/*
    * 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.example.demo;
  
  import org.apache.commons.io.IOUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import javax.faces.context.ExternalContext;
  import javax.faces.context.FacesContext;
  import java.io.IOException;
  import java.io.InputStream;
  import java.lang.invoke.MethodHandles;
  import java.nio.charset.StandardCharsets;
  
  public abstract class SourceFileReader {
  
    private static final Logger LOG = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
  
    public String getSource(final String filename) {
      final FacesContext facesContext = FacesContext.getCurrentInstance();
      final ExternalContext externalContext = facesContext.getExternalContext();
      final String viewId = facesContext.getViewRoot().getViewId();
      final String file = viewId.substring(0, viewId.lastIndexOf("/")) + "/" + filename;
      try (final InputStream resourceAsStream = externalContext.getResourceAsStream(file)) {
        if (resourceAsStream != null) {
          return IOUtils.toString(resourceAsStream, StandardCharsets.UTF_8);
        }
      } catch (final IOException e) {
        LOG.error("", e);
      }
      return null;
    }
  }