/*

  * Copyright (c) 2003-2011, Simon Brown

  * All rights reserved.

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions are met:

  *

  *   - Redistributions of source code must retain the above copyright

  *     notice, this list of conditions and the following disclaimer.

  *

  *   - Redistributions in binary form must reproduce the above copyright

  *     notice, this list of conditions and the following disclaimer in

  *     the documentation and/or other materials provided with the

  *     distribution.

  *

  *   - Neither the name of Pebble nor the names of its contributors may

  *     be used to endorse or promote products derived from this software

  *     without specific prior written permission.

  *

  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

  * POSSIBILITY OF SUCH DAMAGE.

  */

 package net.sourceforge.pebble.web.tagext;

 import java.io.IOException;

 import java.text.DateFormatSymbols;

 import java.text.NumberFormat;

 import java.text.SimpleDateFormat;

 import java.util.ArrayList;

 import java.util.Calendar;

 import java.util.Iterator;

 import java.util.List;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.jsp.JspException;

 import javax.servlet.jsp.JspTagException;

 import javax.servlet.jsp.JspWriter;

 import javax.servlet.jsp.tagext.TagSupport;

 import net.sourceforge.pebble.Constants;

 import net.sourceforge.pebble.domain.Blog;

 import net.sourceforge.pebble.domain.Day;

 import net.sourceforge.pebble.domain.Month;

 import net.sourceforge.pebble.util.I18n;

 import net.sourceforge.pebble.util.UrlRewriter;

 /**

  * A custom tag that outputs a calendar control.

  *

  * @author    Simon Brown

  */

 public class CalendarTag extends TagSupport {

   /**

    * Implementation from the Tag interface - this is called when the opening tag

    * is encountered.

    *

    * @return  an integer specifying what to do afterwards

    * @throws  JspException    if something goes wrong

    */

   public int doStartTag() throws JspException {

     HttpServletRequest request = (HttpServletRequest)pageContext.getRequest();

     Blog blog = (Blog)request.getAttribute(Constants.BLOG_KEY);

     Month month = (Month)request.getAttribute(Constants.MONTHLY_BLOG);

     Day today = blog.getBlogForToday();

     Calendar now = blog.getCalendar();

     if (month == null) {

       month = today.getMonth();

     }

     Calendar firstDayOfMonth = blog.getCalendar();

     firstDayOfMonth.setTime(month.getBlogForDay(1).getDate());

     SimpleDateFormat monthAndYearFormatter = new SimpleDateFormat("MMMM yyyy", blog.getLocale());

     monthAndYearFormatter.setTimeZone(blog.getTimeZone());

     SimpleDateFormat monthFormatter = new SimpleDateFormat("MMM", blog.getLocale());

     monthFormatter.setTimeZone(blog.getTimeZone());

     NumberFormat numberFormatter = NumberFormat.getIntegerInstance(blog.getLocale());

     Month firstMonth = blog.getBlogForFirstMonth();

     try {

       JspWriter out = pageContext.getOut();

       out.write("<div class=\"calendar\">");

       out.write("<table width=\"100%\">");

       out.write("<tr>");

       out.write("<td colspan=\"7\" align=\"center\">");

       if (month.before(firstMonth)) {

         out.write("<b>");

         out.write(monthAndYearFormatter.format(month.getDate()));

         out.write("</b>");

       } else {

         out.write("<b><a href=\"");

         out.write(UrlRewriter.doRewrite(month.getPermalink()));

         out.write("\">");

         out.write(monthAndYearFormatter.format(month.getDate()));

         out.write("</a></b>");

       }

       out.write("</td>");

       out.write("</tr>");

       int firstDayOfWeek = now.getFirstDayOfWeek();

       // write out the calendar header

       DateFormatSymbols symbols = new DateFormatSymbols(blog.getLocale());

       String[] days = symbols.getShortWeekdays();

       out.write("<tr>");

       for (int i = firstDayOfWeek; i <= 7; i++) {

         out.write("<td class=\"calendarDayHeader\" width=\"14%\">" + days[i] + "</td>");

       }

       for (int i = 1; i < firstDayOfWeek; i++) {

         out.write("<td class=\"calendarDayHeader\">" + days[i] + "</td>");

       }

       out.write("</tr>");

       // write out the body of the calendar

       Iterator it = getDatesForCompleteWeeks(blog, month).iterator();

       Calendar cal;

       int count = 0;

       while (it.hasNext()) {

         cal = (Calendar)it.next();

         Day daily = blog.getBlogForDay(cal.getTime());

         String formattedNumber = numberFormatter.format(cal.get(Calendar.DAY_OF_MONTH));

         if (formattedNumber.length() == 1) {

           formattedNumber = " " + formattedNumber;

