import java.util.ArrayList;
import java.util.Scanner;
import java.util.StringTokenizer;

/**
 * Satisfies Problem 19.a.i from Homework 1. Quoting from the assignment:
 * <p>
 * Reads a linear representation of a comparator network on standard
 * input and produces a graphical representation on standard
 * output. Excess whitespace (such as multiple spaces between
 * integers, newlines, and tabs) in the input should be ignored
 * by logically coalescing each contiguous whitespace sequence
 * into a single space character. The output should match the
 * graphical representation presented earlier
 * character-for-character.
 * @author Ed Ropple
 */
public class CnetLinToGraMain {

    /**
     * Reads in the linear numerical representation of the comparator network and
     * passes it to cnetlib's shared functions, which return the graphical
     * representation of the comparator network for display on stdout.
     *
     * @param args      The command line arguments for the program. Are ignored
     *                  by this program.
     */
    public static void main(String[] args) {
        String input = "";

        System.out.println("Enter below a whitespace-delineated list of");
        System.out.println("integers that will serve as the basis for the");
        System.out.println("comparator network this program will use.");
        System.out.println("Enter the character X on a new line to stop");
        System.out.println("reading from standard output. No error handling");
        System.out.println("is done in the case of garbage characters, so");
        System.out.println("proof your own values.");
        System.out.println();

        Boolean breakLoop = false;

        Scanner s = new Scanner(System.in);

        // read from stdin, emerge on X or x
        while (breakLoop == false)
        {
            System.out.print("> ");
            String foo = s.nextLine().trim();
            
            if (foo.length() < 1) continue;
            
            if (foo.charAt(0) == 'X' || foo.charAt(0) == 'x')
            {
                breakLoop = true;
                continue;
            }
            else
            {
                input += foo + " ";
            }
        }

        input = input.trim();

        StringTokenizer st = new StringTokenizer(input);

        if (st.countTokens() % 2 == 1)
        {
            System.err.println("ERROR: Invalid input - odd number of tokens.");
            System.exit(1);
        }

        int numberOfComparators = -1;

        ArrayList<ComparatorPair> comparatorList =
                new ArrayList<ComparatorPair>();

        while (st.hasMoreTokens())
        {
            int x = Integer.parseInt(st.nextToken());
            if (x > numberOfComparators) numberOfComparators = x;

            int y = Integer.parseInt(st.nextToken());
            if (y > numberOfComparators) numberOfComparators = y;

            comparatorList.add(new ComparatorPair(x, y));
        }

        numberOfComparators += 1; // fencepost prevention
        if (numberOfComparators > 10)
        {
            System.err.println("Too many comparators. Can only have from 0-9.");
            System.exit(1);
        }

        ArrayList<String> output = Functions.outputComparatorGraphic(comparatorList);

        System.out.println();
        for (int i = 0; i < output.size(); i++)
        {
            System.out.println(output.get(i));
        }

        System.exit(0);
    }
}