$ebookLibraryPath = '.\OneDrive\Documents\Ebook Library\'
Function Get-Empties {
	PARAM($targetPath)
	Return Get-ChildItem -Path $targetPath -Recurse | Where { $_.PsIsContainer -eq $true } | Where { $_.GetDirectories().Count -eq 0 -and ($_.GetFiles().Count -eq 0) -or ($_.GetFiles().Count -eq 1 -and $_.GetFiles().Name -match "(?i)(.*?)\.opf$")}
}
$failed = @{}
$toEmpty = Get-Empties $ebookLibraryPath

Function Write-Log {
   Param ( [parameter(Mandatory=$true,
    ValueFromPipeline=$true)]
    [string]$logMessage,
    [PSDefaultValue(Help = "Will create a log file in the same directory as the script is run")]
    [string]$Logfile = ".\$(gc env:computername)-delete-dirs.log")

   Add-Content $Logfile -value $($(Get-Date).ToString() + ": " + $logMessage)
}

while($toEmpty.Count -gt 0) {
	try {
		foreach($dir in $toEmpty){Write-Log "Deleting $($dir.FullName) which has LastWriteTime $($dir.LastWriteTime.ToString())"; Remove-Item -LiteralPath $dir.PSPath -Force -Recurse -Confirm}
	}
	catch {
		$ErrorMessage = $_.Exception.Message
		$FailedItem = $_.Exception.ItemName
		Write-Error -Exception $_.Exception
		$failed.Add($failed.Count+1,$dir)
	}
	$toEmpty = Get-Empties $ebookLibraryPath
}