Migrate MLCS values of Jira issues (Cloud)

import com.atlassian.jira.issue.customfields.option.LazyLoadedOption
import com.atlassian.jira.component.ComponentAccessor
import com.atlassian.jira.issue.fields.CustomField
import com.atlassian.jira.issue.Issue
import com.atlassian.jira.issue.CustomFieldManager
import com.atlassian.jira.security.JiraAuthenticationContext
import com.atlassian.jira.bc.issue.search.SearchService
import com.atlassian.jira.issue.search.SearchException
import com.atlassian.jira.web.bean.PagerFilter
import groovy.json.JsonOutput
import groovyx.net.http.RESTClient
import groovyx.net.http.ContentType
 
// Jira Cloud REST API base URL
final String jiraCloudApiBaseUrl = "https://[YourInstance].atlassian.net"
 
// Basic Authentication Encoded String
def encodedAuthString = "your_email:token".bytes.encodeBase64().toString()
 
// Get necessary components
def issueManager = ComponentAccessor.getIssueManager()
def customFieldManager = ComponentAccessor.getCustomFieldManager()
def authenticationContext = ComponentAccessor.getJiraAuthenticationContext()
def searchService = ComponentAccessor.getComponent(SearchService.class)
 
// Define and find the custom field
final String customFieldName = "mlcs employee"
final String cloudCustomFieldId = "customfield_10101"
def customField = customFieldManager.getCustomFieldObjectsByName(customFieldName)?.first()
 
if (customField == null) {
    log.error "Custom field not found: $customFieldName"
    return
}
 
// Fetch issues
def user = authenticationContext.getLoggedInUser()
def query = "\"${customFieldName}\" is not EMPTY"
 
// Parse the JQL query
def parseResult = searchService.parseQuery(user, query)
 
def transformElement(LazyLoadedOption element) {
  String label = element.getValue()
  String optionId = element.getOptionId().toString()
  return [label: label, value: optionId]
}
 
if (!parseResult.isValid()) {
    log.error "Invalid JQL Query: ${query}"
    return
}
 
try {
    def results = searchService.search(user, parseResult.getQuery(), PagerFilter.getUnlimitedFilter())
 
    results.getResults().each { Issue issue ->
       List serverValue = issue.getCustomFieldValue(customField)
        if (serverValue) {
 
           def transformedArray = [:]
 
        // Populate the map
        serverValue.eachWithIndex { element, index ->
            transformedArray["lv$index"] = transformElement(element as LazyLoadedOption)
        }
            
 
            def payload = [
                fields: [
                    (cloudCustomFieldId):  JsonOutput.toJson(transformedArray)
                ]
            ]
 
            def client = new RESTClient(jiraCloudApiBaseUrl)
 
            client.setHeaders([
                'Content-Type' : ContentType.JSON,
                'Authorization': "Basic $encodedAuthString"
            ])
 
            try {
                def response = client.put(
                    path: "/rest/api/3/issue/$issue.key",
                    contentType: ContentType.JSON,
                    body: payload
                )
 
                if (response.status != 204) {
                    log.error("Failed to update issue ${issue.key}: ${response.data}")
                } else {
                    log.info("Issue updated successfully: ${issue.key}")
                }
            } catch(Exception e) {
                log.error("Error updating issue ${issue.key}: ${e.message}")
            }
        }
    }
} catch (SearchException e) {
    log.error("Error executing search: ${e.message}")
}