{-# 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.SWF.PollForDecisionTask
-- 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)
--
-- Used by deciders to get a 'DecisionTask' from the specified decision @taskList@ . A decision task may be returned for any open workflow execution that is using the specified task list. The task includes a paginated view of the history of the workflow execution. The decider should use the workflow type and the history to determine how to properly handle the task.
--
--
-- This action initiates a long poll, where the service holds the HTTP connection open and responds as soon a task becomes available. If no decision task is available in the specified task list before the timeout of 60 seconds expires, an empty result is returned. An empty result, in this context, means that a DecisionTask is returned, but that the value of @taskToken@ is an empty string.
--
-- /Important:/ Deciders should set their client-side socket timeout to at least 70 seconds (10 seconds higher than the timeout)./Important:/ Because the number of workflow history events for a single workflow execution might be very large, the result returned might be split up across a number of pages. To retrieve subsequent pages, make additional calls to @PollForDecisionTask@ using the @nextPageToken@ returned by the initial call. Note that you do __not__ call @GetWorkflowExecutionHistory@ with this @nextPageToken@ . Instead, call @PollForDecisionTask@ again.__Access Control__
--
-- You can use IAM policies to control this action's access to Amazon SWF resources as follows:
--
--     * Use a @Resource@ element with the domain name to limit the action to only specified domains.    * Use an @Action@ element to allow or deny permission to call this action.    * Constrain the @taskList.name@ parameter by using a __Condition__ element with the @swf:taskList.name@ key to allow the action to access only certain task lists.
--
-- If the caller does not have sufficient permissions to invoke the action, or the parameter values fall outside the specified constraints, the action fails. The associated event attribute's __cause__ parameter will be set to OPERATION_NOT_PERMITTED. For details and example IAM policies, see <http://docs.aws.amazon.com/amazonswf/latest/developerguide/swf-dev-iam.html Using IAM to Manage Access to Amazon SWF Workflows> .
--
--
-- This operation returns paginated results.
module Network.AWS.SWF.PollForDecisionTask
    (
    -- * Creating a Request
      pollForDecisionTask
    , PollForDecisionTask
    -- * Request Lenses
    , pfdtNextPageToken
    , pfdtReverseOrder
    , pfdtMaximumPageSize
    , pfdtIdentity
    , pfdtDomain
    , pfdtTaskList

    -- * Destructuring the Response
    , pollForDecisionTaskResponse
    , PollForDecisionTaskResponse
    -- * Response Lenses
    , pfdtrsNextPageToken
    , pfdtrsWorkflowType
    , pfdtrsPreviousStartedEventId
    , pfdtrsEvents
    , pfdtrsTaskToken
    , pfdtrsWorkflowExecution
    , pfdtrsResponseStatus
    , pfdtrsStartedEventId
    ) where

import           Network.AWS.Lens
import           Network.AWS.Pager
import           Network.AWS.Prelude
import           Network.AWS.Request
import           Network.AWS.Response
import           Network.AWS.SWF.Types
import           Network.AWS.SWF.Types.Product

-- | /See:/ 'pollForDecisionTask' smart constructor.
data PollForDecisionTask = PollForDecisionTask'
    { _pfdtNextPageToken   :: !(Maybe Text)
    , _pfdtReverseOrder    :: !(Maybe Bool)
    , _pfdtMaximumPageSize :: !(Maybe Nat)
    , _pfdtIdentity        :: !(Maybe Text)
    , _pfdtDomain          :: !Text
    , _pfdtTaskList        :: !TaskList
    } deriving (Eq,Read,Show,Data,Typeable,Generic)

