package at.gv.egiz.eid.authhandler.modules.sigverify.moasig.impl;

import java.security.Provider;
import java.security.Security;

import javax.annotation.PostConstruct;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Document;

import at.gv.egiz.eid.authhandler.modules.sigverify.moasig.exceptions.MOASigServiceConfigurationException;
import at.gv.egovernment.moa.spss.MOAException;
import at.gv.egovernment.moa.spss.api.Configurator;
import at.gv.egovernment.moaspss.logging.LoggingContext;
import at.gv.egovernment.moaspss.logging.LoggingContextManager;
import iaik.asn1.structures.AlgorithmID;
import iaik.security.ec.provider.ECCelerate;
import iaik.security.provider.IAIK;

public abstract class AbstractSignatureService {
	private static final Logger log = LoggerFactory.getLogger(AbstractSignatureService.class);
	private static boolean isMOASigInitialized = false;
	
	
	@PostConstruct
	private synchronized void initialize() throws MOASigServiceConfigurationException {
		
		if (!isMOASigInitialized) {		
			log.info("Initializing MOA-Sig signature-verification service ... ");
			
	        log.info("Loading Java security providers.");
	        IAIK.addAsProvider();                
	        ECCelerate.addAsProvider();
			                
	        try {
	        	LoggingContextManager.getInstance().setLoggingContext(
	                    new LoggingContext("startup"));
	        	log.debug("MOA-Sig library initialization process ... ");
	        	Configurator.getInstance().init();        	
	        	log.info("MOA-Sig library initialization complete ");
	        	                       
	         } catch (final MOAException e) {
	        	 log.error("MOA-SP initialization FAILED!", e.getWrapped()); 
	             throw new MOASigServiceConfigurationException("service.moasig.04", new Object[] { e
	                      .toString() }, e);
			}
	        
	        Security.insertProviderAt(IAIK.getInstance(), 0);
	        
	        final ECCelerate eccProvider = ECCelerate.getInstance();
	        if (Security.getProvider(eccProvider.getName()) != null)
	        	Security.removeProvider(eccProvider.getName());	        	
	        Security.addProvider(new ECCelerate());
	        
	        fixJava8_141ProblemWithSSLAlgorithms();
			
	        if (log.isDebugEnabled()) {
	        	log.debug("Loaded Security Provider:");
	        	final Provider[] providerList = Security.getProviders();
	        	for (int i=0; i<providerList.length; i++)
	        		log.debug(i + ": " + providerList[i].getName() + " Version " + providerList[i].getVersion());        		
	        	
	        }
	        
	        isMOASigInitialized = true;
	        
		} else
			log.info("MOA-Sig is already initialized. Skipping this steps ... ");
        
        internalInitializer();
        		
	}
	
	/**
	 * Executed in <code>@PostConstruct</code> as last step
	 * 
	 */
	abstract protected void internalInitializer(); 
	
	/**
	 * Get a new {@link Document} from {@link DocumentBuilder} in synchronized form, because 
	 * {@link DocumentBuilderFactory} and {@link DocumentBuilder} are not thread-safe.
	 * 
	 * @return {@link Document}
	 * @throws ParserConfigurationException
	 */
	protected synchronized Document getNewDocumentBuilder() throws ParserConfigurationException {
		final DocumentBuilder docBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder(); 
		return docBuilder.newDocument();
		
	}
	
    private static void fixJava8_141ProblemWithSSLAlgorithms() {
    	log.info("Change AlgorithmIDs to fix problems with Java8 >= 141 ...");
        //new AlgorithmID("1.2.840.113549.1.1.4", "md5WithRSAEncryption", new String[] { "MD5withRSA", "MD5/RSA",  }, null, true);
        new AlgorithmID("1.2.840.113549.1.1.5", "sha1WithRSAEncryption", 
        		new String[] { "SHA1withRSA" , "SHA1/RSA", "SHA-1/RSA", "SHA/RSA", }, null, true);
        new AlgorithmID("1.2.840.113549.1.1.14", "sha224WithRSAEncryption", 
        		new String[] { "SHA224withRSA", "SHA224/RSA", "SHA-224/RSA", }, null, true);
        new AlgorithmID("1.2.840.113549.1.1.11", "sha256WithRSAEncryption", 
        		new String[] { "SHA256withRSA", "SHA256/RSA", "SHA-256/RSA",  }, null, true);
        new AlgorithmID("1.2.840.113549.1.1.12", "sha384WithRSAEncryption", 
        		new String[] { "SHA384withRSA", "SHA384/RSA", "SHA-384/RSA",  }, null, true);
        new AlgorithmID("1.2.840.113549.1.1.13", "sha512WithRSAEncryption", 
        		new String[] { "SHA512withRSA", "SHA512/RSA", "SHA-512/RSA" }, null, true);
        
        log.info("Change AlgorithmIDs finished");
    }
}