// Code generated by smithy-go-codegen DO NOT EDIT.

package kinesis

import (
	"context"
	awsmiddleware "github.com/aws/aws-sdk-go-v2/aws/middleware"
	"github.com/aws/aws-sdk-go-v2/aws/signer/v4"
	"github.com/aws/aws-sdk-go-v2/service/kinesis/types"
	"github.com/aws/smithy-go/middleware"
	smithysync "github.com/aws/smithy-go/sync"
	smithyhttp "github.com/aws/smithy-go/transport/http"
	"sync"
)

// This operation establishes an HTTP/2 connection between the consumer you specify
// in the ConsumerARN parameter and the shard you specify in the ShardId parameter.
// After the connection is successfully established, Kinesis Data Streams pushes
// records from the shard to the consumer over this connection. Before you call
// this operation, call RegisterStreamConsumer to register the consumer with
// Kinesis Data Streams. When the SubscribeToShard call succeeds, your consumer
// starts receiving events of type SubscribeToShardEvent over the HTTP/2 connection
// for up to 5 minutes, after which time you need to call SubscribeToShard again to
// renew the subscription if you want to continue to receive records. You can make
// one call to SubscribeToShard per second per registered consumer per shard. For
// example, if you have a 4000 shard stream and two registered stream consumers,
// you can make one SubscribeToShard request per second for each combination of
// shard and registered consumer, allowing you to subscribe both consumers to all
// 4000 shards in one second. If you call SubscribeToShard again with the same
// ConsumerARN and ShardId within 5 seconds of a successful call, you'll get a
// ResourceInUseException. If you call SubscribeToShard 5 seconds or more after a
// successful call, the second call takes over the subscription and the previous
// connection expires or fails with a ResourceInUseException. For an example of how
// to use this operations, see Enhanced Fan-Out Using the Kinesis Data Streams API.
func (c *Client) SubscribeToShard(ctx context.Context, params *SubscribeToShardInput, optFns ...func(*Options)) (*SubscribeToShardOutput, error) {
	if params == nil {
		params = &SubscribeToShardInput{}
	}

	result, metadata, err := c.invokeOperation(ctx, "SubscribeToShard", params, optFns, c.addOperationSubscribeToShardMiddlewares)
	if err != nil {
		return nil, err
	}

	out := result.(*SubscribeToShardOutput)
	out.ResultMetadata = metadata
	return out, nil
}

type SubscribeToShardInput struct {

	// For this parameter, use the value you obtained when you called
	// RegisterStreamConsumer.
	//
	// This member is required.
	ConsumerARN *string

	// The ID of the shard you want to subscribe to. To see a list of all the shards
	// for a given stream, use ListShards.
	//
	// This member is required.
	ShardId *string

	// The starting position in the data stream from which to start streaming.
	//
	// This member is required.
	StartingPosition *types.StartingPosition

	noSmithyDocumentSerde
}

type SubscribeToShardOutput struct {
	eventStream *SubscribeToShardEventStream

	// Metadata pertaining to the operation's result.
	ResultMetadata middleware.Metadata

	noSmithyDocumentSerde
}

// GetStream returns the type to interact with the event stream.
func (o *SubscribeToShardOutput) GetStream() *SubscribeToShardEventStream {
	return o.eventStream
}

func (c *Client) addOperationSubscribeToShardMiddlewares(stack *middleware.Stack, options Options) (err error) {
	err = stack.Serialize.Add(&awsAwsjson11_serializeOpSubscribeToShard{}, middleware.After)
	if err != nil {
		return err
	}
	err = stack.Deserialize.Add(&awsAwsjson11_deserializeOpSubscribeToShard{}, middleware.After)
	if err != nil {
		return err
	}
	if err = addEventStreamSubscribeToShardMiddleware(stack, options); err != nil {
		return err
	}
	if err = addSetLoggerMiddleware(stack, options); err != nil {
		return err
	}
	if err = awsmiddleware.AddClientRequestIDMiddleware(stack); err != nil {
		return err
	}
	if err = smithyhttp.AddComputeContentLengthMiddleware(stack); err != nil {
		return err
	}
	if err = addResolveEndpointMiddleware(stack, options); err != nil {
		return err
	}
	if err = v4.AddComputePayloadSHA256Middleware(stack); err != nil {
		return err
	}
	if err = addRetryMiddlewares(stack, options); err != nil {
		return err
	}
	if err = addHTTPSignerV4Middleware(stack, options); err != nil {
		return err
	}
	if err = awsmiddleware.AddRawResponseToMetadata(stack); err != nil {
		return err
	}
	if err = awsmiddleware.AddRecordResponseTiming(stack); err != nil {
		return err
	}
	if err = addClientUserAgent(stack); err != nil {
		return err
	}
	if err = addOpSubscribeToShardValidationMiddleware(stack); err != nil {
		return err
	}
	if err = stack.Initialize.Add(newServiceMetadataMiddleware_opSubscribeToShard(options.Region), middleware.Before); err != nil {
		return err
	}
	if err = addRequestIDRetrieverMiddleware(stack); err != nil {
		return err
	}
	if err = addResponseErrorMiddleware(stack); err != nil {
		return err
	}
	if err = addRequestResponseLogging(stack, options); err != nil {
		return err
	}
	return nil
}

