& {
    $ErrorActionPreference = 'Stop'
    $ProgressPreference = 'SilentlyContinue'
    if (-not [Environment]::Is64BitOperatingSystem -or [Environment]::OSVersion.Platform -ne 'Win32NT') {
        throw 'DarwinPC requires Windows x64.'
    }
    $releaseVersion = '0.8.3'
    $expectedHash = 'F577888616D43E488A6BCF9C8EDADA748E1C6B203E1E0597505F58967CE08F8E'
    $downloadUri = 'https://h.firstend.ru/downloads/darwin/0.8.3/DarwinPC.exe'
    $installDirectory = Join-Path ([Environment]::GetFolderPath('LocalApplicationData')) ('Orion\DarwinPC\' + $releaseVersion)
    $executable = Join-Path $installDirectory 'DarwinPC.exe'
    [Net.ServicePointManager]::SecurityProtocol = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12
    New-Item -ItemType Directory -Path $installDirectory -Force | Out-Null

    if (-not (Test-Path -LiteralPath $executable) -or (Get-FileHash -LiteralPath $executable -Algorithm SHA256).Hash -ne $expectedHash) {
        $downloadFile = Join-Path $installDirectory ([Guid]::NewGuid().ToString('N') + '.download')
        try {
            Write-Host 'Downloading DarwinPC...'
            Invoke-WebRequest -UseBasicParsing -Uri $downloadUri -OutFile $downloadFile
            if ((Get-FileHash -LiteralPath $downloadFile -Algorithm SHA256).Hash -ne $expectedHash) {
                throw 'DarwinPC download verification failed.'
            }
            Move-Item -LiteralPath $downloadFile -Destination $executable -Force
        } finally {
            if (Test-Path -LiteralPath $downloadFile) { Remove-Item -LiteralPath $downloadFile -Force }
        }
    }

    $stopInfo = New-Object System.Diagnostics.ProcessStartInfo
    $stopInfo.FileName = $executable
    $stopInfo.Arguments = '--status'
    $stopInfo.UseShellExecute = $false
    $stopInfo.CreateNoWindow = $true
    $stopInfo.RedirectStandardOutput = $true
    $stopInfo.RedirectStandardError = $true
    $previousAgentId = $null
    foreach ($command in @('--status', '--exit')) {
        $stopInfo.Arguments = $command
        $stopProcess = [Diagnostics.Process]::Start($stopInfo)
        try {
            if (-not $stopProcess.WaitForExit(15000)) { throw 'The previous DarwinPC agent did not respond.' }
            if ($command -eq '--status' -and $stopProcess.ExitCode -eq 0) {
                $status = $stopProcess.StandardOutput.ReadToEnd() | ConvertFrom-Json
                $previousAgentId = $status.Data.ProcessId
            }
            if ($command -eq '--status' -and -not $previousAgentId) { break }
        } finally { $stopProcess.Dispose() }
    }
    if ($previousAgentId) {
        $previousAgent = Get-Process -Id $previousAgentId -ErrorAction SilentlyContinue
        if ($previousAgent) {
            try {
                if (-not $previousAgent.WaitForExit(15000)) { throw 'The previous DarwinPC agent is still shutting down.' }
            } finally { $previousAgent.Dispose() }
        }
    }

    Start-Process -FilePath $executable -WindowStyle Hidden
    Write-Host 'DarwinPC started. Allow the Windows firewall setup, then select this PC on your watch.'
}