{-# LANGUAGE DeriveDataTypeable #-}
{-# LANGUAGE DeriveGeneric      #-}
{-# LANGUAGE OverloadedStrings  #-}
{-# LANGUAGE RecordWildCards    #-}
{-# LANGUAGE TypeFamilies       #-}

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

-- Derived from AWS service descriptions, licensed under Apache 2.0.

-- |
-- Module      : Network.AWS.EFS.DescribeFileSystems
-- Copyright   : (c) 2013-2015 Brendan Hay
-- License     : Mozilla Public License, v. 2.0.
-- Maintainer  : Brendan Hay <brendan.g.hay@gmail.com>
-- Stability   : auto-generated
-- Portability : non-portable (GHC extensions)
--
-- Returns the description of a specific Amazon EFS file system if either
-- the file system 'CreationToken' or the 'FileSystemId' is provided;
-- otherwise, returns descriptions of all file systems owned by the
-- caller\'s AWS account in the AWS region of the endpoint that you\'re
-- calling.
--
-- When retrieving all file system descriptions, you can optionally specify
-- the 'MaxItems' parameter to limit the number of descriptions in a
-- response. If more file system descriptions remain, Amazon EFS returns a
-- 'NextMarker', an opaque token, in the response. In this case, you should
-- send a subsequent request with the 'Marker' request parameter set to the
-- value of 'NextMarker'.
--
-- So to retrieve a list of your file system descriptions, the expected
-- usage of this API is an iterative process of first calling
-- 'DescribeFileSystems' without the 'Marker' and then continuing to call
-- it with the 'Marker' parameter set to the value of the 'NextMarker' from
-- the previous response until the response has no 'NextMarker'.
--
-- Note that the implementation may return fewer than 'MaxItems' file
-- system descriptions while still including a 'NextMarker' value.
--
-- The order of file systems returned in the response of one
-- 'DescribeFileSystems' call, and the order of file systems returned
-- across the responses of a multi-call iteration, is unspecified.
--
-- This operation requires permission for the
-- 'elasticfilesystem:DescribeFileSystems' action.
--
-- /See:/ <http://docs.aws.amazon.com/directoryservice/latest/devguide/API_DescribeFileSystems.html AWS API Reference> for DescribeFileSystems.
module Network.AWS.EFS.DescribeFileSystems
    (
    -- * Creating a Request
      describeFileSystems
    , DescribeFileSystems
    -- * Request Lenses
    , dfsFileSystemId
    , dfsCreationToken
    , dfsMarker
    , dfsMaxItems

    -- * Destructuring the Response
    , describeFileSystemsResponse
    , DescribeFileSystemsResponse
    -- * Response Lenses
    , dfsrsFileSystems
    , dfsrsMarker
    , dfsrsNextMarker
    , dfsrsResponseStatus
    ) where

import           Network.AWS.EFS.Types
import           Network.AWS.EFS.Types.Product
import           Network.AWS.Prelude
import           Network.AWS.Request
import           Network.AWS.Response

-- | /See:/ 'describeFileSystems' smart constructor.
data DescribeFileSystems = DescribeFileSystems'
    { _dfsFileSystemId  :: !(Maybe Text)
    , _dfsCreationToken :: !(Maybe Text)
    , _dfsMarker        :: !(Maybe Text)
    , _dfsMaxItems      :: !(Maybe Nat)
    } deriving (Eq,Read,Show,Data,Typeable,Generic)

-- | Creates a value of 'DescribeFileSystems' with the minimum fields required to make a request.
--
-- Use one of the following lenses to modify other fields as desired:
--
-- * 'dfsFileSystemId'
--
-- * 'dfsCreationToken'
--
-- * 'dfsMarker'
--
-- * 'dfsMaxItems'
describeFileSystems
    :: DescribeFileSystems
describeFileSystems =
    DescribeFileSystems'
    { _dfsFileSystemId = Nothing
    , _dfsCreationToken = Nothing
    , _dfsMarker = Nothing
    , _dfsMaxItems = Nothing
    }

-- | Optional string. File system ID whose description you want to retrieve.
dfsFileSystemId :: Lens' DescribeFileSystems (Maybe Text)
dfsFileSystemId = lens _dfsFileSystemId (\ s a -> s{_dfsFileSystemId = a});

