// Code generated by private/model/cli/gen-api/main.go. DO NOT EDIT.

package swf

import (
	"context"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/internal/awsutil"
)

type PollForDecisionTaskInput struct {
	_ struct{} `type:"structure"`

	// The name of the domain containing the task lists to poll.
	//
	// Domain is a required field
	Domain *string `locationName:"domain" min:"1" type:"string" required:"true"`

	// 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.
	Identity *string `locationName:"identity" type:"string"`

	// The maximum number of results that are returned per call. Use nextPageToken
	// to obtain further pages of results.
	//
	// This is an upper limit only; the actual number of results returned per call
	// may be fewer than the specified maximum.
	MaximumPageSize *int64 `locationName:"maximumPageSize" type:"integer"`

	// If NextPageToken is returned there are more results available. The value
	// of NextPageToken is a unique pagination token for each page. Make the call
	// again using the returned token to retrieve the next page. Keep all other
	// arguments unchanged. Each pagination token expires after 60 seconds. Using
	// an expired pagination token will return a 400 error: "Specified token has
	// exceeded its maximum lifetime".
	//
	// The configured maximumPageSize determines how many results can be returned
	// in a single call.
	//
	// The nextPageToken returned by this action cannot be used with GetWorkflowExecutionHistory
	// to get the next page. You must call PollForDecisionTask again (with the nextPageToken)
	// to retrieve the next page of history records. Calling PollForDecisionTask
	// with a nextPageToken doesn't return a new decision task.
	NextPageToken *string `locationName:"nextPageToken" type:"string"`

	// 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.
	ReverseOrder *bool `locationName:"reverseOrder" type:"boolean"`

	// 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 be the literal string arn.
	//
	// TaskList is a required field
	TaskList *TaskList `locationName:"taskList" type:"structure" required:"true"`
}

// String returns the string representation
func (s PollForDecisionTaskInput) String() string {
	return awsutil.Prettify(s)
}

// Validate inspects the fields of the type to determine if they are valid.
func (s *PollForDecisionTaskInput) Validate() error {
	invalidParams := aws.ErrInvalidParams{Context: "PollForDecisionTaskInput"}

	if s.Domain == nil {
		invalidParams.Add(aws.NewErrParamRequired("Domain"))
	}
	if s.Domain != nil && len(*s.Domain) < 1 {
		invalidParams.Add(aws.NewErrParamMinLen("Domain", 1))
	}

	if s.TaskList == nil {
		invalidParams.Add(aws.NewErrParamRequired("TaskList"))
	}
	if s.TaskList != nil {
		if err := s.TaskList.Validate(); err != nil {
			invalidParams.AddNested("TaskList", err.(aws.ErrInvalidParams))
		}
	}

	if invalidParams.Len() > 0 {
		return invalidParams
	}
	return nil
}

// A structure that represents a decision task. Decision tasks are sent to deciders
// in order for them to make decisions.
type PollForDecisionTaskOutput struct {
	_ struct{} `type:"structure"`

	// A paginated list of history events of the workflow execution. The decider
	// uses this during the processing of the decision task.
	//
	// Events is a required field
	Events []HistoryEvent `locationName:"events" type:"list" required:"true"`

	// 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.
	NextPageToken *string `locationName:"nextPageToken" type:"string"`

	// 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.
	PreviousStartedEventId *int64 `locationName:"previousStartedEventId" type:"long"`

	// The ID of the DecisionTaskStarted event recorded in the history.
	//
	// StartedEventId is a required field
	StartedEventId *int64 `locationName:"startedEventId" type:"long" required:"true"`

	// 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.
	//
	// TaskToken is a required field
	TaskToken *string `locationName:"taskToken" min:"1" type:"string" required:"true"`

	// The workflow execution for which this decision task was created.
	//
	// WorkflowExecution is a required field
	WorkflowExecution *WorkflowExecution `locationName:"workflowExecution" type:"structure" required:"true"`

	// The type of the workflow execution for which this decision task was created.
	//
	// WorkflowType is a required field
	WorkflowType *WorkflowType `locationName:"workflowType" type:"structure" required:"true"`
}

// String returns the string representation
func (s PollForDecisionTaskOutput) String() string {
	return awsutil.Prettify(s)
}

const opPollForDecisionTask = "PollForDecisionTask"

