/** 店铺数据结果批量下载任务（任务 113）：打包请求体与下载 job 状态；纯逻辑。 */

export type ShopDataDownloadStatus = 'idle' | 'running' | 'done' | 'failed'

export interface ShopDataDownloadJob {
  status: ShopDataDownloadStatus
  message?: string
  fileCount?: number
  errorCount?: number
}

/** 从 Content-Disposition 解析单文件下载名（rfc5987 优先），失败回默认名。 */
export function shopDataFilenameFromDisposition(disposition: string | undefined, fallback: string): string {
  const text = typeof disposition === 'string' ? disposition : ''
  const encoded = /filename\*=UTF-8''([^;]+)/i.exec(text)
  if (encoded) {
    try {
      const decoded = decodeURIComponent(encoded[1])
      if (decoded.trim()) return decoded.trim()
    } catch {
      // 回退普通 filename
    }
  }
  const plain = /filename="?([^";]+)"?/i.exec(text)
  return plain && plain[1] ? plain[1].trim() : fallback
}

function finitePositive(value: unknown): number | null {
  const number = typeof value === 'number' && Number.isFinite(value)
    ? value
    : typeof value === 'string' && /^\d+$/.test(value.trim())
      ? Number(value.trim())
      : null
  return number === null || number < 1 ? null : Math.floor(number)
}

/** result_id → POST /download-zip 请求体(过滤非法 id，按序去重)。 */
export function toShopDataZipRequest(resultIds: readonly (number | string)[]): { result_ids: number[] } {
  const ids: number[] = []
  const seen = new Set<number>()
  for (const id of resultIds) {
    const parsed = finitePositive(id)
    if (parsed === null || seen.has(parsed)) continue
    seen.add(parsed)
    ids.push(parsed)
  }
  return { result_ids: ids }
}

export function createShopDataDownloadJob(): ShopDataDownloadJob {
  return { status: 'idle' }
}

export function startShopDataDownload(): ShopDataDownloadJob {
  return { status: 'running' }
}

export function succeedShopDataDownload(_job: ShopDataDownloadJob, fileCount: number, errorCount: number): ShopDataDownloadJob {
  return { status: 'done', fileCount, errorCount }
}

export function failShopDataDownload(_job: ShopDataDownloadJob, message: string): ShopDataDownloadJob {
  return { status: 'failed', message }
}