/**
    * Copyright 2005-2012 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 org.kuali.rice.edl.impl;
  
  import java.io.UnsupportedEncodingException;
  import java.util.ArrayList;
  import java.util.Enumeration;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  
  import javax.servlet.http.HttpServletRequest;
  
  import org.apache.commons.fileupload.FileItem;
  import org.apache.commons.fileupload.FileUploadException;
  import org.apache.commons.fileupload.disk.DiskFileItemFactory;
  import org.apache.commons.fileupload.servlet.ServletFileUpload;
  import org.apache.commons.lang.ArrayUtils;
  import org.kuali.rice.kew.api.WorkflowRuntimeException;
  
  
  /**
   * An abstraction that allows for switching between multipart form requests and normal requests when getting
   * request params
   * 
   * @author Kuali Rice Team (rice.collab@kuali.org)
   *
   */
  public class RequestParser {
  
  	private static final String PARSED_MULTI_REQUEST_KEY = "__parsedRequestStruct";
  	private static final String UPLOADED_FILES_KEY = "__uploadedFiles";
  	
  	public static final String WORKFLOW_DOCUMENT_SESSION_KEY = "workflowDocument";
  	public static final String GLOBAL_ERRORS_KEY = "org.kuali.rice.edl.impl.GlobalErrors";
  	public static final String GLOBAL_MESSAGES_KEY = "org.kuali.rice.edl.impl.GlobalMessages";
  	public static final String GLOBAL_FIELD_ERRORS_KEY = "org.kuali.rice.edl.impl.GlobalFieldErrors";
  	
  	private HttpServletRequest request;
  	private Map<String, String[]> additionalParameters = new HashMap<String, String[]>();
  	
  	public RequestParser(HttpServletRequest request) {
  		this.request = request;
  		// setup empty List of errors and messages
  		request.setAttribute(GLOBAL_ERRORS_KEY, new ArrayList());
  		request.setAttribute(GLOBAL_MESSAGES_KEY, new ArrayList());
  		request.setAttribute(GLOBAL_FIELD_ERRORS_KEY, new HashMap<String, String>());
  	}
  
  	private static void parseRequest(HttpServletRequest request) {
  		if (request.getAttribute(PARSED_MULTI_REQUEST_KEY) != null) {
  			return;
  		}
  		
  		Map requestParams = new HashMap();
  		request.setAttribute(PARSED_MULTI_REQUEST_KEY, requestParams);
  		
  		DiskFileItemFactory diskFileItemFactory = new DiskFileItemFactory();
  		diskFileItemFactory.setSizeThreshold(100);
  		ServletFileUpload upload = new ServletFileUpload(diskFileItemFactory);
  		
  		List items = null;
  		try {
  			items = upload.parseRequest(request);	
  		} catch (FileUploadException fue) {
  			throw new WorkflowRuntimeException(fue);
  		}
  		
  		Iterator iter = items.iterator();
  		while (iter.hasNext()) {
  			
  			try {
  				FileItem item = (FileItem) iter.next();
  				if (item.isFormField()) {
  					String fieldName = item.getFieldName();
  					String fieldValue = item.getString("utf-8");
  					String[] paramVals = null;
  					if (requestParams.containsKey(fieldName)) {
  						paramVals = (String[])requestParams.get(fieldName);
  						paramVals = (String[]) ArrayUtils.add(paramVals, fieldValue);
  					} else {
  						paramVals = new String[1];
  						paramVals[0] = fieldValue;
  					}
  					requestParams.put(fieldName, paramVals);
 				} else {
 					List uploadedFiles = (List)request.getAttribute(UPLOADED_FILES_KEY);
 					if (uploadedFiles == null) {
 						uploadedFiles = new ArrayList();
 						request.setAttribute(UPLOADED_FILES_KEY, uploadedFiles);
 					}
 					uploadedFiles.add(item);
 				}
 			} catch (UnsupportedEncodingException e) {
 				throw new WorkflowRuntimeException(e);
 			}
 		}
 	}
 	
 	public String[] getParameterValues(String paramName) {
 		boolean isMultipart = ServletFileUpload.isMultipartContent(this.getRequest());
 	    String[] params = null;
 	    if (isMultipart) {
 	    	parseRequest(this.getRequest());
 	    	params = (String[]) ((Map)request.getAttribute(PARSED_MULTI_REQUEST_KEY)).get(paramName);
 	    } else {
 	    	params = this.getRequest().getParameterValues(paramName);
 	    }
 	    if (params == null) {
 	    	params = additionalParameters.get(paramName);
 	    }
 	    return params;
 	}
 	
 	public void setAttribute(String name, Object value) {
 		this.getRequest().setAttribute(name, value);
 	}
 	
 	public Object getAttribute(String name) {
 		return this.getRequest().getAttribute(name); 
 	}
 	
 	public String getParameterValue(String paramName) {
 		String[] paramVals = getParameterValues(paramName);
 		if (paramVals != null) {
 			return paramVals[0];
 		}
 		return null;
 	}
 	
 	public void setParameterValue(String paramName, String paramValue) {
 	    additionalParameters.put(paramName, new String[] { paramValue });
 	}
 	
 	public void setParameterValue(String paramName, String[] paramValue) {
 	    additionalParameters.put(paramName, paramValue);
 	}
 	
 	public List<String> getParameterNames() {
 	    List<String> names = new ArrayList<String>();
 	    boolean isMultipart = ServletFileUpload.isMultipartContent(this.getRequest());
 	    if (isMultipart) {
 		parseRequest(this.getRequest());
 		Map paramMap = ((Map)request.getAttribute(PARSED_MULTI_REQUEST_KEY));
 		for (Iterator iterator = paramMap.keySet().iterator(); iterator.hasNext();) {
 		    String parameterName = (String)iterator.next();
 		    names.add(parameterName);
 		}
 	    } else { 
 		Enumeration<String> nameEnum = getRequest().getParameterNames();
 		while (nameEnum.hasMoreElements()) {
 		    names.add(nameEnum.nextElement());
 		}
 	    }
 	    return names;
 	}
 
 	public void setRequest(HttpServletRequest request) {
 		this.request = request;
 	}
 	
 	public HttpServletRequest getRequest() {
 		return request;
 	}
 
 	public List getUploadList() {
 		return (List) request.getAttribute(UPLOADED_FILES_KEY);
 	}
 }