-- | Creates a value of 'PollForDecisionTask' with the minimum fields required to make a request.
--
-- Use one of the following lenses to modify other fields as desired:
--
-- * 'pfdtNextPageToken' - If a @NextPageToken@ was returned by a previous call, there are more results available. To retrieve the next page of results, make the call again using the returned token in @nextPageToken@ . Keep all other arguments unchanged. The configured @maximumPageSize@ determines how many results can be returned in a single call. .
--
-- * 'pfdtReverseOrder' - When set to @true@ , returns the events in reverse order. By default the results are returned in ascending order of the @eventTimestamp@ of the events.
--
-- * 'pfdtMaximumPageSize' - The maximum number of results that will be returned per call. @nextPageToken@ can be used to obtain futher pages of results. The default is 1000, which is the maximum allowed page size. You can, however, specify a page size /smaller/ than the maximum. This is an upper limit only; the actual number of results returned per call may be fewer than the specified maximum.
--
-- * 'pfdtIdentity' - Identity of the decider making the request, which is recorded in the DecisionTaskStarted event in the workflow history. This enables diagnostic tracing when problems arise. The form of this identity is user defined.
--
-- * 'pfdtDomain' - The name of the domain containing the task lists to poll.
--
-- * 'pfdtTaskList' - Specifies the task list to poll for decision tasks. The specified string must not start or end with whitespace. It must not contain a @:@ (colon), @/@ (slash), @|@ (vertical bar), or any control characters (\u0000-\u001f | \u007f - \u009f). Also, it must not contain the literal string quotarnquot.
pollForDecisionTask
    :: Text -- ^ 'pfdtDomain'
    -> TaskList -- ^ 'pfdtTaskList'
    -> PollForDecisionTask
pollForDecisionTask pDomain_ pTaskList_ =
    PollForDecisionTask'
    { _pfdtNextPageToken = Nothing
    , _pfdtReverseOrder = Nothing
    , _pfdtMaximumPageSize = Nothing
    , _pfdtIdentity = Nothing
    , _pfdtDomain = pDomain_
    , _pfdtTaskList = pTaskList_
    }

-- | If a @NextPageToken@ was returned by a previous call, there are more results available. To retrieve the next page of results, make the call again using the returned token in @nextPageToken@ . Keep all other arguments unchanged. The configured @maximumPageSize@ determines how many results can be returned in a single call. .
pfdtNextPageToken :: Lens' PollForDecisionTask (Maybe Text)
pfdtNextPageToken = lens _pfdtNextPageToken (\ s a -> s{_pfdtNextPageToken = a});

-- | When set to @true@ , returns the events in reverse order. By default the results are returned in ascending order of the @eventTimestamp@ of the events.
pfdtReverseOrder :: Lens' PollForDecisionTask (Maybe Bool)
pfdtReverseOrder = lens _pfdtReverseOrder (\ s a -> s{_pfdtReverseOrder = a});

-- | The maximum number of results that will be returned per call. @nextPageToken@ can be used to obtain futher pages of results. The default is 1000, which is the maximum allowed page size. You can, however, specify a page size /smaller/ than the maximum. This is an upper limit only; the actual number of results returned per call may be fewer than the specified maximum.
pfdtMaximumPageSize :: Lens' PollForDecisionTask (Maybe Natural)
pfdtMaximumPageSize = lens _pfdtMaximumPageSize (\ s a -> s{_pfdtMaximumPageSize = a}) . mapping _Nat;

-- | Identity of the decider making the request, which is recorded in the DecisionTaskStarted event in the workflow history. This enables diagnostic tracing when problems arise. The form of this identity is user defined.
pfdtIdentity :: Lens' PollForDecisionTask (Maybe Text)
pfdtIdentity = lens _pfdtIdentity (\ s a -> s{_pfdtIdentity = a});

-- | The name of the domain containing the task lists to poll.
pfdtDomain :: Lens' PollForDecisionTask Text
pfdtDomain = lens _pfdtDomain (\ s a -> s{_pfdtDomain = a});

