# Connect to Office 365 (remove these three lines for on-premise usage)
$UserCredential = Get-Credential
$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $UserCredential -Authentication Basic -AllowRedirection
Import-PSSession $Session -DisableNameChecking

#Change this to the email adress of your 360 Syncronize Service Account Mailbox
$TSZ = "exchsync@example.com"

#Change this to include the desired. Examples:
#$users = Get-User -OrganizationalUnit "Sales" 
#$users = get-user johndoe@example.com
$users = get-user

$360ExchangeFolders = "^/Kalender$|^/Opgaver$|^/Calendar$|^/Tasks$"

foreach ($user in $users) {
	Write-Host "user: $user"
	$mailbox = $null
	$mailbox = Get-mailbox -Identity $user.Identity -ErrorAction SilentlyContinue

	if ([bool]$mailbox)
	{
		Write-Host $mailbox.PrimarySmtpAddress
		$alias = $mailbox.alias;

		[string[]] $FolderPaths = Get-MailboxfolderStatistics $alias | % {$_.folderpath}
		if ([bool]$FolderPaths)
		{
			$UsableFolderPaths = $FolderPaths | where { $_ -match $360ExchangeFolders } 
			$UsableExchangeFolderPaths = $UsableFolderPaths | % {$alias + ":" + $_.replace('/','\')} 

			if ([bool]$UsableExchangeFolderPaths)
			{
				foreach ($folder in $UsableExchangeFolderPaths) {
					$folder
					if ([bool](get-mailboxfolderPermission $folder -User $TSZ  -ErrorAction SilentlyContinue))
					{ 
						Write-Host "Changing permission to: Editor" -ForegroundColor Green
						Set-MailboxFolderPermission -Identity $folder -User $TSZ -AccessRights Editor -WarningAction SilentlyContinue
					}
					else { 
						Write-Host "Adding permission: Editor" -ForegroundColor Green
						Add-MailboxFolderPermission -Identity $folder -User $TSZ -AccessRights Editor
					}
				}
			}
			else 
			{
				Write-Host "!No folders found!" -ForegroundColor Red
			}
		}
	}
	else 
	{
		Write-Host "!No mailbox found!" -ForegroundColor Red
	}
}