# Get-hVm.ps1
# Purpose     : Returns collection of objects representing each Virtual Machine on one or more
#               VMware ESX Server hosts.
# Requirements: plink.exe from the Putty project must be in $env:path
# Use -help parameter for instructions

Param (
  $Credential = $(Get-Credential),
  [switch]$Help,
  [switch]$Snapshot,
  [switch]$Verbose
)

# This function converts the SecureString password in $Credential to plaintext we can use with plink.exe
Function GetSecurePass ($SecurePassword) {
  $Ptr = [System.Runtime.InteropServices.Marshal]::SecureStringToCoTaskMemUnicode($SecurePassword)
  $password = [System.Runtime.InteropServices.Marshal]::PtrToStringUni($Ptr)
  [System.Runtime.InteropServices.Marshal]::ZeroFreeCoTaskMemUnicode($Ptr)
  $password
}

# Obtains list of VMX (config files) corresponding to each VM on a given ESX server
Function GetVMX ($user, $pass, $srv) {
  $cmd = "plink.exe $user@$srv -pw $pass"
  $cmd += " vmware-cmd -l"
  Write-Verbose "Command line: $cmd"
  Invoke-Expression $cmd
}

# Queries each VM to see if any snapshots are present.  Slow as Xmas.
Function HasSnapshot ($user, $pass, $srv, $vmx) {
  $cmd = "plink.exe $user@$srv -pw $pass"
  $cmd += " vmware-cmd $vmx hassnapshot"
  Write-Verbose "Command line: $cmd"
  $results = Invoke-Expression $cmd
  if ( $results -match "1" ) { $true }
  else { $false }
}

# Returns help text
Function ShowUsage {
  $helptext = @'
Get-Vm
  Requirements: plink.exe from the Putty project must be in $env:path
  
INPUT: 

  [pipeline] : name or IP of ESX server(s) (REQUIRED)
  Credential : Object containing credentials for ESX server(s) (use 
               Get-Credential cmdlet to create)
  Snapshot   : boolean switch, if true, query snapshots (slow)
  Help       : shows usage

'@
  Write-Host $helptext
}

# Main
if ($help -or !$Credential) { ShowUsage; exit; }
if ($verbose) { $verbosepreference = "continue" }

$username = $credential.UserName -replace "^\\" # strip backslash from beginning of username
$password = GetSecurePass $credential.Password # convert password to plaintext
$collOut = @() # create collection which holds all of the objOut objects

Write-Verbose "$(get-date -f 's') ESX Query Status:`tGetting list of VMs"
# Iterates through each item in the pipeline.  This should be a list of IPs or hostnames of ESX servers.  We hope.
$input | ForEach-Object {
  Write-Verbose "$(get-date -f 's') Querying host: $_..."
  $VmHost = $_
  $VmList = GetVMX $username $password $vmhost # Calls the GetVMX function to obtain list of virtaul machines
  $VmList | ForEach-Object {
    $objOut = "" | Select-Object VmHost, VmName, VMXpath, HasSnapshot # create our output object with desired properties
      Add-Member -InputObject $objOut -MemberType ScriptMethod -Name RemoveSnapshots `
      -Value { "Reserved for future user, nyah!" }
	$objOut.VmHost = $VmHost
	$objOut.VMXpath = $_
    $objOut.VmName = (Split-Path $_ -Leaf) -replace ".vmx$"
	if ($snapshot) {
	  Write-Verbose "$(get-date -f 's') Getting snapshot status for VM: $($objOut.VmName)"
	  $objOut.HasSnapshot = HasSnapshot $username $password $VmHost "$_"
	}
	$collOut += $objOut
  }
}
Write-Verbose "$(get-date -f 's') ESX Query completed"
Write-Output $collOut