// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
// snippet-start:[s3.go.upload_stream]
package main

// snippet-start:[s3.go.upload_stream.imports]
import (
	"compress/gzip"
	"flag"
	"fmt"
	"io"
	"os"

	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/s3/s3manager"
)

// snippet-end:[s3.go.upload_stream.imports]

// UploadStream uploads a stream for a file to a bucket
// Inputs:
//
//	sess is the current session, which provides configuration for the SDK's service clients
//	bucket is the name of the bucket
//	key is the name of the object in the bucket
//	filename is the name of the file to stream to the bucket
//
// Output:
//
//	If success, nil
//	Otherwise, an error from the call to Open or Upload
func UploadStream(sess *session.Session, bucket *string, key *string, filename *string) error {
	// snippet-start:[s3.go.upload_stream.call]
	file, err := os.Open(*filename)
	if err != nil {
		return err
	}

	reader, writer := io.Pipe()

	go func() {
		gw := gzip.NewWriter(writer)
		_, err := io.Copy(gw, file)
		if err != nil {
			return
		}
		file.Close()
		gw.Close()
		writer.Close()
	}()

	uploader := s3manager.NewUploader(sess)

	_, err = uploader.Upload(&s3manager.UploadInput{
		Body:   reader,
		Bucket: bucket,
		Key:    key,
	})
	// snippet-end:[s3.go.upload_stream.call]
	if err != nil {
		return err
	}

	return nil
}

func main() {
	// snippet-start:[s3.go.upload_stream.args]
	bucket := flag.String("b", "", "The bucket to which the stream is uploaded")
	filename := flag.String("f", "", "The file to upload to the bucket")
	key := flag.String("k", "", "The name of the object in the bucket")
	flag.Parse()

	if *bucket == "" || *filename == "" || *key == "" {
		fmt.Println("You must supply a bucket name (-b BUCKET), filename (-f FILENAME), and key value (-k KEY)")
		return
	}

	// snippet-end:[s3.go.upload_stream.args]

	// snippet-start:[s3.go.upload_stream.session]
	sess := session.Must(session.NewSessionWithOptions(session.Options{
		SharedConfigState: session.SharedConfigEnable,
	}))
	// snippet-end:[s3.go.upload_stream.session]

	err := UploadStream(sess, bucket, key, filename)
	if err != nil {
		fmt.Println("Failed to upload " + *filename + " to bucket " + *bucket)
	}

	fmt.Println("Successfully uploaded " + *filename + " to " + *bucket)
}

// snippet-end:[s3.go.upload_stream]
