/** Qwen Edit / PE-I2I prompt helpers. Start still = <image1>; Hero is never a slot. */

export const QWEN21_EDIT_KEEP =
  'Keep the identity, face, body, and pose of the person in <image1>.'

export const QWEN21_EDIT_KEEP_CHANGE =
  `${QWEN21_EDIT_KEEP} Apply only this change:`

/** User omitted <image1> — prepend the keep-identity instruction once. */
export function ensureQwen21EditPrompt(prompt) {
  const text = String(prompt || '').trim()
  if (!text) return text
  if (/<image1>/i.test(text)) return text
  return `${QWEN21_EDIT_KEEP_CHANGE} ${text}`.trim()
}

/**
 * After PE-I2I: if the rewrite dropped every <imageN> token, stitch the
 * keep-identity line onto the rewrite (do not discard the rewrite).
 */
export function stitchQwen21PeEditPrompt(rewritten) {
  const text = String(rewritten || '').trim()
  if (!text) return text
  if (/<image\d+>/i.test(text)) return text
  return `${QWEN21_EDIT_KEEP} ${text}`.trim()
}