package arraylistplay;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;


public class WordList {

    private static final int LIMIT = 1000;
    private static ArrayList <String> words = new ArrayList<>(LIMIT);
    private static int numberOfWords = 0;
    private static Scanner commandReader = new Scanner(System.in);

    public static void main(String[] args){
        try{
            readWords();
            interpreter();
        } catch (FileNotFoundException ex){
            System.out.println("The file was not found. Please think again...");
            System.exit(-1);
        }

    }

    private static Scanner establishScanner (String fn) throws FileNotFoundException{
        String separator = File.separator;
        String homeDirectory = System.getProperty("user.home");
        String path = homeDirectory + separator + "public_html"+ separator + "data" + separator;
        String fullFileName = path + fn;
        return new Scanner(new File(fullFileName));
    }


    private static void readWords () throws FileNotFoundException {
        Scanner scanner = establishScanner("WordListSet.txt");
        while (scanner.hasNext()) {
            words.add(numberOfWords, scanner.next());
            numberOfWords = numberOfWords +1;
        }
    }

    private static void displayWords(){
        for (int x = 0; x< numberOfWords; x=x+1 ){
            System.out.println(words.get(x));
        }
    }

    private static void interpreter() {
        System.out.println(">>>");
        String command = commandReader.next();
        if ( command.equalsIgnoreCase("DISPLAY")){
            interpreterDisplayCommand();
        } else if (command.equalsIgnoreCase("PRINT")){
            interpreterPrintCommand();
        } else if (command.equalsIgnoreCase("SWAP")){
            interpreterSwapCommand();
        } else if (command.equalsIgnoreCase("ADD")){
            interpreterADDCommand();
        } else if (command.equalsIgnoreCase("HELP")){
            interpreterHelpCommand();
        } else if (command.equalsIgnoreCase("EXIT")){
            System.exit(0);
        } else {
            System.out.println("### Unrecognizable command: " + command);
        }
        interpreter();
    }


    private static void interpreterDisplayCommand() {
        displayWords();
    }

    private static void interpreterPrintCommand() {
        String operand = commandReader.next();
        if (operand.equalsIgnoreCase("FIRST")){
            System.out.println(words.get(0));
        } else if (operand.equalsIgnoreCase("LAST")){
            System.out.println(words.get(numberOfWords - 1));
        } else {
            int index = Integer.valueOf(operand);
            System.out.println(words.get(index - 1));
        }
    }

    private static void interpreterHelpCommand() {
        System.out.println("HELP - display a menu of commands");
        System.out.println("DISPLAY - display the list of numbers");
        System.out.println("PRINT - print a number (FIRST; LAST; nth");
        System.out.println("SWAP - exchange two elements (nth; mth)");
        System.out.println("ADD - add a number to the list (FIRST; LAST)");
        System.out.println("EXIT - terminate execution of the program");
    }


    private static void interpreterSwapCommand() {
        int position1 = commandReader.nextInt();
        int position2 = commandReader.nextInt();
        String temp = words.get(position1 - 1);
        words.set(position1 - 1, words.get(position2 - 1));
        words.set(position2 - 1, temp);
    }

    private static void interpreterADDCommand() {
        String position = commandReader.next();
        if (position.equalsIgnoreCase("LAST")){
            addLast();
        } else if (position.equalsIgnoreCase("FIRST")){
            addFirst();
        } else {
            System.out.println("### invalid operand for add command");
        }
        numberOfWords = numberOfWords +1;
    }

    private static void addLast() {
        words.add(numberOfWords, commandReader.next());
    }

    private static void addFirst() {
        for (int x = numberOfWords; x>0; x = x-1){
            words.add(x, words.get(x - 1));
        }
        words.add(0, commandReader.next());
    }


}