/*
    * $Header: /cvsroot/jdbforms/dbforms/src/org/dbforms/servlets/reports/AbstractLineReportServlet.java,v 1.2 2005/12/03 08:09:47 hkollmann Exp $
    * $Revision: 1.2 $
    * $Date: 2005/12/03 08:09:47 $
    *
    * DbForms - a Rapid Application Development Framework
    * Copyright (C) 2001 Joachim Peer <joepeer@excite.com>
    *
    * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
   */
  
  package org.dbforms.servlets.reports;
  
  import org.apache.commons.beanutils.PropertyUtils;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import org.dbforms.util.Util;
  import org.dbforms.util.external.FileUtil;
  
  import java.io.BufferedReader;
  import java.io.ByteArrayOutputStream;
  import java.io.File;
  import java.io.FileReader;
  import java.io.OutputStream;
  
  import javax.servlet.ServletContext;
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import javax.servlet.http.HttpSession;
  
  /***
   * This servlet generates a comma separated values file (CSV). Data is read from
   * the current dbForm, a Collection or a ResultSetVector The template file is in
   * the reports directory with a .cr extension it consists of two lines of text,
   * the first is a list of stirngs to use as header the second a list of comma
   * separated field names. both lines must have the same number of elements.
   * Normally the output file will use the first row as the headers. But if no
   * header line is provided, then no headers are output and every row is data.
   * usage: with a simple goto button: &lt;db:gotoButton destTable="web_parts"
   * destination=" /reports/Artikel"/&gt; or for one record: &lt;db:gotoButton
   * destTable="web_parts" keyToDestPos="currentRow"
   * destination="/reports/Artikel" /&gt; Servlet mapping must be set to handle
   * all /reports by this servlet!!! &lt;servlet/&gt;
   * &lt;servlet-name/&gt;startreport&lt;/servlet-name/&gt;
   * &lt;display-name/&gt;startreport&lt;/display-name/&gt;
   * &lt;servlet-class/&gt;org.dbforms.StartReportServlet&lt;/servlet-class/&gt;
   * &lt;/servlet&gt; &lt;servlet-mapping/&gt;
   * &lt;servlet-name/&gt;startreport&lt;/servlet-name/&gt;
   * &lt;url-pattern/&gt;/reports/&lt;/url-pattern/&gt; &lt;/servlet-mapping&gt;
   * web.xml optional parameters reportdirs list of directories to search for
   * report file reportMimeType mime type to send to browser Parameters
   * filename=xyz.csv name the output file Support for grabbing data from a
   * Collection or an existing ResultSetVector set session variable "jasper.input"
   * to use a Collection object set session variable "jasper.rsv" to use a
   * ResultSetVector object ex &ltc:set var="jasper.rsv" value="${rsv_xxxxx}"
   * scope="session" /&gt
   * 
   * @author Neal Katz
   */
  public abstract class AbstractLineReportServlet extends AbstractReportServlet {
  	private static Log logCat = LogFactory
  			.getLog(AbstractLineReportServlet.class);
  
  	protected abstract String getMimeType();
  
  	protected abstract String getFileExtension();
  
  	protected abstract void writeData(Object[] data) throws Exception;
  
  	protected abstract void openStream(OutputStream out) throws Exception;
  
  	protected abstract void closeStream(OutputStream out) throws Exception;
  
  	private static final String REPORTMIMETYPEPARAM = "reportMimeType";
  
  	private String mimeType = getMimeType();
  
  	private int rownum = 0;
  
  	public void init() throws ServletException {
  		super.init();
  		String value = getServletConfig().getInitParameter(REPORTMIMETYPEPARAM);
  		if (!Util.isNull(value)) {
  			mimeType = value;
  		}
 	}
 
 	protected String getReportFileExtension() {
 		return ".xr";
 	}
 
 	protected void writeHeader(String[] header) throws Exception {
 		writeData(header);
 	}
 
 	private Object getFieldValue(HttpServletRequest request,
 			AbstractJRDataSource dataSource, String search) {
 		Object o = null;
 		search = search.replaceAll("__", ".");
 
 		if (search.startsWith("internal.")) {
 			search = search.substring(search.indexOf("internal."));
 			logCat.debug("Trying to find data for internal value: " + search);
 			o = getInternalValue(search);
 		} else if (search.startsWith("request.")) {
 			search = search.substring(search.indexOf("request."));
 			logCat.debug("Trying to find data for page context value: "
 					+ search);
 			o = getRequestValue(request, search);
 		} else if (search.startsWith("session.")) {
 			search = search.substring(search.indexOf("session."));
 			logCat.debug("Trying to find data for session value: " + search);
 			o = getSessionValue(request.getSession(), search);
 		} else {
 			logCat.debug("Trying to find data for field named: " + search);
 			o = dataSource.getFieldValue(search);
 		}
 		return o;
 
