const ILLEGAL = /[/\\:*?"<>|\u0000-\u001f]/g

export function sanitizeRemarkBaseName(remark) {
  const cleaned = String(remark || '')
    .trim()
    .replace(ILLEGAL, '_')
    .replace(/\s+/g, '_')
    .replace(/_+/g, '_')
    .replace(/^_|_$/g, '')
  if (!cleaned) return ''
  return cleaned.length > 40 ? cleaned.slice(0, 40) : cleaned
}

function splitExt(fileName) {
  const name = String(fileName || '')
  const i = name.lastIndexOf('.')
  if (i <= 0 || i === name.length - 1) return { base: name, ext: '' }
  return { base: name.slice(0, i), ext: name.slice(i) }
}

export function buildApplyAttachmentDisplayName({ remark, originalFileName, index1 }) {
  const original = String(originalFileName || '').trim() || '申请附件'
  const base = sanitizeRemarkBaseName(remark)
  if (!base) return original
  const { ext } = splitExt(original)
  const n = Math.max(1, Math.floor(Number(index1) || 1))
  return `${base}_${n}${ext}`
}