import java.util.HashMap;
import java.util.Map;
import java.util.TreeMap;

public class PhoneBook {

    Map<String, String> phoneBook = new HashMap<String, String>();

    public String add(String name, String number) {

        phoneBook.put(name, number);

        return (name + " " + phoneBook.get(name));

        //           phoneBook.put("Albert", "302-123-4567");
        //           phoneBook.put("Bobby", "302-111-1111");
        //           phoneBook.put("Clyde", "302-222-2222");
        //           phoneBook.put("Drew", "302-333-3333");
        //
        //           System.out.println(phoneBook.size());
        //
        //           System.out.println(phoneBook.get("Clyde" + "\n"));
        //
        //           for(Map.Entry<String, String> list : phoneBook.entrySet()){
        //
        //               String key = list.getKey();
        //               String value = list.getValue();
        //               System.out.println(key + " " + value);
        //
        //           }

    }

    public String remove(String name) {

        phoneBook.remove(name);

        return name;
    }

    public String lookUp(String name) {
        phoneBook.get(name);
        return phoneBook.get(name);
    }

    public String reverseLookUp(String number) {
        String result = "";
        //need to import Entry class
        for (Map.Entry<String, String> entry : phoneBook.entrySet()) {
            if (entry.getValue().equals(number)) {
                result = (entry.getKey());
            }
        }

        return result;
    }

    public String displayPhoneBook(){

        String result = "";
        //this converts a Hash Map into a sorted Tree Map
        TreeMap<String, String> treePhoneBook = new TreeMap<String, String>(phoneBook);

        for (Map.Entry<String, String> entry : treePhoneBook.entrySet()){

            //must append onto the string
            result += (entry.getKey() + " " + entry.getValue() + "\n");

        }

        return result;
    }

}