package at.gv.egovernment.moa.id.proxy;

import java.util.HashMap;
import java.util.Map;

import at.gv.egovernment.moa.id.config.ConfigurationException;
import at.gv.egovernment.moa.id.config.proxy.ProxyConfigurationProvider;
import at.gv.egovernment.moa.id.config.proxy.OAProxyParameter;

/**
 * Factory delivering a {@link LoginParameterResolver} implementation for
 * an online application, initialized from configuration data. 
 * @author Paul Ivancsics
 * @version $Id$
 */
public class LoginParameterResolverFactory {

  /** default login parameter resolver to be used for online application
   *  where no special implementation of the <code>LoginParameterResolver</code> 
   *  interface is configured 
   */
  private static LoginParameterResolver defaultLoginParameterResolver;
  /** mapping from online application public URL prefix to an implementation
   *  of the <code>LoginParameterResolver</code> interface to be used;
   *  if no mapping is given for an online application, the 
   *  <code>DefaultLoginParameterResolver</code> will be used */
  private static Map loginParameterResolverMap;

  /**
   * Initializes the <code>LoginParameterResolver</code> map from the configuration data.
   * @throws ConfigurationException when the configuration cannot be read,
   *          or when a class name configured cannot be instantiated
   */
  public static void initialize() throws ConfigurationException {
    defaultLoginParameterResolver = new DefaultLoginParameterResolver();
    loginParameterResolverMap = new HashMap();
    ProxyConfigurationProvider proxyConf = ProxyConfigurationProvider.getInstance();
    for (int i = 0; i < proxyConf.getOnlineApplicationParameters().length; i++) {
      OAProxyParameter oaParam = proxyConf.getOnlineApplicationParameters()[i];
      String publicURLPrefix = oaParam.getPublicURLPrefix();
      String className = oaParam.getLoginParameterResolverImpl();
      if (className != null) {
        try {
          LoginParameterResolver lpr = (LoginParameterResolver)Class.forName(className).newInstance();
          loginParameterResolverMap.put(publicURLPrefix, lpr); 
        }
        catch (Throwable ex) {
          throw new ConfigurationException("config.07", new Object[] {publicURLPrefix}, ex);
        }
      }
    }
  }
  
  /**
   * Gets the <code>LoginParameterResolver</code> implementation to be used for the given
   * online application.
   * @param publicURLPrefix public URL prefix of the online application
   * @return <code>LoginParameterResolver</code> implementation
   */
  public static LoginParameterResolver getLoginParameterResolver(String publicURLPrefix) {
    LoginParameterResolver lpr = (LoginParameterResolver) loginParameterResolverMap.get(publicURLPrefix);
    if (lpr == null)
      return defaultLoginParameterResolver;
    else
      return lpr;
  }

}