Sum Story Points to Epic.groovy

// Get Story Points field ID
def storyPointsField = get("/rest/api/3/field")
    .asObject(List)
    .body
    .find { it.name == "Story Points" }
    .id

// Cast issue.key to String
def eventIssue = Issues.getByKey(issue.key as String)
def issueType = eventIssue.issueType.name

if (issueType in ["Task", "Story", "Design Task"]) {
    // 1. Identify parent (using parentId → REST → key)
    def parentId = eventIssue.parentId
    if (!parentId) return

    def parentRes = get("/rest/api/3/issue/${parentId}")
        .queryString("fields", "key")
        .asObject(Map)
        .body

    def parentKey = parentRes.key
    def parentIssue = Issues.getByKey(parentKey as String)

    // 2. Fetch childs-tasks via HAPI
    def childIssue = Issues.search("parent = ${parentKey}")
    def childTaskSum = childIssue.collect { it.fields[storyPointsField] ?: 0 }.sum()
    logger.info("Updating parent ${parentKey} with summed SP = ${childTaskSum}")

    // 3. Update the parent issue
    put("/rest/api/3/issue/${parentKey}")
        .header("Content-Type", "application/json")
        .body([fields: [(storyPointsField): childTaskSum]])
        .asString()
}