WORD:
             return new UndoneTaskCommandParser().parse(arguments);
 
+        //Rewind
+        case RewindCommand.COMMAND_WORD:
+            return new RewindCommandParser().parse(arguments);
+
         //Util
         case ClearCommand.COMMAND_WORD:
             return new ClearCommand();

src/main/java/seedu/algobase/logic/parser/RewindCommandParser.java

@@ -0,0 +1,31 @@
+package seedu.algobase.logic.parser;
+
+import static seedu.algobase.commons.core.Messages.MESSAGE_INVALID_COMMAND_FORMAT;
+
+import seedu.algobase.commons.core.index.Index;
+import seedu.algobase.logic.commands.RewindCommand;
+import seedu.algobase.logic.parser.exceptions.ParseException;
+
+/**
+ * Parses input arguments and creates a new RewindCommand object
+ */
+public class RewindCommandParser implements Parser<RewindCommand> {
+
+    /**
+     * Parses {@code userInput} into a command and returns it.
+     *
+     * @param args the user input to be parsed
+     * @throws ParseException if {@code userInput} does not conform the expected format
+     */
+    @Override
+    public RewindCommand parse(String args) throws ParseException {
+        try {
+            Index index = ParserUtil.parseIndex(args);
+            return new RewindCommand(index);
+        } catch (ParseException pe) {
+            throw new ParseException(
+                String.format(MESSAGE_INVALID_COMMAND_FORMAT, RewindCommand.MESSAGE_USAGE), pe);
+        }
+    }
+
+}

src/main/java/seedu/algobase/model/AlgoBase.java

@@ -7,6 +7,8 @@
 
 import javafx.collections.ObservableList;
 import seedu.algobase.commons.exceptions.IllegalValueException;
+import seedu.algobase.model.commandhistory.CommandHistory;
+import seedu.algobase.model.commandhistory.CommandHistoryList;
 import seedu.algobase.model.plan.Plan;
 import seedu.algobase.model.plan.PlanList;
 import seedu.algobase.model.problem.Problem;
@@ -17,13 +19,13 @@
 
 /**
  * Wraps all data at the algobase level
- * Duplicates are not allowed (by .isSameProblem comparison)
  */
 public class AlgoBase implements ReadOnlyAlgoBase {
 
     private final UniqueProblemList problems;
     private final UniqueTagList tags;
     private final PlanList plans;
+    private final CommandHistoryList commandHistories;
 
     /*
      * The 'unusual' code block below is a non-static initialization block, sometimes used to avoid duplication
@@ -36,6 +38,7 @@ public class AlgoBase implements ReadOnlyAlgoBase {
         problems = new UniqueProblemList();
         plans = new PlanList();
         tags = new UniqueTagList();
+        commandHistories = new CommandHistoryList();
     }
 
     public AlgoBase() {}
@@ -225,6 +228,21 @@ public ObservableList<Task> getCurrentTaskList() {
         return plans.getUnmodifiableObservableTaskList();
     }
 
+    //========== Rewind =================================================================
+
+    @Override
+    public ObservableList<CommandHistory> getCommandHistoryList() {
+        return commandHistories.asUnmodifiableObservableList();
+    }
+
+    /**
+     * Adds a {@code CommandHistroy} to AlgoBase.
+     */
+    public void addCommandHistory(CommandHistory history) {
+        requireNonNull(history);
+        commandHistories.add(history);
+    }
+
     //========== Util ===================================================================
 
     @Override

src/main/java/seedu/algobase/model/Model.java

@@ -1,13 +1,13 @@
 package seedu.algobase.model;
 
 import java.nio.file.Path;
-
 import java.util.Comparator;
 import java.util.Set;
 import java.util.function.Predicate;
 
 import javafx.collections.ObservableList;
 import seedu.algobase.commons.core.GuiSettings;
+import seedu.algobase.model.commandhistory.CommandHistory;
 import seedu.algobase.model.gui.GuiState;
 import seedu.algobase.model.plan.Plan;
 import seedu.algobase.model.problem.Problem;
@@ -206,4 +206,18 @@ public interface Model {
 