-- | Optional string. Restricts the list to the file system with this
-- creation token (you specify a creation token at the time of creating an
-- Amazon EFS file system).
dfsCreationToken :: Lens' DescribeFileSystems (Maybe Text)
dfsCreationToken = lens _dfsCreationToken (\ s a -> s{_dfsCreationToken = a});

-- | Optional string. Opaque pagination token returned from a previous
-- 'DescribeFileSystems' operation. If present, specifies to continue the
-- list from where the returning call had left off.
dfsMarker :: Lens' DescribeFileSystems (Maybe Text)
dfsMarker = lens _dfsMarker (\ s a -> s{_dfsMarker = a});

-- | Optional integer. Specifies the maximum number of file systems to return
-- in the response. This parameter value must be greater than 0. The number
-- of items Amazon EFS returns will be the minimum of the 'MaxItems'
-- parameter specified in the request and the service\'s internal maximum
-- number of items per page.
dfsMaxItems :: Lens' DescribeFileSystems (Maybe Natural)
dfsMaxItems = lens _dfsMaxItems (\ s a -> s{_dfsMaxItems = a}) . mapping _Nat;

instance AWSRequest DescribeFileSystems where
        type Rs DescribeFileSystems =
             DescribeFileSystemsResponse
        request = get eFS
        response
          = receiveJSON
              (\ s h x ->
                 DescribeFileSystemsResponse' <$>
                   (x .?> "FileSystems" .!@ mempty) <*> (x .?> "Marker")
                     <*> (x .?> "NextMarker")
                     <*> (pure (fromEnum s)))

instance ToHeaders DescribeFileSystems where
        toHeaders = const mempty

instance ToPath DescribeFileSystems where
        toPath = const "/2015-02-01/file-systems"

instance ToQuery DescribeFileSystems where
        toQuery DescribeFileSystems'{..}
          = mconcat
              ["FileSystemId" =: _dfsFileSystemId,
               "CreationToken" =: _dfsCreationToken,
               "Marker" =: _dfsMarker, "MaxItems" =: _dfsMaxItems]

-- | /See:/ 'describeFileSystemsResponse' smart constructor.
data DescribeFileSystemsResponse = DescribeFileSystemsResponse'
    { _dfsrsFileSystems    :: !(Maybe [FileSystemDescription])
    , _dfsrsMarker         :: !(Maybe Text)
    , _dfsrsNextMarker     :: !(Maybe Text)
    , _dfsrsResponseStatus :: !Int
    } deriving (Eq,Read,Show,Data,Typeable,Generic)

-- | Creates a value of 'DescribeFileSystemsResponse' with the minimum fields required to make a request.
--
-- Use one of the following lenses to modify other fields as desired:
--
-- * 'dfsrsFileSystems'
--
-- * 'dfsrsMarker'
--
-- * 'dfsrsNextMarker'
--
-- * 'dfsrsResponseStatus'
describeFileSystemsResponse
    :: Int -- ^ 'dfsrsResponseStatus'
    -> DescribeFileSystemsResponse
describeFileSystemsResponse pResponseStatus_ =
    DescribeFileSystemsResponse'
    { _dfsrsFileSystems = Nothing
    , _dfsrsMarker = Nothing
    , _dfsrsNextMarker = Nothing
    , _dfsrsResponseStatus = pResponseStatus_
    }

-- | An array of file system descriptions.
dfsrsFileSystems :: Lens' DescribeFileSystemsResponse [FileSystemDescription]
dfsrsFileSystems = lens _dfsrsFileSystems (\ s a -> s{_dfsrsFileSystems = a}) . _Default . _Coerce;

-- | A string, present if provided by caller in the request.
dfsrsMarker :: Lens' DescribeFileSystemsResponse (Maybe Text)
dfsrsMarker = lens _dfsrsMarker (\ s a -> s{_dfsrsMarker = a});

-- | A string, present if there are more file systems than returned in the
-- response. You can use the 'NextMarker' in the subsequent request to
-- fetch the descriptions.
dfsrsNextMarker :: Lens' DescribeFileSystemsResponse (Maybe Text)
dfsrsNextMarker = lens _dfsrsNextMarker (\ s a -> s{_dfsrsNextMarker = a});

-- | The response status code.
dfsrsResponseStatus :: Lens' DescribeFileSystemsResponse Int
dfsrsResponseStatus = lens _dfsrsResponseStatus (\ s a -> s{_dfsrsResponseStatus = a});