-- | Specifies the task list to poll for decision tasks. The specified string must not start or end with whitespace. It must not contain a @:@ (colon), @/@ (slash), @|@ (vertical bar), or any control characters (\u0000-\u001f | \u007f - \u009f). Also, it must not contain the literal string quotarnquot.
pfdtTaskList :: Lens' PollForDecisionTask TaskList
pfdtTaskList = lens _pfdtTaskList (\ s a -> s{_pfdtTaskList = a});

instance AWSPager PollForDecisionTask where
        page rq rs
          | stop (rs ^. pfdtrsNextPageToken) = Nothing
          | stop (rs ^. pfdtrsEvents) = Nothing
          | otherwise =
            Just $ rq &
              pfdtNextPageToken .~ rs ^. pfdtrsNextPageToken

instance AWSRequest PollForDecisionTask where
        type Rs PollForDecisionTask =
             PollForDecisionTaskResponse
        request = postJSON swf
        response
          = receiveJSON
              (\ s h x ->
                 PollForDecisionTaskResponse' <$>
                   (x .?> "nextPageToken") <*> (x .?> "workflowType")
                     <*> (x .?> "previousStartedEventId")
                     <*> (x .?> "events" .!@ mempty)
                     <*> (x .?> "taskToken")
                     <*> (x .?> "workflowExecution")
                     <*> (pure (fromEnum s))
                     <*> (x .:> "startedEventId"))

instance Hashable PollForDecisionTask

instance NFData PollForDecisionTask

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

instance ToJSON PollForDecisionTask where
        toJSON PollForDecisionTask'{..}
          = object
              (catMaybes
                 [("nextPageToken" .=) <$> _pfdtNextPageToken,
                  ("reverseOrder" .=) <$> _pfdtReverseOrder,
                  ("maximumPageSize" .=) <$> _pfdtMaximumPageSize,
                  ("identity" .=) <$> _pfdtIdentity,
                  Just ("domain" .= _pfdtDomain),
                  Just ("taskList" .= _pfdtTaskList)])

instance ToPath PollForDecisionTask where
        toPath = const "/"

instance ToQuery PollForDecisionTask where
        toQuery = const mempty

-- | A structure that represents a decision task. Decision tasks are sent to deciders in order for them to make decisions.
--
--
--
-- /See:/ 'pollForDecisionTaskResponse' smart constructor.
data PollForDecisionTaskResponse = PollForDecisionTaskResponse'
    { _pfdtrsNextPageToken          :: !(Maybe Text)
    , _pfdtrsWorkflowType           :: !(Maybe WorkflowType)
    , _pfdtrsPreviousStartedEventId :: !(Maybe Integer)
    , _pfdtrsEvents                 :: !(Maybe [HistoryEvent])
    , _pfdtrsTaskToken              :: !(Maybe Text)
    , _pfdtrsWorkflowExecution      :: !(Maybe WorkflowExecution)
    , _pfdtrsResponseStatus         :: !Int
    , _pfdtrsStartedEventId         :: !Integer
    } deriving (Eq,Read,Show,Data,Typeable,Generic)

