/*
    * 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.hadoop.chukwa.datastore;
  
  import java.io.File;
  import java.io.IOException;
  import java.nio.charset.Charset;
  import java.util.HashMap;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.json.simple.JSONObject;
  import org.json.simple.JSONValue;
  import org.apache.hadoop.chukwa.conf.ChukwaConfiguration;
  import org.apache.hadoop.chukwa.hicc.HiccWebServer;
  import org.apache.hadoop.chukwa.rest.bean.CatalogBean;
  import org.apache.hadoop.chukwa.rest.bean.WidgetBean;
  import org.apache.hadoop.chukwa.util.ExceptionUtil;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FSDataInputStream;
  import org.apache.hadoop.fs.FSDataOutputStream;
  import org.apache.hadoop.fs.FileStatus;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  
  public class WidgetStore {
    private static Log log = LogFactory.getLog(WidgetStore.class);
    private static Configuration config = new Configuration();
    private static ChukwaConfiguration chukwaConf = new ChukwaConfiguration();
    private static String hiccPath = null;
    private static CatalogBean catalog = null;
    private static HashMap<String, WidgetBean> list = new HashMap<String, WidgetBean>();
    
    static {
      config = HiccWebServer.getConfig();
      hiccPath = config.get("fs.defaultFS")+File.separator+chukwaConf.get("chukwa.data.dir")+File.separator+"hicc"+File.separator+"widgets";
    }
    public WidgetStore() throws IllegalAccessException {
    }
  
    public void set(WidgetBean widget) throws IllegalAccessException {
      try {
        StringBuilder widgetPath = new StringBuilder();
        widgetPath.append(hiccPath);
        widgetPath.append(File.separator);
        widgetPath.append(widget.getId());
        widgetPath.append(".descriptor");
        Path widgetFile = new Path(widgetPath.toString());
        FileSystem fs;
        try {
          fs = FileSystem.get(config);
          FSDataOutputStream out = fs.create(widgetFile,true);
          out.writeBytes(widget.deserialize().toString());
          out.close();
        } catch (IOException ex) {
          log.error(ExceptionUtil.getStackTrace(ex));
        }
        cacheWidgets();
      } catch (Exception e) {
        log.error(ExceptionUtil.getStackTrace(e));
        throw new IllegalAccessException("Unable to access user view database.");
      }
    }
    
    public static void cacheWidgets() throws IllegalAccessException {
      StringBuilder widgetPath = new StringBuilder();
      widgetPath.append(hiccPath);
      Path widgetFiles = new Path(widgetPath.toString());
      FileSystem fs;
      catalog = new CatalogBean();
      catalog.setId("root");
      catalog.setLabel("root");
      try {
        fs = FileSystem.get(config);
        FileStatus[] fstatus = fs.listStatus(widgetFiles);
        if(fstatus!=null) {
          for(int i=0;i<fstatus.length;i++) {
            long size = fstatus[i].getLen();
            FSDataInputStream widgetStream = fs.open(fstatus[i].getPath());
            byte[] buffer = new byte[(int)size];
            widgetStream.readFully(buffer);
            widgetStream.close();
            try {
             JSONObject widgetBuffer = (JSONObject) JSONValue.parse(new String(buffer, Charset.forName("UTF-8")));
             WidgetBean widget = new WidgetBean(widgetBuffer);
             catalog.addCatalog(widget);
             list.put(widget.getId(),widget);
           } catch (Exception e) {
             log.error(ExceptionUtil.getStackTrace(e));
           }
         }
       }
     } catch (IOException ex) {
       log.error(ExceptionUtil.getStackTrace(ex));
       throw new IllegalAccessException("Unable to access user view database."); 
     }    
   }
 
   public static CatalogBean getCatalog() throws IllegalAccessException {
     if(catalog==null) {
       cacheWidgets();
     }
     return catalog;
   }
   
   public static HashMap<String, WidgetBean> list() throws IllegalAccessException {
     if(list.size()==0) {
       cacheWidgets();
     }
     return list;
   }
 }