List all configured IIS application pools.

    Returns:
        dict: A dictionary of IIS application pools and their details.

    CLI Example:

    .. code-block:: bash

        salt '*' win_iis.list_apppools

def list_apppools():
    '''
    List all configured IIS application pools.

    Returns:
        dict: A dictionary of IIS application pools and their details.

    CLI Example:

    .. code-block:: bash

        salt '*' win_iis.list_apppools
    '''
    ret = dict()
    ps_cmd = []
    ps_cmd.append(r"Get-ChildItem -Path 'IIS:\AppPools' | Select-Object Name, State")

    # Include the equivalent of output from the Applications column, since this
    # isn't a normal property, we have to populate it via filtered output from
    # the Get-WebConfigurationProperty cmdlet.
    ps_cmd.append(r", @{ Name = 'Applications'; Expression = { $AppPool = $_.Name;")
    ps_cmd.append("$AppPath = 'machine/webroot/apphost';")
    ps_cmd.append("$FilterBase = '/system.applicationHost/sites/site/application';")
    ps_cmd.append('$FilterBase += "[@applicationPool = \'$($AppPool)\' and @path";')
    ps_cmd.append('$FilterRoot = "$($FilterBase) = \'/\']/parent::*";')
    ps_cmd.append('$FilterNonRoot = "$($FilterBase) != \'/\']";')
    ps_cmd.append('Get-WebConfigurationProperty -Filter $FilterRoot -PsPath $AppPath -Name Name')
    ps_cmd.append(r'| ForEach-Object { $_.Value };')
    ps_cmd.append('Get-WebConfigurationProperty -Filter $FilterNonRoot -PsPath $AppPath -Name Path')
    ps_cmd.append(r"| ForEach-Object { $_.Value } | Where-Object { $_ -ne '/' }")
    ps_cmd.append('} }')

    cmd_ret = _srvmgr(cmd=ps_cmd, return_json=True)

    try:
        items = salt.utils.json.loads(cmd_ret['stdout'], strict=False)
    except ValueError:
        raise CommandExecutionError('Unable to parse return data as Json.')

    for item in items:
        applications = list()

        # If there are no associated apps, Applications will be an empty dict,
        # if there is one app, it will be a string, and if there are multiple,
        # it will be a dict with 'Count' and 'value' as the keys.

        if isinstance(item['Applications'], dict):
            if 'value' in item['Applications']:
                applications += item['Applications']['value']
        else:
            applications.append(item['Applications'])

        ret[item['name']] = {'state': item['state'], 'applications': applications}

    if not ret:
        log.warning('No application pools found in output: %s',
                    cmd_ret['stdout'])

    return ret