DHCP Scope/Option/Policy Migration

#Requires -Version 3.0 -Modules DhcpServer -RunAsAdministrator
[CmdletBinding(DefaultParameterSetName="CopyScopes")]
param
(
    [parameter(Mandatory=$true, Position=0)]
    [string] $NewDhcpServer,

    [parameter(Mandatory=$false)]
    [switch] $CreateNewCimSession,

    [parameter(Mandatory=$false)]
    [Microsoft.Management.Infrastructure.CimSession] $CimSession,

    [parameter(Mandatory=$false, Position=1)]
    [pscredential] $Credential,

    [parameter(Mandatory=$false, Position=2)]
    [string] $OldDhcpServer = $env:COMPUTERNAME,

    [parameter(Mandatory=$true, ParameterSetName="CopyScopes")]
    [string] $NewPrefixName,

    [parameter(Mandatory=$false, ParameterSetName="CopyScopes")]
    [switch] $IncludeInactiveScopes,

    [parameter(Mandatory=$true, ParameterSetName="CopyOptionsDefinitions")]
    [switch] $PerformOptionsCopy,

    [parameter(Mandatory=$true, ParameterSetName="CopyServerPolicies")]
    [switch] $PerformPoliciesCopy,

    [parameter(Mandatory=$false)]
    [bool] $Confirm = $true,

    [parameter(Mandatory=$false)]
    [switch] $Force
)

$ra = @{ ErrorAction = "Stop" };
if ($PSBoundParameters.ContainsKey("CreateNewCimSession"))
{
    $cimSes = New-CimSession -Authentication CredSsp -ComputerName $NewDhcpServer -Credential $Credential -ErrorAction Stop;
    $ra.CimSession = $cimSes;
}
elseif ($PSBoundParameters.ContainsKey("CimSession"))
{
    $ra.CimSession = $CimSession;
}
else
{
    $ra.ComputerName = $NewDhcpServer;
}
$la = @{ ComputerName = $OldDhcpServer; ErrorAction = "Stop" };

#region Option Definitions Operation
if ($PSBoundParameters.ContainsKey("PerformOptionsCopy"))
{
    # Recreate missing 'Option Definitions' on the new DHCP Server.
    $optDefs = Get-DhcpServerv4OptionDefinition @la -All;
    $newDefs = Get-DhcpServerv4OptionDefinition @ra -All;
    $differences = Compare-Object -ReferenceObject $optDefs -DifferenceObject $newDefs -Property OptionId | `
        Where-Object -FilterScript { $_.SideIndicator -eq '<=' } | `
        Select-Object -ExpandProperty InputObject;
    if (@($differences).Count -ne 0)
    {
        Write-Host "The following Options are " -f Yellow -NoNewline;
        Write-Host "NOT" -f Red -NoNewline;
        Write-Host " on the destination DHCP server:`n" -f Yellow
        Write-Host "$([string]::Join(', ', [string[]]@($differences)))" -f Cyan;

        if ($PSBoundParameters.ContainsKey("Force"))
        {
            foreach ($def in $differences)
            {
                $opt = Get-DhcpServerv4OptionDefinition @la -OptionId $def;
                Add-DhcpServerv4OptionDefinition @ra -Name $opt.Name -OptionId $opt.OptionId -Description $opt.Description `
                    -Type $opt.Type -MultiValued:$opt.MultiValued -VendorClass $opt.VendorClass `
                    -DefaultValue $opt.DefaultValue -Confirm:$Confirm;
            }
        }
        else
        {
            Write-Host "`nTo add the missing DHCP server option definitions, re-run this script with the `"-Force`" switch." -f Yellow;
        }
    }
    else
    {
        Write-Host "All Options are present on the destination DHCP server!" -f Green;
    }
}
#endregion

#region Copy Scopes Operation
if ($PSBoundParameters.ContainsKey("NewPrefixName"))
{

    if (-not $PSBoundParameters.ContainsKey("IncludeNonActiveScopes"))
    {
        $scopes = Get-DhcpServerv4Scope @la | ? State -ne "Inactive"   # Get all scopes on old DHCP server.
    }
    else
    {
        $scopes = Get-DhcpServerv4Scope @la;    # Get all scopes on old DHCP server.
    }

    $sCount = @($scopes).Count;
    # Copy the scopes to the new server and leave in a 'Disabled' state.
    for ($i = 1; $i -le $sCount; $i++)
    {
        $scope = $scopes[$i-1];
        Write-Progress -Activity "Adding Scopes" -Status "Copying Scope $i/$sCount... $($scope.ScopeId)" `
            -Id 1 -PercentComplete (($i/$sCount)*100);

