# Script to join domain inside of MDT.
# Technolog Networks, 2024-08-12
# iRaven

# General necessities.
$CompName = $env:COMPUTERNAME
$TSEnv = New-Object -ComObject Microsoft.SMS.TSEnvironment
$MDTPath = $Global:TSEnv.Value("DeployRoot")
Start-Transcript -Path "$MDTPath\_Logs\$CompName-JoinDomain.log" -Append
$CompType = $args[0]
$SubType = $args[1]

Function CheckDomainJoin { # Check if we're already domain joined
    if ((gwmi Win32_ComputerSystem).partofdomain -eq $true -and (gwmi Win32_ComputerSystem).domain -eq "technolog.net") {
        write-host "Already part of the domain!"
        return true
    } else {
        write-host "Not part of the domain yet (or joined to another)!"
        return false
    }
}

Function FilterComputerOU {
    if ($CompType -like "WKS") {
        New-ItemProperty -Path "HKLM:\System\CurrentControlSet\Control\LSA" -Name NetJoinLegacyAccountReuse -Value 1
        $PCNamePrefix = ($CompName.Substring(0,$CompName.IndexOf("-")))
        # Domain credentials to join WKS to domain
        . "$MDTPath\_Scripts\Credentials-MDTJoinDomain.ps1"

        Write-Host "Auto-detecting computer name $CompName..."
        # Filter out OUs
        if ($PCNamePrefix -like "XH") {
            Write-Host "Detected computer name as XH - domain joining to Personal WKS OU"
            $Script.DomainOU = "OU=Personal,OU=Workstations,DC=technolog,DC=net"
        }
        elseif ($PCNamePrefix -like "TNG" -or $PCNamePrefix -like "NH" -or $PCNamePrefix -like "IR") {
            Write-Host "Detected computer name as TNG, NH, or IR - domain joining to Standard WKS OU"
            $Script.DomainOU = "OU=Generic,OU=Workstations,DC=technolog,DC=net"
        } elseif ($PCNamePrefix -like "TEST") {
            Write-Host "Detected computer name as TEST - domain joining to Testing WKS OU"
            $Script.DomainOU = "OU=TestingWKS,OU=Workstations,DC=technolog,DC=net"
        } else {
            Write-Host "Computer name is unusual - domain joining to Standard WKS OU"
            $Script.DomainOU = "OU=Workstations,DC=technolog,DC=net"
        }
    } elseif ($CompType -like "Server") {
        $DomainCredential = Get-Credential -Message "To join this server to the domain, enter your domain credentials."
        # Filter out SubType var for server tiers
        if ($null -ne $SubType) {
            $Script.DomainOU = "OU=$SubType,OU=Domain Servers,DC=technolog,DC=net"
        } else {
            $Script.DomainOU = "OU=Domain Servers,DC=technolog,DC=net"
        }
    } elseif ($CompType -like "Utility") {
        . "$MDTPath\_Scripts\Credentials-MDTJoinDomain.ps1"

        Write-Host "Domain joining to Utility OU"
        $Script.DomainOU = "OU=Utility,OU=Workstations,DC=technolog,DC=net"
    } else {
        . "$MDTPath\_Scripts\Credentials-MDTJoinDomain.ps1"
        Write-Host "Domain joining to generic Computers OU"
    
    }
}

Function JoinDomainOU {
    # Perform domain join with filtered OU from above   
    if ([boolean](get-variable "DomainOU" -ErrorAction SilentlyContinue)) {
        try {
            Add-Computer -DomainName technolog.net -Credential $DomainCredential -OUPath $DomainOU -Restart
        } catch {
            Write-Host "Couldn't join the domain with OU $DomainOU"
        }
    } else {
        try {
            Add-Computer -DomainName technolog.net -Credential $DomainCredential -Restart
        } catch {
            Write-Host "Couldn't join the domain!"
        }
    }
}

if ((CheckDomainJoin) -eq $false) {
    FilterComputerOU
    JoinDomainOU
}
Stop-Transcript