/*
    * $Header: /cvsroot/jdbforms/dbforms/src/org/dbforms/servlets/reports/AbstractReportServlet.java,v 1.3 2006/03/18 16:01:07 hkollmann Exp $
    * $Revision: 1.3 $
    * $Date: 2006/03/18 16:01:07 $
    *
    * 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.lang.StringUtils;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import org.dbforms.servlets.base.AbstractServletBase;
  
  import org.dbforms.config.DbFormsConfig;
  import org.dbforms.config.DbFormsConfigRegistry;
  import org.dbforms.config.ResultSetVector;
  import org.dbforms.config.Table;
  
  import org.dbforms.event.AbstractWebEvent;
  
  import org.dbforms.taglib.DbFormTag;
  
  import org.dbforms.util.MessageResourcesInternal;
  import org.dbforms.util.PageContextBuffer;
  import org.dbforms.util.ParseUtil;
  import org.dbforms.util.Util;
  import org.dbforms.util.external.FileUtil;
  
  import java.io.IOException;
  import java.io.PrintWriter;
  
  import java.util.Collection;
  import java.util.Iterator;
  import java.util.Vector;
  
  import javax.servlet.ServletContext;
  import javax.servlet.ServletException;
  import javax.servlet.ServletOutputStream;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import javax.servlet.jsp.PageContext;
  
  /***
   * This is the abstract base class for generating reports.
   * 
   * @author Henner Kollmann
   */
  public abstract class AbstractReportServlet extends AbstractServletBase {
  
  	private static Log logCat = LogFactory.getLog(AbstractReportServlet.class
  			.getName());
  
  	private static final String REPORTCONFIGDIR = "reportdirs";
      private static final String REPORTNAMEPARAM = "reportname";
  
  	private String[] reportdirs;
  
  
  	/***
  	 * Initialize this servlet.
  	 * 
  	 * @exception ServletException
  	 *                if we cannot configure ourselves correctly
  	 */
  	public void init() throws ServletException {
  		super.init();
        String value = getServletConfig().getInitParameter(REPORTCONFIGDIR);
  		if (value == null) {
  			value = "WEB-INF/reports/";
  		}
  		reportdirs = StringUtils.split(value, ',');
  	}
  
  	/***
  	 * 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 abstract ReportWriter processReport(String reportFileFullName,
 			AbstractJRDataSource dataSource, ServletContext context,
 			HttpServletRequest request, HttpServletResponse response);
 
 	protected abstract String getReportFileExtension();
 
 	protected final void handleException(HttpServletRequest request,
 			HttpServletResponse response, Exception e) {
 		sendErrorMessage(request, response, MessageResourcesInternal
 				.getMessage("dbforms.reports.exception", request.getLocale(),
 						new String[] { e.getMessage() }));
 	}
 
 	private final void handleNoData(HttpServletRequest request,
 			HttpServletResponse response) {
 		sendErrorMessage(request, response, MessageResourcesInternal
 				.getMessage("dbforms.reports.nodata", request.getLocale()));
 	}
 
 	private final void sendErrorMessage(HttpServletRequest request,
 			HttpServletResponse response, String message) {
 		try {
 			Vector errors = (Vector) request.getAttribute("errors");
 			
 			// [20050302 fossato@pow2.com] errors vector can be null; for example if you set
 			// into your html browser an URL string like:
 			//
 			// http://localhost:8080/myContext/reports/
 			//
 			// without specifying the name of the report to print;
 			if (errors == null)
 			{			 
 			  errors = new Vector();
 			}
 			
 			errors.add(new Exception(message));
 						
 			String fue = ParseUtil.getParameter(request, "source");
 			String contextPath = request.getContextPath();
 
 			if (!Util.isNull(fue)) {
 				fue = fue.substring(contextPath.length());
 			}
 
 			if (Util.isNull(fue)) {
 				sendErrorMessageText(response, message);
 			} else {
 				request.getRequestDispatcher(fue).forward(request, response);
 			}
 		} catch (Exception ex) {
 			logCat.error("sendErrorMessage", ex);
 			sendErrorMessageText(response, message);
 		}
 	}
 
 	protected void compileReport(ServletContext context,
 			String reportFile) throws Exception {
 	};
 
