import { getMerchantUnifiedOrders } from '../api/unifiedOrders'
import { getMerchantCustomsForOrder, isMerchantCustomsUnavailable, type MerchantCustomsContainer } from '../api/customs'
import { isCustomsOrderCandidate } from './customsEligibility'

export interface CustomsDocumentRow {
  order: { id: string; orderNo: string | null; businessSummary: { inboundCode: string } }
  detail: MerchantCustomsContainer
}

// Isolated from the shared order store: scan sequential pages, with at most
// four document requests in flight. Inconsistent pagination must be visible.
export async function readCustomsDocuments() {
  const records: CustomsDocumentRow[] = []
  const seen = new Set<string>()
  let expectedTotal: number | undefined
  let failedCount = 0
  const size = 200
  for (let page = 1; ; page += 1) {
    const response = await getMerchantUnifiedOrders({ page, size, taxMode: 'TAX_REFUND', loaded: true })
    const total = Number(response.total)
    const pages = Number(response.pages)
    if (!Number.isSafeInteger(total) || total < 0 || Number(response.page) !== page
      || Number(response.size) !== size || pages !== Math.ceil(total / size)
      || (expectedTotal !== undefined && total !== expectedTotal)
      || response.records.length !== Math.min(size, Math.max(0, total - (page - 1) * size))) {
      throw new Error('订单分页数据不完整或已变化，请重新加载报关资料')
    }
    expectedTotal = total
    for (const row of response.records) {
      const id = String(row.orderId)
      if (seen.has(id)) throw new Error('订单分页存在重复记录，请重新加载报关资料')
      seen.add(id)
    }
    const candidates = response.records.filter(row => isCustomsOrderCandidate({ status: row.mainStatus, taxMode: row.taxMode ?? 'BUY_DECLARATION' }))
    for (let offset = 0; offset < candidates.length; offset += 4) {
      const results = await Promise.all(candidates.slice(offset, offset + 4).map(async row => {
        const id = String(row.orderId)
        try {
          const detail = await getMerchantCustomsForOrder(id)
          if (!detail.inbounds.some(item => item.orderId === id && item.taxMode === 'TAX_REFUND')) return null
          return { order: { id, orderNo: row.orderNo, businessSummary: { inboundCode: row.inboundCode ?? '' } }, detail }
        } catch (error) {
          if (!isMerchantCustomsUnavailable(error)) failedCount += 1
          return null
        }
      }))
      for (const result of results) if (result) records.push(result)
    }
    if (page >= pages) break
  }
  return { records, failedCount }
}