package bradleyross.j2ee.servlets;
import java.io.StringWriter;
import java.io.PrintWriter;
import java.io.IOException;
import java.sql.Date;
import java.util.Vector;
import java.util.Enumeration;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import bradleyross.library.database.DatabaseProperties;
import bradleyross.library.helpers.GenericPrinter;
import bradleyross.library.helpers.StringHelpers;
/**
 * Used by code for servlets to pass information about a specific 
 * HTTP request.
 * 
 * @see bradleyross.j2ee.servlets.UploadServlet.ThisPage
 * 
 * @author Bradley Ross
 *
 */
public class ThisPage 
{
        /**
         * Request object.
         */
        private HttpServletRequest request = null;
        /**
         * Response object.
         */
        private HttpServletResponse response = null;
        /**
         * Servlet configuration.
         */
        protected ServletConfig config = null;
        /**
         * Application (context) configuration.
         */
        protected ServletContext context = null;
        /**
         * Input stream from HTTP request.
         * @see #getInputStream()
         */
        protected ServletInputStream input = null;
        /**
         * Used to pass information on database connection.
         * @see #setDatabase(DatabaseProperties)
         * @see #getDatabase()
         */
        protected DatabaseProperties data = null;
        /**
         * Starting date of date range.
         * @see #setStartDate(Date)
         * @see #getStartDate()
         */
        protected Date startDate = null;
        /**
         * Ending date of date range.
         * @see #setEndDate(Date)
         * @see #getEndDate()
         */
        protected Date endDate = null;
        /**
         * PrintWriter object for response.
         * 
         * <p>The value is only set when the method
         *    {@link #getWriter()} is called.</p>
         * @see #getWriter()
         */
        private PrintWriter writer = null;
        /**
         * Used internally to store information for page.
         * 
         */
        private StringWriter stringWriter = null;
        /**
         * This is the printer object that will be used by servlet code.  
         * <p>The
         *    material is passed to a StringWriter that can be cleared and
         *    rewritten before sending the material to the response object.</p>
         * @see #getPrinter()
         */
        private GenericPrinter printer = null;
        /**
         * Object for sending information to HTTP response
         * as a binary stream.
         * 
         * @see #getOutputStream()
         */
        private ServletOutputStream outputStream = null;
        /**
         * A list of warning or error messages that will appear
         * on the web page generated by the servlet.
         * 
         * <p>The text of the messages are processed by
         *    {@link StringHelpers#escapeHTML(String) } before
         *    being sent to the web page.  The surrounding tags
         *    will also have to be added.</p>
         * <p>The error page is generated by calling
         *    {@link #errorMessage()}.</p>
         */
        protected Vector<String> messageList = null;
        /**
         * Cancel processing if set to true.
         * 
         * <p>The flag is set when 
         *    {@link #errorMessage()} or {@link #sendContents() }
         *    is called.</p>
         */
        protected boolean terminateRequest = false;
        /**
         * Get the value of terminateRequest
         * 
         * @see #terminateRequest
         * @return Value of flag
         */
        public boolean getTerminateRequest()
        {
                return terminateRequest;
        }
        /**
         * Clear the contents of the StringWriter object.
         */
        public void clearWriter()
        {
                stringWriter = new StringWriter();
                printer = new GenericPrinter(stringWriter);
        }
        /**
         * Obtains the PrintWriter object for sending the page contents
         * as a character string.
         * <p>The only public means of calling this method is to use
         *    {@link #sendContents()}.</p>
         * @return PrintWriter object
         * @throws IOException if io errors
         */
        protected PrintWriter getWriter() throws IOException
        {
                if (writer == null)
                {
                        writer = response.getWriter();
                }
                return writer;
        }
        /**
         * Send the contents of the StringWriter object to
         * the response object.
         * 
         * @throws IOException if database appear
         */
        public void sendContents() throws IOException
        {
                getWriter().write(stringWriter.toString());
                terminateRequest = true;
        }
        /**
         * Default constructor added to allow subclassing.
