$ErrorActionPreference = "Stop"

$MetadataFolder = "$env:LOCALAPPDATA\MyEtwMetadata\ById"
$MetadataSearchByNameFolder = "$env:LOCALAPPDATA\MyEtwMetadata\ByName"


if (-not (Test-Path $MetadataFolder)) {
    New-Item -ItemType Directory -Path $MetadataFolder | Out-Null
}

if (-not (Test-Path $MetadataSearchByNameFolder)) {
    New-Item -ItemType Directory -Path $MetadataSearchByNameFolder | Out-Null
}

function _SanitizeFileName {
    param ([Parameter(Mandatory = $true)]$FileName)

    [System.IO.Path]::GetInvalidFileNameChars() | ForEach-Object -Process {
        $FileName = $FileName.Replace($_, [char]'_')
    }
    $FileName
}

Write-Output "Initializing ETW providers metadata... "
wevtutil.exe ep | ForEach-Object -Process {
    $ProviderName = $_
    Write-Debug $ProviderName
    $xml = $(wevtutil.exe gp /f:xml "$_" 2>$null)
    if ($LASTEXITCODE -eq 0 -and $xml) {
        $metadata = [xml]$xml
        $metadata.Save($(Join-Path -Path $MetadataFolder -ChildPath "$($metadata.provider.guid).xml"));
        $metadata.provider.guid | Out-File $(
            Join-Path -Path $MetadataSearchByNameFolder -ChildPath "$(_SanitizeFileName $ProviderName).txt")
    }
    else {
        Write-Warning "Invalid metadata for '$ProviderName'"
    }
}

function _ResolveKeywords {
    param (
        [Parameter(Mandatory = $true)]$Metadata,
        [Parameter(Mandatory = $true)][ulong]$Keywords
    )

    if ($Metadata.provider.keywords) {
        $Metadata.provider.keywords.keyword | ForEach-Object -Process {
            $MaskValue = [ulong]::Parse($_.mask.TrimStart(@('0', 'x', 'X')), [System.Globalization.NumberStyles]::HexNumber)
            if ($Keywords -band $MaskValue) {
                [PSCustomObject]@{
                    Name  = $_.name
                    Value = $MaskValue
                }
            }
        }
    }
}

# ** EXPORTS **

function Get-EtwProvidersFromWprProfile {
    param (
        [Parameter(Mandatory = $true)][string]$WprProfilePath
    )

    if (-not (Test-Path $MetadataFolder)) {
        Write-Error "No metadata found - please run Initialize-EtwProvidersMetadata first."
    }

    function ParseProvider([Parameter(ValueFromPipeline = $true, Mandatory = $true)]$ProviderData) {
        begin {}
        process {
            $MetadataPath = (Join-Path -Path $MetadataFolder -ChildPath "$($ProviderData.Name).xml")
            if (-not (Test-Path $MetadataPath)) {
                Write-Warning "No metadata found for provider '$($ProviderData.Name)'"
                return
            }

            Write-Debug "Parsing provider '$($ProviderData.Name))'"
            $Metadata = [xml](Get-Content $MetadataPath)

            [ulong]$Keywords = 0
            if ($ProviderData.Keywords) {
                $ProviderData.Keywords.Keyword.Value | ForEach-Object -Process {
                    $Keywords = $Keywords -bor ([ulong]::Parse($_.TrimStart(@('0', 'x', 'X')), [System.Globalization.NumberStyles]::HexNumber)) }
            }
            else {
                $Keywords = [ulong]::MaxValue
            }

            [ulong]$CaptureOnSaveKeywords = 0
            if ($ProviderData.CaptureOnSaveKeywords) {
                $ProviderData.CaptureStateOnSave.Keyword.Value | ForEach-Object -Process {
                    $CaptureOnSaveKeywords = $CaptureOnSaveKeywords -bor ([ulong]::Parse($_.TrimStart(@('0', 'x', 'X')), [System.Globalization.NumberStyles]::HexNumber)) }
            }

            [PSCustomObject]@{
                Id                    = $ProviderData.Name
                Name                  = $Metadata.provider.name
                Keywords              = _ResolveKeywords $Metadata $Keywords
                CaptureOnSaveKeywords = _ResolveKeywords $Metadata $CaptureOnSaveKeywords
            }
        }
        end {}
    }
    
    $xml = [xml](Get-Content $WprProfilePath)

    $xml.WindowsPerformanceRecorder.Profiles.EventProvider | ParseProvider
}

function Get-EtwProviderMetadata {
    param([Parameter(ValueFromPipeline = $true, Mandatory = $true)]$ProviderName)

    $ProviderId = $ProviderName
    $Path = $(Join-Path -Path $MetadataSearchByNameFolder -ChildPath "$(_SanitizeFileName $ProviderName).txt")
    if (Test-Path $Path) {
        $ProviderId = Get-Content $Path
    }

    $MetadataPath = (Join-Path -Path $MetadataFolder -ChildPath "$ProviderId.xml")
    if (-not (Test-Path $MetadataPath)) {
        Write-Error "No metadata found for provider '$($ProviderId)'"
    }

    $Metadata = [xml](Get-Content $MetadataPath)

    [PSCustomObject]@{
        Id       = $ProviderId
        Name     = $Metadata.provider.name
        Keywords = _ResolveKeywords $Metadata $([ulong]::MaxValue)
    }
}