/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
    *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  
  package org.apache.myfaces.tobago.internal.config;
  
  import org.apache.myfaces.tobago.config.TobagoConfig;
  import org.apache.myfaces.tobago.exception.TobagoConfigurationException;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.xml.sax.SAXException;
  
  import javax.enterprise.context.ApplicationScoped;
  import javax.enterprise.inject.Produces;
  import javax.inject.Inject;
  import javax.inject.Named;
  import javax.servlet.ServletContext;
  import javax.servlet.ServletException;
  import javax.xml.parsers.ParserConfigurationException;
  import java.io.IOException;
  import java.lang.invoke.MethodHandles;
  import java.net.URISyntaxException;
  import java.net.URL;
  import java.util.ArrayList;
  import java.util.Enumeration;
  import java.util.List;
  
  @Named
  @ApplicationScoped
  public class TobagoConfigBuilder {
  
    private static final Logger LOG = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
  
    private static final String WEB_INF_TOBAGO_CONFIG_XML = "WEB-INF/tobago-config.xml";
    private static final String META_INF_TOBAGO_CONFIG_XML = "META-INF/tobago-config.xml";
  
    @Inject
    private ServletContext servletContext;
  
    private TobagoConfigImpl tobagoConfig;
  
    @Produces
    public TobagoConfig buildTobagoConfig() {
      if (tobagoConfig == null) {
        init();
      }
      return tobagoConfig;
    }
  
    private void init() {
      final List<TobagoConfigFragment> configFragmentList = new ArrayList<>();
      try {
        configFromClasspath(configFragmentList);
        configFromWebInf(configFragmentList);
        final TobagoConfigSorter sorter = new TobagoConfigSorter(configFragmentList);
        final TobagoConfigMerger merger = new TobagoConfigMerger(sorter.topologicalSort());
        tobagoConfig = merger.merge();
        // prepare themes
        tobagoConfig.resolveThemes();
        tobagoConfig.initDefaultValidatorInfo();
        tobagoConfig.lock();
        servletContext.setAttribute(TobagoConfig.TOBAGO_CONFIG, tobagoConfig);
      } catch (final Exception e) {
        final String error = "Tobago can't be initialized! Application will not run correctly!";
        LOG.error(error, e);
        throw new TobagoConfigurationException(error, e);
      }
    }
  
    private void configFromWebInf(final List<TobagoConfigFragment> configFragmentList)
        throws IOException, SAXException, ParserConfigurationException, URISyntaxException {
  
      final URL url = servletContext.getResource("/" + WEB_INF_TOBAGO_CONFIG_XML);
      if (url != null) {
        configFragmentList.add(new TobagoConfigParser().parse(url));
      }
    }
  
    private void configFromClasspath(final List<TobagoConfigFragment> configFragmentList)
        throws ServletException {
  
      try {
        if (LOG.isInfoEnabled()) {
          LOG.info("Searching for '" + META_INF_TOBAGO_CONFIG_XML + "'");
       }
       final ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
       final Enumeration<URL> urls = classLoader.getResources(META_INF_TOBAGO_CONFIG_XML);
       while (urls.hasMoreElements()) {
         final URL themeUrl = urls.nextElement();
         try {
           final TobagoConfigFragment fragment = new TobagoConfigParser().parse(themeUrl);
           fragment.setUrl(themeUrl);
           configFragmentList.add(fragment);
 
           // tomcat uses jar
           // weblogic uses zip
           // IBM WebSphere uses wsjar
           final String protocol = themeUrl.getProtocol();
           if (!"file".equals(protocol) && !"jar".equals(protocol)
               && !"zip".equals(protocol) && !"wsjar".equals(protocol)) {
             LOG.warn("Unknown protocol '" + themeUrl + "'");
           }
         } catch (final Exception e) {
           throw new Exception(e.getClass().getName() + " on themeUrl: " + themeUrl, e);
         }
       }
     } catch (final Exception e) {
       final String msg = "while loading ";
       LOG.error(msg, e);
       throw new ServletException(msg, e);
     }
   }
 }