/*
    * 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.ajax;
  
  
  import org.apache.myfaces.tobago.internal.ajax.AjaxInternalUtils;
  import org.apache.myfaces.tobago.internal.util.ResponseUtils;
  import org.apache.myfaces.tobago.util.ComponentUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import javax.faces.component.UIComponent;
  import javax.faces.context.FacesContext;
  import javax.servlet.http.HttpServletResponse;
  import java.io.IOException;
  import java.io.PrintWriter;
  import java.io.Writer;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.StringTokenizer;
  
  public class AjaxUtils {
  
    private static final Logger LOG = LoggerFactory.getLogger(AjaxUtils.class);
  
    public static boolean isAjaxRequest(FacesContext facesContext) {
      Map parameterMap = facesContext.getExternalContext().getRequestParameterMap();
      String ajaxComponentIds = (String) parameterMap.get(AjaxInternalUtils.TOBAGO_PARTIAL_IDS);
      return ajaxComponentIds != null;
    }
  
    public static void removeAjaxComponent(FacesContext facesContext, String clientId) {
      Map<String, UIComponent> ajaxComponents = AjaxInternalUtils.getAjaxComponents(facesContext);
      if (ajaxComponents != null) {
        ajaxComponents.remove(clientId);
      }
    }
  
    public static void addAjaxComponent(FacesContext facesContext, String clientId) {
      addAjaxComponent(facesContext, facesContext.getViewRoot().findComponent(clientId));
    }
  
    public static void addAjaxComponent(FacesContext facesContext, UIComponent component) {
      if (component == null) {
        LOG.warn("Ignore AjaxComponent: null");
        return;
      }
      Map<String, UIComponent> ajaxComponents = AjaxInternalUtils.getAjaxComponents(facesContext);
      if (ajaxComponents != null) {
        ajaxComponents.put(component.getClientId(facesContext), component);
      }
    }
  
    public static Set<String> getRequestPartialIds(FacesContext facesContext) {
      Map parameterMap = facesContext.getExternalContext().getRequestParameterMap();
      String ajaxComponentIds = (String) parameterMap.get(AjaxInternalUtils.TOBAGO_PARTIAL_IDS);
      if (ajaxComponentIds != null) {
        StringTokenizer tokenizer = new StringTokenizer(ajaxComponentIds, ",");
        Set<String> ajaxComponents = new HashSet<String>(tokenizer.countTokens());
        while (tokenizer.hasMoreTokens()) {
          String ajaxId = tokenizer.nextToken();
          ajaxComponents.add(ajaxId);
        }
        return ajaxComponents;
      }
      return Collections.EMPTY_SET;
    }
  
    /**
     *
     * @param context
     * @return true if a UIMessage component has added to renderedPartially
     */
    public static boolean addUIMessagesToRenderedPartially(FacesContext context) {
      if (!isAjaxRequest(context)) {
        return false;
      }
      List<String> list = AjaxInternalUtils.getMessagesComponentIds(context);
     Iterator clientIds = context.getClientIdsWithMessages();
     boolean added = false;
 
     if (clientIds.hasNext()) { // messages in the partial part
       for (String componentClientId: list) {
         added = AjaxInternalUtils.addNextPossibleAjaxComponent(context, componentClientId);
       }
     } else {  // checking for an existing shown error on page
       for (String componentClientId: list) {
         if (context.getExternalContext().getRequestParameterMap().containsKey(
             componentClientId + ComponentUtils.SUB_SEPARATOR + "messagesExists")) {
           added = AjaxInternalUtils.addNextPossibleAjaxComponent(context, componentClientId);
         }
       }
     }
     return added;
   }
 
   public static boolean redirect(FacesContext facesContext, String url) throws IOException {
     if (!isAjaxRequest(facesContext)) {
       return false;
     }
     HttpServletResponse httpServletResponse
           = (HttpServletResponse) facesContext.getExternalContext().getResponse();
     Writer writer = httpServletResponse.getWriter();
     String contentType = "application/json; charset=UTF-8";
     ResponseUtils.ensureContentTypeHeader(facesContext, contentType);
     ResponseUtils.ensureNoCacheHeader(facesContext);
     redirectInternal(writer, url);
     writer.close();
     facesContext.responseComplete();
     return true;
   }
 
   private static void redirectInternal(Writer writer, String url) throws IOException {
     writer.flush(); // is needed in some cases, e. g. TOBAGO-1094
     writer.write("{\n  \"tobagoAjaxResponse\": true,\n");
     writer.write("  \"responseCode\": 302,\n");
     writer.write("  \"location\": \"");
     writer.write(url);
     writer.write("\"\n}\n");
     writer.flush();
   }
 
   public static void redirect(HttpServletResponse response, String url) throws IOException {
     PrintWriter writer = response.getWriter();
     String contentType = "application/json; charset=UTF-8";
     ResponseUtils.ensureContentTypeHeader(response, contentType);
     ResponseUtils.ensureNoCacheHeader(response);
     redirectInternal(writer, url);
   }
 }