using namespace System.Management.Automation
using namespace System.Management.Automation.Language

Register-ArgumentCompleter -Native -CommandName 'wallswitch' -ScriptBlock {
    param($wordToComplete, $commandAst, $cursorPosition)

    $commandElements = $commandAst.CommandElements
    $command = @(
        'wallswitch'
        for ($i = 1; $i -lt $commandElements.Count; $i++) {
            $element = $commandElements[$i]
            if ($element -isnot [StringConstantExpressionAst] -or
                $element.StringConstantType -ne [StringConstantType]::BareWord -or
                $element.Value.StartsWith('-') -or
                $element.Value -eq $wordToComplete) {
                break
        }
        $element.Value
    }) -join ';'

    $completions = @(switch ($command) {
        'wallswitch' {
            [CompletionResult]::new('-b', '-b', [CompletionResultType]::ParameterName, 'Set a minimum file size (in bytes) for searching image files')
            [CompletionResult]::new('--min_size', '--min_size', [CompletionResultType]::ParameterName, 'Set a minimum file size (in bytes) for searching image files')
            [CompletionResult]::new('-B', '-B ', [CompletionResultType]::ParameterName, 'Set a maximum file size (in bytes) for searching image files')
            [CompletionResult]::new('--max_size', '--max_size', [CompletionResultType]::ParameterName, 'Set a maximum file size (in bytes) for searching image files')
            [CompletionResult]::new('-g', '-g', [CompletionResultType]::ParameterName, 'Generate shell completions and exit the program')
            [CompletionResult]::new('--generate', '--generate', [CompletionResultType]::ParameterName, 'Generate shell completions and exit the program')
            [CompletionResult]::new('-d', '-d', [CompletionResultType]::ParameterName, 'Set the minimum dimension that the height and width must satisfy')
            [CompletionResult]::new('--min_dimension', '--min_dimension', [CompletionResultType]::ParameterName, 'Set the minimum dimension that the height and width must satisfy')
            [CompletionResult]::new('-D', '-D ', [CompletionResultType]::ParameterName, 'Set the maximum dimension that the height and width must satisfy')
            [CompletionResult]::new('--max_dimension', '--max_dimension', [CompletionResultType]::ParameterName, 'Set the maximum dimension that the height and width must satisfy')
            [CompletionResult]::new('-i', '-i', [CompletionResultType]::ParameterName, 'Set the interval (in seconds) between each wallpaper displayed')
            [CompletionResult]::new('--interval', '--interval', [CompletionResultType]::ParameterName, 'Set the interval (in seconds) between each wallpaper displayed')
            [CompletionResult]::new('-m', '-m', [CompletionResultType]::ParameterName, 'Set the number of monitors [default: 2]')
            [CompletionResult]::new('--monitor', '--monitor', [CompletionResultType]::ParameterName, 'Set the number of monitors [default: 2]')
            [CompletionResult]::new('-o', '-o', [CompletionResultType]::ParameterName, 'Inform monitor orientation: Horizontal (side-by-side) or Vertical (stacked)')
            [CompletionResult]::new('--orientation', '--orientation', [CompletionResultType]::ParameterName, 'Inform monitor orientation: Horizontal (side-by-side) or Vertical (stacked)')
            [CompletionResult]::new('-p', '-p', [CompletionResultType]::ParameterName, 'Set number of pictures (or images) per monitor [default: 1]')
            [CompletionResult]::new('--pictures_per_monitor', '--pictures_per_monitor', [CompletionResultType]::ParameterName, 'Set number of pictures (or images) per monitor [default: 1]')
            [CompletionResult]::new('-c', '-c', [CompletionResultType]::ParameterName, 'Read the configuration file and exit the program')
            [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'Read the configuration file and exit the program')
            [CompletionResult]::new('-s', '-s', [CompletionResultType]::ParameterName, 'Sort the images found')
            [CompletionResult]::new('--sort', '--sort', [CompletionResultType]::ParameterName, 'Sort the images found')
            [CompletionResult]::new('-v', '-v', [CompletionResultType]::ParameterName, 'Show intermediate runtime messages')
            [CompletionResult]::new('--verbose', '--verbose', [CompletionResultType]::ParameterName, 'Show intermediate runtime messages')
            [CompletionResult]::new('-h', '-h', [CompletionResultType]::ParameterName, 'Print help (see more with ''--help'')')
            [CompletionResult]::new('--help', '--help', [CompletionResultType]::ParameterName, 'Print help (see more with ''--help'')')
            [CompletionResult]::new('-V', '-V ', [CompletionResultType]::ParameterName, 'Print version')
            [CompletionResult]::new('--version', '--version', [CompletionResultType]::ParameterName, 'Print version')
            break
        }
    })

    $completions.Where{ $_.CompletionText -like "$wordToComplete*" } |
        Sort-Object -Property ListItemText
}