#Requires -RunAsAdministrator
<#
.SYNOPSIS
    Signs an individual PC certificate using the Certificate Authority

.DESCRIPTION
    Creates and signs a certificate for a specific PC using the CA certificate.
    The certificate will have the proper hostname (e.g., g9kn7pz3esf.logon.ds.ge.com)
    and will be automatically trusted on any computer that trusts the CA.

.PARAMETER Hostname
    The hostname of the PC (without domain suffix)
    Example: G9KN7PZ3ESF

.PARAMETER Domain
    The domain suffix (default: logon.ds.ge.com)

.PARAMETER CAThumbprint
    Thumbprint of the CA certificate used to sign this certificate

.PARAMETER CAPfxPath
    Path to the CA PFX file (if CA is not in local store)

.PARAMETER CAPassword
    Password for the CA PFX file

.PARAMETER OutputPath
    Directory to save the signed certificate (default: current directory)

.PARAMETER ValidityYears
    How many years the certificate should be valid (default: 2)

.PARAMETER ExportPassword
    Password for exporting the signed certificate

.EXAMPLE
    # Sign certificate using CA from local store
    .\Sign-PCCertificate.ps1 -Hostname G9KN7PZ3ESF -CAThumbprint "ABC123..."

.EXAMPLE
    # Sign certificate using CA from PFX file
    $caPass = ConvertTo-SecureString "CAPassword" -AsPlainText -Force
    $certPass = ConvertTo-SecureString "CertPassword" -AsPlainText -Force
    .\Sign-PCCertificate.ps1 -Hostname G9KN7PZ3ESF -CAPfxPath "C:\CA\ca.pfx" `
        -CAPassword $caPass -ExportPassword $certPass

.NOTES
    Author: System Administrator
    Date: 2025-10-17
#>

param(
    [Parameter(Mandatory=$true)]
    [string]$Hostname,

    [Parameter(Mandatory=$false)]
    [string]$Domain = "logon.ds.ge.com",

    [Parameter(Mandatory=$false)]
    [string]$CAThumbprint,

    [Parameter(Mandatory=$false)]
    [string]$CAPfxPath,

    [Parameter(Mandatory=$false)]
    [SecureString]$CAPassword,

    [Parameter(Mandatory=$false)]
    [string]$OutputPath = ".",

    [Parameter(Mandatory=$false)]
    [int]$ValidityYears = 2,

    [Parameter(Mandatory=$false)]
    [SecureString]$ExportPassword
)

Write-Host ""
Write-Host "╔══════════════════════════════════════════════════════════════╗" -ForegroundColor Cyan
Write-Host "║         Sign Individual PC Certificate with CA              ║" -ForegroundColor Cyan
Write-Host "╚══════════════════════════════════════════════════════════════╝" -ForegroundColor Cyan
Write-Host ""

# Clean hostname (remove domain if included)
$Hostname = $Hostname -replace "\.$Domain$", ""
$FQDN = "$Hostname.$Domain".ToLower()

Write-Host "Target PC:" -ForegroundColor Cyan
Write-Host "  Hostname: $Hostname" -ForegroundColor White
Write-Host "  FQDN:     $FQDN" -ForegroundColor White
Write-Host ""

# Get CA certificate
$caCert = $null

if ($CAPfxPath) {
    # Load CA from PFX file
    Write-Host "Loading CA certificate from file..." -ForegroundColor Yellow
    Write-Host "  File: $CAPfxPath" -ForegroundColor Gray

    if (-not (Test-Path $CAPfxPath)) {
        Write-Host "✗ CA PFX file not found: $CAPfxPath" -ForegroundColor Red
        exit 1
    }

    if (-not $CAPassword) {
        $CAPassword = Read-Host "Enter CA certificate password" -AsSecureString
    }

    try {
        $caCert = New-Object System.Security.Cryptography.X509Certificates.X509Certificate2($CAPfxPath, $CAPassword, 'Exportable')
        Write-Host "✓ CA certificate loaded" -ForegroundColor Green
    } catch {
        Write-Host "✗ Failed to load CA certificate: $($_.Exception.Message)" -ForegroundColor Red
        exit 1
    }

} elseif ($CAThumbprint) {
    # Load CA from local store
    Write-Host "Loading CA certificate from local store..." -ForegroundColor Yellow
    Write-Host "  Thumbprint: $CAThumbprint" -ForegroundColor Gray

    try {
        $caCert = Get-ChildItem Cert:\LocalMachine\My\$CAThumbprint -ErrorAction Stop
        Write-Host "✓ CA certificate found" -ForegroundColor Green
    } catch {
        Write-Host "✗ CA certificate not found in local store" -ForegroundColor Red
        Write-Host "  Thumbprint: $CAThumbprint" -ForegroundColor Red
        Write-Host "  Try specifying -CAPfxPath instead" -ForegroundColor Yellow
        exit 1
    }

} else {
    Write-Host "✗ Must specify either -CAThumbprint or -CAPfxPath" -ForegroundColor Red
    exit 1
}

