source: trunk/eraser/Eraser.Manager/Schedule.cs @ 2516

/* 
 * $Id$
 * Copyright 2008-2012 The Eraser Project
 * Original Author: Joel Low <lowjoel@users.sourceforge.net>
 * Modified By:
 * 
 * This file is part of Eraser.
 * 
 * Eraser is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 * 
 * Eraser 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 General Public License for more details.
 * 
 * A copy of the GNU General Public License can be found at
 * <http://www.gnu.org/licenses/>.
 */

using System;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;
using System.Runtime.Serialization;
using System.Security.Permissions;
using System.Globalization;
using Eraser.Util;

namespace Eraser.Manager
{
    /// <summary>
    /// Base class for all schedule types.
    /// </summary>
    [Serializable]
    public abstract class Schedule : ISerializable
    {
        #region Default values
        [Serializable]
        private class RunManuallySchedule : Schedule
        {
            #region Object serialization
            public RunManuallySchedule(SerializationInfo info, StreamingContext context)
            {
            }

            [SecurityPermission(SecurityAction.Demand, SerializationFormatter = true)]
            public override void GetObjectData(SerializationInfo info, StreamingContext context)
            {
            }
            #endregion

            public RunManuallySchedule()
            {
            }

            public override string UIText
            {
                get { return string.Empty; }
            }
        }

        [Serializable]
        private class RunNowSchedule : Schedule
        {
            #region Object serialization
            public RunNowSchedule(SerializationInfo info, StreamingContext context)
            {
            }

            [SecurityPermission(SecurityAction.Demand, SerializationFormatter = true)]
            public override void GetObjectData(SerializationInfo info, StreamingContext context)
            {
            }
            #endregion

            public RunNowSchedule()
            {
            }

            public override string UIText
            {
                get { return string.Empty; }
            }
        }

        [Serializable]
        private class RunOnRestartSchedule : Schedule
        {
            #region Object serialization
            public RunOnRestartSchedule(SerializationInfo info, StreamingContext context)
            {
            }

            [SecurityPermission(SecurityAction.Demand, SerializationFormatter = true)]
            public override void GetObjectData(SerializationInfo info, StreamingContext context)
            {
            }
            #endregion

            public RunOnRestartSchedule()
            {
            }

            public override string UIText
            {
                get { return S._("Running on restart"); }
            }
        }
        #endregion

        /// <summary>
        /// Retrieves the text that should be displayed detailing the nature of
        /// the schedule for use in user interface elements.
        /// </summary>
        public abstract string UIText
        {
            get;
        }

        /// <summary>
        /// The owner of this schedule item.
        /// </summary>
        public Task Owner
        {
            get;
            internal set;
        }

        /// <summary>
        /// Populates a SerializationInfo with the data needed to serialize the
        /// target object.
        /// </summary>
        /// <param name="info">The SerializationInfo to populate with data.</param>
        /// <param name="context">The destination for this serialization.</param>
        [SecurityPermission(SecurityAction.Demand, SerializationFormatter = true)]
        public abstract void GetObjectData(SerializationInfo info, StreamingContext context);

        /// <summary>
        /// The global value for tasks which should be run manually.
        /// </summary>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Security", "CA2104:DoNotDeclareReadOnlyMutableReferenceTypes")]
        public static readonly Schedule RunManually = new RunManuallySchedule();

        /// <summary>
        /// The global value for tasks which should be run immediately.
        /// </summary>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Security", "CA2104:DoNotDeclareReadOnlyMutableReferenceTypes")]
        public static readonly Schedule RunNow = new RunNowSchedule();

        /// <summary>
        /// The global value for tasks which should be run when the computer is
        /// restarted
        /// </summary>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Security", "CA2104:DoNotDeclareReadOnlyMutableReferenceTypes")]
        public static readonly Schedule RunOnRestart = new RunOnRestartSchedule();
    }

