package aQute.bnd.signing;

import java.io.*;
import java.security.*;
import java.security.KeyStore.*;
import java.util.*;
import java.util.jar.*;
import java.util.regex.*;

import aQute.lib.base64.*;
import aQute.lib.osgi.*;

/**
 * This class is used with the aQute.lib.osgi package, it signs jars with DSA
 * signature.
 * 
 * -sign: md5, sha1
 */
public class Signer extends Processor {
    static Pattern  METAINFDIR   = Pattern.compile("META-INF/[^/]*");
    String         digestNames[]    = new String[] { "MD5" };
    File           keystoreFile  = new File("keystore");
    String         password;
    String         alias;

    public void signJar(Jar jar) {
        if (digestNames == null || digestNames.length == 0)
            error("Need at least one digest algorithm name, none are specified");

        if (keystoreFile == null || !keystoreFile.getAbsoluteFile().exists()) {
            error("No such keystore file: " + keystoreFile);
            return;
        }

        if (alias == null) {
            error("Private key alias not set for signing");
            return;
        }

        MessageDigest digestAlgorithms[] = new MessageDigest[digestNames.length];

        getAlgorithms(digestNames, digestAlgorithms);

        try {
            Manifest manifest = jar.getManifest();
            manifest.getMainAttributes().putValue("Signed-By", "Bnd");

            // Create a new manifest that contains the
            // Name parts with the specified digests

            ByteArrayOutputStream o = new ByteArrayOutputStream();
            manifest.write(o);
            doManifest(jar, digestNames, digestAlgorithms, o);
            o.flush();
            byte newManifestBytes[] = o.toByteArray();
            jar.putResource("META-INF/MANIFEST.MF", new EmbeddedResource(
                    newManifestBytes, 0));

            // Use the bytes from the new manifest to create
            // a signature file

            byte[] signatureFileBytes = doSignatureFile(digestNames,
                    digestAlgorithms, newManifestBytes);
            jar.putResource("META-INF/BND.SF", new EmbeddedResource(
                    signatureFileBytes, 0));

            // Now we must create an RSA signature
            // this requires the private key from the keystore

            KeyStore keystore = KeyStore.getInstance(KeyStore.getDefaultType());

            KeyStore.PrivateKeyEntry privateKeyEntry = null;

            try {
                java.io.FileInputStream keystoreInputStream = new java.io.FileInputStream(
                        keystoreFile);
                keystore.load(keystoreInputStream, password == null ? null
                        : password.toCharArray());
                keystoreInputStream.close();
                privateKeyEntry =  (PrivateKeyEntry) keystore.getEntry(
                        alias, new KeyStore.PasswordProtection(password
                                .toCharArray()));
            } catch (Exception e) {
                error("No able to load the private key from the give keystore("+keystoreFile.getAbsolutePath()+") with alias "+alias+" : "
                        + e);
                return;
            }
            PrivateKey privateKey = privateKeyEntry.getPrivateKey();

            Signature signature = Signature.getInstance("MD5withRSA");
            signature.initSign(privateKey);

            signature.update(signatureFileBytes);

            signature.sign();

            // TODO, place the SF in a PCKS#7 structure ...
            // no standard class for this? The following
            // is an idea but we will to have do ASN.1 BER
            // encoding ...

         
            
            ByteArrayOutputStream tmpStream = new ByteArrayOutputStream();
            jar.putResource("META-INF/BND.RSA", new EmbeddedResource(tmpStream
                    .toByteArray(), 0));
        } catch (Exception e) {
            error("During signing: " + e);
        }
    }

    private byte[] doSignatureFile(String[] digestNames,
            MessageDigest[] algorithms, byte[] manbytes) {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        PrintStream ps = new PrintStream(out);
        ps.print("Signature-Version: 1.0\r\n");

        for (int a = 0; a < algorithms.length; a++) {
            if (algorithms[a] != null) {
                byte[] digest = algorithms[a].digest(manbytes);
                ps.print(digestNames[a] + "-Digest-Manifest: ");
                ps.print(new Base64(digest));
                ps.print("\r\n");
            }
        }
        return out.toByteArray();
    }

    private void doManifest(Jar jar, String[] digestNames,
            MessageDigest[] algorithms, OutputStream out) throws Exception {

        for (Map.Entry<String,Resource> entry : jar.getResources().entrySet()) {
            String name = entry.getKey();
            if (!METAINFDIR.matcher(name).matches()) {
                out.write("\r\n".getBytes());
                out.write("Name: ".getBytes());
                out.write(name.getBytes());
                out.write("\r\n".getBytes());

                digest(algorithms, entry.getValue());
                for (int a = 0; a < algorithms.length; a++) {
                    if (algorithms[a] != null) {
                        byte[] digest = algorithms[a].digest();
                        String header = digestNames[a] + "-Digest: "
                                + new Base64(digest) + "\r\n";
                        out.write(header.getBytes());
                    }
                }
            }
        }
    }

    private void digest(MessageDigest[] algorithms, Resource r)
            throws Exception {
        InputStream in = r.openInputStream();
        byte[] data = new byte[1024];
        int size = in.read(data);
        while (size > 0) {
            for (int a = 0; a < algorithms.length; a++) {
                if (algorithms[a] != null) {
                    algorithms[a].update(data, 0, size);
                }
            }
            size = in.read(data);
        }
    }

    private void getAlgorithms(String[] digestNames, MessageDigest[] algorithms) {
        for (int i = 0; i < algorithms.length; i++) {
            String name = digestNames[i];
            try {
                algorithms[i] = MessageDigest.getInstance(name);
            } catch (NoSuchAlgorithmException e) {
                error("Specified digest algorithm " + digestNames[i]
                        + ", but not such algorithm was found: " + e);
            }
        }
    }

    public void setPassword(String string) {
        password = string;
    }

    public void setKeystore(File keystore) {
        this.keystoreFile = keystore;
    }

    public void setAlias(String string) {
        this.alias = string;
    }
}