-- | Creates a value of 'PollForDecisionTaskResponse' with the minimum fields required to make a request.
--
-- Use one of the following lenses to modify other fields as desired:
--
-- * 'pfdtrsNextPageToken' - If a @NextPageToken@ was returned by a previous call, there are more results available. To retrieve the next page of results, make the call again using the returned token in @nextPageToken@ . Keep all other arguments unchanged. The configured @maximumPageSize@ determines how many results can be returned in a single call.
--
-- * 'pfdtrsWorkflowType' - The type of the workflow execution for which this decision task was created.
--
-- * 'pfdtrsPreviousStartedEventId' - The ID of the DecisionTaskStarted event of the previous decision task of this workflow execution that was processed by the decider. This can be used to determine the events in the history new since the last decision task received by the decider.
--
-- * 'pfdtrsEvents' - A paginated list of history events of the workflow execution. The decider uses this during the processing of the decision task.
--
-- * 'pfdtrsTaskToken' - The opaque string used as a handle on the task. This token is used by workers to communicate progress and response information back to the system about the task.
--
-- * 'pfdtrsWorkflowExecution' - The workflow execution for which this decision task was created.
--
-- * 'pfdtrsResponseStatus' - -- | The response status code.
--
-- * 'pfdtrsStartedEventId' - The ID of the @DecisionTaskStarted@ event recorded in the history.
pollForDecisionTaskResponse
    :: Int -- ^ 'pfdtrsResponseStatus'
    -> Integer -- ^ 'pfdtrsStartedEventId'
    -> PollForDecisionTaskResponse
pollForDecisionTaskResponse pResponseStatus_ pStartedEventId_ =
    PollForDecisionTaskResponse'
    { _pfdtrsNextPageToken = Nothing
    , _pfdtrsWorkflowType = Nothing
    , _pfdtrsPreviousStartedEventId = Nothing
    , _pfdtrsEvents = Nothing
    , _pfdtrsTaskToken = Nothing
    , _pfdtrsWorkflowExecution = Nothing
    , _pfdtrsResponseStatus = pResponseStatus_
    , _pfdtrsStartedEventId = pStartedEventId_
    }

-- | If a @NextPageToken@ was returned by a previous call, there are more results available. To retrieve the next page of results, make the call again using the returned token in @nextPageToken@ . Keep all other arguments unchanged. The configured @maximumPageSize@ determines how many results can be returned in a single call.
pfdtrsNextPageToken :: Lens' PollForDecisionTaskResponse (Maybe Text)
pfdtrsNextPageToken = lens _pfdtrsNextPageToken (\ s a -> s{_pfdtrsNextPageToken = a});

-- | The type of the workflow execution for which this decision task was created.
pfdtrsWorkflowType :: Lens' PollForDecisionTaskResponse (Maybe WorkflowType)
pfdtrsWorkflowType = lens _pfdtrsWorkflowType (\ s a -> s{_pfdtrsWorkflowType = a});

-- | The ID of the DecisionTaskStarted event of the previous decision task of this workflow execution that was processed by the decider. This can be used to determine the events in the history new since the last decision task received by the decider.
pfdtrsPreviousStartedEventId :: Lens' PollForDecisionTaskResponse (Maybe Integer)
pfdtrsPreviousStartedEventId = lens _pfdtrsPreviousStartedEventId (\ s a -> s{_pfdtrsPreviousStartedEventId = a});

-- | A paginated list of history events of the workflow execution. The decider uses this during the processing of the decision task.
pfdtrsEvents :: Lens' PollForDecisionTaskResponse [HistoryEvent]
pfdtrsEvents = lens _pfdtrsEvents (\ s a -> s{_pfdtrsEvents = a}) . _Default . _Coerce;

-- | The opaque string used as a handle on the task. This token is used by workers to communicate progress and response information back to the system about the task.
pfdtrsTaskToken :: Lens' PollForDecisionTaskResponse (Maybe Text)
pfdtrsTaskToken = lens _pfdtrsTaskToken (\ s a -> s{_pfdtrsTaskToken = a});

-- | The workflow execution for which this decision task was created.
pfdtrsWorkflowExecution :: Lens' PollForDecisionTaskResponse (Maybe WorkflowExecution)
pfdtrsWorkflowExecution = lens _pfdtrsWorkflowExecution (\ s a -> s{_pfdtrsWorkflowExecution = a});

-- | -- | The response status code.
pfdtrsResponseStatus :: Lens' PollForDecisionTaskResponse Int
pfdtrsResponseStatus = lens _pfdtrsResponseStatus (\ s a -> s{_pfdtrsResponseStatus = a});

-- | The ID of the @DecisionTaskStarted@ event recorded in the history.
pfdtrsStartedEventId :: Lens' PollForDecisionTaskResponse Integer
pfdtrsStartedEventId = lens _pfdtrsStartedEventId (\ s a -> s{_pfdtrsStartedEventId = a});

instance NFData PollForDecisionTaskResponse