/*
 * SignHandler.java
 *
 * Created on den 9 januari 2005, 10:06
 */

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

/**
 *
 * @author Henrik Johansson
 */
public class SignHandler {
    private String dataName;
    private String privateKeyName;
    private String signatureName;
    private String signatureAlgorithm = "SHA1withDSA";
    private int bufSize = 1024;
    
    /** Creates a new instance of SignHandler */
    public SignHandler() {
    }
    
    /** Creates a new instance of SignHandler */
    public SignHandler(String dataName, String privateKeyName, String signatureName) {
        this.setDataName(dataName);
        this.setPrivateKeyName(privateKeyName);
        this.setSignatureName(signatureName);
    }
    
    public void createSignature() {
        try {
            // ladda nyckeln
            FileInputStream keyfis = new FileInputStream(getPrivateKeyName());
            ObjectInputStream key = new ObjectInputStream(keyfis);
            PrivateKey pk = (PrivateKey) key.readObject();
            key.close();
            key.close();
            
            // skapa signatur
            Signature s = Signature.getInstance(getSignatureAlgorithm());
            s.initSign(pk);
            FileInputStream input = new FileInputStream(getDataName());
            byte[] buf = new byte[getBufSize()];
            int count = 0;
            while((count = input.read(buf, 0, getBufSize())) != -1) {
                s.update(buf, 0, count);
            }
            input.close();
            byte[] signature = s.sign();
            
            // spara signaturen
            FileOutputStream out = new FileOutputStream(getSignatureName());
            out.write(signature);
            out.close();
        } catch(Exception e) {
            e.printStackTrace();
        }
    }

    public String getDataName() {
        return dataName;
    }

    public void setDataName(String dataName) {
        this.dataName = dataName;
    }

    public String getPrivateKeyName() {
        return privateKeyName;
    }

    public void setPrivateKeyName(String privateKeyName) {
        this.privateKeyName = privateKeyName;
    }

    public String getSignatureName() {
        return signatureName;
    }

    public void setSignatureName(String signatureName) {
        this.signatureName = signatureName;
    }  

    public String getSignatureAlgorithm() {
        return signatureAlgorithm;
    }

    public void setSignatureAlgorithm(String signatureAlgorithm) {
        this.signatureAlgorithm = signatureAlgorithm;
    }

    public int getBufSize() {
        return bufSize;
    }

    public void setBufSize(int bufSize) {
        this.bufSize = bufSize;
    }
    
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        if(args.length != 3) {
            System.err.println("SignHandler måste anropas med tre argument, <data> <privateKey> <signature>.");
            System.exit(1);
        }
        SignHandler sh = new SignHandler(args[0], args[1], args[2]);
        sh.createSignature();
    }  
}