package algs34;
import stdlib.*;
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
/* ***********************************************************************
 *  Compilation:  javac OneWay.java
 *  Execution:    java OneWay password
 *
 *  Compute the SHA1 of the command line argument.
 *
 *
 * % java OneWay "The quick brown fox jumps over the lazy dog"
 * 2fd4e1c6 7a2d28fc ed849ee1 bb76e739 1b93eb12
 *
 *  % java OneWay test
 *  a94a8fe5 ccb19ba6 1c4c0873 d391e987 982fbbd3
 *
 *  % java OneWay ""
 *  da39a3ee 5e6b4b0d 3255bfef 95601890 afd80709
 *
 *************************************************************************/
import java.security.NoSuchAlgorithmException;

public class XOneWay {

  public static void main(String[] args) {
    args = new String[] { "test" };
    args = new String[] { "test1" };
    //args = new String[] { "The quick brown fox jumps over the lazy dog" };

    // get the sha1 encoding object
    MessageDigest sha1;
    try { sha1 = MessageDigest.getInstance("SHA1"); } catch (NoSuchAlgorithmException e) { StdOut.println(e); return; }

    // get the input string as a byte array
    String password = args[0];
    byte[] input;
    try { input = password.getBytes("ISO-8859-1"); } catch (UnsupportedEncodingException e) { StdOut.println(e); return; }

    // perform the conversion
    byte[] hash = sha1.digest(input);

    // print bytes as hex, careful to handle leading 0s and 2s complement
    StdOut.print(hash.length + ": " + password.hashCode () + ":");
    String hex = "0123456789abcdef";
    for (int i = 0; i < hash.length; i++) {
      if (i % 4 == 0) StdOut.print(" ");
      StdOut.print(hex.charAt((hash[i] & 0xF0) >> 4));
      StdOut.print(hex.charAt((hash[i] & 0x0F) >> 0));
    }
    StdOut.println();
  }


}