/*
    * 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.commons.monitoring.reporting.web.template;
  
  import org.apache.commons.monitoring.reporting.web.plugin.PluginRepository;
  import org.apache.velocity.Template;
  import org.apache.velocity.VelocityContext;
  import org.apache.velocity.app.Velocity;
  import org.apache.velocity.runtime.RuntimeConstants;
  import org.apache.velocity.runtime.log.JdkLogChute;
  import org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader;
  
  import java.io.PrintWriter;
  import java.util.Map;
  import java.util.Properties;
  
  public final class Templates {
      private static String mapping;
  
      public static void init(final String context, final String filterMapping) {
          final Properties velocityConfiguration = new Properties();
          velocityConfiguration.setProperty(RuntimeConstants.RUNTIME_LOG_LOGSYSTEM_CLASS, JdkLogChute.class.getName());
          velocityConfiguration.setProperty(RuntimeConstants.ENCODING_DEFAULT, "UTF-8");
          velocityConfiguration.setProperty(RuntimeConstants.INPUT_ENCODING, "UTF-8");
          velocityConfiguration.setProperty(RuntimeConstants.OUTPUT_ENCODING, "UTF-8");
          velocityConfiguration.setProperty(RuntimeConstants.RUNTIME_REFERENCES_STRICT, Boolean.TRUE.toString());
          velocityConfiguration.setProperty(RuntimeConstants.RUNTIME_REFERENCES_STRICT_ESCAPE, Boolean.TRUE.toString());
          velocityConfiguration.setProperty(RuntimeConstants.RESOURCE_LOADER, "monitoring");
          velocityConfiguration.setProperty(RuntimeConstants.VM_LIBRARY, "/templates/macro.vm");
          velocityConfiguration.setProperty("monitoring." + RuntimeConstants.RESOURCE_LOADER + ".class", ClasspathResourceLoader.class.getName());
          Velocity.init(velocityConfiguration);
  
          if (filterMapping.isEmpty()) {
              mapping = context;
          } else {
              mapping = context + filterMapping;
          }
      }
  
      public static void htmlRender(final PrintWriter writer, final String template, final Map<String, ?> variables) {
          final VelocityContext context = newVelocityContext(variables);
          context.put("mapping", mapping);
          context.put("currentTemplate", template);
          context.put("plugins", PluginRepository.PLUGIN_INFO);
          if (context.get("templateId") == null) {
              context.put("templateId", template.replace(".vm", ""));
          }
  
          final Template velocityTemplate = Velocity.getTemplate("/templates/page.vm", "UTF-8");
          velocityTemplate.merge(context, writer);
      }
  
      public static void render(final PrintWriter writer, final String template, final Map<String, ?> variables) {
          final VelocityContext context = newVelocityContext(variables);
          context.put("mapping", mapping);
          final Template velocityTemplate = Velocity.getTemplate(template, "UTF-8");
          velocityTemplate.merge(context, writer);
      }
  
      private static VelocityContext newVelocityContext(final Map<String, ?> variables) {
          final VelocityContext context;
          if (variables.isEmpty()) {
              context = new VelocityContext();
          } else {
              context = new VelocityContext(variables);
          }
          return context;
      }
  
      private Templates() {
          // no-op
      }
  }