import { delivery as defaultDeliveryApi, ledger as defaultLedgerApi } from '../api';
import artikelAutomat from '../automats/artikelAutomat';

/**
 * @typedef {Object} DeliveryLineLedgerStatus
 * @property {number} id - Manifestarticle ID
 * @property {string} sku - Article SKU
 * @property {string} name - Article Name
 * @property {number} targetAmount - Expected delivery quantity
 * @property {number} bookedAmount - Quantity booked in ledger
 * @property {number} remainingAmount - Quantity remaining to be booked
 * @property {boolean} isBooked - Whether this position is fully booked
 * @property {Array<Object>} ledgerEntries - Ledger entries for this line
 */

/**
 * @typedef {Object} DeliveryLedgerSummary
 * @property {number} deliveryId
 * @property {Object} delivery - Full delivery object with lines
 * @property {'empty' | 'booked' | 'partial' | 'unbooked'} status
 * @property {number} totalPositions
 * @property {number} bookedPositions
 * @property {number} totalQuantity
 * @property {number} bookedQuantity
 * @property {Array<DeliveryLineLedgerStatus>} lines
 */

/**
 * Fetches delivery lines and checks ledger entries for each line to compute the booking status.
 *
 * @param {number|string} deliveryId
 * @param {Object} [options]
 * @param {Object} [options.deliveryApi]
 * @param {Object} [options.ledgerApi]
 * @returns {Promise<DeliveryLedgerSummary>}
 */
export async function fetchDeliveryLedgerSummary(deliveryId, { deliveryApi = defaultDeliveryApi, ledgerApi = defaultLedgerApi } = {}) {
  const res = await deliveryApi.get(deliveryId);
  const delivery = res?.delivery ?? res;
  const rawLines = Array.isArray(delivery?.lines) ? delivery.lines : [];

  if (rawLines.length === 0) {
    return {
      deliveryId,
      delivery,
      status: 'empty',
      totalPositions: 0,
      bookedPositions: 0,
      totalQuantity: 0,
      bookedQuantity: 0,
      lines: [],
    };
  }

  // Fetch ledger entries for each line in parallel
  const linesWithLedger = await Promise.all(
    rawLines.map(async (line) => {
      let ledgerEntries = [];
      try {
        const ledgerRes = await ledgerApi.listByManifestarticleId(line.id, 'DELIVERY');
        ledgerEntries = Array.isArray(ledgerRes?.ledger) ? ledgerRes.ledger : [];
      } catch (err) {
        console.error(`[deliveryLedger] Failed to fetch ledger for line ${line.id}:`, err);
      }

      const deliveryEntries = ledgerEntries.filter(
        (e) => String(e.transaction_type).toUpperCase() === 'DELIVERY'
      );
      const bookedAmount = deliveryEntries.reduce((sum, e) => sum + Number(e.amount || 0), 0);
      const targetAmount = Number(line.amount || 0);
      const remainingAmount = Math.max(0, targetAmount - bookedAmount);
      const isBooked = targetAmount > 0 ? bookedAmount >= targetAmount : bookedAmount > 0;

      return {
        ...line,
        targetAmount,
        bookedAmount,
        remainingAmount,
        isBooked,
        ledgerEntries: deliveryEntries,
      };
    })
  );

  const totalPositions = linesWithLedger.length;
  const bookedPositions = linesWithLedger.filter((l) => l.isBooked).length;
  const totalQuantity = linesWithLedger.reduce((sum, l) => sum + l.targetAmount, 0);
  const bookedQuantity = linesWithLedger.reduce((sum, l) => sum + l.bookedAmount, 0);

  let status = 'unbooked';
  if (totalPositions === 0) {
    status = 'empty';
  } else if (bookedPositions === totalPositions && bookedQuantity >= totalQuantity) {
    status = 'booked';
  } else if (bookedPositions > 0 || bookedQuantity > 0) {
    status = 'partial';
  } else {
    status = 'unbooked';
  }

  return {
    deliveryId,
    delivery,
    status,
    totalPositions,
    bookedPositions,
    totalQuantity,
    bookedQuantity,
    lines: linesWithLedger,
  };
}

/**
 * Books specified delivery lines to the ledger as goods receipts (DELIVERY).
 *
 * @param {Object} params
 * @param {Object} params.delivery - The delivery object (used for transaction memo and fallback)
 * @param {Array<{ manifestarticleId?: number, id?: number, amount: number, sku?: string }>} params.linesToBook
 * @param {number|string} params.warehouseId - Mandatory warehouse ID
 * @param {Object} [params.ledgerApi]
 * @param {string} [params.transactionText]
 * @returns {Promise<Array<Object>>}
 */
export async function bookDeliveryLines({
  delivery,
  linesToBook,
  warehouseId,
  ledgerApi = defaultLedgerApi,
  transactionText,
}) {
  const numericWarehouseId = Number(warehouseId);
  if (!numericWarehouseId || numericWarehouseId <= 0) {
    throw new Error('Bitte wählen Sie ein Lager aus.');
  }

  if (!Array.isArray(linesToBook) || linesToBook.length === 0) {
    return [];
  }

  const memo = String(
    transactionText != null && transactionText !== ''
      ? transactionText
      : `Lieferung ${delivery?.number || delivery?.id || ''}`
  ).trim();

  const results = [];
  for (const item of linesToBook) {
    const manifestarticleId = Number(item.manifestarticleId ?? item.id);
    const amount = Number(item.amount);

    if (!manifestarticleId || !Number.isFinite(amount) || amount <= 0) {
      continue;
    }

    const res = await ledgerApi.add({
      manifestarticle_id: manifestarticleId,
      warehouse_id: numericWarehouseId,
      transaction_type: 'DELIVERY',
      amount,
      transaction_text: memo,
    });
    results.push(res?.ledger ?? res);

    if (item.sku) {
      void artikelAutomat.actions.reloadArticle(item.sku).catch(() => {});
    }
  }

  return results;
}