    /// <summary>
    /// Recurring runs schedule type.
    /// </summary>
    [Serializable]
    public class RecurringSchedule : Schedule
    {
        #region Overridden members
        public override string UIText
        {
            get
            {
                string result = string.Empty;
                switch (type)
                {
                    case RecurringScheduleUnit.Daily:
                        if (frequency != 1)
                            result = S._("Once every {0} days", frequency);
                        else
                            result = S._("Once every day");
                        break;
                    case RecurringScheduleUnit.Weekdays:
                        result = S._("Every weekday");
                        break;
                    case RecurringScheduleUnit.Weekly:
                        if ((weeklySchedule & DaysOfWeek.Monday) != 0)
                            result = S._("Every Monday, {0}");
                        if ((weeklySchedule & DaysOfWeek.Tuesday) != 0)
                            result += S._("Every Tuesday, {0}");
                        if ((weeklySchedule & DaysOfWeek.Wednesday) != 0)
                            result += S._("Every Wednesday, {0}");
                        if ((weeklySchedule & DaysOfWeek.Thursday) != 0)
                            result += S._("Every Thursday, {0}");
                        if ((weeklySchedule & DaysOfWeek.Friday) != 0)
                            result += S._("Every Friday, {0}");
                        if ((weeklySchedule & DaysOfWeek.Saturday) != 0)
                            result += S._("Every Saturday, {0}");
                        if ((weeklySchedule & DaysOfWeek.Sunday) != 0)
                            result += S._("Every Sunday, {0}");

                        result = string.Format(CultureInfo.CurrentCulture, result,
                            frequency == 1 ?
                                S._("once every {0} week.", frequency) :
                                S._("once every {0} weeks.", frequency));
                        break;
                    case RecurringScheduleUnit.Monthly:
                        if (frequency == 1)
                            result = S._("On day {0} of every month", monthlySchedule);
                        else
                            result = S._("On day {0} of every {1} months", monthlySchedule,
                                frequency);
                        break;
                }

                return result + S._(", at {0}", executionTime.TimeOfDay.ToString());
            }
        }
        #endregion

        #region Object serialization
        protected RecurringSchedule(SerializationInfo info, StreamingContext context)
        {
            type = (RecurringScheduleUnit)info.GetValue("Type", typeof(RecurringScheduleUnit));
            frequency = (int)info.GetValue("Frequency", typeof(int));
            executionTime = (DateTime)info.GetValue("ExecutionTime", typeof(DateTime));
            weeklySchedule = (DaysOfWeek)info.GetValue("WeeklySchedule", typeof(DaysOfWeek));
            monthlySchedule = (int)info.GetValue("MonthlySchedule", typeof(int));

            LastRun = (DateTime)info.GetDateTime("LastRun");
            NextRunCache = (DateTime)info.GetDateTime("NextRun");
        }

        [SecurityPermission(SecurityAction.Demand, SerializationFormatter = true)]
        public override void GetObjectData(SerializationInfo info, StreamingContext context)
        {
            info.AddValue("Type", type);
            info.AddValue("Frequency", frequency);
            info.AddValue("ExecutionTime", executionTime);
            info.AddValue("WeeklySchedule", weeklySchedule);
            info.AddValue("MonthlySchedule", monthlySchedule);
            info.AddValue("LastRun", LastRun);
            info.AddValue("NextRun", NextRunCache);
        }
        #endregion

        /// <summary>
        /// Constructor.
        /// </summary>
        public RecurringSchedule()
        {
        }

        /// <summary>
        /// The type of schedule.
        /// </summary>
        public RecurringScheduleUnit ScheduleType
        {
            get { return type; }
            set
            {
                type = value;
                if (Owner != null)
                    Owner.OnTaskEdited();
            }
        }

