#Requires -version 2.0

# https://blogs.technet.microsoft.com/heyscriptingguy/2009/12/17/hey-scripting-guy-can-i-share-my-microsoft-outlook-calendar-via-e-mail/
# https://msdn.microsoft.com/en-us/library/bb208062.aspx
# https://msdn.microsoft.com/en-us/library/bb208061(v=office.12).aspx
# https://cjoprey.wordpress.com/archived/getting-another-user%E2%80%99s-outlook-folder%E2%80%A6/

Add-Type -AssemblyName microsoft.office.interop.outlook
$olFolders = "Microsoft.Office.Interop.Outlook.OlDefaultFolders" -as [type]
$olCalendarDetail = "Microsoft.Office.Interop.Outlook.olCalendarDetail" -as [type]
$olCalendarMailFormat = "Microsoft.Office.Interop.Outlook.olCalendarMailFormat" -as [type]
$outlook = New-Object -ComObject outlook.application
$class = @"
using Microsoft.Office.Interop.Outlook;public class MyOL
{
public MAPIFolder GetCalendar(string userName)
{
Application oOutlook = new Application();
NameSpace oNs = oOutlook.GetNamespace("MAPI");
Recipient oRep = oNs.CreateRecipient(userName);
MAPIFolder calendar = oNs.GetSharedDefaultFolder(oRep, OlDefaultFolders.olFolderCalendar);
return calendar;
}
}
"@
Add-Type $class -ReferencedAssemblies Microsoft.Office.Interop.Outlook

$MyOL = New-Object MyOL

# whose calendar you want
$folder = $MyOL.GetCalendar("NAMEOFPERSONWHOCALENDARYOUHAVEACCESSTO")

$CalendarSharing=$folder.GetCalendarExporter()

# make the below olFullDetails or olFreeBusyOnly if you want
$CalendarSharing.CalendarDetail = $olCalendarDetail::olFreeBusyAndSubject

$CalendarSharing.startDate = Get-Date

# change this to (Get-Date).addDays(7) if you want more than one day
$CalendarSharing.endDate = (Get-Date).addDays(7)

$CalendarSharing.RestrictToWorkingHours = $false
$CalendarSharing.IncludeAttachments = $false
$CalendarSharing.IncludePrivateDetails = $false

# make the below olCalendarMailFormat::olCalendarMailFormatDailySchedule if you want
$MailItem = $CalendarSharing.ForwardAsICal($olCalendarMailFormat::olCalendarMailFormatEventList)

$MailItem.DeleteAfterSubmit = $true

# configure recipient
$MailItem.Recipients.Add("EMAILWHEREYOUWANTCALENDARTOGO")

$MailItem.Send()