package seedu.address.logic.commands;

import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

import seedu.address.commons.exceptions.IllegalValueException;

//@@author A0139145E 
/**
 * Lists all persons in the address book to the user.
 */
public class ListCommand extends Command {

    public static final String COMMAND_WORD = "list";
    public static final String COMMAND_ALIAS = "ls";

    public static final String LIST_KEYWORD_ALL = "all";
    public static final String LIST_KEYWORD_OD = "od";
    public static final String LIST_KEYWORD_DONE = "done";
    public static final String LIST_KEYWORDS = LIST_KEYWORD_ALL + "/" + LIST_KEYWORD_OD + "/" + LIST_KEYWORD_DONE;
    public static Set<String> keywordsList = new HashSet<>(Arrays.asList(LIST_KEYWORDS.split("/")));
    
    
    public static final String MESSAGE_LIST_USAGE = COMMAND_WORD + ": Lists the tasks in the address book.\n"
            + "Parameters: list " + LIST_KEYWORDS + "\n"
            + "Example: " + COMMAND_WORD
            + " done";

    public static final String MESSAGE_SUCCESS = "Listed %1$s tasks";

    private final String keyword;

    public ListCommand(String key) throws IllegalValueException{
        
        if (keywordsList.contains(key)) {
            this.keyword = key;
        }
        else {
            throw new IllegalValueException(MESSAGE_LIST_USAGE);
        }
    }

    @Override
    public CommandResult execute() {
        String taskStatus;

        switch (keyword) {
        case LIST_KEYWORD_ALL:
            taskStatus = "all";
            model.updateFilteredListToShowAll();
            break;

        case LIST_KEYWORD_DONE:
            taskStatus = "completed";
            model.updateFilteredTaskListByStatus("DONE");
            break;

        case LIST_KEYWORD_OD:
            taskStatus = "overdue and expired";
            model.updateFilteredTaskListByStatus("OVERDUE", "EXPIRE");
            break;

        default:
            taskStatus = "";
            assert false : "Missing case in switch statement";
            break;
        }

        return new CommandResult(String.format(MESSAGE_SUCCESS, taskStatus));
    }

}

@@ -220,31 +220,28 @@
 sons in the 
-address
+task
  book to the

Update code quality