package com.example.oop.multiplication;

import java.util.Arrays;
import java.util.Scanner;

import static java.util.stream.Collectors.joining;

class MultiplicationTable {

    private final int size;

    public MultiplicationTable(int size) {
        this.size = size;
    }

    public int[][] content() {
        if (size <= 0) {
            throw new IllegalArgumentException(String.format("Size must be positive, but is: %d", size));
        }
        int[][] result = new int[size][size];
        for (int row = 0; row < size; ++row) {
            for (int col = 0; col < size; ++col) {
                result[col][row] = (row + 1) * (col + 1);
            }
        }
        return result;
    }
}

class FromString implements PositiveInteger {

    private final String string;

    public FromString(String string) {
        this.string = string;
    }

    @Override
    public int get() {
        Integer parsed = Integer.valueOf(string);
        if (parsed <= 0) {
            throw new IllegalArgumentException("Value is not positive: " + parsed);
        }
        return parsed;
    }
}

class IntMatrix {

    private final int[][] body;

    public IntMatrix(int[][] body) {
        this.body = body;
    }

    @Override
    public String toString() {
        return Arrays.stream(body).map(this::printRow).collect(joining("\n"));
    }

    private String printRow(int[] row) {
        return Arrays.stream(row).mapToObj(String::valueOf).collect(joining(" "));
    }
}

interface PositiveInteger {
    int get();
}

class MultiplicationTableApp implements Runnable {

    @Override
    public void run() {
        Scanner scanner = new Scanner(System.in);
        boolean success = false;
        do {
            System.out.println("Enter size:");
            String userInput = scanner.nextLine();
            PositiveInteger size;
            try {
                size = new FromString(userInput);
                System.out.println(new IntMatrix(new MultiplicationTable(size.get()).content()).toString());
                success = true;
            } catch (IllegalArgumentException exception) {
                System.out.println("Invalid input: " + exception.getMessage());
                System.out.println("Try again");
            }
        } while (!success);
    }
}

public class App {

    public static void main(String[] args) {
        new MultiplicationTableApp().run();
    }
}