         }

         if (count % 7 == 0) {

           out.write("<tr>");

         }

         // output padding if the date to display isn't in the month

         if (cal.get(Calendar.MONTH) != firstDayOfMonth.get(Calendar.MONTH)) {

           out.write("<td class=\"calendarDay\">&nbsp;");

         } else if (now.get(Calendar.YEAR) == cal.get(Calendar.YEAR) &&

           now.get(Calendar.MONTH) == cal.get(Calendar.MONTH) &&

           now.get(Calendar.DAY_OF_MONTH) == cal.get(Calendar.DAY_OF_MONTH)) {

           out.write("<td class=\"calendarToday\">");

           if (daily.hasBlogEntries()) {

             out.write("&nbsp;<a href=\"" + UrlRewriter.doRewrite(daily.getPermalink()) + "\">" + formattedNumber + "</a>&nbsp;");

           } else {

             out.write(" " + formattedNumber + " ");

           }

         } else {

           if (daily.hasBlogEntries()) {

             out.write("<td class=\"calendarDayWithEntries\">");

             out.write("&nbsp;<a href=\"" + UrlRewriter.doRewrite(daily.getPermalink()) + "\">" + formattedNumber + "</a>&nbsp;");

           } else {

             out.write("<td class=\"calendarDay\">");

             out.write(" " + formattedNumber + " ");

           }

         }

         out.write("</td>");

         if (count % 7 == 6) {

           out.write("</tr>");

         }

         count++;

       }

       // write out the footer of the calendar

       Month previous = month.getPreviousMonth();

       Month next = month.getNextMonth();

       out.write("<tr>");

       out.write("<td colspan=\"7\" align=\"center\">");

       // only display the previous month link if there are blog entries

       if (previous.before(firstMonth)) {

         out.write(monthFormatter.format(previous.getDate()));

       } else {

         out.write("<a href=\"" + UrlRewriter.doRewrite(previous.getPermalink()) + "\">" + monthFormatter.format(previous.getDate()) + "</a>");

       }

       String todayText = I18n.getMessage(blog, "common.today");

       out.write("  |  ");

       out.write("<a href=\"" + UrlRewriter.doRewrite(today.getPermalink()) + "\">" + todayText + "</a>");

       out.write("  |  ");

       // only display the next month date if it's not in the future

       if (next.getDate().after(now.getTime()) || next.before(firstMonth)) {

         out.write(monthFormatter.format(next.getDate()));

       } else {

         out.write("<a href=\"" + UrlRewriter.doRewrite(next.getPermalink()) + "\">" + monthFormatter.format(next.getDate()) + "</a>");

       }

       out.write("</td>");

       out.write("</tr>");

       out.write("</table>");

       out.write("</div>");

     } catch (IOException ioe) {

       throw new JspTagException(ioe.getMessage());

     }

     return SKIP_BODY;

   }

   /**

    * Gets a list of dates that should be displayed for the given month. This

    * method adds dates either side of the month, padding the list so that it

    * contains a number of complete weeks. For example, if the first day of the

    * month for the blog's locale is Monday and the given month starts on a

    * Tuesday, this method will add in that previous Monday to present

    * back a complete week. The same happens for the end of the month. This

    * makes rendering easier since we just have a 7xN grid.

    *

    * @param blog    a Blog instance

    * @param month   the month

    * @return  a List of Calendar instances

    */

   private List getDatesForCompleteWeeks(Blog blog, Month month) {

     List dates = new ArrayList();

     Calendar start = blog.getCalendar();

     start.setTime(month.getBlogForDay(1).getDate());

     Calendar end = blog.getCalendar();

     end.setTime(month.getBlogForDay(month.getLastDayInMonth()).getDate());

     Calendar cal;

     // put all days in month into a list

     for (int i = 1; i <= month.getLastDayInMonth(); i++) {

       cal = (Calendar)start.clone();

       cal.set(Calendar.DAY_OF_MONTH, i);

       dates.add(cal);

     }

     // pad out before the start of the month, until the first day of the week

     cal = (Calendar)start.clone();

     while (cal.get(Calendar.DAY_OF_WEEK) != cal.getFirstDayOfWeek()) {

       cal.add(Calendar.DATE, -1);

       dates.add(0, cal.clone());

     }

     // pad out after month, until the last day of the week

     cal = (Calendar)end.clone();

     cal.add(Calendar.DATE, 1);

     while (cal.get(Calendar.DAY_OF_WEEK) != cal.getFirstDayOfWeek()) {

       dates.add(cal.clone());

       cal.add(Calendar.DATE, 1);

     }

     return dates;

   }

 }