     /** Returns an unmodifiable view of the filtered Plan list */
     ObservableList<Task> getCurrentTaskList();
+
+    //=========== Rewind ================================================================
+
+    /**
+     * Returns an unmodifiable view of the filtered CommandHistory list.
+     */
+    ObservableList<CommandHistory> getCommandHistoryList();
+
+    /**
+     * Adds the given {@code CommandHistory}.
+     * @param history the added history
+     */
+    void addCommandHistory(CommandHistory history);
+
 }

src/main/java/seedu/algobase/model/ModelManager.java

@@ -14,6 +14,7 @@
 import javafx.collections.transformation.SortedList;
 import seedu.algobase.commons.core.GuiSettings;
 import seedu.algobase.commons.core.LogsCenter;
+import seedu.algobase.model.commandhistory.CommandHistory;
 import seedu.algobase.model.gui.GuiState;
 import seedu.algobase.model.plan.Plan;
 import seedu.algobase.model.problem.Problem;
@@ -34,6 +35,7 @@ public class ModelManager implements Model {
     private final SortedList<Problem> sortedProblems;
     private final FilteredList<Plan> filteredPlans;
     private final FilteredList<Task> filteredTasks;
+    private final FilteredList<CommandHistory> filteredCommandHistories;
 
     /**
      * Initializes a ModelManager with the given algoBase and userPrefs.
@@ -52,6 +54,7 @@ public ModelManager(ReadOnlyAlgoBase algoBase, ReadOnlyUserPrefs userPrefs) {
         sortedProblems = new SortedList<>(filteredProblems);
         filteredPlans = new FilteredList<>(this.algoBase.getPlanList());
         filteredTasks = new FilteredList<>(this.algoBase.getCurrentTaskList());
+        filteredCommandHistories = new FilteredList<>(this.algoBase.getCommandHistoryList());
     }
 
     public ModelManager() {
@@ -137,8 +140,7 @@ public void setProblem(Problem target, Problem editedProblem) {
     }
 
     /**
-     * Returns an unmodifiable view of the list of {@code Problem} backed by the internal list of
-     * {@code versionedAlgoBase}
+     * Returns an unmodifiable view of the list of {@code Problem}.
      */
     @Override
     public ObservableList<Problem> getFilteredProblemList() {
@@ -288,6 +290,28 @@ public ObservableList<Task> getCurrentTaskList() {
         return filteredTasks;
     }
 
+    //========== Rewind =================================================================
+
+    /**
+     * Returns an unmodifiable view of the list of {@code CommandHistory}.
+     */
+    @Override
+    public ObservableList<CommandHistory> getCommandHistoryList() {
+        return filteredCommandHistories;
+    }
+
+    /**
+     * Adds the given {@code CommandHistory}.
+     *
+     * @param history the added history
+     */
+    @Override
+    public void addCommandHistory(CommandHistory history) {
+        requireNonNull(history);
+        algoBase.addCommandHistory(history);
+    }
+
+
     //========== Util ===================================================================
 
     @Override

src/main/java/seedu/algobase/model/ReadOnlyAlgoBase.java

@@ -1,6 +1,7 @@
 package seedu.algobase.model;
 
 import javafx.collections.ObservableList;
+import seedu.algobase.model.commandhistory.CommandHistory;
 import seedu.algobase.model.plan.Plan;
 import seedu.algobase.model.problem.Problem;
 import seedu.algobase.model.tag.Tag;
@@ -28,4 +29,9 @@ public interface ReadOnlyAlgoBase {
      */
     ObservableList<Task> getCurrentTaskList();
 
+    /**
+     * Returns an unmodifiable view of the command history.
+     */
+    ObservableList<CommandHistory> getCommandHistoryList();
+
 }

src/main/java/seedu/algobase/model/commandhistory/CommandHistory.java

@@ -0,0 +1,16 @@
+package seedu.algobase.model.commandhistory;
+
+/**
+ * Represents a command history in AlgoBase.
+ */
+public class CommandHistory {
+    private final String commandText;
+
+    public CommandHistory(String commandText) {
+        this.commandText = commandText;
+    }
+
+    public String getCommandText() {
+        return commandText;
+    }
+}