package com.atlassian.core.cron.generator;
   
   import com.atlassian.core.cron.CronEditorBean;
   import com.atlassian.core.i18n.I18nTextProvider;
   import com.atlassian.core.util.map.EasyMap;
   import org.apache.commons.lang.StringUtils;
   import org.apache.commons.lang.Validate;
   
   import java.text.NumberFormat;
  import java.util.Arrays;
  import java.util.Map;
  
  /**
   * Describes Cron Expressions in human readable text.
   */
  public class CronExpressionDescriptor
  {
      private static final Map<String, String> MINUTE_INCREMENT_TO_MESG_KEY = EasyMap.build(
              "15", "cron.editor.every.15.minutes",
              "30", "cron.editor.every.30.minutes",
              "60", "cron.editor.every.hour",
              "120", "cron.editor.every.2.hours",
              "180", "cron.editor.every.3.hours"
      );
  
      private static final Map<String, String> DAY_NUMBERS = EasyMap.build(
              "1", "sunday",
              "2", "monday",
              "3", "tuesday",
              "4", "wednesday",
              "5", "thursday",
              "6", "friday",
              "7", "saturday"
      );
  
      private static final String CRON_EDITOR_KEY_PREFIX = "cron.editor.";
      private static final int MINUTES_DIGITS = 2;
      private static final int DAYS_IN_WEEK = 7;
      private static final String LAST_COMMA_REGEX = ",([^,]*)$";
  
      private final I18nTextProvider i18n;
  
  
      /**
       * Creates a Descriptor for
       * @param i18n the I18nBean.
       */
      public CronExpressionDescriptor(I18nTextProvider i18n)
      {
          Validate.notNull(i18n, "I18nTextProvider must nnot be null");
          this.i18n = i18n;
      }
  
      /**
       * Returns the translated name of the day for the given day number using
       * our cron editor day numbering scheme.
       * @param number the day number.
       * @return the name of the day.
       */
      private String getDay(String number)
      {
          String keypart = DAY_NUMBERS.get(number);
          Validate.notNull(keypart, "Unable to get day for number '" + number + "'. CronEditorBean likely to be inconsistent");
          return i18n.getText(CRON_EDITOR_KEY_PREFIX + keypart);
      }
  
      /**
       * Renders a nice locale-specific and human readable description of the given
       * cronEditorBean's schedule or, if this can't be understood, the underlying
       * cron expression.
       *
       * @param bean the cronEditorBean.
       * @return the description.
       */
      public String getPrettySchedule(CronEditorBean bean)
      {
          if (bean.isAdvancedMode()) {
              return bean.getCronString();
          }
          StringBuilder desc = new StringBuilder();
          if (bean.isDailyMode())
          {
              desc.append(i18n.getText("cron.editor.daily")).append(" ");
              desc.append(getTimePart(bean));
          }
          else if (bean.isDayPerWeekMode())
          {
              desc.append(getDayPerWeekDescriptor(bean));
          }
          else if (bean.isDaysPerMonthMode())
          {
              desc.append(getDayPerMonthDescriptor(bean));
          }
  
          return desc.toString();
      }
  
      private String getDayPerWeekDescriptor(CronEditorBean bean)
      {
         StringBuilder desc = new StringBuilder();
         desc.append(i18n.getText("cron.editor.each"));
         desc.append(" ");
 
         String[] daysArray = bean.getSpecifiedDaysPerWeek().split(",");
         Arrays.sort(daysArray);
         String daysString = StringUtils.join(daysArray, ",");
         daysString = daysString.replaceAll(LAST_COMMA_REGEX, " and $1"); // replace last comma with "and"
         for (int i = 1; i <= DAYS_IN_WEEK; i++)
         {
             String dayNum = Integer.toString(i);
             daysString = daysString.replaceAll(dayNum, getDay(dayNum));
         }
         daysString = daysString.replaceAll(",", ", ");
         desc.append(daysString).append(" ");
 
         desc.append(getTimePart(bean));
         return desc.toString();
     }
 
     /**
      * Renders the day per month mode description either the numeric day
      * (e.g. 1st day of the month) or the ordinal day of week of month (e.g. last Monday of the month)
      * @param bean the bean whose state is rendered.
      * @return the rendered description.
      */
     private String getDayPerMonthDescriptor(CronEditorBean bean)
     {
         StringBuilder desc = new StringBuilder();
         if (bean.isDayOfWeekOfMonth())
         {
             String ordinal = i18n.getText("cron.editor.ordinal." + bean.getDayInMonthOrdinal());
             String ordinalWeekday = ordinal + " " + getDay(bean.getSpecifiedDaysPerWeek());
             desc.append(i18n.getText("cron.editor.the.of.every.month", new String[]{ordinalWeekday}));
             desc.append(" ");
             desc.append(getTimePart(bean));
         }
         else
         {
             // numeric day of month
             desc.append(i18n.getText("cron.editor.the.day.of.every.month", new String[]{i18n.getText("cron.editor.nth." + bean.getDayOfMonth())}));
             desc.append(" ");
             desc.append(getTimePart(bean));
         }
         return desc.toString();
     }
 
     /**
      * Renders the time as a run once (e.g. "at 5:25 pm") or a repetition in a range
      * (e.g. "every 3 hours from 1:00 pm to 10:00 pm")
      *
      * @param bean the bean containing the time state.
      * @return the rendered description.
      */
     private String getTimePart(CronEditorBean bean)
     {
         StringBuilder desc = new StringBuilder();
         if (!bean.isRange())
         {
             desc.append(getRunOnce(bean));
         }
         else
         {
             desc.append(getRepeatInRange(bean));
         }
         return desc.toString();
     }
 
     /**
      * Renders the run-once time like this "at 5:25 pm".
      *
      * @param bean contains the run once time.
      * @return a description of the run once time.
      */
     private String getRunOnce(CronEditorBean bean)
     {
         StringBuilder desc = new StringBuilder();
         desc.append(i18n.getText("cron.editor.at"));
         desc.append(" ");
         desc.append(bean.getHoursRunOnce()).append(":").append(getPaddedMinutes(bean.getMinutes())).append(" ").append(bean.getHoursRunOnceMeridian());
         return desc.toString();
     }
 
     /**
      * Renders the repetition in a time range like this "every 3 hours from 1:00 pm to 10:00 pm".
      *
      * @param bean containing the repeat and range.
      * @return the rendered description.
      */
     private String getRepeatInRange(CronEditorBean bean)
     {
         StringBuilder desc = new StringBuilder();
         String increment = bean.getIncrementInMinutes();
         if (increment.equals("0"))
         {
             // once per day, we leave this expression out
         }
         else
         {
             String key = MINUTE_INCREMENT_TO_MESG_KEY.get(increment);
             desc.append(i18n.getText(key));
         }
 
         if (!bean.is24HourRange())
         {
             desc.append(" ");
             desc.append(i18n.getText("cron.editor.from"));
             desc.append(" ");
             desc.append(bean.getHoursFrom()).append(":00 ").append(bean.getHoursFromMeridian());
             desc.append(" ");
             desc.append(i18n.getText("cron.editor.to"));
             desc.append(" ");
             desc.append(bean.getHoursTo()).append(":00 ").append(bean.getHoursToMeridian());
         }
         return desc.toString();
     }
 
     private String getPaddedMinutes(String minutes)
     {
         NumberFormat format = NumberFormat.getInstance();
         format.setMinimumIntegerDigits(MINUTES_DIGITS);
         return format.format(Integer.parseInt(minutes));
     }
 }