/*
    * Licensed under the GPL License. You may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *   https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
    *
    * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
    * WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
    * PURPOSE.
   */
  package psiprobe.jsp;
  
  import java.io.IOException;
  import java.io.UnsupportedEncodingException;
  import java.net.URLEncoder;
  import java.util.Collections;
  
  import javax.servlet.jsp.JspException;
  import javax.servlet.jsp.tagext.TagSupport;
  
  import org.springframework.web.bind.ServletRequestUtils;
  
  /**
   * The Class ParamToggleTag.
   */
  public class ParamToggleTag extends TagSupport {
  
    /** The Constant serialVersionUID. */
    private static final long serialVersionUID = 1L;
  
    /** The param. */
    private String param = "size";
  
    @Override
    public int doStartTag() throws JspException {
      boolean getSize =
          ServletRequestUtils.getBooleanParameter(pageContext.getRequest(), param, false);
      StringBuilder query = new StringBuilder();
  
      String encoding = pageContext.getResponse().getCharacterEncoding();
      for (String name : Collections.list(pageContext.getRequest().getParameterNames())) {
        if (!param.equals(name)) {
          try {
            String value = ServletRequestUtils.getStringParameter(pageContext.getRequest(), name, "");
            String encodedValue = URLEncoder.encode(value, encoding);
            if (query.length() > 0) {
              query.append('&');
            }
            query.append(name).append('=').append(encodedValue);
          } catch (UnsupportedEncodingException e) {
            throw new JspException(e);
          }
        }
      }
  
      if (query.length() > 0) {
        query.append('&');
      }
      // size param has to be last
      query.append(param).append('=').append(!getSize);
  
      try {
        pageContext.getOut().print(query);
      } catch (IOException e) {
        throw new JspException("Exception printing query string to JspWriter", e);
      }
      return EVAL_BODY_INCLUDE;
    }
  
    /**
     * Gets the param.
     *
     * @return the param
     */
    public String getParam() {
      return param;
    }
  
    /**
     * Sets the param.
     *
     * @param param the new param
     */
    public void setParam(String param) {
      this.param = param;
    }
  
  }