// PollForDecisionTaskRequest returns a request value for making API operation for
// Amazon Simple Workflow Service.
//
// 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.
//
// Deciders should set their client side socket timeout to at least 70 seconds
// (10 seconds higher than the timeout).
//
// 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 doesn't 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 is set to OPERATION_NOT_PERMITTED.
// For details and example IAM policies, see Using IAM to Manage Access to Amazon
// SWF Workflows (https://docs.aws.amazon.com/amazonswf/latest/developerguide/swf-dev-iam.html)
// in the Amazon SWF Developer Guide.
//
//    // Example sending a request using PollForDecisionTaskRequest.
//    req := client.PollForDecisionTaskRequest(params)
//    resp, err := req.Send(context.TODO())
//    if err == nil {
//        fmt.Println(resp)
//    }
func (c *Client) PollForDecisionTaskRequest(input *PollForDecisionTaskInput) PollForDecisionTaskRequest {
	op := &aws.Operation{
		Name:       opPollForDecisionTask,
		HTTPMethod: "POST",
		HTTPPath:   "/",
		Paginator: &aws.Paginator{
			InputTokens:     []string{"nextPageToken"},
			OutputTokens:    []string{"nextPageToken"},
			LimitToken:      "maximumPageSize",
			TruncationToken: "",
		},
	}

	if input == nil {
		input = &PollForDecisionTaskInput{}
	}

	req := c.newRequest(op, input, &PollForDecisionTaskOutput{})

	return PollForDecisionTaskRequest{Request: req, Input: input, Copy: c.PollForDecisionTaskRequest}
}

// PollForDecisionTaskRequest is the request type for the
// PollForDecisionTask API operation.
type PollForDecisionTaskRequest struct {
	*aws.Request
	Input *PollForDecisionTaskInput
	Copy  func(*PollForDecisionTaskInput) PollForDecisionTaskRequest
}

// Send marshals and sends the PollForDecisionTask API request.
func (r PollForDecisionTaskRequest) Send(ctx context.Context) (*PollForDecisionTaskResponse, error) {
	r.Request.SetContext(ctx)
	err := r.Request.Send()
	if err != nil {
		return nil, err
	}

	resp := &PollForDecisionTaskResponse{
		PollForDecisionTaskOutput: r.Request.Data.(*PollForDecisionTaskOutput),
		response:                  &aws.Response{Request: r.Request},
	}

	return resp, nil
}

// NewPollForDecisionTaskRequestPaginator returns a paginator for PollForDecisionTask.
// Use Next method to get the next page, and CurrentPage to get the current
// response page from the paginator. Next will return false, if there are
// no more pages, or an error was encountered.
//
// Note: This operation can generate multiple requests to a service.
//
//   // Example iterating over pages.
//   req := client.PollForDecisionTaskRequest(input)
//   p := swf.NewPollForDecisionTaskRequestPaginator(req)
//
//   for p.Next(context.TODO()) {
//       page := p.CurrentPage()
//   }
//
//   if err := p.Err(); err != nil {
//       return err
//   }
//
func NewPollForDecisionTaskPaginator(req PollForDecisionTaskRequest) PollForDecisionTaskPaginator {
	return PollForDecisionTaskPaginator{
		Pager: aws.Pager{
			NewRequest: func(ctx context.Context) (*aws.Request, error) {
				var inCpy *PollForDecisionTaskInput
				if req.Input != nil {
					tmp := *req.Input
					inCpy = &tmp
				}

				newReq := req.Copy(inCpy)
				newReq.SetContext(ctx)
				return newReq.Request, nil
			},
		},
	}
}

// PollForDecisionTaskPaginator is used to paginate the request. This can be done by
// calling Next and CurrentPage.
type PollForDecisionTaskPaginator struct {
	aws.Pager
}

func (p *PollForDecisionTaskPaginator) CurrentPage() *PollForDecisionTaskOutput {
	return p.Pager.CurrentPage().(*PollForDecisionTaskOutput)
}

// PollForDecisionTaskResponse is the response type for the
// PollForDecisionTask API operation.
type PollForDecisionTaskResponse struct {
	*PollForDecisionTaskOutput

	response *aws.Response
}

// SDKResponseMetdata returns the response metadata for the
// PollForDecisionTask request.
func (r *PollForDecisionTaskResponse) SDKResponseMetdata() *aws.Response {
	return r.response
}