        /// <summary>
        /// The frequency of the event. This value is valid only with Daily,
        /// Weekly and Monthly schedules.
        /// </summary>
        public int Frequency
        {
            get
            {
                if (ScheduleType != RecurringScheduleUnit.Daily && ScheduleType != RecurringScheduleUnit.Weekly &&
                    ScheduleType != RecurringScheduleUnit.Monthly)
                    throw new InvalidOperationException("The ScheduleUnit of the schedule " +
                        "does not require a frequency value, this field would contain garbage.");

                return frequency;
            }
            set
            {
                if (value == 0)
                    throw new ArgumentException(S._("The frequency of the recurrence should " +
                        "be greater than one"));

                frequency = value;
                if (Owner != null)
                    Owner.OnTaskEdited();
            }
        }

        /// <summary>
        /// The time of day where the task will be executed.
        /// </summary>
        public DateTime ExecutionTime
        {
            get { return executionTime; }
            set
            {
                executionTime = value;
                if (Owner != null)
                    Owner.OnTaskEdited();
            }
        }

        /// <summary>
        /// The days of the week which this task should be run. This is valid only
        /// with Weekly schedules. This field is the DaysOfWeek enumerations
        /// ORed together.
        /// </summary>
        public DaysOfWeek WeeklySchedule
        {
            get
            {
                if (ScheduleType != RecurringScheduleUnit.Weekly)
                    throw new InvalidOperationException("The ScheduleUnit of the schedule " +
                        "does not require the WeeklySchedule value, this field would contain garbage");

                return weeklySchedule;
            }
            set
            {
                if (value == 0)
                    throw new ArgumentException(S._("The WeeklySchedule should have at " +
                        "least one day where the task should be run."));

                weeklySchedule = value;
                if (Owner != null)
                    Owner.OnTaskEdited();
            }
        }

        /// <summary>
        /// The nth day of the month on which this task will run. This is valid
        /// only with Monthly schedules
        /// </summary>
        public int MonthlySchedule
        {
            get
            {
                if (ScheduleType != RecurringScheduleUnit.Monthly)
                    throw new InvalidOperationException("The ScheduleUnit of the schedule does " +
                        "not require the MonthlySchedule value, this field would contain garbage");

                return monthlySchedule;
            }
            set
            {
                monthlySchedule = value;

                if (Owner != null)
                    Owner.OnTaskEdited();
            }
        }

        /// <summary>
        /// The last time this task was executed. This value is used for computing
        /// the next time the task should be run.
        /// </summary>
        public DateTime LastRun
        {
            get;
            private set;
        }

        /// <summary>
        /// Computes the next run time based on the last run time, the current
        /// schedule, and the current time. The timestamp returned will be the next
        /// time from now which fulfils the schedule.
        /// </summary>
        public DateTime NextRun
        {
            get
            {
                //Get a good starting point, either now, or the last time the task
                //was run.
                DateTime nextRun = LastRun;
                if (nextRun == DateTime.MinValue)
                    nextRun = DateTime.Now;
                nextRun = new DateTime(nextRun.Year, nextRun.Month, nextRun.Day, executionTime.Hour,
                    executionTime.Minute, executionTime.Second);

                switch (ScheduleType)
                {
                    case RecurringScheduleUnit.Daily:
                    {
                        //First assume that it is today that we are running the schedule
                        long daysToAdd = (DateTime.Now - nextRun).Days;
                        nextRun = nextRun.AddDays(daysToAdd);

                        //If we have passed today's run time, schedule it after the next
                        //frequency
                        if (nextRun < DateTime.Now)
                            nextRun = nextRun.AddDays(frequency);
                        break;
                    }
                    case RecurringScheduleUnit.Weekdays:
                    {
                        while (nextRun < DateTime.Now ||
                            LastRun.DayOfWeek == DayOfWeek.Saturday ||
                            LastRun.DayOfWeek == DayOfWeek.Sunday)
                            nextRun = nextRun.AddDays(1);
                        break;
                    }
                    case RecurringScheduleUnit.Weekly:
                    {
                        if (weeklySchedule == 0)
                            break;

                        //Find the next eligible day to run the task within this week.
                        do
                        {
                            if (CanRunOnDay(nextRun) && nextRun >= DateTime.Now)
                                break;
                            nextRun = nextRun.AddDays(1);
                        }
                        while (nextRun.DayOfWeek < DayOfWeek.Saturday);

