Param(
    [Parameter(Mandatory = $true, HelpMessage = "Base URL of the site (e.g., https://www.example.com)")]
    [ValidatePattern('^https?://')]
    [string]$BaseUrl,

    [Parameter(Mandatory = $true, HelpMessage = "Root folder containing the website files")]
    [string]$RootPath,

    [Parameter(HelpMessage = "Output file path for sitemap.xml (default: <RootPath>\sitemap.xml)")]
    [string]$OutputPath = "$RootPath\sitemap.xml"
)

# Ensure the root path exists
if (-not (Test-Path -Path $RootPath -PathType Container)) {
    Write-Error "RootPath '$RootPath' does not exist or is not a directory."
    exit 1
}

# Resolve full paths
$RootPath = (Resolve-Path -Path $RootPath).ProviderPath
if ($OutputPath -eq "$RootPath\sitemap.xml") {
    $OutputPath = Join-Path -Path $RootPath -ChildPath "sitemap.xml"
}
$OutputPath = (Resolve-Path -Path (Split-Path -Parent $OutputPath) -ErrorAction SilentlyContinue).ProviderPath + "\" + (Split-Path -Leaf $OutputPath)

# Gather files to include in the sitemap
$extensions = @('*.html','*.htm','*.aspx','*.php','*.asp','*.jsp')
$files = Get-ChildItem -Path $RootPath -Recurse -File -Include $extensions -ErrorAction SilentlyContinue

if ($files.Count -eq 0) {
    Write-Warning "No files matching extensions $($extensions -join ', ') were found under $RootPath."
    exit 0
}

# Create XML document
[xml]$xml = New-Object System.Xml.XmlDocument
$decl = $xml.CreateXmlDeclaration('1.0','UTF-8',$null)
$xml.AppendChild($decl) | Out-Null

$urlset = $xml.CreateElement('urlset')
$urlset.SetAttribute('xmlns','http://www.sitemaps.org/schemas/sitemap/0.9')
$xml.AppendChild($urlset) | Out-Null

foreach ($file in $files) {
    # Build relative URL path
    $relativePath = $file.FullName.Substring($RootPath.Length).TrimStart('\','/')
    $url = ($BaseUrl.TrimEnd('/') + '/' + $relativePath) -replace '\\','/'

    $urlElement = $xml.CreateElement('url')

    $loc = $xml.CreateElement('loc')
    $loc.InnerText = $url
    $urlElement.AppendChild($loc) | Out-Null

    $lastmod = $xml.CreateElement('lastmod')
    $lastmod.InnerText = $file.LastWriteTimeUtc.ToString('yyyy-MM-ddTHH:mm:ssZ')
    $urlElement.AppendChild($lastmod) | Out-Null

    $urlset.AppendChild($urlElement) | Out-Null
}

# Save the sitemap
try {
    $xml.Save($OutputPath)
    Write-Host "Sitemap successfully generated:" -ForegroundColor Green
    Write-Host "  Path : $OutputPath"
    Write-Host "  URLs : $($files.Count)"
}
catch {
    Write-Error "Failed to save sitemap to '$OutputPath'. $_"
    exit 1
}