Add a calendar ics with Powershell

JesseG985 

# Define the URLs for downloading and the save paths
$urls = @(
    "https://outlook.office365.com/owa/calendar/XXX/XXX/reachcalendar.ics",
    "https://outlook.office365.com/owa/calendar/XXX/XXX/reachcalendar.ics"
)

# Get the path to the "CalendarFiles" directory for the current user
$basePath = "C:\Company\CalendarUpdates\CalendarFiles"
if (-not (Test-Path $basePath)) {
    $newDirectory = New-Item -Path $basePath -ItemType Directory -Force
    $newDirectory.Attributes += "Hidden"
}

$savePaths = @(
    "$basePath\MeetingRoomA.ics",
    "$basePath\MeetingRoomB.ics"
)

# Download the files
for ($i = 0; $i -lt $urls.Length; $i++) {
    Invoke-WebRequest -Uri $urls[$i] -OutFile $savePaths[$i]
}

# Define the path to the folder containing the ICS files
$ICSpath = $basePath
$ICSlist = Get-ChildItem $ICSpath -Filter *.ics

# Create the function to delete an existing appointment
function DeleteAppointment {
    param ($eventData, $folder)

    $Start = [datetime]::ParseExact($eventData["DTSTART"], "yyyyMMddTHHmmss", $null)
    $End = [datetime]::ParseExact($eventData["DTEND"], "yyyyMMddTHHmmss", $null)

    foreach ($item in $folder.Items) {
        if ($item.Start -eq $Start -and $item.End -eq $End -and $item.Subject -eq $eventData["SUMMARY"]) {
            $item.Delete()
            break
        }
    }
}

# Create the function to create an appointment
function CreateAppointment {
    param ($eventData, $folder)

    if (-not $eventData["DTSTART"] -or -not $eventData["DTEND"] -or -not $eventData["SUMMARY"]) {
        return
    }

    try {
        # Delete the existing event if it exists
        DeleteAppointment $eventData $folder

        # Add the new event
        $Start = [datetime]::ParseExact($eventData["DTSTART"], "yyyyMMddTHHmmss", $null)
        $End = [datetime]::ParseExact($eventData["DTEND"], "yyyyMMddTHHmmss", $null)

        $appointment = $folder.Items.Add(1) # 1 corresponds to olAppointmentItem
        $appointment.Start = $Start
        $appointment.End = $End
        $appointment.Subject = $eventData["SUMMARY"]
        if ($eventData["LOCATION"]) { $appointment.Location = $eventData["LOCATION"] }
        $appointment.Categories = "Presentations"
        $appointment.BusyStatus = 0 # 0=Free
        $appointment.ReminderMinutesBeforeStart = 15 # Customize if desired
        $appointment.ReminderSet = $false # Disable reminders

        $appointment.Save()
    } catch {
        # Error while creating the appointment
    }
}

# Create a new folder in Outlook named after the ICS file
function CreateOutlookFolder {
    param ($folderName)

    $outlook = New-Object -ComObject Outlook.Application
    $namespace = $outlook.GetNamespace("MAPI")
    $calendarFolder = $namespace.GetDefaultFolder(9) # 9 corresponds to the Calendar folder

    $importedFolder = $calendarFolder.Folders | Where-Object { $_.Name -eq $folderName }

    if (-not $importedFolder) {
        $importedFolder = $calendarFolder.Folders.Add($folderName)
    }

    return $importedFolder
}

# Process the ICS files and add appointments to a folder named after the file
foreach ($file in $ICSlist) {
    $folderName = [System.IO.Path]::GetFileNameWithoutExtension($file.Name)
    $importedFolder = CreateOutlookFolder -folderName $folderName

    # Retrieve the content of the ICS file
    $content = Get-Content $file.FullName -Encoding UTF8

    # List of events to add to Outlook
    $eventsToAdd = @()

    $eventData = @{}
    $content | ForEach-Object {
        if ($_ -match '^DTSTART;TZID=.*:(\d{8}T\d{6})') {
            $eventData["DTSTART"] = $matches[1]
        } elseif ($_ -match '^DTEND;TZID=.*:(\d{8}T\d{6})') {
            $eventData["DTEND"] = $matches[1]
        } elseif ($_ -match '^SUMMARY:(.*)$') {
            $eventData["SUMMARY"] = $matches[1]
        } elseif ($_ -match '^LOCATION:(.*)$') {
            $eventData["LOCATION"] = $matches[1]
        } elseif ($_ -match '^END:VEVENT$') {
            # Add the event to the list of events to add
            $eventsToAdd += $eventData
            $eventData = @{}
        }
    }

    # Retrieve the current events in Outlook
    $currentEvents = @()
    foreach ($item in $importedFolder.Items) {
        $currentEvents += @{
            "DTSTART" = $item.Start.ToString("yyyyMMddTHHmmss")
            "DTEND" = $item.End.ToString("yyyyMMddTHHmmss")
            "SUMMARY" = $item.Subject
            "LOCATION" = $item.Location
        }
    }

    # Compare and update events in Outlook
    foreach ($event in $eventsToAdd) {
        $found = $false

        # Check if the event already exists in Outlook
        foreach ($item in $importedFolder.Items) {
            if ($item.Start.ToString("yyyyMMddTHHmmss") -eq $event["DTSTART"] -and
                $item.End.ToString("yyyyMMddTHHmmss") -eq $event["DTEND"] -and
                $item.Subject -eq $event["SUMMARY"] -and
                ($item.Location -eq $event["LOCATION"] -or (!$item.Location -and !$event["LOCATION"]))) {
                
                # The event already exists with the same details
                $found = $true
                break
            }
        }

        if (!$found) {
            # The event doesn't exist, create a new appointment
            CreateAppointment $event $importedFolder
        }
    }

    # Delete events in Outlook that are not in $eventsToAdd
    foreach ($item in $importedFolder.Items) {
        $found = $false

        foreach ($event in $eventsToAdd) {
            if ($item.Start.ToString("yyyyMMddTHHmmss") -eq $event["DTSTART"] -and
                $item.End.ToString("yyyyMMddTHHmmss") -eq $event["DTEND"] -and
                $item.Subject -eq $event["SUMMARY"] -and
                ($item.Location -eq $event["LOCATION"] -or (!$item.Location -and !$event["LOCATION"]))) {
                
                # The event in Outlook is also in $eventsToAdd
                $found = $true
                break
            }
        }

        if (!$found) {
            # The event in Outlook is not in $eventsToAdd, delete it
            $item.Delete()
        }
    }

    # Release the COM objects for this folder
    [System.Runtime.Interopservices.Marshal]::ReleaseComObject($importedFolder) | Out-Null
}