/*
    * #%L
    * wcm.io
    * %%
    * Copyright (C) 2015 wcm.io
    * %%
    * Licensed 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.
   * #L%
   */
  package io.wcm.caravan.hal.docs.impl.reader;
  
  import io.wcm.caravan.hal.docs.impl.model.Service;
  
  import java.io.InputStream;
  import java.net.URL;
  
  import org.osgi.framework.Bundle;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Reader for service model files.
   */
  public final class ServiceModelReader {
  
    /**
     * Classpath prefix where HAL documentation files are stored.
     */
    public static final String DOCS_CLASSPATH_PREFIX = "HAL-DOCS-INF";
  
    /**
     * Filename with serialized model information for HAL documentation.
     */
    public static final String SERVICE_DOC_FILE = "serviceDoc.json";
  
    private static final Logger log = LoggerFactory.getLogger(ServiceModelReader.class);
  
    private ServiceModelReader() {
      // static methods only
    }
  
    /**
     * Reads service model from bundle classpath.
     * @param bundle Bundle
     * @return Service model or null if not found or not parseable.
     */
    public static Service read(Bundle bundle) {
      String resourcePath = DOCS_CLASSPATH_PREFIX + "/" + SERVICE_DOC_FILE;
      URL bundleResource = bundle.getResource(resourcePath);
      if (bundleResource == null) {
        return null;
      }
      try (InputStream is = bundleResource.openStream()) {
        return new ServiceJson().read(is);
      }
      catch (Throwable ex) {
        log.error("Unable to parse JSON file " + resourcePath + " from bundle " + bundle.getSymbolicName());
        return null;
      }
    }
  
  }