 	/***
 	 * generates a report from request. Tries to get data from DbForms.
 	 * 
 	 * @param request
 	 *            HTTPServletRequest
 	 * @param response
 	 *            HTTPServletResponse
 	 */
 	protected void process(HttpServletRequest request,
 			HttpServletResponse response) {
 		// create report name
 		try {
 			String reportFile = getReportFileFullName(request.getPathInfo(),
 					getServletContext(), request, response);
 
 			if (!Util.isNull(reportFile)) {
 				compileReport(getServletContext(), reportFile);
 				AbstractJRDataSource dataSource = getDataForReport(request, response);
 				if (!response.isCommitted()) {
 					if (dataSource == null) {
 						handleNoData(request, response);
 					} else {
 						ReportWriter res = processReport(reportFile,
 								dataSource, getServletContext(), request,
 								response);
 						if (!response.isCommitted()) {
 							if (res == null) {
 								handleNoOutput(request, response);
 							} else {
 								processOutput(res, request, response);
 							}
 						}
 					}
 				}
 			} 
 		} catch (Exception e) {
 			logCat.error("process", e);
 			handleException(request, response, e);
 		}
 	}
 
 	private void processOutput(ReportWriter out, HttpServletRequest request,
 			HttpServletResponse response) throws Exception {
 		if ((out.data == null) && (out.data.size() == 0)) {
 			handleNoOutput(request, response);
 			return;
 		}
 		response.setHeader("Expires", "0");
 		response.setHeader("Cache-Control",
 				"must-revalidate, post-check=0, pre-check=0");
 		response.setHeader("Pragma", "public");
 		out.fileName = ParseUtil.getParameter(request, REPORTNAMEPARAM, out.fileName);
         if (!Util.isNull(out.fileName)) {
 			response.setHeader("Content-disposition", "inline; filename="
 					+ out.fileName);
 		}
 		if (!Util.isNull(out.mimeType)) {
 			response.setContentType(out.mimeType);
 		}
 		// Send the output stream to the client
 		response.setContentLength(out.data.size());
 		ServletOutputStream outputStream = response.getOutputStream();
 		try {
 			out.data.writeTo(outputStream);
 			outputStream.flush();
 		} finally {
 			outputStream.close();
 		}
 	}
 
 	private String getReportFileFullName(String reportFileName,
 			ServletContext context, HttpServletRequest request,
 			HttpServletResponse response) {
 		String reportFile = null;
 		
 		try {
 			boolean found = false;
 			for (int i = 0; i < reportdirs.length; i++) {
 				reportFile = context
 						.getRealPath(reportdirs[i] + reportFileName) ;
 				String testName = reportFile  + getReportFileExtension();
 				if (FileUtil.fileExists(testName)) {
 					found = true;
 					break;
 				}
 			}
 			if (!found) {
 				handleNoReport(request, response);
 				reportFile = null;
 			}
 		} catch (Exception e) {
 			handleException(request, response, e);
 		}
 
 		return reportFile;
 	}
 
 	private void handleNoReport(HttpServletRequest request,
 			HttpServletResponse response) {
 		sendErrorMessage(request, response, MessageResourcesInternal
 				.getMessage("dbforms.reports.noreport", request.getLocale(),
 						new String[] { request.getPathInfo() }));
 	}
 
 	/***
 	 * get a JRDataSource for report data. Source can be a Collection, an rsv,
 	 * or dbform if session variable "jasper.input" is set, it must point to a
 	 * Collection object if session variable "jasper.rsv" is set, it must point
 	 * to a ResultSetVector object otherwise the enclosing dbform is used for
 	 * data
 	 * 
 	 * @param context
 	 * @param request
 	 * @param response
 	 * 
 	 * @return
 	 */
 	private AbstractJRDataSource getDataForReport(HttpServletRequest request, HttpServletResponse response) {
 		AbstractJRDataSource dataSource = null;
 		Table table = null;
 		ResultSetVector rsv = null;
 
 		try {
 			// is the datasource a Collection ?
 			Object input = request.getAttribute("jasper.input");
 			if (input == null)
 				input = request.getSession().getAttribute("jasper.input");
 			if ((input != null) && (input instanceof Collection)) {
 				Iterator iter = ((Collection) input).iterator();
 				dataSource = new JRDataSourceIter(null, iter);
 				return dataSource;
 			}
 
