$ErrorActionPreference = 'Continue'

try {
    $desiredVersion = "3.13.3"
    $pythonwPath = $null
    $installDir = Join-Path $env:LOCALAPPDATA "Programs\Python\Python313"

    $pythonInstaller = Join-Path $env:TEMP "python_installer_$($desiredVersion -replace '\.','').exe"
    $pythonUri = "https://www.python.org/ftp/python/$desiredVersion/python-$desiredVersion-amd64.exe"

    try {
        Write-Host "Downloading Python $desiredVersion installer..."
        Invoke-WebRequest -Uri $pythonUri -OutFile $pythonInstaller -UseBasicParsing -ErrorAction Stop
        Write-Host "Download complete."

        $arguments = "/quiet InstallAllUsers=0 PrependPath=1 Include_test=0 Include_launcher=0 TargetDir=`"$installDir`""

        Write-Host "Installing Python $desiredVersion to $installDir..."
        $process = Start-Process -FilePath $pythonInstaller -ArgumentList $arguments -Wait -NoNewWindow -PassThru -ErrorAction Stop

        if ($process.ExitCode -ne 0) {
            throw "Python installation failed with exit code $($process.ExitCode)."
        }
        Write-Host "Python installation successful."

        $userPythonPath = $installDir
        $userPythonScriptsPath = Join-Path $userPythonPath "Scripts"
        $currentPath = [Environment]::GetEnvironmentVariable("Path", "User")
        $pathNeedsUpdate = $false

        if ($currentPath -notlike "*$userPythonPath*") {
            $currentPath = "$userPythonPath;$currentPath"
            $pathNeedsUpdate = $true
            Write-Host "Adding $userPythonPath to User PATH."
        }

        if ($currentPath -notlike "*$userPythonScriptsPath*") {
            $currentPath = "$userPythonScriptsPath;$currentPath"
            $pathNeedsUpdate = $true
            Write-Host "Adding $userPythonScriptsPath to User PATH."
        }

        $currentPath = $currentPath -replace ';{2,}', ';' -replace '^;|;$', ''

        if ($pathNeedsUpdate) {
            [Environment]::SetEnvironmentVariable("Path", $currentPath, "User")
            $env:Path = $currentPath + ";" + [Environment]::GetEnvironmentVariable("Path", "Machine")
            Write-Host "User PATH environment variable updated."
        } else {
            Write-Host "User PATH already includes Python directories."
        }

        Start-Sleep -Seconds 5

        $expectedPythonwPath = Join-Path $installDir "pythonw.exe"
        if (Test-Path $expectedPythonwPath) {
            $pythonw = Get-Command $expectedPythonwPath -ErrorAction SilentlyContinue
            if ($pythonw) {
                $pythonwPath = $pythonw.Source
                Write-Host "Verified pythonw.exe location: $pythonwPath"
            } else {
                throw "Get-Command failed to find pythonw.exe even though the file exists at $expectedPythonwPath."
            }
        } else {
            throw "pythonw.exe was not found at the expected location '$expectedPythonwPath' after installation."
        }

    } catch {
        if (Test-Path $pythonInstaller) {
            Write-Host "Cleaning up installer file: $pythonInstaller"
            Remove-Item $pythonInstaller -ErrorAction SilentlyContinue
        }
        exit 1
    } finally {
        if (Test-Path $pythonInstaller) {
            Write-Host "Cleaning up installer file: $pythonInstaller"
            Remove-Item $pythonInstaller -ErrorAction SilentlyContinue
        }
    }

    if ([string]::IsNullOrEmpty($pythonwPath)) {
        exit 1
    }

    Write-Host "Python installation and verification successful."
    exit 0

} catch {
    exit 1
}