func newServiceMetadataMiddleware_opSubscribeToShard(region string) *awsmiddleware.RegisterServiceMetadata {
	return &awsmiddleware.RegisterServiceMetadata{
		Region:        region,
		ServiceID:     ServiceID,
		SigningName:   "kinesis",
		OperationName: "SubscribeToShard",
	}
}

// SubscribeToShardEventStream provides the event stream handling for the SubscribeToShard operation.
//
// For testing and mocking the event stream this type should be initialized via
// the NewSubscribeToShardEventStream constructor function. Using the functional options
// to pass in nested mock behavior.
type SubscribeToShardEventStream struct {
	// SubscribeToShardEventStreamReader is the EventStream reader for the
	// SubscribeToShardEventStream events. This value is automatically set by the SDK
	// when the API call is made Use this member when unit testing your code with the
	// SDK to mock out the EventStream Reader.
	//
	// Must not be nil.
	Reader SubscribeToShardEventStreamReader

	done      chan struct{}
	closeOnce sync.Once
	err       *smithysync.OnceErr
}

// NewSubscribeToShardEventStream initializes an SubscribeToShardEventStream.
// This function should only be used for testing and mocking the SubscribeToShardEventStream
// stream within your application.
//
// The Reader member must be set before reading events from the stream.
func NewSubscribeToShardEventStream(optFns ...func(*SubscribeToShardEventStream)) *SubscribeToShardEventStream {
	es := &SubscribeToShardEventStream{
		done: make(chan struct{}),
		err:  smithysync.NewOnceErr(),
	}
	for _, fn := range optFns {
		fn(es)
	}
	return es
}

// Events returns a channel to read events from.
func (es *SubscribeToShardEventStream) Events() <-chan types.SubscribeToShardEventStream {
	return es.Reader.Events()
}

// Close closes the stream. This will also cause the stream to be closed.
// Close must be called when done using the stream API. Not calling Close
// may result in resource leaks.
//
// Will close the underlying EventStream writer and reader, and no more events can be
// sent or received.
func (es *SubscribeToShardEventStream) Close() error {
	es.closeOnce.Do(es.safeClose)
	return es.Err()
}

func (es *SubscribeToShardEventStream) safeClose() {
	close(es.done)

	es.Reader.Close()
}

// Err returns any error that occurred while reading or writing EventStream Events
// from the service API's response. Returns nil if there were no errors.
func (es *SubscribeToShardEventStream) Err() error {
	if err := es.err.Err(); err != nil {
		return err
	}

	if err := es.Reader.Err(); err != nil {
		return err
	}

	return nil
}

func (es *SubscribeToShardEventStream) waitStreamClose() {
	type errorSet interface {
		ErrorSet() <-chan struct{}
	}

	var outputErrCh <-chan struct{}
	if v, ok := es.Reader.(errorSet); ok {
		outputErrCh = v.ErrorSet()
	}
	var outputClosedCh <-chan struct{}
	if v, ok := es.Reader.(interface{ Closed() <-chan struct{} }); ok {
		outputClosedCh = v.Closed()
	}

	select {
	case <-es.done:
	case <-outputErrCh:
		es.err.SetError(es.Reader.Err())
		es.Close()

	case <-outputClosedCh:
		if err := es.Reader.Err(); err != nil {
			es.err.SetError(es.Reader.Err())
		}
		es.Close()

	}
}
