package at.gv.egovernment.moa.id.config.auth;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

import org.w3c.dom.Element;

import at.gv.egovernment.moa.id.config.ConfigurationBuilder;
import at.gv.egovernment.moa.id.config.ConfigurationException;
import at.gv.egovernment.moa.id.config.ConfigurationProvider;
import at.gv.egovernment.moa.id.config.ConnectionParameter;
import at.gv.egovernment.moa.logging.Logger;
import at.gv.egovernment.moa.util.DOMUtils;
import at.gv.egovernment.moa.util.FileUtils;

/**
 * A class providing access to the Auth Part of the MOA-ID configuration data.
 * 
 * <p>Configuration data is read from an XML file, whose location is given by
 * the <code>moa.id.configuration</code> system property.</p>
 * <p>This class implements the Singleton pattern. The <code>reload()</code>
 * method can be used to update the configuration data. Therefore, it is not
 * guaranteed that consecutive calls to <code>getInstance()</code> will return
 * the same <code>AuthConfigurationProvider</code> all the time. During the
 * processing of a web service request, the current
 * <code>TransactionContext</code> should be used to obtain the
 * <code>AuthConfigurationProvider</code> local to that request.</p>
 * 
 * @author Patrick Peck
 * @author Stefan Knirsch
 * 
 * @version $Id$
 */
public class AuthConfigurationProvider extends ConfigurationProvider {
	
  /**  DEFAULT_ENCODING is "UTF-8" */
  private static final String DEFAULT_ENCODING="UTF-8";
  /**
   * The name of the generic configuration property giving the authentication session time out.
   */
  public static final String AUTH_SESSION_TIMEOUT_PROPERTY =
    "AuthenticationSession.TimeOut";
  /**
   * The name of the generic configuration property giving the authentication data time out.
   */
  public static final String AUTH_DATA_TIMEOUT_PROPERTY =
    "AuthenticationData.TimeOut";

  /**
   * BKUSelectionType HTMLComplete, according to schema type <code>BKUSelectionType</code>
   */
  public static final String BKU_SELECTION_TYPE_HTMLCOMPLETE = 
    "HTMLComplete";
    
  /**
   * BKUSelectionType HTMLSelect, according to schema type <code>BKUSelectionType</code>
   */
  public static final String BKU_SELECTION_TYPE_HTMLSELECT = 
    "HTMLSelect";
    
  /** Singleton instance. <code>null</code>, if none has been created. */
  private static AuthConfigurationProvider instance;

  //
  // configuration data
  //

  /**
	 * configuration files containing transformations for rendering in the 
	 * secure viewer of the security layer implementation;
	 * multiple files can be given for different mime types
	 */
  private String[] transformsInfoFileNames;
	/**
	 * transformations for rendering in the secure viewer of the security layer implementation,
	 * read from {@link transformsInfoFileNames};
	 * multiple transformation can be given for different mime types
	 */
  private String[] transformsInfos;
  /**
   * parameters for connection to MOA SP component
   */
  private ConnectionParameter moaSpConnectionParameter;
	/**
	 * trust profile ID to be used for verifying the identity link signature via MOA ID SP
	 */  
  private String moaSpIdentityLinkTrustProfileID;
	/**
	 * trust profile ID to be used for verifying the AUTH block signature via MOA ID SP
	 */  
  private String moaSpAuthBlockTrustProfileID;
	/**
	 * transformations to be used for verifying the AUTH block signature via MOA ID SP
	 */  
  private String[] moaSpAuthBlockVerifyTransformsInfoIDs;
  /**
   * X509 SubjectNames which will be trusted
   */
  private String[] identityLinkX509SubjectNames;
 
  /**
   * configuration parameters for online applications
   */
  private OAAuthParameter[] onlineApplicationAuthParameters;
  /**
   * the Selection Type of the bku Selection Element
   */
  private String bKUSelectionType;
  /**
   * is the bku Selection Element present?
   */
  private boolean bKUSelectable;
  /**
   * the bku Selection Connection Parameters
   */
  private ConnectionParameter bKUConnectionParameter;
 /**
   * Return the single instance of configuration data.
   * 
   * @return AuthConfigurationProvider The current configuration data.
   * @throws ConfigurationException 
   */
  public static synchronized AuthConfigurationProvider getInstance()
    throws ConfigurationException {

    if (instance == null) {
      reload();
    }
    return instance;
  }

  /**
   * Reload the configuration data and set it if successful.
   * 
   * @return AuthConfigurationProvider The loaded configuration data.
   * @throws ConfigurationException Failure to load the configuration data.
   */
  public static synchronized AuthConfigurationProvider reload()
    throws ConfigurationException {
    String fileName = System.getProperty(ConfigurationProvider.CONFIG_PROPERTY_NAME);
    if (fileName == null) {
      throw new ConfigurationException("config.01", null);
    }
    Logger.info("Loading MOA-ID-AUTH configuration " + fileName);

    instance = new AuthConfigurationProvider(fileName);
    return instance;
  }

  /**
   * Constructor for AuthConfigurationProvider.
   * @param fileName
   * @throws ConfigurationException
   */
  public AuthConfigurationProvider(String fileName)
    throws ConfigurationException {

    load(fileName);
  }

  /**
   * Load the configuration data from XML file with the given name and build
   * the internal data structures representing the MOA ID configuration.
   * 
   * @param fileName The name of the XML file to load.
   * @throws ConfigurationException The MOA configuration could not be
   * read/built.
   */
  private void load(String fileName) throws ConfigurationException {
    InputStream stream = null;
    Element configElem;
    ConfigurationBuilder builder;

