/// <summary>
/// PreviousOccurrence(DateTime, DateRange),
/// Return the previous occurrence in the schedule for the given date, from within the
/// specified date range. Returns null if nothing is found.
/// See PreviousOccurrence(DateTime) for additional details.
/// </summary>
public DateTime?PreviousOccurrence(DateTime aDate, DateRange during)
{
// Make sure that our search begins no later than the end of the during range.
DateTime duringEnding = during.EndDateTime.SafeAddDays(1);
if (aDate > duringEnding)
{
aDate = duringEnding;
}
// Make sure that our search begins no later than the end of the event limits range.
DateRange eventLimits = _event.GetEventLimitsAsDateRange();
DateTime eventEnding = eventLimits.EndDateTime.SafeAddDays(1);
if (aDate > eventEnding)
{
aDate = eventEnding;
}
// Find the loop limit date for this search.
// This should be the latest available start date from all the applicable limiting ranges.
DateTime earliestSearchDate = during.StartDateTime;
if (eventLimits.StartDateTime > earliestSearchDate)
{
earliestSearchDate = eventLimits.StartDateTime;
}
// Perform the search.
DateTime?occurrence = null;
while (aDate >= earliestSearchDate)
{
// Get a working range for this search.
var workingRange = DateRangeForPreviousOrNextOccurrence(aDate, true, earliestSearchDate);
// Find the previous occurrence.
var dates = Occurrences(workingRange).OrderByDescending(o => o.Date);
occurrence = dates.SkipWhile(o => o >= aDate.Date).FirstOrDefault();
occurrence = (occurrence == default(DateTime)) ? null : occurrence;
// Break the loop if an occurrence was found.
if (occurrence != null)
{
break;
}
// Increment the search date to search an earlier DateRange.
aDate = workingRange.StartDateTime.AddDays(-1);
}
// Make sure that our result is no earlier than the start of the event limits range.
if (occurrence != null && occurrence < eventLimits.StartDateTime)
{
occurrence = null;
}
// Make sure that our result is no earlier than the start of the during range.
if (occurrence != null && occurrence < during.StartDateTime)
{
occurrence = null;
}
return(occurrence);
}
/// <summary>
/// RoughlyEstimateMinimumEventOccurrences,
/// This will return a very rough, and conservative, guess of the minimum number of occurrences
/// that should be generated by a particular event.
/// </summary>
static public int RoughlyEstimateMinimumEventOccurrences(Event eventInstance)
{
if (eventInstance.HasBrokenZeroOccurrenceConfiguration())
{
return(0);
}
int repeatInterval = eventInstance.RepeatInterval;
DateRange eventLimits = eventInstance.GetEventLimitsAsDateRange();
TimeSpan timeSpan = eventLimits.EndDateTime - eventLimits.StartDateTime;
int spanDays = timeSpan.Days;
int spanWeeks = timeSpan.Days / 7;
int result = 0;
switch (eventInstance.FrequencyTypeOptions)
{
case FrequencyTypeEnum.None:
result = 1;
break;
case FrequencyTypeEnum.Daily:
result = (spanDays / repeatInterval) - 1;
break;
case FrequencyTypeEnum.Weekly:
int includedDays = 0;
includedDays += eventInstance.DaysOfWeekOptions.HasFlag(DayOfWeekEnum.Mon) ? 1 : 0;
includedDays += eventInstance.DaysOfWeekOptions.HasFlag(DayOfWeekEnum.Tue) ? 1 : 0;
includedDays += eventInstance.DaysOfWeekOptions.HasFlag(DayOfWeekEnum.Wed) ? 1 : 0;
includedDays += eventInstance.DaysOfWeekOptions.HasFlag(DayOfWeekEnum.Thu) ? 1 : 0;
includedDays += eventInstance.DaysOfWeekOptions.HasFlag(DayOfWeekEnum.Fri) ? 1 : 0;
includedDays += eventInstance.DaysOfWeekOptions.HasFlag(DayOfWeekEnum.Sat) ? 1 : 0;
includedDays += eventInstance.DaysOfWeekOptions.HasFlag(DayOfWeekEnum.Sun) ? 1 : 0;
result = ((spanWeeks / repeatInterval) * includedDays) - 1;
break;
case FrequencyTypeEnum.Monthly:
int spanMonths = spanDays / 31;
result = (spanMonths / repeatInterval) - 1;
break;
case FrequencyTypeEnum.Quarterly:
int spanQuarters = spanDays / 92;
result = (spanQuarters / repeatInterval) - 1;
break;
case FrequencyTypeEnum.Yearly:
int spanYears = spanDays / 365;
result = (spanYears / repeatInterval) - 1;
break;
}
return((result > 0) ? result : 0);
}
/// <summary>
/// RoughlyEstimateMinimumEventOccurrences,
/// This will return a very rough, and conservative, guess of the minimum number of occurrences
/// that should be generated by a particular event.
/// </summary>
public static int RoughlyEstimateMinimumEventOccurrences(Event eventInstance)
{
if (eventInstance.HasBrokenZeroOccurrenceConfiguration()) { return 0; }
int repeatInterval = eventInstance.RepeatInterval;
DateRange eventLimits = eventInstance.GetEventLimitsAsDateRange();
TimeSpan timeSpan = eventLimits.EndDateTime - eventLimits.StartDateTime;
int spanDays = timeSpan.Days;
int spanWeeks = timeSpan.Days / 7;
int result = 0;
switch (eventInstance.FrequencyTypeOptions)
{
case FrequencyTypeEnum.None:
result = 1;
break;
case FrequencyTypeEnum.Daily:
result = (spanDays / repeatInterval) - 1;
break;
case FrequencyTypeEnum.Weekly:
int includedDays = 0;
includedDays += eventInstance.DaysOfWeekOptions.HasFlag(DayOfWeekEnum.Mon) ? 1 : 0;
includedDays += eventInstance.DaysOfWeekOptions.HasFlag(DayOfWeekEnum.Tue) ? 1 : 0;
includedDays += eventInstance.DaysOfWeekOptions.HasFlag(DayOfWeekEnum.Wed) ? 1 : 0;
includedDays += eventInstance.DaysOfWeekOptions.HasFlag(DayOfWeekEnum.Thu) ? 1 : 0;
includedDays += eventInstance.DaysOfWeekOptions.HasFlag(DayOfWeekEnum.Fri) ? 1 : 0;
includedDays += eventInstance.DaysOfWeekOptions.HasFlag(DayOfWeekEnum.Sat) ? 1 : 0;
includedDays += eventInstance.DaysOfWeekOptions.HasFlag(DayOfWeekEnum.Sun) ? 1 : 0;
result = ((spanWeeks / repeatInterval) * includedDays) - 1;
break;
case FrequencyTypeEnum.EveryWeekDay:
result = ((spanWeeks / repeatInterval) * 5) - 1;
break;
case FrequencyTypeEnum.EveryMonWedFri:
result = ((spanWeeks / repeatInterval) * 3) - 1;
break;
case FrequencyTypeEnum.EveryTuTh:
result = ((spanWeeks / repeatInterval) * 2) - 1;
break;
case FrequencyTypeEnum.Monthly:
int spanMonths = spanDays / 31;
result = (spanMonths / repeatInterval) - 1;
break;
case FrequencyTypeEnum.Quarterly:
int spanQuarters = spanDays / 92;
result = (spanQuarters / repeatInterval) - 1;
break;
case FrequencyTypeEnum.Yearly:
int spanYears = spanDays / 365;
result = (spanYears / repeatInterval) - 1;
break;
}
return (result > 0) ? result : 0;
}