import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLDecoder;
import java.security.CodeSource;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.Provider;
import java.security.ProviderException;
import java.security.Security;
import java.security.UnrecoverableKeyException;
import java.security.cert.Certificate;
import java.security.cert.CertificateException;
import java.util.NoSuchElementException;
import java.util.ResourceBundle;

import sun.security.pkcs11.SunPKCS11;

import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.PdfSignatureAppearance;
import com.lowagie.text.pdf.PdfStamper;

/*
import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.PdfSignatureAppearance;
import com.itextpdf.text.pdf.PdfStamper;
*/

/**
 *
 * @author Jan Peter Stotz
 *
 */
public class JPdfSign {

    private static PrivateKey privateKey;

    private static Certificate[] certificateChain;

    private static ResourceBundle bundle = ResourceBundle.getBundle("strings");

    private static String PRODUCTNAME = bundle.getString("productname");

    private static String VERSION = bundle.getString("version");

    private static String JAR_FILENAME = bundle.getString("jar-filename");

    public static void main(String[] args) {
        // for (int i = 0; i < args.length; i++) {
        // System.out.println("arg[" + i + "] :" + args[i]);
        // }
        if (args.length < 2)
            showUsage();

        try {

            String pkcs12FileName = args[0].trim();
            String pdfInputFileName = args[1];
            String pdfOutputFileName = args[2];
            boolean usePKCS12 = !(pkcs12FileName.equals("-PKCS11"));

            String passwdfile = "";
            if (args.length == 4) {
                passwdfile = args[3];
            }
            // System.out.println("");
            // System.out.println("pdfInputFileName : " + pdfInputFileName);
            // System.out.println("pdfOutputFileName: " + pdfOutputFileName);

            if (usePKCS12)
                readPrivateKeyFromPKCS12(pkcs12FileName, passwdfile);
            else
                readPrivateKeyFromPKCS11();

            PdfReader reader = null;
            try {
                reader = new PdfReader(pdfInputFileName);
            } catch (IOException e) {
                System.err
                        .println("An unknown error accoured while opening the input PDF file: \""
                                + pdfInputFileName + "\"");
                e.printStackTrace();
                System.exit(-1);
            }
            FileOutputStream fout = null;
            try {
                fout = new FileOutputStream(pdfOutputFileName);
            } catch (FileNotFoundException e) {
                System.err
                        .println("An unknown error accoured while opening the output PDF file: \""
                                + pdfOutputFileName + "\"");
                e.printStackTrace();
                System.exit(-1);
            }
            PdfStamper stp = null;
            try {
                stp = PdfStamper.createSignature(reader, fout, '\0', null, true);
                PdfSignatureAppearance sap = stp.getSignatureAppearance();
                sap.setCrypto(privateKey, certificateChain, null, PdfSignatureAppearance.WINCER_SIGNED);
                // sap.setCrypto(privateKey, certificateChain, null, null);
                // sap.setReason("I'm the author");
                // sap.setLocation("Lisbon");
                // sap.setVisibleSignature(new Rectangle(100, 100, 200, 200), 1,
                // null);
                sap.setCertified(true);
                stp.close();
            } catch (Exception e) {
                System.err
                        .println("An unknown error accoured while signing the PDF file:");
                e.printStackTrace();
                System.exit(-1);
            }
        } catch (KeyStoreException kse) {
            System.err
                    .println("An unknown error accoured while initializing the KeyStore instance:");
            kse.printStackTrace();
            System.exit(-1);
        }
    }

    private static void readPrivateKeyFromPKCS11() throws KeyStoreException {
        // Initialize PKCS#11 provider from config file
        String configFileName = getConfigFilePath("pkcs11.cfg");

        Provider p = null;
        try {
            p = new SunPKCS11(configFileName);
            Security.addProvider(p);
        } catch (ProviderException e) {
            System.err
                    .println("Unable to load PKCS#11 provider with config file: "
                            + configFileName);
            e.printStackTrace();
            System.exit(-1);
        }
        String pkcs11PIN = "000000";
        System.out.print("Please enter the smartcard pin: ");
        try {
            BufferedReader in = new BufferedReader(new InputStreamReader(
                    System.in));
            pkcs11PIN = in.readLine();
            // System.out.println(pkcs11PIN);
            // System.out.println(pkcs11PIN.length());
        } catch (Exception e) {
            System.err
                    .println("An unknown error accoured while reading the PIN:");
            e.printStackTrace();
            System.exit(-1);
        }
        KeyStore ks = null;
        try {
            ks = KeyStore.getInstance("pkcs11", p);
            ks.load(null, pkcs11PIN.toCharArray());
        } catch (NoSuchAlgorithmException e) {
            System.err
                    .println("An unknown error accoured while reading the PKCS#11 smartcard:");
            e.printStackTrace();
            System.exit(-1);
        } catch (CertificateException e) {
            System.err
                    .println("An unknown error accoured while reading the PKCS#11 smartcard:");
            e.printStackTrace();
            System.exit(-1);
        } catch (IOException e) {
            System.err
                    .println("An unknown error accoured while reading the PKCS#11 smartcard:");
            e.printStackTrace();
            System.exit(-1);
        }