    try {
      // load the main config file
      stream = new BufferedInputStream(new FileInputStream(fileName));
      configElem = DOMUtils.parseXmlValidating(stream);
    } catch (Throwable t) {
      throw new ConfigurationException("config.03", null, t);
    } 
    finally {
      try {
        if (stream != null) {
          stream.close();
        }
      } catch (IOException e) {
      }
    }
		try {
      // build the internal datastructures
      builder = new ConfigurationBuilder(configElem);
      bKUConnectionParameter = builder.buildAuthBKUConnectionParameter();
      bKUSelectable = (bKUConnectionParameter!=null);
      bKUSelectionType = builder.buildAuthBKUSelectionType();
		  genericConfiguration = builder.buildGenericConfiguration();
		  transformsInfoFileNames = builder.buildTransformsInfoFileNames();
		  loadTransformsInfos();
	    moaSpConnectionParameter = builder.buildMoaSpConnectionParameter();
	    moaSpIdentityLinkTrustProfileID = builder.getMoaSpIdentityLinkTrustProfileID();
	    moaSpAuthBlockTrustProfileID = builder.getMoaSpAuthBlockTrustProfileID();
	    moaSpAuthBlockVerifyTransformsInfoIDs = builder.buildMoaSpAuthBlockVerifyTransformsInfoIDs();
	    onlineApplicationAuthParameters  = builder.buildOnlineApplicationAuthParameters();
      identityLinkX509SubjectNames =  builder.getIdentityLink_X509SubjectNames();
      defaultChainingMode = builder.getDefaultChainingMode();
      chainingModes = builder.buildChainingModes();  
      trustedCACertificates = builder.getTrustedCACertificates();    } 
    catch (Throwable t) {
      throw new ConfigurationException("config.02", null, t);
  	}
  }

  /**
   * Loads the <code>transformsInfos</code> from files.
   * @throws Exception on any exception thrown
   */
  private void loadTransformsInfos() throws Exception {
	 	transformsInfos = new String[transformsInfoFileNames.length];
  	for (int i = 0; i < transformsInfoFileNames.length; i++) {
  		String fileURL = transformsInfoFileNames[i];
			String transformsInfo = FileUtils.readURL(fileURL, DEFAULT_ENCODING);
 			transformsInfos[i] = transformsInfo;
  	}
  }
  /**
   * Return a string array with all filenames leading
   * to the Transforms Information for the Security Layer
   * @return String[] of filenames to the Security Layer Transforms Information
   */
  public String[] getTransformsInfoFileNames()  {
  	return transformsInfoFileNames;
  }
  
  /**
   * Build an array of the OnlineApplication Parameters containing information 
   * about the authentication component
   * @return An OAProxyParameter array containing beans
   * with all relevant information for theauthentication component of the online 
   * application
   */
  public OAAuthParameter[] getOnlineApplicationParameters() {
    return onlineApplicationAuthParameters;
  }

  /**
   * Provides configuration information regarding the online application behind
   * the given URL, relevant to the MOA-ID Auth component.
   * 
   * @param oaURL URL requested for an online application
   * @return an <code>OAAuthParameter</code>, or <code>null</code>
   * 					if none is applicable
   */
  public OAAuthParameter getOnlineApplicationParameter(String oaURL) {
  	OAAuthParameter[] oaParams = getOnlineApplicationParameters();
  	for (int i = 0; i < oaParams.length; i++) {
  		OAAuthParameter oaParam = oaParams[i];
  		if (oaURL.indexOf(oaParam.getPublicURLPrefix()) == 0)
  			return oaParam;
  	}
    return null;
  }

  /**
   * Return a string with a url-reference to the VerifyAuthBlock trust 
   * profile id within the moa-sp part of the authentication component
   * 
   * @return String with a url-reference to the VerifyAuthBlock trust profile ID
   */
  public String getMoaSpAuthBlockTrustProfileID() {
    return moaSpAuthBlockTrustProfileID;
  }

  /**
   * Return a string array with references to all verify transform info 
   * IDs within the moa-sp part of the authentication component
   * @return A string array containing all urls to the 
   * verify transform info IDs
   */
  public String[] getMoaSpAuthBlockVerifyTransformsInfoIDs() {
    return moaSpAuthBlockVerifyTransformsInfoIDs;
  }

  /**
   * Return a ConnectionParameter bean containing all information
   * of the authentication component moa-sp element 
   * @return ConnectionParameter of the authentication component moa-sp element 
   */
  public ConnectionParameter getMoaSpConnectionParameter() {
    return moaSpConnectionParameter;
  }

  /**
   * Return a string with a url-reference to the VerifyIdentityLink trust 
   * profile id within the moa-sp part of the authentication component
   * @return String with a url-reference to the VerifyIdentityLink trust profile ID
   */
  public String getMoaSpIdentityLinkTrustProfileID() {
    return moaSpIdentityLinkTrustProfileID;
  }
  /**
   * Returns the transformsInfos.
   * @return String[]
   */
  public String[] getTransformsInfos() {
    return transformsInfos;
  }

  /**
   * Returns the identityLinkX509SubjectNames.
   * @return String[]
   */
  public String[] getIdentityLinkX509SubjectNames() {
    return identityLinkX509SubjectNames;
  }

  /**
   * Returns the bKUConnectionParameter.
   * @return ConnectionParameter
   */
  public ConnectionParameter getBKUConnectionParameter() {
    return bKUConnectionParameter;
  }

  /**
   * Returns the bKUSelectable.
   * @return boolean
   */
  public boolean isBKUSelectable() {
    return bKUSelectable;
  }

  /**
   * Returns the bKUSelectionType.
   * @return String
   */
  public String getBKUSelectionType() {
    return bKUSelectionType;
  }

}