import { string } from 'alga-js'

// Already-returned quantity per shipment line (M_InOutLine_ID → qty), used by
// the mobile + desktop return pages to cap what can still be returned.
//
// Only quantities that were PHYSICALLY received count: a completed M_RMA is
// just the return authorization (marketplace-imported Amazon/Shopify RMAs are
// created Completed with the expected qty before the parcel ever arrives).
// The actual receipt is the customer-return M_InOut (MovementType C+) linked
// via M_RMA_ID, with lines linked via M_RMALine_ID — that is what quick-rma
// creates, and what it checks before reusing an "orphaned" RMA. Counting bare
// RMA lines locked lines at "Remaining 0/1" for returns that had never been
// processed.
//
// `excludeRmaId` skips one RMA entirely (the page was reached through that
// RMA's external number, so it's the authorization being fulfilled right now).
export const useReturnedQty = () => {
  const headers = () => ({ headers: useRequestHeaders(['cookie']) })

  const getReturnedQtyMap = async (shipmentId: number | string, excludeRmaId: number | null = null): Promise<Record<number, number>> => {
    const returnedQtyMap: Record<number, number> = {}
    if (!shipmentId) return returnedQtyMap
    try {
      const rmaRes: any = await $fetch(
        '/api/filters/m_rma/' + string.urlEncode(`InOut_ID eq ${shipmentId} AND DocStatus eq 'CO'`) + '&$expand=m_rmaline&$top=50',
        headers()
      )
      const rmas: any[] = (rmaRes?.records || []).filter((rma: any) => !(excludeRmaId && rma.id === excludeRmaId))
      if (rmas.length === 0) return returnedQtyMap

      // RMA line → shipment line, plus the authorized qty per RMA line as a
      // fallback for legacy receipts whose lines carry no M_RMALine_ID.
      const shipLineByRmaLine: Record<number, number> = {}
      const rmaLinesByRma: Record<number, any[]> = {}
      for (const rma of rmas) {
        const lines = rma.m_rmaline || rma.M_RMALine || []
        rmaLinesByRma[rma.id] = lines
        for (const rmaLine of lines) {
          const inOutLineId = rmaLine.M_InOutLine_ID?.id
          if (inOutLineId) shipLineByRmaLine[rmaLine.id] = inOutLineId
        }
      }

      const receiptRes: any = await $fetch(
        '/api/filters/m_inout/' + string.urlEncode(`M_RMA_ID in (${rmas.map(r => r.id).join(',')}) AND (DocStatus eq 'CO' OR DocStatus eq 'CL')`)
          + '&$select=M_RMA_ID,MovementType&$expand=m_inoutline($select=MovementQty,M_RMALine_ID)&$top=100',
        headers()
      )
      for (const receipt of (receiptRes?.records || [])) {
        const rmaId = receipt.M_RMA_ID?.id
        const lines: any[] = receipt.m_inoutline || receipt.M_InOutLine || []
        const linked = lines.filter(l => l.M_RMALine_ID?.id)
        if (linked.length > 0) {
          for (const line of linked) {
            const inOutLineId = shipLineByRmaLine[line.M_RMALine_ID.id]
            if (inOutLineId) {
              returnedQtyMap[inOutLineId] = (returnedQtyMap[inOutLineId] || 0) + Math.abs(line.MovementQty || 0)
            }
          }
        } else if (rmaId && rmaLinesByRma[rmaId]) {
          // Receipt exists but its lines aren't linked — attribute the RMA's
          // authorized quantities instead (pre-M_RMALine_ID data).
          for (const rmaLine of rmaLinesByRma[rmaId]) {
            const inOutLineId = rmaLine.M_InOutLine_ID?.id
            if (inOutLineId) {
              returnedQtyMap[inOutLineId] = (returnedQtyMap[inOutLineId] || 0) + Math.abs(rmaLine.Qty || 0)
            }
          }
        }
      }
    } catch (e) {
      console.warn('Could not fetch existing returns for shipment:', e)
    }
    return returnedQtyMap
  }

  return { getReturnedQtyMap }
}