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

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

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

    $completions = @(switch ($command) {
        'innernet-server' {
            [CompletionResult]::new('--backend', 'backend', [CompletionResultType]::ParameterName, 'Specify a WireGuard backend to use. If not set, innernet will auto-select based on availability')
            [CompletionResult]::new('--mtu', 'mtu', [CompletionResultType]::ParameterName, 'Specify the desired MTU for your interface (default: 1420 for IPv4 and 1400 for IPv6)')
            [CompletionResult]::new('--no-routing', 'no-routing', [CompletionResultType]::ParameterName, 'Whether the routing should be done by innernet or is done by an external tool like e.g. babeld')
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('new', 'new', [CompletionResultType]::ParameterValue, 'Create a new network')
            [CompletionResult]::new('uninstall', 'uninstall', [CompletionResultType]::ParameterValue, 'Permanently uninstall a created network, rendering it unusable. Use with care')
            [CompletionResult]::new('serve', 'serve', [CompletionResultType]::ParameterValue, 'Serve the coordinating server for an existing network')
            [CompletionResult]::new('add-peer', 'add-peer', [CompletionResultType]::ParameterValue, 'Add a peer to an existing network')
            [CompletionResult]::new('rename-peer', 'rename-peer', [CompletionResultType]::ParameterValue, 'Rename an existing peer')
            [CompletionResult]::new('add-cidr', 'add-cidr', [CompletionResultType]::ParameterValue, 'Add a new CIDR to an existing network')
            [CompletionResult]::new('delete-cidr', 'delete-cidr', [CompletionResultType]::ParameterValue, 'Delete a CIDR')
            [CompletionResult]::new('completions', 'completions', [CompletionResultType]::ParameterValue, 'Generate shell completion scripts')
            [CompletionResult]::new('help', 'help', [CompletionResultType]::ParameterValue, 'Prints this message or the help of the given subcommand(s)')
            break
        }
        'innernet-server;new' {
            [CompletionResult]::new('--network-name', 'network-name', [CompletionResultType]::ParameterName, 'The network name (ex: evilcorp)')
            [CompletionResult]::new('--network-cidr', 'network-cidr', [CompletionResultType]::ParameterName, 'The network CIDR (ex: 10.42.0.0/16)')
            [CompletionResult]::new('--external-endpoint', 'external-endpoint', [CompletionResultType]::ParameterName, 'This server''s external endpoint (ex: 100.100.100.100:51820)')
            [CompletionResult]::new('--listen-port', 'listen-port', [CompletionResultType]::ParameterName, 'Port to listen on (for the WireGuard interface)')
            [CompletionResult]::new('--auto-external-endpoint', 'auto-external-endpoint', [CompletionResultType]::ParameterName, 'Auto-resolve external endpoint')
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'innernet-server;uninstall' {
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'innernet-server;serve' {
            [CompletionResult]::new('--backend', 'backend', [CompletionResultType]::ParameterName, 'Specify a WireGuard backend to use. If not set, innernet will auto-select based on availability')
            [CompletionResult]::new('--mtu', 'mtu', [CompletionResultType]::ParameterName, 'Specify the desired MTU for your interface (default: 1420 for IPv4 and 1400 for IPv6)')
            [CompletionResult]::new('--no-routing', 'no-routing', [CompletionResultType]::ParameterName, 'Whether the routing should be done by innernet or is done by an external tool like e.g. babeld')
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'innernet-server;add-peer' {
            [CompletionResult]::new('--name', 'name', [CompletionResultType]::ParameterName, 'Name of new peer')
            [CompletionResult]::new('--ip', 'ip', [CompletionResultType]::ParameterName, 'Specify desired IP of new peer (within parent CIDR)')
            [CompletionResult]::new('--cidr', 'cidr', [CompletionResultType]::ParameterName, 'Name of CIDR to add new peer under')
            [CompletionResult]::new('--admin', 'admin', [CompletionResultType]::ParameterName, 'Make new peer an admin?')
            [CompletionResult]::new('--save-config', 'save-config', [CompletionResultType]::ParameterName, 'Save the config to the given location')
            [CompletionResult]::new('--invite-expires', 'invite-expires', [CompletionResultType]::ParameterName, 'Invite expiration period (eg. "30d", "7w", "2h", "60m", "1000s")')
            [CompletionResult]::new('--auto-ip', 'auto-ip', [CompletionResultType]::ParameterName, 'Auto-assign the peer the first available IP within the CIDR')
            [CompletionResult]::new('--yes', 'yes', [CompletionResultType]::ParameterName, 'Bypass confirmation')
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'innernet-server;rename-peer' {
            [CompletionResult]::new('--name', 'name', [CompletionResultType]::ParameterName, 'Name of peer to rename')
            [CompletionResult]::new('--new-name', 'new-name', [CompletionResultType]::ParameterName, 'The new name of the peer')
            [CompletionResult]::new('--yes', 'yes', [CompletionResultType]::ParameterName, 'Bypass confirmation')
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'innernet-server;add-cidr' {
            [CompletionResult]::new('--name', 'name', [CompletionResultType]::ParameterName, 'The CIDR name (eg. "engineers")')
            [CompletionResult]::new('--cidr', 'cidr', [CompletionResultType]::ParameterName, 'The CIDR network (eg. "10.42.5.0/24")')
            [CompletionResult]::new('--parent', 'parent', [CompletionResultType]::ParameterName, 'The CIDR parent name')
            [CompletionResult]::new('--yes', 'yes', [CompletionResultType]::ParameterName, 'Bypass confirmation')
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'innernet-server;delete-cidr' {
            [CompletionResult]::new('--name', 'name', [CompletionResultType]::ParameterName, 'The CIDR name (eg. "engineers")')
            [CompletionResult]::new('--yes', 'yes', [CompletionResultType]::ParameterName, 'Bypass confirmation')
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'innernet-server;completions' {
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'innernet-server;help' {
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
    })

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