sadasd

import java.util.*;
import java.io.*;

public class TextBuddy {
    public static final String WELCOME_MESSAGE = "Welcome to TextBuddy! %1$s is ready for use!";
    public static final String COMMAND_MESSAGE = "command: ";
    public static final String ADD_MESSAGE = "Added %1$s to %2$s";
    public static final String DELETE_MESSAGE = "Deleted from %1$s: \"%2$s\"";
    public static final String CLEAR_MESSAGE = "All data cleared from %1$s";

    public static final String ERROR_IS_EMPTY_MESSAGE = "Error! %1$s is empty!";
    public static final String ERROR_CANNOT_ADD_MESSAGE = "Error! No data to add!";
    public static final String ERROR_CANNOT_DELETE_NULL_MESSAGE = "Error! No specified data to delete!";
    public static final String ERROR_CANNOT_DELETE_MESSAGE = "Error! Unable to delete %1$s from %2$s";
    public static final String ERROR_CANNOT_SAVE_MESSAGE = "Error! Cannot save data to ";
    public static final String ERROR_INVALID_COMMAND_MESSAGE = "Error! Invalid command!";

    public static final String STRING_ADD = "add";
    public static final String STRING_DELETE = "delete";
    public static final String STRING_CLEAR = "clear";
    public static final String STRING_DISPLAY = "display";
    public static final String STRING_EXIT = "exit";

    public static final int NOT_FOUND = -1;

    public static void main(String[] args){
        String fileName = args[0];
        File outputFile = new File(fileName);
        ArrayList<String> textFile = new ArrayList<String>();
        Scanner sc = new Scanner(System.in);
        linePrinter(WELCOME_MESSAGE, fileName, null);
        executeCommand(textFile, fileName, outputFile, sc);
    }

    // this method is the main driver for the program as
    // it reads inputs from the user or file and executes them
    private static void executeCommand(ArrayList<String> textFile, String fileName, File outputFile, Scanner sc){
        String commandEntered = null;
        do{
            commandLinePrinter(COMMAND_MESSAGE);
            commandEntered = sc.nextLine();
            runCommands(commandEntered, textFile, fileName);
            saveDataToFile(textFile, fileName, outputFile);
        } while (commandEntered != null);
    }

    private static void runCommands(String commandEntered, ArrayList<String> textFile, String fileName){
        if (commandEntered == null){
            return;
        }

        String commandWord = getCommandWord(commandEntered);

        switch (commandWord){
        case STRING_ADD:
            addData(textFile, commandEntered, fileName);
            break;
        case STRING_DELETE:
            deleteData(textFile, commandEntered, fileName);
            break;
        case STRING_DISPLAY:
            displayData(textFile, fileName);
            break;
        case STRING_CLEAR:
            clearData(textFile, fileName);
            break;
        case STRING_EXIT:
            exit();
            break;
        default:
            linePrinter(ERROR_INVALID_COMMAND_MESSAGE, null, null);
            break;
        }
    }

    private static String getCommandWord (String commandEntered){
        int indexOfFirstSpace = commandEntered.indexOf(' ');
        if (indexOfFirstSpace == NOT_FOUND){
            return commandEntered;
        }
        String commandWord = commandEntered.substring(0, indexOfFirstSpace);
        return commandWord;
    }

    private static String getCommandData(String commandEntered){
        int lengthOfCommand = commandEntered.length();
        int indexOfFirstSpace = commandEntered.indexOf(' ');
        if (indexOfFirstSpace == NOT_FOUND){
            return null;
        }
        String commandData = commandEntered.substring(indexOfFirstSpace + 1, lengthOfCommand);
        return commandData;
    }

    private static void addData(ArrayList<String> textFile, String commandEntered, String fileName){
        String commandData = getCommandData(commandEntered);

        if(commandData != null){
            textFile.add(commandData);
            linePrinter(ADD_MESSAGE, commandData, fileName);
        }
        else{
            linePrinter(ERROR_CANNOT_ADD_MESSAGE, null, null);
        }
    }

    private static void deleteData(ArrayList<String> textFile, String commandEntered, String fileName){
        String commandData = getCommandData(commandEntered);

        if(isEmptyCommandData(commandData)){
            linePrinter(ERROR_CANNOT_DELETE_NULL_MESSAGE, null, null);
        }
        else{
            try{
                int commandDataToInteger = Integer.parseInt(commandData);
                String deletedData = textFile.get(commandDataToInteger - 1);
                textFile.remove(commandDataToInteger - 1);
                linePrinter(DELETE_MESSAGE, fileName, deletedData);
            } catch(IndexOutOfBoundsException e) {
                linePrinter(ERROR_CANNOT_DELETE_MESSAGE, commandData, fileName);
            }
        }
    }

    private static boolean isEmptyCommandData(String commandData){
        if (commandData == null){
            return true;
        }
        return false;
    }

    private static void displayData(ArrayList<String> textFile, String fileName){
        if (textFile.size() > 0){
            printData(textFile);
        }
        else {
            linePrinter(ERROR_IS_EMPTY_MESSAGE, fileName, null);
        }
    }

    private static void printData(ArrayList<String> textFile){
        for (int counter = 0; counter < textFile.size(); counter++){
            System.out.println((counter + 1) + ". " + textFile.get(counter));
        }
    }

    private static void clearData(ArrayList<String> textFile, String fileName){
        if (isEmptyTextFile(textFile)){
            linePrinter(ERROR_IS_EMPTY_MESSAGE, fileName, null);
        }
        else{
            textFile.clear();
            linePrinter(CLEAR_MESSAGE, fileName, null);
        }
    }

    private static boolean isEmptyTextFile(ArrayList<String> textFile){
        if (textFile.isEmpty()){
            return true;
        }
        return false;
    }

    private static void exit(){
        System.exit(0);
    }

    private static void saveDataToFile(ArrayList<String> textFile, String fileName, File outputFile){
        try{
            FileWriter writer = new FileWriter(outputFile);
            saveData(writer, textFile, fileName, outputFile);
            writer.close();
        } catch (IOException e){
            linePrinter(ERROR_CANNOT_SAVE_MESSAGE, fileName, null);
        }
    }

    private static void saveData(FileWriter writer, ArrayList<String> textFile, String fileName, File outputFile){
        try{
            for (int counter = 0; counter < textFile.size(); counter++){
                writer.write(textFile.get(counter) + "\r\n");
            }
        } catch (IOException e){
            linePrinter(ERROR_CANNOT_SAVE_MESSAGE, fileName, null);
        }
    }

    private static void commandLinePrinter(String commandLine){
        System.out.print(commandLine);
    }

    private static void linePrinter(String textConstant, String variableText1, String variableText2){
        String text = String.format(textConstant, variableText1, variableText2);
        System.out.println(text);
    }
}