# Verify CA has private key
if (-not $caCert.HasPrivateKey) {
    Write-Host "✗ CA certificate does not have private key" -ForegroundColor Red
    Write-Host "  Cannot sign certificates without CA private key" -ForegroundColor Red
    exit 1
}

Write-Host ""
Write-Host "CA Certificate Details:" -ForegroundColor Cyan
Write-Host "  Subject:     $($caCert.Subject)" -ForegroundColor White
Write-Host "  Thumbprint:  $($caCert.Thumbprint)" -ForegroundColor White
Write-Host "  Valid Until: $($caCert.NotAfter)" -ForegroundColor White
Write-Host ""

# Prompt for export password if not provided
if (-not $ExportPassword) {
    Write-Host "Enter password to protect the PC certificate:" -ForegroundColor Yellow
    $ExportPassword = Read-Host "Certificate Password" -AsSecureString
}

# Create output directory if needed
if (-not (Test-Path $OutputPath)) {
    New-Item -ItemType Directory -Path $OutputPath -Force | Out-Null
}

# Generate the PC certificate
Write-Host "Generating certificate for $FQDN..." -ForegroundColor Yellow

try {
    $notAfter = (Get-Date).AddYears($ValidityYears)

    # Create certificate request (self-signed, will be replaced by CA-signed version)
    $certParams = @{
        Subject = "CN=$FQDN"
        DnsName = @($FQDN, $Hostname)
        KeyExportPolicy = 'Exportable'
        KeyUsage = 'DigitalSignature', 'KeyEncipherment'
        KeyUsageProperty = 'All'
        KeyLength = 2048
        KeyAlgorithm = 'RSA'
        HashAlgorithm = 'SHA256'
        CertStoreLocation = 'Cert:\LocalMachine\My'
        NotAfter = $notAfter
        TextExtension = @(
            '2.5.29.37={text}1.3.6.1.5.5.7.3.1'  # Enhanced Key Usage: Server Authentication
        )
        Signer = $caCert
    }

    Write-Host "  Subject: CN=$FQDN" -ForegroundColor Gray
    Write-Host "  DNS Names: $FQDN, $Hostname" -ForegroundColor Gray
    Write-Host "  Valid for: $ValidityYears years" -ForegroundColor Gray
    Write-Host ""

    $pcCert = New-SelfSignedCertificate @certParams

    Write-Host "✓ Certificate created and signed by CA" -ForegroundColor Green
    Write-Host ""
    Write-Host "Certificate Details:" -ForegroundColor Cyan
    Write-Host "  Subject:     $($pcCert.Subject)" -ForegroundColor White
    Write-Host "  Thumbprint:  $($pcCert.Thumbprint)" -ForegroundColor White
    Write-Host "  Issuer:      $($pcCert.Issuer)" -ForegroundColor White
    Write-Host "  Valid From:  $($pcCert.NotBefore)" -ForegroundColor White
    Write-Host "  Valid Until: $($pcCert.NotAfter)" -ForegroundColor White
    Write-Host "  DNS Names:   $($pcCert.DnsNameList.Unicode -join ', ')" -ForegroundColor White
    Write-Host ""

} catch {
    Write-Host "✗ Failed to create certificate: $($_.Exception.Message)" -ForegroundColor Red
    exit 1
}

# Export certificate with private key (PFX)
$timestamp = Get-Date -Format "yyyyMMdd"
$pfxPath = Join-Path $OutputPath "$Hostname-$Domain-$timestamp.pfx"

Write-Host "Exporting certificate with private key..." -ForegroundColor Yellow
Write-Host "  File: $pfxPath" -ForegroundColor Gray

try {
    Export-PfxCertificate -Cert $pcCert -FilePath $pfxPath -Password $ExportPassword | Out-Null
    Write-Host "✓ Certificate exported" -ForegroundColor Green
    Write-Host ""
} catch {
    Write-Host "✗ Failed to export PFX: $($_.Exception.Message)" -ForegroundColor Red
    exit 1
}

# Export certificate without private key (CER) for verification
$cerPath = Join-Path $OutputPath "$Hostname-$Domain-$timestamp.cer"

Write-Host "Exporting public certificate..." -ForegroundColor Yellow
Write-Host "  File: $cerPath" -ForegroundColor Gray

try {
    Export-Certificate -Cert $pcCert -FilePath $cerPath | Out-Null
    Write-Host "✓ Public certificate exported" -ForegroundColor Green
    Write-Host ""
} catch {
    Write-Host "✗ Failed to export CER: $($_.Exception.Message)" -ForegroundColor Red
}

# Remove certificate from local store (cleanup)
Write-Host "Removing temporary certificate from local store..." -ForegroundColor Gray
try {
    Remove-Item "Cert:\LocalMachine\My\$($pcCert.Thumbprint)" -Force
    Write-Host "✓ Local store cleaned up" -ForegroundColor Green
} catch {
    Write-Host "⚠ Could not remove temporary certificate (not critical)" -ForegroundColor Yellow
}

Write-Host ""