        String alias = "";
        try {
            alias = (String) ks.aliases().nextElement();
            privateKey = (PrivateKey) ks.getKey(alias, pkcs11PIN.toCharArray());
        } catch (NoSuchElementException e) {
            System.err
                    .println("An unknown error accoured while retrieving the private key:");
            System.err
                    .println("The selected PKCS#12 file does not contain any private keys.");
            e.printStackTrace();
            System.exit(-1);
        } catch (NoSuchAlgorithmException e) {
            System.err
                    .println("An unknown error accoured while retrieving the private key:");
            e.printStackTrace();
            System.exit(-1);
        } catch (UnrecoverableKeyException e) {
            System.err
                    .println("An unknown error accoured while retrieving the private key:");
            e.printStackTrace();
            System.exit(-1);
        }
        certificateChain = ks.getCertificateChain(alias);
    }

    protected static void readPrivateKeyFromPKCS12(String pkcs12FileName, String pwdFile)
            throws KeyStoreException {
        String pkcs12Password = "";
        KeyStore ks = null;
        if (!pwdFile.equals("")) {
            try {
                FileInputStream pwdfis = new FileInputStream(pwdFile);
                byte[] pwd = new byte[1024];
                try {
                    do {
                        int r = pwdfis.read(pwd);
                        if (r < 0) {
                            break;
                        }
                        pkcs12Password += new String(pwd);
                        pkcs12Password = pkcs12Password.trim();
                    } while (pwdfis.available() > 0);
                    pwdfis.close();
                } catch (IOException ex) {
                    System.err
                        .println("Can't read password file: " + pwdFile);
                }
            } catch (FileNotFoundException fnfex) {
                System.err
                    .println("Password file not found: " + pwdFile);
            }
        } else {
            System.out.print("Please enter the password for \"" + pkcs12FileName
                    + "\": ");
            try {
                BufferedReader in = new BufferedReader(new InputStreamReader(
                        System.in));
                pkcs12Password = in.readLine();
            } catch (Exception e) {
                System.err
                        .println("An unknown error accoured while reading the password:");
                e.printStackTrace();
                System.exit(-1);
            }
        }

        try {
            ks = KeyStore.getInstance("pkcs12");
            ks.load(new FileInputStream(pkcs12FileName), pkcs12Password
                    .toCharArray());
        } catch (NoSuchAlgorithmException e) {
            System.err
                    .println("An unknown error accoured while reading the PKCS#12 file:");
            e.printStackTrace();
            System.exit(-1);
        } catch (CertificateException e) {
            System.err
                    .println("An unknown error accoured while reading the PKCS#12 file:");
            e.printStackTrace();
            System.exit(-1);
        } catch (FileNotFoundException e) {
            System.err.println("Unable to open the PKCS#12 keystore file \""
                    + pkcs12FileName + "\":");
            System.err
                    .println("The file does not exists or missing read permission.");
            System.exit(-1);
        } catch (IOException e) {
            System.err
                    .println("An unknown error accoured while reading the PKCS#12 file:");
            e.printStackTrace();
            System.exit(-1);
        }
        String alias = "";
        try {
            alias = (String) ks.aliases().nextElement();
            privateKey = (PrivateKey) ks.getKey(alias, pkcs12Password
                    .toCharArray());
        } catch (NoSuchElementException e) {
            System.err
                    .println("An unknown error accoured while retrieving the private key:");
            System.err
                    .println("The selected PKCS#12 file does not contain any private keys.");
            e.printStackTrace();
            System.exit(-1);
        } catch (NoSuchAlgorithmException e) {
            System.err
                    .println("An unknown error accoured while retrieving the private key:");
            e.printStackTrace();
            System.exit(-1);
        } catch (UnrecoverableKeyException e) {
            System.err
                    .println("An unknown error accoured while retrieving the private key:");
            e.printStackTrace();
            System.exit(-1);
        }
        certificateChain = ks.getCertificateChain(alias);
    }

    protected static String getConfigFilePath(String configFilename) {
        CodeSource source = JPdfSign.class.getProtectionDomain()
                .getCodeSource();
        URL url = source.getLocation();

        String jarPath = URLDecoder.decode(url.getFile());
        File f = new File(jarPath);
        try {
            jarPath = f.getCanonicalPath();
        } catch (IOException e) {
        }
        if (!f.isDirectory()) {
            f = new File(jarPath);
            jarPath = f.getParent();
        }
        System.out.println(jarPath);
        if (jarPath.length() > 0) {
            return jarPath + File.separator + configFilename;
        } else
            return configFilename;
    }

    public static void showUsage() {
        System.out.println("jPdfSign v" + VERSION
                + " by Jan Peter Stotz - jpstotz@gmx.de\n");
        System.out.println(PRODUCTNAME + " usage:");
        System.out
                .println("\nFor using a PKCS#12 (.p12) file as signature certificate and private key source:");
        System.out.print("\tjava -jar " + JAR_FILENAME);
        System.out
                .println(" pkcs12FileName pdfInputFileName pdfOutputFileName");
        System.out
                .println("\nFor using a PKCS#11 smartcard as signature certificate and private key source:");
        System.out.print("\tjava -jar" + JAR_FILENAME);
        System.out.println(" -PKCS11 pdfInputFileName pdfOutputFileName");
        System.exit(0);
    }
}