                        while (nextRun < DateTime.Now || !CanRunOnDay(nextRun))
                        {
                            //Find the next eligible day to run the task
                            nextRun = nextRun.AddDays(7 * (frequency - 1));
                            for (int daysInWeek = 7; daysInWeek-- != 0; nextRun = nextRun.AddDays(1))
                            {
                                if (CanRunOnDay(nextRun) && nextRun >= DateTime.Now)
                                    break;
                            }
                        }

                        break;
                    }
                    case RecurringScheduleUnit.Monthly:
                        if (LastRun == DateTime.MinValue)
                        {
                            //Since the schedule has never been used, find the next time
                            //to run the task. If the current day is less than the
                            //scheduled day, leave it alone. Otherwise, go to the
                            //following month.
                            while (monthlySchedule < nextRun.Day)
                                nextRun = nextRun.AddDays(1);
                        }
                        else
                        {
                            //Step the number of months since the last run
                            while (nextRun < DateTime.Now)
                                nextRun = nextRun.AddMonths(frequency);
                        }

                        //Set the day of the month which the task is supposed to run.
                        nextRun = nextRun.AddDays(monthlySchedule - nextRun.Day);
                        break;
                }

                return nextRun;
            }
        }

        /// <summary>
        /// Gets whether the previous run was missed.
        /// </summary>
        public bool MissedPreviousSchedule
        {
            get
            {
                return LastRun != DateTime.MinValue && NextRun != NextRunCache;
            }
        }

        /// <summary>
        /// Returns true if the task can run on the given date. Applies only for
        /// weekly tasks.
        /// </summary>
        /// <param name="date">The date to run on.</param>
        /// <returns>True if the task will be run on the date.</returns>
        private bool CanRunOnDay(DateTime date)
        {
            if (ScheduleType != RecurringScheduleUnit.Weekly)
                throw new ArgumentException("The ScheduleUnit of the schedule does " +
                    "not use the WeeklySchedule value, this field would contain garbage");
            return ((int)weeklySchedule & (1 << (int)date.DayOfWeek)) != 0;
        }

        /// <summary>
        /// Reschedules the task.
        /// </summary>
        /// <param name="lastRun">The last time the task was run.</param>
        internal void Reschedule(DateTime lastRun)
        {
            LastRun = lastRun;
            NextRunCache = NextRun;
        }

        private RecurringScheduleUnit type;
        private int frequency;
        private DateTime executionTime;
        private DaysOfWeek weeklySchedule;
        private int monthlySchedule;

        /// <summary>
        /// The next time the task is scheduled to run - this is cached from the previous
        /// calculation of the next run time to determine if the task's schedule was missed
        /// </summary>
        private DateTime NextRunCache;
    }

    /// <summary>
    /// The types of schedule
    /// </summary>
    public enum RecurringScheduleUnit
    {
        /// <summary>
        /// Daily schedule type
        /// </summary>
        Daily,

        /// <summary>
        /// Weekdays-only schedule type
        /// </summary>
        Weekdays,

        /// <summary>
        /// Weekly schedule type
        /// </summary>
        Weekly,

        /// <summary>
        /// Monthly schedule type
        /// </summary>
        Monthly
    }

    /// <summary>
    /// The days of the week, with values usable in a bitfield.
    /// </summary>
    [Flags]
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1714:FlagsEnumsShouldHavePluralNames")]
    public enum DaysOfWeek
    {
        None = 0,
        Sunday = 1 << DayOfWeek.Sunday,
        Monday = 1 << DayOfWeek.Monday,
        Tuesday = 1 << DayOfWeek.Tuesday,
        Wednesday = 1 << DayOfWeek.Wednesday,
        Thursday = 1 << DayOfWeek.Thursday,
        Friday = 1 << DayOfWeek.Friday,
        Saturday = 1 << DayOfWeek.Saturday
    }
}