# Get-HighestEA-DomainWide.ps1
# Searches the whole AD domain for computer names matching EA<number>L or EA<number>D
# and prints the highest.

$regex = '^EA(\d+)(L|D)$'

# Bind to RootDSE to get domain DN
try {
    $root = [ADSI]"LDAP://RootDSE"
    $base = [string]$root.defaultNamingContext
    Write-Host "Searching domain base: $base"
} catch {
    Write-Host "FAILED: Cannot bind to LDAP RootDSE"
    Write-Host "Reason: $($_.Exception.Message)"
    exit 1
}

$entry = New-Object System.DirectoryServices.DirectoryEntry("LDAP://$base")
$searcher = New-Object System.DirectoryServices.DirectorySearcher($entry)
$searcher.PageSize = 1000
$searcher.Filter = "(&(objectCategory=computer)(name=EA*))"
$null = $searcher.PropertiesToLoad.Add("name")

$maxAllNum = -1; $maxAllName = $null
$maxLNum   = -1; $maxLName   = $null
$maxDNum   = -1; $maxDName   = $null
$matched   = 0

foreach ($r in $searcher.FindAll()) {
    $name = [string]$r.Properties["name"][0]
    if ($name -match $regex) {
        $matched++
        $num = [int]$Matches[1]
        $suf = $Matches[2]

        if ($num -gt $maxAllNum) { $maxAllNum = $num; $maxAllName = $name }
        if ($suf -eq 'L' -and $num -gt $maxLNum) { $maxLNum = $num; $maxLName = $name }
        if ($suf -eq 'D' -and $num -gt $maxDNum) { $maxDNum = $num; $maxDName = $name }
    }
}

Write-Host ""
Write-Host "Matched EA<number>L/D: $matched"
if ($maxAllNum -ge 0) {
    Write-Host "Highest overall: $maxAllName (Number: $maxAllNum)"
} else {
    Write-Host "Highest overall: (none found)"
}

if ($maxLNum -ge 0) { Write-Host "Highest L:       $maxLName (Number: $maxLNum)" } else { Write-Host "Highest L:       (none found)" }
if ($maxDNum -ge 0) { Write-Host "Highest D:       $maxDName (Number: $maxDNum)" } else { Write-Host "Highest D:       (none found)" }