# Create a hashed secure password file from the client input
# Read-Host -AsSecureString | ConvertFrom-SecureString | Out-File D:\secure-password.txt

$svc_account_username = "<username>"
$svc_account_password = get-content D:\secure-password.txt | ConvertTo-SecureString

# Parameter input variables
$vcenter = "<FQDN vCenter>"
$vcenter_host = "<FQDN Host>"

$portgroup_check = "dvv" #parameter to look for / name of the distributed switch vlan
$portgroup_replace = "stv" #parameter to replace with / name vlan on the new standard switch

$standard_switch = "<name new standard switch>"

$vms= @()
$dpgs = @()

Function OpenConnection {
    param(
     [Parameter()]
     [string]$vcenter,
     [Parameter()]
     [string]$username,
     [Parameter()]
     [securestring]$password
    )

    # Create a credential
    $cred = New-Object System.Management.Automation.PSCredential -ArgumentList ($username, $password) -ErrorAction Stop

    # Connect to vCenter
    if ($cred) {
        $connection = Connect-VIServer -Server $vcenter -Credential $cred -Force -ErrorAction Stop
    } else {
        $connection = $null
    }
    
    return $connection
}

Function GetHostVM {
    param(
     [Parameter()]
     [string]$vcenter_host
    )
    $vms = Get-VMHost -Name $vcenter_host -ErrorAction SilentlyContinue | Get-VM -ErrorAction SilentlyContinue | Select-Object -Property Name, @{N='PortGroupName';E={(Get-NetworkAdapter -VM $_).NetworkName -join '|'}}

    return $vms
}

Function GetVM {
    param(
     [Parameter()]
     [string]$vcenter_host
    )
    $vms = Get-VM -ErrorAction SilentlyContinue | Select-Object -Property Name, @{N='HostName';E={$_.VMHost.Name}}, @{N='PortGroupName';E={(Get-NetworkAdapter -VM $_).NetworkName -join '|'}} | Where-Object  {$_.HostName -like @($vcenter_host.Substring(0,7)+"*")}

    return $vms
}

Function CloseConnection {
    param(
     [Parameter()]
     [string]$vcenter
    )
    # Close vCenter connection
    Disconnect-VIServer -Server $vcenter -Confirm:$false
}

Function CheckPortGroup {
    param (
     [Parameter()]
     [string]$vcenter,
     [Parameter()]
     [string]$vcenter_host,
     [Parameter()]
     [string]$portgroup,
     [Parameter()]
     [string]$portgroup_check,
     [Parameter()]
     [string]$portgroup_replace,
     [Parameter()]
     [string]$standard_switch
    )

    $portgroup = $portgroup -replace $portgroup_check, $portgroup_replace

    $pg = Get-VirtualPortGroup -Server $vcenter -VMHost $vcenter_host -Name $portgroup -VirtualSwitch $standard_switch -ErrorAction SilentlyContinue

    return $pg
}

Function NewPortGroup {
    param (
     [Parameter()]
     [string]$vcenter,
     [Parameter()]
     [string]$vcenter_host,
     [Parameter()]
     [string]$portgroup,
     [Parameter()]
     [string]$portgroup_check,
     [Parameter()]
     [string]$portgroup_replace,
     [Parameter()]
     [string]$standard_switch,
     [Parameter()]
     [string]$vlan_id
    )

    $portgroup = $portgroup -replace $portgroup_check, $portgroup_replace

    $pg = New-VirtualPortGroup -Server $vcenter -Name $portgroup -VirtualSwitch $standard_switch -VLanId $vlan_id -ErrorAction SilentlyContinue

    return $pg
}

Function CheckStandardSwitch {
    param (
     [Parameter()]
     [string]$vcenter,
     [Parameter()]
     [string]$vcenter_host,
     [Parameter()]
     [string]$standard_switch
    )

    $svs = Get-VirtualSwitch -VMHost $vcenter_host -Name $standard_switch -Server $vcenter -ErrorAction SilentlyContinue

    return $svs
}

Function NewStandardSwitch {
    param (
     [Parameter()]
     [string]$vcenter,
     [Parameter()]
     [string]$vcenter_host,
     [Parameter()]
     [string]$standard_switch
    )

    $svs = New-VirtualSwitch -VMHost $vcenter_host -Name $standard_switch -Server $vcenter -ErrorAction SilentlyContinue

    return $svs
}

$connection = OpenConnection -vcenter $vcenter -username $svc_account_username -password $svc_account_password

if ($connection) {
    # Get the vm that are running on a host
    #$vms = GetHostVM -vcenter_host $vcenter_host
    $vms = GetVM -vcenter_host $vcenter_host


    # Get the distinct portgroups for those vm
    $dpgs =  $vms.portgroupname -split {$_ -like "*|*"} | Select-Object $_ -Unique | Sort-Object $_

    # Check if the temporary standard switch exists
    $vs_exists = CheckStandardSwitch -vcenter $vcenter -vcenter_host $vcenter_host -standard_switch $standard_switch

    if (!$vs_exists) {
        # Create the temporary standard switch
        $svs = NewStandardSwitch -vcenter $vcenter -vcenter_host $vcenter_host -standard_switch $standard_switch
    }

    foreach ($dpg in $dpgs) {
        # Check if the standard portgroup exists on the host
        if ($dpg -like @('*'+$portgroup_check+'*')) {
            $pg_exists = CheckPortGroup -vcenter $vcenter -vcenter_host $vcenter_host -portgroup $dpg -portgroup_check $portgroup_check -portgroup_replace $portgroup_replace -standard_switch $standard_switch

            if (!$pg_exists) {
                # Create standard portgroup on the host
                $svpg = NewPortGroup -vcenter $vcenter -vcenter_host $vcenter_host -portgroup $dpg -portgroup_check $portgroup_check -portgroup_replace $portgroup_replace -standard_switch $standard_switch -vlan_id $dpg.Substring($dpg.Length-3,3)
            }
        } else {
            Write-Host "Portgroup" $dpg "out of range." -ForegroundColor Red
        }
    }

    CloseConnection -vcenter $vcenter
}