import utils.LinkedIssueTransitions
import utils.FieldCopy

final String LINK_TYPE_NAME       = "is cloned by"
final String TARGET_PROJECT_KEY   = "CSD"
final String SOURCE_FIELD_ID      = "customfield_11501"   // ADF
final String TARGET_FIELD_ID      = "customfield_11501"
final String LOG_PREFIX           = "[CopyField->LinkedIssue]"

def sourceKey = issue?.key?.toString()
if (!sourceKey) {
  logger.warn("${LOG_PREFIX} Kein issue.key im Kontext. Abbruch.")
  return
}

// Source laden: Links + Feld
def issueResp = get("/rest/api/3/issue/${sourceKey}")
  .queryString("fields", "issuelinks,${SOURCE_FIELD_ID}")
  .asObject(Map)

if (issueResp.status != 200) {
  logger.warn("${LOG_PREFIX} Konnte ${sourceKey} nicht laden (${issueResp.status}). Body=${issueResp.body}")
  return
}

def sourceJson = issueResp.body

// Ziel ermitteln
def targetKey = LinkedIssueTransitions.findSingleLinkedTargetKey(
  sourceJson,
  LINK_TYPE_NAME,
  TARGET_PROJECT_KEY
)

if (!targetKey) {
  logger.warn("${LOG_PREFIX} Kein eindeutiges Ziel-Ticket gefunden (erwartet genau 1 Link ins Projekt ${TARGET_PROJECT_KEY}). Abbruch.")
  return
}

// Feldwert lesen (ADF)
def value = FieldCopy.getFieldValue(sourceJson, SOURCE_FIELD_ID)

// Falls leer: Ziel unverändert lassen
if (value == null) {
  logger.warn("${LOG_PREFIX} Source-Feld ${SOURCE_FIELD_ID} ist null/leer in ${sourceKey}. Zielfeld bleibt unverändert.")
  return
}

logger.info("${LOG_PREFIX} Kopiere ${SOURCE_FIELD_ID} von ${sourceKey} nach ${targetKey}")

def body = FieldCopy.buildSingleFieldUpdateBody(TARGET_FIELD_ID, value)

def putResp = put("/rest/api/3/issue/${targetKey}")
  .header("Content-Type", "application/json")
  .body(body)
  .asObject(Map)

if (putResp.status == 204) {
  logger.info("${LOG_PREFIX} OK: Feld ${TARGET_FIELD_ID} in ${targetKey} aktualisiert.")
} else {
  logger.warn("${LOG_PREFIX} Feld-Update fehlgeschlagen: status=${putResp.status}, body=${putResp.body}")
}