         */
        public ThisPage()
        { ; }
        /**
         * 
         * @param requestValue request object
         * @param responseValue response object
         * @param configValue servlet config object
         * @throws IOException if io errors
         */
        public ThisPage(HttpServletRequest requestValue, HttpServletResponse responseValue, ServletConfig configValue)
        throws IOException
        {
                request = requestValue;
                response = responseValue;
                config = configValue;
                context = config.getServletContext();           
                stringWriter = new StringWriter();
                printer = new GenericPrinter(stringWriter);
                messageList = new Vector<String>();     
        }
        /**
         * Set the object containing database connection properties.
         * @see #data
         * @param databaseValue Object containing database properties
         */
        public void setDatabase (DatabaseProperties databaseValue)
        {
                data = databaseValue;
        }
        /**
         * Get the object containing database connection properties.
         * @see #data
         * @return Object containing database connection properties
         */
        public DatabaseProperties getDatabase()
        {
                return data;
        }
        /**
         * Gets request object.
         * @return Request object
         */
        public HttpServletRequest getRequest()
        {
                return request;
        }
        /**
         * Gets response object.
         * @return Response object
         */
        public HttpServletResponse getResponse()
        {
                return response;
        }
        /**
         * Get servlet configuration.
         * <p>Parameters that are specified for a single servlet belong to
         *    this object.</p>
         * @return Servlet configuration object
         */
        public ServletConfig getConfig()
        {
                return config;
        }
        /**
         * Get application context.
         * <p>Parameters that belong to the entire application belong to
         *    this object.</p>
         *    @see #context
         * @return Application context
         */
        public ServletContext getContext()
        {
                return context;
        }
        /**
         * Return the input object obtaining information from the
         * HTTP request.
         * 
         * @see #input
         * @return ServletInputStream object
         */
        public ServletInputStream getInputStream()
        {
                return input;
        }
        /**
         * Obtain the output stream for sending information to the
         * browser as a stream of bytes.  
         * 
         * <p>If this method is called,
         *    the {@link #sendContents()} and {@link #errorMessage()}
         *    messages can not be used.</p>
         *    
         * @return ServletOutputStream object
         * @throws IOException if io errors
         */
        public ServletOutputStream getOutputStream() throws IOException
        {
                if (outputStream == null)
                {
                        outputStream = response.getOutputStream();
                }
                return outputStream;
        }
        /**
         * Get the generic printer object.
         * @see #printer
         * @return GenericPrinter object
         */
        public GenericPrinter getPrinter()
        {
                if (stringWriter == null)
                {
                        stringWriter = new StringWriter();
                }
                if (printer == null)
                {
                        printer = new GenericPrinter(stringWriter);
                }
                return printer;
        }
        /**
         * Returns list of messages for the error page.
         * @return List of messages
         */
        public Vector<String> getMessageList()
        {
                return messageList;
        }
        /**
         * Add a message to the list of messages for the
         * error page.
         * 
         * @see #messageList
         * @param value Message to be added
         */
        public void addMessage(String value)
        {
                messageList.add(value);
        }
        /**
         * Adds a description of an exception to the list
         * of messages for the error page.
         * 
         * @see #messageList
         * 
         * @param e Exception to be described
         */
        public void addException(Exception e)
        {
                StringWriter str = new StringWriter();
                PrintWriter p = new PrintWriter(str);
                p.println(e.getClass().getName() + " " + e.getMessage());
                e.printStackTrace(p);
                messageList.add(str.toString());
        }
        /**
         * Generates an error page based on the calls to the
         * addMessage and addException methods.
         * 
         * @see #addMessage(String)
         * @see #addException(Exception)
         * @throws IOException if io errors
         */
        public void errorMessage() throws IOException
        {
                clearWriter();
                GenericPrinter out = getPrinter();
                out.println("<html><head><title>Error encountered</title></head>");
                out.println("<body><h1>Error encountered</h1>");
                messageList.trimToSize();
                out.print("<p>Please print this page for aid in debugging.  This page contains " +
                        " a list of actions taken by the servlet as well as the actual error message.</p>");
                out.println("<h2>Start of messages</h2>");
                int size = messageList.size();
                if (size > 0)
                {
                        out.println("<ul>");
                        for (int i = 0; i < size; i++)
                        {
                                out.println("<li>" + StringHelpers.escapeHTML(messageList.elementAt(i)) + "</li>");
                        }
                        out.println("</ul>");
                }
                else
                {
                        out.println("<p>There are no messages waiting</p>");
                }
                out.println("<h2>List of parameters</h2>");
                Enumeration<?> nameList = request.getParameterNames();
                while (nameList.hasMoreElements())
                {
                        String name = (String) nameList.nextElement();
                        out.println("<p>" + 
                                        StringHelpers.escapeHTML(name + " = " + request.getParameter(name)) +"</p>");
                }
                out.println("</body></html>");
                sendContents();
                terminateRequest = true;
                return;
        }
        /**
         * Set start date of date range.
