[CmdletBinding()]
param(
    [Parameter(Mandatory=$true,ValueFromPipeline=$true,ValueFromPipelineByPropertyName=$true)][Alias('Cn')][string[]] $ComputerName
)

process {
    foreach ($Computer in $ComputerName) {
        Write-Verbose "Processing $Computer"
        $Output = @(.\PsLoggedon.exe -l "\\$Computer" 2> $env:TEMP\psloggedon.tmp)
        if ($Output -imatch 'Error') {
            New-Object PSObject -Property @{
                ComputerName = $Computer
                Date         = $null
                Domain       = $null
                User         = $null
                Error        = ($Output | Where-Object { $_ -match '\S' }) -join ' ; '
            } | Select ComputerName, Date, Domain, User, Error
        }
        $Output | ForEach-Object {
            if ($_ -match '\s+(?<DateTime>(?:.?unknown time.?|\d{1,2}/\d{1,2}/\d{4}\s+\d{1,2}:\d{1,2}:\d{1,2}\s+[ap]m))\s+(?<DomainUser>\S+)') {
                $DomainUser = $Matches.DomainUser
                if ($Matches.DateTime -imatch 'unknown time') {
                    $Date = $null
                }
                else {
                    $Date = $Matches.DateTime
                }
                if ($Date) {
                    # Pad single digits in date and time with zeroes (I'm a magician).
                    # This is so that we can use [datetime]::ParseExact() in one format rather
                    # than having like 10 if/else statements and repeated code.
                    # ... And I sort of really wanted that sortable date object.
                    ## Bugs made me abandon this idea...
                    #$Date = $Date -replace '(?<!\d)(\d(?:[/:\s]|$))', '0$1'
                    #Write-Host -Fore Green $Date
                    #$Date = [datetime]::ParseExact($Date, 'MM/dd/yyyy hh:mm:ss tt', [CultureInfo]::InvariantCulture) # buggy, works on other host with US locale
                    #$Date = Get-Date -UFormat '%M/%d/%Y %r' ... uh, $Date
                    
                    # And I ended up with a cast...
                    $Date = [datetime]$Date
                }
                New-Object PSObject -Property @{
                    ComputerName = $Computer
                    Date         = $Date
                    Domain       = $DomainUser.Split('\')[0]
                    User         = $DomainUser.Split('\')[1]
                    Error        = $null
                }
            }
        } | Select ComputerName, Date, Domain, User, Error
    }
}