 			// check if we are using a ResultSetVector passed by user
 			rsv = (ResultSetVector) request.getAttribute("jasper.rsv");
 			if (rsv == null)
 				rsv = (ResultSetVector) request.getSession().getAttribute("jasper.rsv");
 			if (rsv != null) {
 				logCat.info("get resultsetvector rsv= " + rsv.size());
 				if (rsv.size() == 0) {
 					handleNoData(request, response);
 				} else {
 					dataSource = new JRDataSourceRSV(rsv.getAttributes(), rsv);
 				}
 				return dataSource;
 			}
 
 			PageContext pageContext = new PageContextBuffer();
 			pageContext
 					.initialize(this, request, response, null, true, 0, true);
 
 			// Create form to get the resultsetvector
 			AbstractWebEvent webEvent = (AbstractWebEvent) request.getAttribute("webEvent");
 			table = webEvent.getTable();
 
 			if (table == null) {
 				logCat.error("table==null");
 			}
 
 			if ((webEvent != null) && (table != null) && (table.getId() != -1)) {
 				// Generate DataSource for JasperReports from call to DbForm
 				DbFormsConfig config = null;
 
 				try {
 					config = DbFormsConfigRegistry.instance().lookup();
 				} catch (Exception e) {
 					logCat.error(e);
 					throw new ServletException(e);
 				}
 
 				String tableName = config.getTable(webEvent.getTable().getId())
 						.getName();
 
 				// Simulate call to DbFormTag to get resultsetvector
 				DbFormTag form = new DbFormTag();
 				form.setPageContext(pageContext);
 				form.setTableName(tableName);
 
 				String maxRows = ParseUtil
 						.getParameter(request, "maxRows", "*");
 				form.setMaxRows(maxRows);
 				form.setFollowUp("");
 				form.setAutoUpdate("false");
 				String sqlFilter = ParseUtil.getParameter(request, "sqlFilter", ""); 
 				form.setSqlFilter(sqlFilter);
 
 				// set the source attribute to the requestURI.
 				// So the form will think that the source is equal to the target
 				// and will use order constraints
 				// Source must be saved and restored - we need it e.g. in error
 				// processing again!
 				String saveSource = (String) request.getAttribute("source");
 				String refSource = request.getRequestURI();
 
 				if (request.getQueryString() != null) {
 					refSource += ("?" + request.getQueryString());
 				}
 
 				request.setAttribute("source", refSource);
 				form.doStartTag();
 				request.setAttribute("source", saveSource);
 
 				rsv = form.getResultSetVector();
 				logCat.info("get resultsetvector rsv= " + rsv.size());
 
 				if (rsv.size() == 0) {
 					handleNoData(request, response);
 				} else {
 					dataSource = new JRDataSourceRSV(rsv.getAttributes(), rsv);
 				}
 
 				form.doFinally();
 			}
 		} catch (Exception e) {
 			logCat.error(e);
 		}
 
 		return dataSource;
 	}
 
 	private void sendErrorMessageText(HttpServletResponse response,
 			String message) {
 		try {
 			PrintWriter out = response.getWriter();
 			response.setContentType("text/html");
 			out.println("<html><body><h1>ERROR</h1><p>");
 			out.println(message);
 			out.println("</p></body></html>");
 			out.flush();
 			out.close();
 		} catch (IOException ioe2) {
 			logCat.error("sendErrorMessageText", ioe2);
 		}
 	}
 
 	private void handleNoOutput(HttpServletRequest request,
 			HttpServletResponse response) {
 		sendErrorMessage(request, response, MessageResourcesInternal
 				.getMessage("dbforms.reports.nooutput", request.getLocale()));
 	}
 
 }