automatically switch between dark and light mode in Windows. Edit camera name in Auto-DarkLight and min and max brightness

Auto-DarkLight.ps1

function Get-CameraBrightness {
    param(
        [Parameter(Mandatory)]
        [string]$CameraName
    )

    $output = ffmpeg -f dshow -i video="$CameraName" -frames:v 1 -vf "signalstats,metadata=print:key=lavfi.signalstats.YAVG:file=-" -f null - 2>&1

    if (($output -join "`n") -match "signalstats\.YAVG=([\d\.]+)") {
        return [double]$local:Matches[1]
    } else {
        throw ("Could not find brightness value in FFmpeg output: " + $output)
    }
}

function Auto-DarkLight {
    $b = Get-CameraBrightness "ASUS 5M webcam"
    Write-Host "Brightness: $b"
    if ($b -gt 120) {
        Set-ItemProperty 'HKCU:\Software\Microsoft\Windows\CurrentVersion\Themes\Personalize' AppsUseLightTheme 1
        Set-ItemProperty 'HKCU:\Software\Microsoft\Windows\CurrentVersion\Themes\Personalize' SystemUsesLightTheme 1
    } elseif ($b -lt 110) {
        Set-ItemProperty 'HKCU:\Software\Microsoft\Windows\CurrentVersion\Themes\Personalize' AppsUseLightTheme 0
        Set-ItemProperty 'HKCU:\Software\Microsoft\Windows\CurrentVersion\Themes\Personalize' SystemUsesLightTheme 0
    }
}