{-# LANGUAGE DataKinds                   #-}
{-# LANGUAGE DeriveGeneric               #-}
{-# LANGUAGE FlexibleInstances           #-}
{-# LANGUAGE GeneralizedNewtypeDeriving  #-}
{-# LANGUAGE LambdaCase                  #-}
{-# LANGUAGE NoImplicitPrelude           #-}
{-# LANGUAGE OverloadedStrings           #-}
{-# LANGUAGE RecordWildCards             #-}
{-# LANGUAGE TypeFamilies                #-}

{-# OPTIONS_GHC -fno-warn-unused-imports #-}

-- Module      : Network.AWS.IAM.ListUsers
-- Copyright   : (c) 2013-2014 Brendan Hay <brendan.g.hay@gmail.com>
-- License     : This Source Code Form is subject to the terms of
--               the Mozilla Public License, v. 2.0.
--               A copy of the MPL can be found in the LICENSE file or
--               you can obtain it at http://mozilla.org/MPL/2.0/.
-- Maintainer  : Brendan Hay <brendan.g.hay@gmail.com>
-- Stability   : experimental
-- Portability : non-portable (GHC extensions)
--
-- Derived from AWS service descriptions, licensed under Apache 2.0.

-- | Lists the IAM users that have the specified path prefix. If no path prefix is
-- specified, the action returns all users in the AWS account. If there are
-- none, the action returns an empty list.
--
-- You can paginate the results using the 'MaxItems' and 'Marker' parameters.
--
-- <http://docs.aws.amazon.com/IAM/latest/APIReference/API_ListUsers.html>
module Network.AWS.IAM.ListUsers
    (
    -- * Request
      ListUsers
    -- ** Request constructor
    , listUsers
    -- ** Request lenses
    , luMarker
    , luMaxItems
    , luPathPrefix

    -- * Response
    , ListUsersResponse
    -- ** Response constructor
    , listUsersResponse
    -- ** Response lenses
    , lurIsTruncated
    , lurMarker
    , lurUsers
    ) where

import Network.AWS.Prelude
import Network.AWS.Request.Query
import Network.AWS.IAM.Types
import qualified GHC.Exts

data ListUsers = ListUsers
    { _luMarker     :: Maybe Text
    , _luMaxItems   :: Maybe Nat
    , _luPathPrefix :: Maybe Text
    } deriving (Eq, Ord, Show)

-- | 'ListUsers' constructor.
--
-- The fields accessible through corresponding lenses are:
--
-- * 'luMarker' @::@ 'Maybe' 'Text'
--
-- * 'luMaxItems' @::@ 'Maybe' 'Natural'
--
-- * 'luPathPrefix' @::@ 'Maybe' 'Text'
--
listUsers :: ListUsers
listUsers = ListUsers
    { _luPathPrefix = Nothing
    , _luMarker     = Nothing
    , _luMaxItems   = Nothing
    }

-- | Use this parameter only when paginating results, and only in a subsequent
-- request after you've received a response where the results are truncated. Set
-- it to the value of the 'Marker' element in the response you just received.
luMarker :: Lens' ListUsers (Maybe Text)
luMarker = lens _luMarker (\s a -> s { _luMarker = a })

-- | Use this parameter only when paginating results to indicate the maximum
-- number of user names you want in the response. If there are additional user
-- names beyond the maximum you specify, the 'IsTruncated' response element is 'true'
-- . This parameter is optional. If you do not include it, it defaults to 100.
luMaxItems :: Lens' ListUsers (Maybe Natural)
luMaxItems = lens _luMaxItems (\s a -> s { _luMaxItems = a }) . mapping _Nat

-- | The path prefix for filtering the results. For example: '/division_abc/subdivision_xyz/', which would get all user names whose path starts with '/division_abc/subdivision_xyz/'.
--
-- This parameter is optional. If it is not included, it defaults to a slash
-- (/), listing all user names.
luPathPrefix :: Lens' ListUsers (Maybe Text)
luPathPrefix = lens _luPathPrefix (\s a -> s { _luPathPrefix = a })

data ListUsersResponse = ListUsersResponse
    { _lurIsTruncated :: Maybe Bool
    , _lurMarker      :: Maybe Text
    , _lurUsers       :: List "member" User
    } deriving (Eq, Show)

-- | 'ListUsersResponse' constructor.
--
-- The fields accessible through corresponding lenses are:
--
-- * 'lurIsTruncated' @::@ 'Maybe' 'Bool'
--
-- * 'lurMarker' @::@ 'Maybe' 'Text'
--
-- * 'lurUsers' @::@ ['User']
--
listUsersResponse :: ListUsersResponse
listUsersResponse = ListUsersResponse
    { _lurUsers       = mempty
    , _lurIsTruncated = Nothing
    , _lurMarker      = Nothing
    }

-- | A flag that indicates whether there are more user names to list. If your
-- results were truncated, you can make a subsequent pagination request using
-- the 'Marker' request parameter to retrieve more users in the list.
lurIsTruncated :: Lens' ListUsersResponse (Maybe Bool)
lurIsTruncated = lens _lurIsTruncated (\s a -> s { _lurIsTruncated = a })

-- | If 'IsTruncated' is 'true', this element is present and contains the value to
-- use for the 'Marker' parameter in a subsequent pagination request.
lurMarker :: Lens' ListUsersResponse (Maybe Text)
lurMarker = lens _lurMarker (\s a -> s { _lurMarker = a })

-- | A list of users.
lurUsers :: Lens' ListUsersResponse [User]
lurUsers = lens _lurUsers (\s a -> s { _lurUsers = a }) . _List

instance ToPath ListUsers where
    toPath = const "/"

instance ToQuery ListUsers where
    toQuery ListUsers{..} = mconcat
        [ "Marker"     =? _luMarker
        , "MaxItems"   =? _luMaxItems
        , "PathPrefix" =? _luPathPrefix
        ]

instance ToHeaders ListUsers

instance AWSRequest ListUsers where
    type Sv ListUsers = IAM
    type Rs ListUsers = ListUsersResponse

    request  = post "ListUsers"
    response = xmlResponse

instance FromXML ListUsersResponse where
    parseXML = withElement "ListUsersResult" $ \x -> ListUsersResponse
        <$> x .@? "IsTruncated"
        <*> x .@? "Marker"
        <*> x .@? "Users" .!@ mempty

instance AWSPager ListUsers where
    page rq rs
        | stop (rs ^. lurIsTruncated) = Nothing
        | otherwise = Just $ rq
            & luMarker .~ rs ^. lurMarker