{-# 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.DynamoDBStreams.GetRecords
-- Copyright   : (c) 2013-2016 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)
--
-- Retrieves the stream records from a given shard.
--
--
-- Specify a shard iterator using the @ShardIterator@ parameter. The shard iterator specifies the position in the shard from which you want to start reading stream records sequentially. If there are no stream records available in the portion of the shard that the iterator points to, @GetRecords@ returns an empty list. Note that it might take multiple calls to get to a portion of the shard that contains stream records.
--
module Network.AWS.DynamoDBStreams.GetRecords
    (
    -- * Creating a Request
      getRecords
    , GetRecords
    -- * Request Lenses
    , grLimit
    , grShardIterator

    -- * Destructuring the Response
    , getRecordsResponse
    , GetRecordsResponse
    -- * Response Lenses
    , grrsRecords
    , grrsNextShardIterator
    , grrsResponseStatus
    ) where

import           Network.AWS.DynamoDBStreams.Types
import           Network.AWS.DynamoDBStreams.Types.Product
import           Network.AWS.Lens
import           Network.AWS.Prelude
import           Network.AWS.Request
import           Network.AWS.Response

-- | Represents the input of a /GetRecords/ operation.
--
--
--
-- /See:/ 'getRecords' smart constructor.
data GetRecords = GetRecords'
    { _grLimit         :: !(Maybe Nat)
    , _grShardIterator :: !Text
    } deriving (Eq,Read,Show,Data,Typeable,Generic)

-- | Creates a value of 'GetRecords' with the minimum fields required to make a request.
--
-- Use one of the following lenses to modify other fields as desired:
--
-- * 'grLimit' - The maximum number of records to return from the shard. The upper limit is 1000.
--
-- * 'grShardIterator' - A shard iterator that was retrieved from a previous GetShardIterator operation. This iterator can be used to access the stream records in this shard.
getRecords
    :: Text -- ^ 'grShardIterator'
    -> GetRecords
getRecords pShardIterator_ =
    GetRecords'
    { _grLimit = Nothing
    , _grShardIterator = pShardIterator_
    }

-- | The maximum number of records to return from the shard. The upper limit is 1000.
grLimit :: Lens' GetRecords (Maybe Natural)
grLimit = lens _grLimit (\ s a -> s{_grLimit = a}) . mapping _Nat;

-- | A shard iterator that was retrieved from a previous GetShardIterator operation. This iterator can be used to access the stream records in this shard.
grShardIterator :: Lens' GetRecords Text
grShardIterator = lens _grShardIterator (\ s a -> s{_grShardIterator = a});

instance AWSRequest GetRecords where
        type Rs GetRecords = GetRecordsResponse
        request = postJSON dynamoDBStreams
        response
          = receiveJSON
              (\ s h x ->
                 GetRecordsResponse' <$>
                   (x .?> "Records" .!@ mempty) <*>
                     (x .?> "NextShardIterator")
                     <*> (pure (fromEnum s)))

instance Hashable GetRecords

instance NFData GetRecords

instance ToHeaders GetRecords where
        toHeaders
          = const
              (mconcat
                 ["X-Amz-Target" =#
                    ("DynamoDBStreams_20120810.GetRecords" ::
                       ByteString),
                  "Content-Type" =#
                    ("application/x-amz-json-1.0" :: ByteString)])

instance ToJSON GetRecords where
        toJSON GetRecords'{..}
          = object
              (catMaybes
                 [("Limit" .=) <$> _grLimit,
                  Just ("ShardIterator" .= _grShardIterator)])

instance ToPath GetRecords where
        toPath = const "/"

instance ToQuery GetRecords where
        toQuery = const mempty

-- | Represents the output of a /GetRecords/ operation.
--
--
--
-- /See:/ 'getRecordsResponse' smart constructor.
data GetRecordsResponse = GetRecordsResponse'
    { _grrsRecords           :: !(Maybe [Record])
    , _grrsNextShardIterator :: !(Maybe Text)
    , _grrsResponseStatus    :: !Int
    } deriving (Eq,Read,Show,Data,Typeable,Generic)

-- | Creates a value of 'GetRecordsResponse' with the minimum fields required to make a request.
--
-- Use one of the following lenses to modify other fields as desired:
--
-- * 'grrsRecords' - The stream records from the shard, which were retrieved using the shard iterator.
--
-- * 'grrsNextShardIterator' - The next position in the shard from which to start sequentially reading stream records. If set to @null@ , the shard has been closed and the requested iterator will not return any more data.
--
-- * 'grrsResponseStatus' - -- | The response status code.
getRecordsResponse
    :: Int -- ^ 'grrsResponseStatus'
    -> GetRecordsResponse
getRecordsResponse pResponseStatus_ =
    GetRecordsResponse'
    { _grrsRecords = Nothing
    , _grrsNextShardIterator = Nothing
    , _grrsResponseStatus = pResponseStatus_
    }

-- | The stream records from the shard, which were retrieved using the shard iterator.
grrsRecords :: Lens' GetRecordsResponse [Record]
grrsRecords = lens _grrsRecords (\ s a -> s{_grrsRecords = a}) . _Default . _Coerce;

-- | The next position in the shard from which to start sequentially reading stream records. If set to @null@ , the shard has been closed and the requested iterator will not return any more data.
grrsNextShardIterator :: Lens' GetRecordsResponse (Maybe Text)
grrsNextShardIterator = lens _grrsNextShardIterator (\ s a -> s{_grrsNextShardIterator = a});

-- | -- | The response status code.
grrsResponseStatus :: Lens' GetRecordsResponse Int
grrsResponseStatus = lens _grrsResponseStatus (\ s a -> s{_grrsResponseStatus = a});

instance NFData GetRecordsResponse