/**
    * Copyright 2005-2013 The Kuali Foundation
    *
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
    *
   * 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 edu.samplu.common;
  
  import freemarker.template.Configuration;
  import freemarker.template.Template;
  import freemarker.template.TemplateException;
  import org.apache.commons.io.FileUtils;
  import org.springframework.ui.freemarker.FreeMarkerTemplateUtils;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.Enumeration;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.Map;
  import java.util.Properties;
  
  /**
   * FreemarkerUtil loads properties from user defined InputStream.  systemPropertiesOverride should be used to override properties
   * using a given key to identify them from JVM args. (i.e. -Dkey.name to override the name property in the key file.)
   * TODO setup so the loading and overriding of properties is done for the user rather then them having to call it.
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class FreemarkerUtil {
  
      protected Configuration cfg;
  
      /**
       * Calls ftlWrite that also accepts a key, using the output getName as the key.
       * @param output
       * @param template
       * @return
       * @throws java.io.IOException
       * @throws freemarker.template.TemplateException
       */
      public static File ftlWrite(File output, Template template, InputStream inputStream) throws IOException, TemplateException {
  
          return ftlWrite(output.getName(), output, template, inputStream);
      }
  
      /**
       * Loads properties from user defined properties file, if not available uses resource file
       *
       * writes processed template  to file
       * @param key
       * @param output
       * @param template
       * @throws IOException
       * @throws TemplateException
       */
      public static File ftlWrite(String key, File output, Template template, InputStream inputStream) throws IOException, TemplateException {
          Properties props = loadProperties(inputStream);
          props.put("baseName", output.getName().substring(0, output.getName().indexOf("ST")));
          props.put("className", output.getName().substring(0, output.getName().indexOf("ST"))); // backwards compatibility
          if (output.getName().contains("TmplMthd")) { // Template method pattern
              props.put("className", output.getName().substring(0, output.getName().indexOf("TmplMthd")));
          }
  
          systemPropertiesOverride(props, key);
          transformNumberedTestPropertiesToList(props);
          File outputFile = writeTemplateToFile(output, template, props);
  
          return outputFile;
      }
  
      protected static Properties loadProperties(InputStream inputStream) throws IOException {
          Properties props = new Properties();
  
          if(inputStream != null) {
              props.load(inputStream);
          }
  
          return props;
      }
  
      protected static void transformNumberedTestPropertiesToList(Properties props) {
          Iterator keys = props.keySet().iterator();
          Map<String, String> keyLists = new HashMap<String, String>();
          while (keys.hasNext()) {
              String key = (String)keys.next();
              if (Character.isDigit(key.charAt(key.length()-1))) {
                  keyLists.put(key, props.getProperty(key));
              }
          }
 
         Iterator listKeys = keyLists.keySet().iterator();
         while (listKeys.hasNext()) {
             String key = (String)listKeys.next();
             props.remove(key);
         }
 
         if (keyLists.values().size() == 0) { // backwards compatibility
             keyLists.put("test1", (String)props.get("className"));
         }
 
         props.put("tests", keyLists.values());
     }
 
     /**
      *
      * @param file
      * @param template
      * @param props
      * @return
      * @throws IOException
      * @throws freemarker.template.TemplateException
      */
     protected static File writeTemplateToFile(File file, Template template, Properties props) throws IOException, TemplateException {
         String output = FreeMarkerTemplateUtils.processTemplateIntoString(template, props);
         FileUtils.writeStringToFile(file, output);
 
         return file;
     }
 
     /**
      * -Dkey.propertyname= to override the property value for propertyname.
      * @param props
      */
     public static void systemPropertiesOverride(Properties props, String key) {
         Enumeration<?> names = props.propertyNames();
         Object nameObject;
         String name;
         while (names.hasMoreElements()) {
             nameObject = names.nextElement();
             if (nameObject instanceof String) {
                 name = (String)nameObject;
                 props.setProperty(name, System.getProperty(key + "." + name, props.getProperty(name)));
             }
         }
     }
 
 }