package com.company;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;
public class Main {
    static void condition(){
        System.out.println("This program converts a string according to the rule: ");
        System.out.println("1)If the string length > N, then the program will discard the first characters.");
        System.out.println("2)If the string length < N, then the program will add '.'");
    }
    static String inputFromFile() throws IOException {
        final int min = 1;
        final int max = 50;
        Scanner input = new Scanner(System.in);
        String sentence = "";
        String inputFile;
        boolean isNotCorrect;
        do {
            System.out.println("Enter the name of the file from which you want to read information: ");
            inputFile = input.nextLine();
            inputFile += ".txt";
            Scanner in = new Scanner(new File(inputFile));
            isNotCorrect = false;
            while (in.hasNext())
                sentence = sentence + in.nextLine();
            in.close();
            if((sentence.length() < min) || (sentence.length() > max)){
                isNotCorrect = true;
                System.out.println("Enter string length from interval [" + min + "..." + max + "]: ");
            }
        }while (isNotCorrect);
        System.out.println("Source string: " + sentence);
        return sentence;
    }
    static char choiseInput(){
        Scanner in = new Scanner(System.in);
        char input;
        boolean isNotCorrect;
        do {
            input = in.next().charAt(0);;
            input = (Character.toUpperCase(input));
            if ((input == 'Y') || (input == 'N')) {
                isNotCorrect = false;
            }
            else{
                isNotCorrect = true;
                System.out.println("Incorrect input. Enter Y(Yes) or N(No): ");
                }
        }while (isNotCorrect);
        return input;
    }
    static String checkInputString() {
        Scanner in = new Scanner(System.in);
        final int min = 1;
        final int max = 50;
        boolean isNotCorrect;
        String sentence;
        do {
            sentence = in.nextLine();
            if ((sentence.length() >= min) && (sentence.length() <= max)) {
                isNotCorrect = false;
            } else {
                System.out.println("Enter string length from interval [" + min + "..." + max + "]: ");
                isNotCorrect = true;
            }
        }while (isNotCorrect);
        return sentence;
    }
    static String inputFromConsole() {
        String sentence;
        System.out.println("Please, enter a string: ");
        sentence = checkInputString();
        return sentence;
    }
    static int CheckInput() {
        Scanner in = new Scanner(System.in);
        final int min = 1;
        final int max = 50;
        int n;
        boolean isNotCorrect;
        do {
            n = in.nextInt();
            if ((n >= min) && (n <= max)) {
                isNotCorrect = false;
            }
            else {
                isNotCorrect = true;
                System.out.println("Enter number from interval [" + min + "..." + max + "]: ");
            }
        }while (isNotCorrect);
        return n;
    }
    static void stringConversion(String sentence, int n) {
        int i;
        int len;
        char[] split;
        len = sentence.length();
        split = sentence.toCharArray();
        if (len > n) {
            System.out.println("Final string: ");
            for (i = len - n; i < len; i++) {
                System.out.print(split[i]);
            }
            System.out.println();
        }
        if (len < n) {
            for (i = len + 1; i <= n; i++) {
                sentence = "." + sentence;
            }
            System.out.println("Final string: " + sentence);
        }
        if (len == n) {
            System.out.println("Final string: " + sentence);
        }
    }
    static void outputInFile(String sentence) throws IOException {
        Scanner in = new Scanner(System.in);
        int i;
        String outputFileName;
        System.out.println("Enter the file name for the entry: ");
         outputFileName = in.nextLine();
         outputFileName = outputFileName + ".txt";
         FileWriter filewriter = new FileWriter(new File(outputFileName));
         filewriter.write("Final string: ");
         filewriter.write(sentence);
         filewriter.flush();
         }
    public static void main(String[] args) throws IOException {
        String sentence;
        int n;
        boolean isNotCorrect = false;
        condition();
        System.out.println("Would you like to use File input instead of Console input? Enter Y(Yes) or N(No): ");
        if (choiseInput() == 'N') {
            sentence = inputFromConsole();
            System.out.println("Enter N: ");
            n = CheckInput();
            stringConversion(sentence, n);
            System.out.println("Would you like to write down the answer to File? Enter Y(Yes) or N(No): ");
            if (choiseInput() == 'Y') {
                outputInFile(sentence);
                System.out.println("Program end");
            }else{
                System.out.println("Program end");
            }
        }else{
            do{
                try {
                    isNotCorrect = false;
                    sentence = inputFromFile();
                    System.out.println("Enter N: ");
                    n = CheckInput();
                    stringConversion(sentence,n);
                    System.out.println("Would you like to write down the answer to File? Enter Y(Yes) or N(No): ");
                    if (choiseInput() == 'Y') {
                        outputInFile(sentence);
                        System.out.println("Program end");
                    }else{
                        System.out.println("Program end");
                    }
                }catch (FileNotFoundException e){
                    isNotCorrect = true;
                    System.out.println("Mistake! The specified file was not found");
                }
            }while (isNotCorrect);
        }
    }
}