Lab4task2

import java.util.Scanner;
import java.util.NoSuchElementException;
import java.io.*;

public class Main {
    private static final Scanner scan = new Scanner(System.in);

    public static int choiceCheck() {
        int choice;
        choice = 0;
        boolean isIncorrect;
        do {
            isIncorrect = false;
            try {
                choice = Integer.parseInt(scan.nextLine());
            } catch (Exception err) {
                System.out.println("Error! Input a number");
                isIncorrect = true;
            }
            if (!isIncorrect && (choice < 1 || choice > 2)) {
                System.out.println("Error! Input 1 or 2");
                isIncorrect = true;
            }

        } while (isIncorrect);
        return choice;
    }

    public static int inputCheck() {
        boolean isIncorrect;
        int n;
        n = 0;
        System.out.println("Input n");
        do {
            isIncorrect = false;
            try {
                n = Integer.parseInt(scan.nextLine());
            } catch (Exception err) {
                System.out.println("Error! Input a number");
                isIncorrect = true;
            }
            if (!isIncorrect && (n < 1)) {
                System.out.println("Error! Input a number greater than 0");
                isIncorrect = true;
            }
        } while (isIncorrect);
        return n;
    }

    public static int[] inputCheckArray(int n, int[] arr) {
        int i;
        boolean isIncorrect;
        for (i = 0; i < n; i++) {
            do {
                isIncorrect = false;
                try {
                    arr[i] = Integer.parseInt(scan.nextLine());
                } catch (Exception err) {
                    System.out.println("Error! Input a number");
                    isIncorrect = true;
                }
            } while (isIncorrect);
        }
        return arr;
    }

    public static String checkInputFilePath() {
        String path;
        boolean isIncorrect;
        do {
            System.out.println("Input path to the file:");
            isIncorrect = false;
            path = scan.nextLine();
            File inputFile = new File(path);
            if (!inputFile.exists()) {
                isIncorrect = true;
                System.out.println("Could not find the file");
            } else if ((!inputFile.canRead()) || (!inputFile.canWrite())) {
                isIncorrect = true;
                System.out.println("Could not open the file");
            }
        } while (isIncorrect);
        return path;
    }


    public static int[] fileCheckArray(int n) {
        String path;
        boolean isIncorrect;
        int i, j, n1, c;
        int[] arr;
        do {
            isIncorrect = false;
            path = checkInputFilePath();
            File inputFile = new File(path);
            Scanner scan2 = null;
            try {
                scan2 = new Scanner(inputFile);
            } catch (FileNotFoundException e) {
                throw new RuntimeException(e);
            }
            try {
                n = scan2.nextInt();
            } catch (Exception e) {
                isIncorrect = true;
                System.out.print("The data is incorrect");
            }
            if ((!isIncorrect) && (n < 2)) {
                isIncorrect = true;
                System.out.println("The data is incorrect");
            }
            arr = new int[n];
            try {
                for (i = 0; i < n; i++) {
                    arr[i] = scan2.nextInt();
                }
            } catch (NoSuchElementException e) {
                System.out.println("The data is incorrect\n");
                isIncorrect = true;
                scan2.close();
            }
        } while (isIncorrect);

        return arr;
    }


    public static int[] inputChoice(int n) {
        int choice;
        int[] arr;
        System.out.println("Choose input option:\n1.Input through console\n2.Input through file");
        choice = choiceCheck();
        if (choice == 1) {
            n = inputCheck();
            arr = new int[n];
            arr = inputCheckArray(n, arr);
        } else {
            arr = fileCheckArray(n);
        }
        return arr;
    }

    public static String checkOutputFilePath() {
        String path;

        System.out.println("Input file path and the name of the file for\nexample С:\\Projects\\Number\\FileName.txt. If the\nfile does not exist, then it will be created\nautomatically in the given directory");
        path = scan.nextLine();
        File outputFile = new File(path);
        if (outputFile.isFile()) {
            if (!outputFile.canRead()) {
                System.out.println("Could not open the file");
            }
        }
        return path;
    }


    public static int findMax(int[] arr, int max, int i) {
        if (i == 0){
            return max;
        }
        else{
            if (max < arr[i]){
                    max = arr[i];
                    return findMax(arr, arr[i], i-1);
            }else {
                return findMax(arr, max, i - 1);
            }
        }
    }

    public static void outputMax(int max) {
        System.out.println(max);
    }

    public static void outputFile(int max) {
        String path;
        path = checkOutputFilePath();
        try (PrintWriter pw = new PrintWriter((path))) {
            pw.print(max);
        } catch (IOException ex) {
            System.out.println("Unsuccessful output");
        }
    }

    public static void outputChoice(int max) {
        int choice;
        System.out.println("Choose output option:\n1.Output through console\n2.Output through file");
        choice = choiceCheck();
        if (choice == 1) {
            outputMax(max);
        } else {
            outputFile(max);
        }
        scan.close();
    }


    public static void main(String[] args) {
        int[] arr;
        int n, max;
        n = 0;
        arr = inputChoice(n);
        n = arr.length-1;
        max = findMax(arr, arr[n], n);
        outputChoice(max);
    }
}