 	}
 
 	private Object getInternalValue(String search) {
 		Object obj = null;
 		try {
 			logCat.debug("Trying to find data for internal var : " + search);
 			if (search.equalsIgnoreCase("rownum")) {
 				return new Integer(rownum);
 			}
 		} catch (Exception e) {
 			logCat.error("getInternalValue: " + e);
 		}
 
 		return obj;
 	}
 
 	private Object getRequestValue(HttpServletRequest request, String search) {
 		Object obj = null;
 		int pos;
 		try {
 			pos = search.indexOf(".");
 			if (pos == -1) {
 				// simple type, 'search' is an object in the session
 				obj = request.getAttribute(search);
 			} else {
 				// complex, 'search' is really a bean
 				// complex, 'search' is really a bean
 				String search_bean = search.substring(0, pos);
 				search = search.substring(pos + 1);
 				Object bean = request.getAttribute(search_bean);
 				if (bean != null) {
 					logCat.debug("calling PropertyUtils.getProperty "
 							+ search_bean + " " + search);
 					obj = PropertyUtils.getProperty(bean, search);
 				}
 			}
 		} catch (Exception e) {
 			logCat.error("getPageContextValue: " + e);
 		}
 
 		return obj;
 	}
 
 	private Object getSessionValue(HttpSession session, String search) {
 		Object obj = null;
 		int pos;
 		try {
 			pos = search.indexOf(".");
 			if (pos == -1) {
 				// simple type, 'search' is an object in the session
 				obj = session.getAttribute(search);
 			} else {
 				// complex, 'search' is really a bean
 				String search_bean = search.substring(0, pos);
 				search = search.substring(pos + 1);
 				Object bean = session.getAttribute(search_bean);
 				if (bean != null) {
 					logCat.debug("calling PropertyUtils.getProperty "
 							+ search_bean + " " + search);
 					obj = PropertyUtils.getProperty(bean, search);
 				}
 			}
 		} catch (Exception e) {
 			logCat.error("getSessionValue: " + e);
 		}
 
 		return obj;
 	}
 
 	private ByteArrayOutputStream fillReport(HttpServletRequest request,
 			String[] header, String[] fields, AbstractJRDataSource dataSource)
 			throws Exception {
 		ByteArrayOutputStream res = new ByteArrayOutputStream();
 		openStream(res);
 		writeHeader(header);
 		// Write out the data
 		Object[] data = new Object[fields.length];
 		while (dataSource.next()) {
 			rownum++;
 			for (int i = 0; i < fields.length; i++) {
 				data[i] = getFieldValue(request, dataSource, fields[i]);
 			}
 			writeData(data);
 		}
 		closeStream(res);
 		return res;
 	}
 
 	/***
 	 * generates a report.
 	 * 
 	 * @param reportFileFullName
 	 *            filename of report to process reportHTTPServletRequest
 	 *            generated by getReportFile! getReportFile should be called
 	 *            before fetching data, so that error handling of report not
 	 *            found e.g. could be processed first!
 	 * @param dataSource
 	 *            data for the report
 	 * @param context
 	 *            ServletContext
 	 * @param request
 	 *            HTTPServletRequest
 	 * @param response
 	 *            HTTPServletResponse
 	 */
 	protected ReportWriter processReport(String reportFileFullName,
 			AbstractJRDataSource dataSource, ServletContext context,
 			HttpServletRequest request, HttpServletResponse response) {
 
 		try {
 			File f = new File(reportFileFullName + getReportFileExtension());
 			BufferedReader in = new BufferedReader(new FileReader(f));
 			try {
 				String line1 = in.readLine();
 				String line2 = in.readLine();
 				String fields = null;
 				String headers = null;
 				if (Util.isNull(line2)) {
 					fields = line1;
 				} else {
 					headers = line1;
 					fields = line2;
 				}
 				if (Util.isNull(fields)) {
 					logCat.error("no fields found");
 					return null;
 				}
 				String[] reportFields = fields.split(",");
 				String[] headerFields;
 				if (headers != null) {
 					headerFields = headers.split(",");
 				} else {
 					headerFields = new String[] {};
 				}
 				if (reportFields.length != headerFields.length) {
 					logCat.error("reportFields.length != headerFields.length");
 					headerFields = reportFields;
 				}
 				if (reportFields.length == 0) {
 					logCat.error("no fields found");
 					return null;
 				}
 
 				ReportWriter res = new ReportWriter();
 				res.data = fillReport(request, headerFields, reportFields,
 						dataSource);
 				if (res.data != null) {
 					res.fileName = FileUtil.filename(reportFileFullName)
 							+ getFileExtension();
 					res.mimeType = mimeType;
 				}
 				return res;
 			} finally {
 				in.close();
 			}
 		} catch (Exception e) {
 			logCat.error("read report file", e);
 			handleException(request, response, e);
 			return null;
 		}
 	}
 
 }