sdm03/src/main/java/com/github/dtschust/zork/repl/actions/MoveAction.java

package com.github.dtschust.zork.repl.actions;

import com.github.dtschust.zork.ZorkGame;
import com.github.dtschust.zork.repl.Action;
import com.github.dtschust.zork.types.ZorkDirection;

import java.io.PrintStream;
import java.util.List;
import java.util.Optional;

/**
 * If it's not a "Special Action", just treat it normally
 * Execute a user action or an action command from some <action> element that is not one of the "Special Commands"
 * Movement
 */
public class MoveAction implements Action {

    @Override
    public boolean matchesInput(List<String> arguments) {
        return ZorkDirection.fromShort(arguments.get(0)).isPresent();
    }

    @Override
    public int getMaximumArgCount() {
        return 1;
    }

    @Override
    public boolean run(ZorkGame game, List<String> arguments, PrintStream stream) {
        // we are guaranteed to have a valid short direction name by matchesInput
        final ZorkDirection direction = ZorkDirection.fromShort(arguments.get(0)).orElseThrow(() ->
                new IllegalStateException("unreachable"));

        final Optional<String> roomName = game.getCurrentRoom().getBorderingRoom(direction);

        if (roomName.isPresent() && game.changeRoom(roomName.get())) {
            stream.println(game.getCurrentRoom().getDescription());
        } else {
            stream.println("Can't go that way.");
        }
        return true;
    }
}