        Add-DhcpServerv4Scope @ra -Name "$NewPrefixName - $($scope.Name)" -SubnetMask $scope.SubnetMask `
            -StartRange $scope.StartRange -EndRange $scope.EndRange -State Inactive -Description $scope.Description `
            -SuperscopeName $scope.SuperscopeName -MaxBootpClients $scope.MaxBootpClients -Type $scope.Type `
            -ActivatePolicies $scope.ActivatePolicies -Delay $scope.Delay -LeaseDuration $scope.LeaseDuration `
            -NapEnable:$scope.NapEnable -NapProfile $scope.NapProfile -Confirm:$Confirm;

        # Get all scope options and copy them to the new server's scope.
        $sourceOpts = Get-DhcpServerv4OptionValue @la -ScopeId $scope.ScopeId -All;
        $oCount = @($sourceOpts).Count;
        for ($o = 1; $o -le $oCount; $o++)
        {
            $opt = $sourceOpts[$o-1];
            Write-Progress -Activity "Adding Scope Options" -Status "Copying Option $o/$oCount..." `
                -Id 2 -ParentId 1 -PercentComplete (($o/$oCount)*100);

            Set-DhcpServerv4OptionValue @ra -ScopeId $scope.ScopeId -OptionId $opt.OptionId -Value $opt.Value -Confirm:$Confirm;
        }
        Write-Progress -Activity "Adding Scope Options" -Id 2 -Completed;

        # Get all the scope reservations and copy them to the new server's scope.
        $sourceRes = Get-DhcpServerv4Reservation @la -ScopeId $scope.ScopeId;
        $rCount = @($sourceRes).Count;
        for ($r = 1; $r -le $rCount; $r++)
        {
            $resv = $sourceRes[$r-1];
            Write-Progress -Activity "Adding Scope Reservations" -Status "Copying Reservation $r/$rCount... $($resv.IPAddress.ToString())" `
                -Id 3 -ParentId 1 -PercentComplete (($r/$rCount)*100);

            Add-DhcpServerv4Reservation @ra -ScopeId $scope.ScopeId -ClientId $resv.ClientId `
                -Name $resv.Name -Description $resv.Description -Type $resv.Type -IPAddress $resv.IPAddress -Confirm:$Confirm;
        }
        Write-Progress -Activity "Adding Scope Reservations" -Id 3 -Completed;

        # Get all the scope leases and copy them to the new server's scope.
        $sourceLeases = Get-DhcpServerv4Lease @la -ScopeId $scope.ScopeId -AllLeases;
        $lCount = @($sourceLeases).Count;
        for ($l = 1; $l -le $lCount; $l++)
        {
            $lease = $sourceLeases[$l-1];
            Write-Progress -Activity "Adding Scope Leases" -Status "Copying Lease $r/$rCount..." `
                -Id 4 -ParentId 1 -PercentComplete (($l/$lCount)*100);

            Add-DhcpServerv4Lease @ra -ScopeId $scope.ScopeId -IPAddress $lease.IPAddress -AddressState $lease.AddressState `
                -HostName $lease.HostName -Description $lease.Description -DnsRR $lease.DnsRR -DnsRegistration $lease.DnsRegistration `
                -ClientType $lease.ClientType -LeaseExpiryTime $lease.LeaseExpiryTime -NapCapable $lease.NapCapable -NapStatus $lease.NapStatus `
                -ProbationEnds $lease.ProbationEnds -ClientId $lease.ClientId -Confirm:$Confirm;
        }
        Write-Progress -Activity "Adding Scope Leases" -Id 4 -Completed;
    }
    Write-Progress -Activity "Adding Scopes" -Id 1 -Completed;
}
#endregion

#region Server Policies Operation
if ($PSBoundParameters.ContainsKey("PerformPoliciesCopy"))
{
    Write-Host "Copying Server Policies... " -f Yellow -NoNewline;
    try
    {
        $policies = Get-DhcpServerv4Policy @la;
        $properties = @($policies)[0] | Get-Member -MemberType Property | Where-Object -FilterScript {
            $_.Name -ne "PSComputerName"
        };

        foreach ($p in $policies)
        {
            $hash = @{}
            foreach ($prop in $properties)
            {
                if (($p.$prop -is [string] -and [string]::IsNullOrEmpty($p.$prop)) -or ($p.$prop -isnot [string] -and $null -eq $p.$prop))
                {
                    continue;
                }
                $hash.Add($prop, $p.$prop);
            }
            Add-DhcpServerv4Policy @ra @hash -Confirm:$Confirm;
        }
        Write-Host "Done!" -f Green;
    }
    catch
    {
        Write-Host "FAILED!`n" -f Red;
        Write-Host $_.Exception.Message -f Red;
    }
}
#endregion