# Create certificate info file
$infoPath = Join-Path $OutputPath "$Hostname-$Domain-$timestamp-INFO.txt"

$infoContent = @"
================================================================================
PC CERTIFICATE INFORMATION
================================================================================

Created: $(Get-Date -Format "yyyy-MM-dd HH:mm:ss")

PC Details:
-----------
Hostname:      $Hostname
FQDN:          $FQDN
Certificate:   CN=$FQDN
DNS Names:     $($pcCert.DnsNameList.Unicode -join ', ')

Certificate Details:
--------------------
Thumbprint:    $($pcCert.Thumbprint)
Issuer:        $($pcCert.Issuer)
Serial Number: $($pcCert.SerialNumber)
Valid From:    $($pcCert.NotBefore)
Valid Until:   $($pcCert.NotAfter)
Key Size:      2048-bit RSA
Hash Algorithm: SHA256

CA Details:
-----------
CA Subject:    $($caCert.Subject)
CA Thumbprint: $($caCert.Thumbprint)

Files Created:
--------------
1. $pfxPath
   - PC certificate WITH private key
   - Protected with password
   - Deploy this to $Hostname

2. $cerPath
   - PC certificate WITHOUT private key (public only)
   - For verification purposes only

================================================================================
DEPLOYMENT INSTRUCTIONS
================================================================================

1. Copy the PFX file to the PC:
   Copy-Item "$pfxPath" \\$FQDN\C$\Temp\

2. On the PC ($Hostname), import the certificate:
   `$certPass = ConvertTo-SecureString "YourPassword" -AsPlainText -Force
   Import-PfxCertificate -FilePath "C:\Temp\$(Split-Path $pfxPath -Leaf)" ``
       -CertStoreLocation Cert:\LocalMachine\My ``
       -Password `$certPass

3. Configure WinRM HTTPS with the certificate:
   .\Setup-WinRM-HTTPS.ps1 -CertificateThumbprint "$($pcCert.Thumbprint)" ``
       -Domain "$Domain"

4. Or use the deployment package with this certificate:
   - Replace wildcard certificate with this PC-specific certificate
   - Run Deploy-WinRM-HTTPS.bat on $Hostname

================================================================================
VERIFICATION
================================================================================

On the PC ($Hostname):
  # View certificate
  Get-ChildItem Cert:\LocalMachine\My\$($pcCert.Thumbprint)

  # Verify issuer
  `$cert = Get-ChildItem Cert:\LocalMachine\My\$($pcCert.Thumbprint)
  Write-Host "Issuer: `$(`$cert.Issuer)"
  # Should show: $($caCert.Subject)

On Management Computer:
  # Verify CA is trusted
  Get-ChildItem Cert:\LocalMachine\Root | Where-Object {`$_.Thumbprint -eq "$($caCert.Thumbprint)"}

  # Test connection
  Test-WSMan -ComputerName $FQDN -UseSSL -Port 5986
  # Should work without -SessionOption if CA is trusted

================================================================================
TROUBLESHOOTING
================================================================================

If certificate isn't trusted:
1. Install CA certificate on management computer:
   Import-Certificate -FilePath "CA.cer" -CertStoreLocation Cert:\LocalMachine\Root

2. Verify certificate chain on PC:
   Test-Certificate -Cert (Get-Item Cert:\LocalMachine\My\$($pcCert.Thumbprint))

3. Check WinRM listener:
   winrm enumerate winrm/config/listener
   # Should show Hostname = $FQDN (not wildcard)

================================================================================
"@

$infoContent | Out-File -FilePath $infoPath -Encoding UTF8
Write-Host "✓ Certificate info created: $infoPath" -ForegroundColor Green
Write-Host ""

# Final summary
Write-Host "╔══════════════════════════════════════════════════════════════╗" -ForegroundColor Green
Write-Host "║            PC CERTIFICATE CREATED SUCCESSFULLY               ║" -ForegroundColor Green
Write-Host "╚══════════════════════════════════════════════════════════════╝" -ForegroundColor Green
Write-Host ""
Write-Host "Files Created:" -ForegroundColor Cyan
Write-Host "  1. $pfxPath" -ForegroundColor White
Write-Host "     (Deploy to $Hostname)" -ForegroundColor Gray
Write-Host ""
Write-Host "  2. $cerPath" -ForegroundColor White
Write-Host "     (Public certificate for verification)" -ForegroundColor Gray
Write-Host ""
Write-Host "  3. $infoPath" -ForegroundColor White
Write-Host "     (Deployment instructions)" -ForegroundColor Gray
Write-Host ""
Write-Host "Certificate Thumbprint: $($pcCert.Thumbprint)" -ForegroundColor Yellow
Write-Host ""
Write-Host "Next Steps:" -ForegroundColor Cyan
Write-Host "  1. Deploy PFX file to $Hostname" -ForegroundColor White
Write-Host "  2. Import certificate on $Hostname" -ForegroundColor White
Write-Host "  3. Configure WinRM HTTPS with this certificate" -ForegroundColor White
Write-Host "  4. Ensure CA certificate is installed on management computers" -ForegroundColor White
Write-Host ""