param(
  [string]$ClusterName
)

$csvName = ".\$($ClusterName)-$(Get-Date -Format 'yyyy-MM-dd-hh-mm')-LUN.csv"

$rndNum = Get-Random -Maximum 99999

$LunInfoDef = @'
public string ClusterName;
public string CanonicalName;
public string UsedBy;
public string DSC;
public string SizeGB;
'@
$LunInfoDef = "public struct LunInfo" + $rndNum + "{`n" + $LunInfoDef

$esxServers = Get-Cluster $ClusterName | Get-VMHost | Sort-Object -Property Name
$esxServers | ForEach-Object {
  $LunInfoDef += ("`n`tpublic string " + ($_.Name.Split(".")[0]) + ";")
}
$LunInfoDef += "`n}"

Add-Type -Language CsharpVersion3 -TypeDefinition $LunInfoDef

$scsiTab = @{}
$esxServers | ForEach-Object {
  $esxImpl = $_

  # $scsiTab layout
  # Key: #
  # Value:
  # 1) canonicalname
  # 2) datastorename or VM/harddiskname
  # 3) capacity (GB)
  # 4) LunId
  # 5) datastoreclustername
  #

  # Get SCSI LUNs
  if (([Version]$esxImpl.Version).Major -lt 6) {
    $esxImpl | Get-ScsiLun | Where-Object { $_.LunType -eq "Disk" } | ForEach-Object {

      $key = $esxImpl.Name.Split(".")[0] + "#" + $_.CanonicalName.Split(".")[1]
      if (!$scsiTab.ContainsKey($key)) {
        $lunId = $_.RuntimeName.Split('L')[1]
        $scsiTab[$key] = $_.CanonicalName, "", $_.CapacityGB, $lunId, ""
      }
    }
  } Else {
    $esxImpl.ExtensionData.Config.StorageDevice.ScsiLun | Where-Object { $_.LunType -eq 'disk' } | ForEach-Object {
      $key = $esxImpl.Name.Split(".")[0] + "#" + $_.CanonicalName.Split(".")[1]
      $capacityGB = $_.Capacity.Block * $_.Capacity.BlockSize / 1GB
      $lunUuid = $_.Uuid
      $lun = $esxImpl.ExtensionData.Config.StorageDevice.MultipathInfo.Lun | Where-Object { $_.Id -eq $lunUuid }
      $lunId = $lun.Path[0].Name.Split('L')[1]
      $scsiTab[$key] = $_.CanonicalName, "", $capacityGB, $lunId, ""
    }
  }

  # Get the VMFS datastores
  $esxImpl | Get-Datastore | Where-Object { $_.Type -eq "VMFS" } | Get-View | ForEach-Object {
    $dsName = $_.Name
    $dscName = ''
    if ($_.Parent.Type -eq 'StoragePod') {
      $dscName = Get-View -Id $_.Parent -Property Name -Server $esxImpl.Uid.Split('@')[1].Split(':')[0] | Select-Object -ExpandProperty Name
    }
    $_.Info.Vmfs.Extent | ForEach-Object {
      $key = $esxImpl.Name.Split(".")[0] + "#" + $_.DiskName.Split(".")[1]
      $scsiTab[$key][1] = $dsName
      $scsiTab[$key][4] = $dscName
    }
  }
}

# Get the RDM disks
Get-Cluster $ClusterName | Get-VM | Get-View | ForEach-Object {
  $vm = $_
  $vm.Config.Hardware.Device | Where-Object { $_.gettype().Name -eq "VirtualDisk" } | ForEach-Object {
    if ($_.Backing.PSObject.Properties['CompatibilityMode'] -and "physicalMode", "virtualmode" -contains $_.Backing.CompatibilityMode) {
      $disk = $_.Backing.LunUuid.Substring(10, 32)
      $key = (Get-View $vm.Runtime.Host -Server $esxImpl.Uid.Split('@')[1].Split(':')[0]).Name.Split(".")[0] + "#" + $disk
      $scsiTab[$key][1] = $vm.Name + "/" + $_.DeviceInfo.Label
    }
  }
}

$scsiTab.GetEnumerator() | Group-Object -Property { $_.Key.Split("#")[1] } | ForEach-Object {
  $lun = New-Object ("LunInfo" + $rndNum)
  $lun.ClusterName = $ClusterName
  $_.Group | ForEach-Object {
    $esxName = $_.Key.Split("#")[0]
    $lun.$esxName = $_.Value[3]
    if (!$lun.CanonicalName) { $lun.CanonicalName = $_.Value[0] }
    if (!$lun.UsedBy) { $lun.UsedBy = $_.Value[1] }
    if (!$lun.SizeGB) { $lun.SizeGB = [math]::Round($_.Value[2], 0) }
    $lun.DSC = $_.Value[4]
  }
  $lun
} | Export-Csv $csvName -NoTypeInformation -UseCulture
Invoke-Item $csvName