/*
 * Copyright 2000-2004 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.jetspeed.scheduler;

import java.util.Calendar;
import java.lang.Comparable;
import java.util.Date;

/**
 * This is a wrapper for a scheduled job.  It is modeled after the
 * Unix scheduler cron.
 *
 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
 * @version $Id: JobEntry.java,v 1.2 2004/03/08 00:45:07 jford Exp $
 */
public class JobEntry
    extends BaseJobEntry
    implements Comparable
{

    /** indicates if job is currently running */
    private boolean jobIsActive = false;

    /** Next runtime. **/
    private long runtime = 0;

    /** schedule types **/
    private static final int SECOND = 0;
    private static final int MINUTE = 1;
    private static final int WEEK_DAY = 2;
    private static final int DAY_OF_MONTH = 3;
    private static final int DAILY = 4;


    /**
     * default constructor
     */
    public JobEntry()
    {
    }

    /**
     * Constuctor.
     *
     * Schedule a job to run on a certain point of time.<br>
     *
     * Example 1: Run the DefaultScheduledJob at 8:00am every 15th of
     * the month - <br>
     *
     * JobEntry je = new JobEntry(0,0,8,15,"DefaultScheduledJob");<br>
     *
     * Example 2: Run the DefaultScheduledJob at 8:00am every day -
     * <br>
     *
     * JobEntry je = new JobEntry(0,0,8,-1,"DefaultScheduledJob");<br>
     *
     * Example 3: Run the DefaultScheduledJob every 2 hours. - <br>
     *
     * JobEntry je = new JobEntry(0,120,-1,-1,"DefaultScheduledJob");<br>
     *
     * Example 4: Run the DefaultScheduledJob every 30 seconds. - <br>
     *
     * JobEntry je = new JobEntry(30,-1,-1,-1,"DefaultScheduledJob");<br>
     *
     * @param sec Value for entry "seconds".
     * @param min Value for entry "minutes".
     * @param hour Value for entry "hours".
     * @param wd Value for entry "week days".
     * @param day_mo Value for entry "month days".
     * @param task Task to execute.
     * @exception Exception, a generic exception.
     */
    public JobEntry(int sec,
                    int min,
                    int hour,
                    int wd,
                    int day_mo,
                    String task)
        throws Exception
    {
        if ( task == null || task.length() == 0 )
        {
            throw new Exception("Error in JobEntry. " + 
                "Bad Job parameter. Task not set.");
        }
        
        setSecond(sec);
        setMinute(min);
        setHour(hour);
        setWeekDay(wd);
        setDayOfMonth(day_mo);
        setTask(task);

        calcRunTime();
    }

    /**
     * Compares one JobEntry to another JobEntry based on the JobId
     */
    public int compareTo(Object je)
    {
        int result = -1;
        if (je instanceof JobEntry)
        {
            if (jobId == ((JobEntry)je).getJobId())
            {
                return 0;
            }
            else
            {
                if (jobId > ((JobEntry)je).getJobId())
                {
                    return 1;
                }
            }
            
        }
        return result;
    }

    /**
     * Sets whether the job is running.
     *
     * @param isActive Whether the job is running.
     */
    public void setActive(boolean isActive)
    {
        jobIsActive = isActive;
    }

    /**
     * Check to see if job is currently active/running
     *
     * @return true if job is currently geing run by the
     *  workerthread, otherwise false
     */
     public boolean isActive()
     {
        return jobIsActive;
     }

    /**
     * Get the next runtime for this job as a long.
     *
     * @return The next run time as a long.
     */
    public long getNextRuntime()
    {
        return runtime;
    }

    /**
     * Get the next runtime for this job as a String.
     *
     * @return The next run time as a String.
     */
    public String getNextRunAsString()
    {
        return new Date(runtime).toString();
    }

    /**
     * Calculate how long before the next runtime.<br>
     *
     * The runtime determines it's position in the job queue.
     * Here's the logic:<br>
     *
     * 1. Create a date the represents when this job is to run.<br>
     *
     * 2. If this date has expired, them "roll" appropriate date
     * fields forward to the next date.<br>
     *
     * 3. Calculate the diff in time between the current time and the
     * next run time.<br>
     *
     * @exception Exception, a generic exception.
     */
    public void calcRunTime()
        throws Exception
    {
        Calendar schedrun = Calendar.getInstance();
        Calendar now = Calendar.getInstance();
 
