You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: transformer.go
    path of file: ./repos/rudder-server/enterprise/replay/replayer
    
    the code of the file until where you have to start completion: package replayer

import (
	"encoding/json"
	"strings"
	"time"

	"github.com/google/uuid"
)

type Payload struct {
	Batch      json.RawMessage `json:"batch"`
	ReceivedAt string          `json:"receivedAt"`
	RequestIP  string          `json:"requestIP"`
	WriteKey   string          `json:"writeKey"`
}
type Params struct {
	SourceID string `json:"source_id"`
}

func transformArchivalToBackup(input []byte, path string) ([]byte, error) {
	var originalPayload struct {
		CreatedAt time.Time       `json:"createdAt"`
		MessageID string
    
func transformArchivalToBackup(input []byte, path string) ([]byte, error) {
	var originalPayload struct {
		CreatedAt time.Time       `json:"createdAt"`
		MessageID string          `json:"messageId"`
		Payload   json.RawMessage `json:"payload"`
		UserID    string          `json:"userId"`
	}
	var sourceId string
	err := json.Unmarshal(input, &originalPayload)
	if err != nil {
		return nil, err
	}
	if len(strings.Split(path, "/")) == 7 {
		sourceId = strings.Split(path, "/")[1]
	} else {
		sourceId = strings.Split(path, "/")[0]
	}
	desiredPayload := struct {
		CreatedAt    time.Time `json:"created_at"`
		CustomVal    string    `json:"custom_val"`
		EventCount   int       `json:"event_count"`
		EventPayload Payload   `json:"event_payload"`
		ExpireAt     string    `json:"expire_at"`
		JobID        int       `json:"job_id"`
		Parameters   Params    `json:"parameters"`
		UserID       string    `json:"user_id"`
		UUID         string    `json:"uuid"`
		WorkspaceID  string    `json:"workspace_id"`
	}{
		CreatedAt: originalPayload.CreatedAt,
		CustomVal: "GW",
		EventPayload: Payload{
			Batch: originalPayload.Payload,
		},
		UUID: uuid.NewString(),
		Parameters: Params{
			SourceID: sourceId,
		},
		EventCount: 1,
		UserID:     originalPayload.UserID,
	}
	desiredJSON, err := json.Marshal(desiredPayload)
	if err != nil {
		return nil, err
	}
	return desiredJSON, nil
}