#Requires -RunAsAdministrator

<#
.SYNOPSIS
    Removes unsupported Microsoft .NET Core / ASP.NET Core / Windows Desktop Runtime / SDK 3.1.x components.
.DESCRIPTION
    Queries HKLM uninstall registry locations (64-bit and 32-bit) for .NET 3.1.x components,
    executes quiet uninstallation for both MSI and Executable/Bundle bootstrappers,
    cleans orphaned runtime directories, and verifies removal.
#>

$ErrorActionPreference = "Continue"

Write-Host "Starting .NET Core 3.1 remediation..." -ForegroundColor Cyan

$registryPaths = @(
    "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\*",
    "HKLM:\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\*"
)

# Search pattern targeting 3.1.x runtimes, SDKs, targeting packs, and hosting bundles
$targetApps = foreach ($path in$registryPaths) {
    Get-ItemProperty $path -ErrorAction SilentlyContinue | Where-Object {
        (
            $_.DisplayName -match "Microsoft .*\b3\.1\.\d+\b" -or
            $_.DisplayName -match "Microsoft \.NET (Core|SDK|Runtime|Windows Desktop|ASP\.NET Core).*3\.1"
        ) -and ($_.UninstallString -or$_.QuietUninstallString)
    }
}

if (-not $targetApps) {
    Write-Host "No .NET Core 3.1 components found. System is clean." -ForegroundColor Green
    exit 0
}

Write-Host "Found $($targetApps.Count) .NET Core 3.1 component(s) to remove:" -ForegroundColor Yellow
foreach ($app in$targetApps) {
    Write-Host " - $($app.DisplayName) ($($app.DisplayVersion))" -ForegroundColor Yellow
}

foreach ($app in$targetApps) {
    Write-Host "`nAttempting to remove: $($app.DisplayName)..." -ForegroundColor Cyan

    $uninstallCmd = if ($app.QuietUninstallString) { $app.QuietUninstallString } else { $app.UninstallString }

    if ($uninstallCmd -match "\{[A-Fa-f0-9\-]{36}\}") {
        # Standard MSI Uninstall
        $productCode = $Matches[0]
        Write-Host "Executing MSI uninstall for GUID: $productCode" -ForegroundColor Gray
        $proc = Start-Process -FilePath "msiexec.exe" -ArgumentList "/x $productCode /qn /norestart" -Wait -PassThru -NoNewWindow
    }
    else {
        # Executable / WiX Burn Bootstrapper Uninstall
        Write-Host "Executing Bootstrapper EXE uninstall..." -ForegroundColor Gray
        
        # Parse EXE path and arguments safely
        if ($uninstallCmd -match '^"([^"]+)"(.*)$') {
            $exePath = $Matches[1]
            $exeArgs = "$($Matches[2]) /uninstall /quiet /norestart".Trim()
        }
        elseif ($uninstallCmd -match '^(\S+)(.*)$') {
            $exePath = $Matches[1]
            $exeArgs = "$($Matches[2]) /uninstall /quiet /norestart".Trim()
        }
        else {
            $exePath = $uninstallCmd
            $exeArgs = "/uninstall /quiet /norestart"
        }

        $proc = Start-Process -FilePath $exePath -ArgumentList $exeArgs -Wait -PassThru -NoNewWindow -ErrorAction SilentlyContinue
    }

    # Evaluate return codes (0 = Success, 3010 = Success, reboot required)
    if ($proc.ExitCode -in @(0, 3010)) {
        Write-Host "Successfully processed uninstall for $($app.DisplayName)." -ForegroundColor Green
    } else {
        Write-Host "Warning: Uninstall process returned exit code $($proc.ExitCode) for $($app.DisplayName)." -ForegroundColor Yellow
    }
}

# Clean residual 3.1.x folder remnants from dotnet installation directories
$dotnetPaths = @(
    "$env:ProgramFiles\dotnet",
    "${env:ProgramFiles(x86)}\dotnet"
)

foreach ($basePath in $dotnetPaths) {
    if (Test-Path $basePath) {
        Get-ChildItem -Path $basePath -Recurse -Directory -ErrorAction SilentlyContinue | Where-Object {
            $_.Name -like "3.1.*"
        } | ForEach-Object {
            Write-Host "Removing leftover directory: $($_.FullName)" -ForegroundColor Yellow
            Remove-Item -Path $_.FullName -Recurse -Force -ErrorAction SilentlyContinue
        }
    }
}

# Final Verification
Write-Host "`nVerifying remaining .NET Core 3.1 components..." -ForegroundColor Cyan

$remainingApps = foreach ($path in$registryPaths) {
    Get-ItemProperty $path -ErrorAction SilentlyContinue | Where-Object {
        (
            $_.DisplayName -match "Microsoft .*\b3\.1\.\d+\b" -or
            $_.DisplayName -match "Microsoft \.NET (Core|SDK|Runtime|Windows Desktop|ASP\.NET Core).*3\.1"
        ) -and ($_.UninstallString -or$_.QuietUninstallString)
    }
}

if ($remainingApps) {
    Write-Host "ERROR: Some .NET Core 3.1 components remain installed:" -ForegroundColor Red
    $remainingApps | ForEach-Object {
        Write-Host " - $($_.DisplayName) ($($_.DisplayVersion))" -ForegroundColor Red
    }
    exit 1
}
else {
    Write-Host ".NET Core 3.1 remediation completed successfully." -ForegroundColor Green
    exit 0
}