        switch( evaluateJobType() )
        {
        case SECOND:
            // SECOND (every so many seconds...)
            schedrun.add(Calendar.SECOND, getSecond());
            runtime = schedrun.getTime().getTime();
            break;

        case MINUTE:
            // MINUTE (every so many minutes...)
            schedrun.add(Calendar.SECOND, getSecond());
            schedrun.add(Calendar.MINUTE, getMinute());
            runtime = schedrun.getTime().getTime();
            break;

        case WEEK_DAY:
            // WEEKDAY (day of the week)
            schedrun.set(Calendar.SECOND, getSecond());
            schedrun.set(Calendar.MINUTE, getMinute());
            schedrun.set(Calendar.HOUR_OF_DAY, getHour());
            schedrun.set(Calendar.DAY_OF_WEEK, getWeekDay());

            if ( now.before(schedrun) )
            {
                // Scheduled time has NOT expired.
                runtime = schedrun.getTime().getTime();
            }
            else
            {
                // Scheduled time has expired; roll to the next week.
                schedrun.add(Calendar.DAY_OF_WEEK,7);
                runtime = schedrun.getTime().getTime();
            }
            break;

        case DAY_OF_MONTH:
            // DAY_OF_MONTH (date of the month)
            schedrun.set(Calendar.SECOND, getSecond());
            schedrun.set(Calendar.MINUTE, getMinute());
            schedrun.set(Calendar.HOUR_OF_DAY, getHour());
            schedrun.set(Calendar.DAY_OF_MONTH, getDayOfMonth());

            if ( now.before(schedrun) )
            {
                // Scheduled time has NOT expired.
                runtime = schedrun.getTime().getTime();
            }
            else
            {
                // Scheduled time has expired; roll to the next month.
                schedrun.add(Calendar.MONTH,1);
                runtime = schedrun.getTime().getTime();
            }
            break;

        case DAILY:
            // DAILY (certain hour:minutes of the day)
            schedrun.set(Calendar.SECOND, getSecond());
            schedrun.set(Calendar.MINUTE, getMinute());
            schedrun.set(Calendar.HOUR_OF_DAY, getHour());

            // Scheduled time has NOT expired.
            if ( now.before(schedrun) )
            {
                runtime = schedrun.getTime().getTime();
            }
            else
            {
                // Scheduled time has expired; roll forward 24 hours.
                schedrun.add(Calendar.HOUR_OF_DAY,24);
                runtime = schedrun.getTime().getTime();
            }
            break;

        default:
            // Do nothing.
        }
    }

    /**
     * What schedule am I on?
     *
     * I know this is kinda ugly!  If you can think of a cleaner way
     * to do this, please jump in!
     *
     * @return A number specifying the type of schedule. See
     * calcRunTime().
     * @exception Exception, a generic exception.
     */
    private int evaluateJobType()
        throws Exception
    {

        // First start by checking if it's a day of the month job.
        if ( getDayOfMonth() < 0 )
        {
            // Not a day of the month job... check weekday.
            if ( getWeekDay() < 0 )
            {
                // Not a weekday job...check if by the hour.
                if ( getHour() < 0 )
                {
                    // Not an hourly job...check if it is by the minute
                    if ( getMinute() < 0 )
                    {
                        // Not a by the minute job so must be by the second
                        if ( getSecond() < 0)
                            throw new Exception("Error in JobEntry. Bad Job parameter.");

                        return SECOND;
                    }
                    else
                    {
                        // Must be a job run by the minute so we need minutes and
                        // seconds.
                        if ( getMinute() < 0 || getSecond() < 0 )
                            throw new Exception("Error in JobEntry. Bad Job parameter.");

                        return MINUTE;
                    }
                }
                else
                {
                    // Must be a daily job by hours minutes, and seconds.  In
                    // this case, we need the minute, second, and hour params.
                    if ( getMinute() < 0 || getHour() < 0 || getSecond() < 0)
                        throw new Exception("Error in JobEntry. Bad Job parameter.");

                    return DAILY;
                }
            }
            else
            {
                // Must be a weekday job.  In this case, we need
                // minute, second, and hour params
                if ( getMinute() < 0 || getHour() < 0 || getSecond() < 0 )
                    throw new Exception("Error in JobEntry. Bad Job parameter.");

                return WEEK_DAY;
            }
        }
        else
        {
            // Must be a day of the month job.  In this case, we need
            // minute, second, and hour params
            if ( getMinute() < 0 || getHour() < 0 )
                throw new Exception("Error in JobEntry. Bad Job parameter.");

            return DAY_OF_MONTH;
        }
    }

}
