import java.io.*;
import java.security.*;

public class SignHandler {

   public static void main(String[] args) {
      // Läs in privata nyckeln
      PrivateKey privateKey = (PrivateKey) KeyHandler.loadKey(args[1]);
      System.out.println("DONE LOADING PRIVATE KEY");

      // Gör en signatur och verifikations maskin
      Signature signAndVerifyEngine = null;
      try {
         signAndVerifyEngine = Signature.getInstance("SHA1withDSA", "SUN");
         System.out.println("DONE MAKING SIGNATURE/VERIFYING ENGINE");
      } catch(NoSuchAlgorithmException nsae) {
         System.out.println("NoSuchAlgorithmException generated");
      } catch(NoSuchProviderException nspe) {
         System.out.println("NoSuchProviderException generated");
      }

      // Initialisera maskinen
      try {
         signAndVerifyEngine.initSign(privateKey);
      } catch(InvalidKeyException ike) {
         System.out.println("InvalidKeyException generated");
      }

      // Tillför maskinen text-meddelandet
      try {
         BufferedInputStream bis = new BufferedInputStream(new FileInputStream(args[0]));
         byte[] buffer = new byte[1024];
         int length;
         while(bis.available() != 0) {
            length = bis.read(buffer);
            signAndVerifyEngine.update(buffer, 0, length);
         }
         bis.close();
         System.out.println("DONE DELIVERING DATA TO SIGNATURE/VERIFYING ENGINE");
      } catch(SignatureException ike) {
         System.out.println("SignatureException generated");
      } catch(IOException ioe) {
         System.out.println("IOException generated");
      }

      // Signera
      byte[] signature = null;
      try {
         signature = signAndVerifyEngine.sign();
         System.out.println("DONE MESSAGE SIGNED");
      } catch(SignatureException se) {
         System.out.println("SignatureException");
      }      

      // Spara signaturen
      try {
         FileOutputStream fos = new FileOutputStream(args[2]);
         fos.write(signature);
         fos.close();
         System.out.println("DONE SAVING SIGNATURE");
      } catch (IOException ioe) {
         System.out.println("IOException generated");
      }
   }
}