         * @see #startDate
         * @param value Date to be used for start of date range
         */
        public void setStartDate(Date value)
        {
                startDate = value;
        }
        /**
         * Return start date for date range.
         * @see #startDate
         * @return Start of date range
         */
        public Date getStartDate()
        {
                return startDate;
        }
        /**
         * Set end date of date range.
         * @see #endDate
         * @param value Date to be used for end of date range
         */
        public void setEndDate(Date value)
        {
                endDate = value;
        }
        /**
         * Return end date of date range.
         * @see #endDate
         * @return End date of date range
         */
        public Date getEndDate()
        {
                return endDate;
        }
        /**
         * Controls amount of diagnostic output.
         * 
         * <p>More positive values mean more diagnostic listings.</p>
         */
        protected int debugLevel = 0;
        /**
         * Gets value of debugLevel.
         * 
         * @see #debugLevel
         * @return Value of debugLevel
         */
        public int getDebugLevel()
        {
                return debugLevel;
        }
        /**
         * Sets value of debugLevel
         * @see #debugLevel
         * @param value Value to be used
         */
        public void setDebugLevel(int value)
        {
                debugLevel = value;
        }
        /**
         * Indicates that the document should be displayed in the browser if 
         * possible.
         * 
         * @see #mode
         */
        public static final int NORMAL = 0;
        /**
         * Indicates that the document should be downloaded to the
         * client machine.
         * 
         * @see #mode
         */
        public static final int DOWNLOAD = 1;
        /**
         * Indicates the mode of operation.  The two possible values
         * are defined by the static integer values NORMAL and DOWNLOAD.
         */
        protected int mode = 0;
        /**
         * Contains the MIME code for the document to be displayed.
         */
        protected String mimeType = null;
        /** 
         * The byte array contains the contents of the document to be displayed.
         */
        protected byte[] contents = null;
        /**
         * File name to be associated with the download.
         */
        protected String fileName = null;
        /**
         * Set the MIME code for the document.
         * 
         * @param value MIME code
         */
        public void setMimeType (String value)
        {
                mimeType = value;
        }
        /**
         * Get the MIME code for the document.
         * 
         * @return MIME code
         */
        public String getMimeType()
        {
                return mimeType;
        }
        /**
         * Set the filename associated with the item to be downloaded.
         * 
         * @param value File name
         */
        public void setFileName (String value)
        {
                fileName = value;
        }
        /**
         * Get the filename associated with the item to be downloaded.
         * @return File name
         */
        public String getFileName()
        {
                return fileName;
        }
        /**
         * Get the byte array to be used to display the downloaded item.
         * 
         * @return Contents of downloaded item
         */
        public byte[] getContents()
        {
                return contents;
        }
        /**
         * Set the byte array to be used to display the downloaded item.
         * 
         * @param value Contents of downloaded item
         */
        public void setContents(byte value[])
        {
                contents = value;
        }
        /**
         * Set the mode of operation
         * @param value Mode of operation
         * @throws IOException if io errors
         */
        public void setMode (int value) throws IOException
        {
                if (mode != NORMAL && mode != DOWNLOAD)
                {
                        addMessage("Illegal mode of operation");
                        throw new IOException("Illegal mode of operation");
                }
                mode = value;
        }
        /**
         * Get the mode of operation.
         * 
         * @return Mode of operation
         */
        public int getMode ()
        {
                return mode;
        }
        /**
         * Address to be used for redirecting servlet.
         */
        protected String redirectAddress = null;
        /**
         * Set redirectAddress.
         * @see #redirectAddress
         * @param value Value to be used
         */
        public void setRedirectAddress(String value)
        {
                redirectAddress = value;
        }
        /**
         * Get redirectAddress.
         * @see #redirectAddress
         * @return Value of redirectAddress
         */
        public String getRedirectAddress()
        {
                return redirectAddress;
        }
}