import resolveSelectedCompanyAccess from '../companyuser/resolveSelectedCompanyAccess.js';
import taxEnsure from '../tax/ensure.js';
import { insertLines, parseDate } from '../manifestLines.js';
import { assertUniqueManifestNumber } from '../manifestDoc/helpers.js';
import makeRunner from '../runner.js';
import shippingCreate from '../shipping/create.js';
import { loadShipment, queriesFor } from './helpers.js';
import { syncOrderSummary } from '../order/syncSummary.js';
import { syncRetoureSummary } from '../retoure/syncSummary.js';
import { syncShipmentSummary } from './syncSummary.js';

function requireId(val, name) {
  const n = Number(val);
  if (!Number.isInteger(n) || n <= 0) {
    throw new Error(`${name} is required`);
  }
  return n;
}

/**
 * Creates a new shipment manifest for an order.
 * Validates that all article positions belong to the order and do not exceed remaining ordered quantities.
 *
 * @param {import('../../providers/provider.js').DatabaseProvider} provider
 */
export default function create(provider) {
  const access = resolveSelectedCompanyAccess(provider);
  const ensureTax = taxEnsure(provider);
  const createShipping = shippingCreate(provider);
  const q = queriesFor(provider);

  /**
   * Creates a shipment manifest for an order containing specified items from the order.
   * On individual lines, amount is optional and defaults to the remaining unshipped quantity.
   *
   * @param {number} googleAuthId - The id of the Google auth user.
   * @param {object} input - The shipment input.
   * @param {number} input.orderId - The parent order manifest id.
   * @param {Array<{sku?: string, orderLineId?: number, amount?: number, name?: string, pu?: number, net?: number, rebate?: number, taxrate?: number, comment?: string}>} input.lines - The shipment positions. Order lines with a SKU are referenced by `sku`; SKU-less order lines by `orderLineId` (matched across shipments by name).
   * @param {string|Date} [input.date] - Optional shipment date (defaults to current date).
   * @param {'new'|'delivered'} [input.state='new'] - Optional delivery state (defaults to 'new').
   * @param {string} [input.externalNumber] - Optional external delivery note number (defaults to order.externalNumber or order.number).
   * @param {object} input.shipping - Required shipping (package) created atomically with the shipment, so a shipment never exists without a carrier.
   * @param {number} input.shipping.carrierId - The carrier id.
   * @param {string} input.shipping.type - Shipping type.
   * @param {string} input.shipping.state - Shipping state ('shipped' or other).
   * @param {string} [input.shipping.trackingCode] - Carrier tracking code.
   * @param {number} [input.shipping.warehouseId] - Optional warehouse ID for stock deduction when state is 'shipped'.
   * @param {object} [tx] - Optional transaction.
   * @returns {Promise<object>} The created shipment manifest.
   * @throws {Error} If order not found, invalid lines, shipping/carrier missing or invalid, or article ceiling invariant exceeded.
   *
   * @example
   * const shipment = await store.shipment.create(googleAuthId, {
   *   orderId: 10,
   *   lines: [{ sku: 'ITEM-A', amount: 5 }],
   *   shipping: { carrierId: 1, type: 'parcel', state: 'draft' }
   * });
   */
  return async (googleAuthId, input = {}, tx) => {
    const orderId = requireId(input.orderId, 'Order');

    if (!Array.isArray(input.lines) || input.lines.length === 0) {
      throw new Error('Invalid lines');
    }

    if (!input.shipping || typeof input.shipping !== 'object') {
      throw new Error('Shipping is required');
    }
    requireId(input.shipping.carrierId, 'Carrier');

    const shipmentDate = parseDate(input.date) || new Date();

    const run = async (runner, innerTx) => {
      const { companyId } = await access(googleAuthId, runner);

      // 1. Retrieve parent order header
      const orderRes = await runner.query(q.GET_ORDER_HEADER, {
        orderId,
        companyId,
      });
      const order = orderRes.rows[0];
      if (!order) {
        throw new Error('Order not found');
      }

      const externalNumber = input.externalNumber !== undefined
        ? (input.externalNumber?.trim?.() ? input.externalNumber.trim() : null)
        : (order.externalNumber ?? order.number ?? null);

      // 2. Retrieve parent order lines
      const orderLinesRes = await runner.query(q.GET_ORDER_LINES, {
        orderId,
      });
      const orderLines = orderLinesRes.rows ?? [];
      if (orderLines.length === 0) {
        throw new Error('Order has no lines');
      }

      // Lines are keyed by SKU; SKU-less lines are keyed by name (shipment lines copy the name).
      const lineKey = (sku, name) => {
        const s = String(sku ?? '').trim();
        return s || `\u0000name:${String(name ?? '').trim()}`;
      };
      const orderAmountBySku = new Map();
      const orderLineBySku = new Map();
      const orderLineById = new Map();

      for (const ol of orderLines) {
        const key = lineKey(ol.sku, ol.name);
        orderLineById.set(Number(ol.id), ol);
        orderAmountBySku.set(key, (orderAmountBySku.get(key) || 0) + Number(ol.amount || 0));
        if (!orderLineBySku.has(key)) {
          orderLineBySku.set(key, ol);
        }
      }

      // 3. Retrieve shipment prefix from numbers table
      const prefixRes = await runner.query(q.GET_SHIPMENT_PREFIX, { companyId });
      const shipmentPrefix = prefixRes.rows[0]?.prefix?.trim?.() || '-L-';

      // 4. Retrieve already shipped amounts across existing shipment manifests of this order
      const pattern = `${order.number}${shipmentPrefix}%`;
      const shippedRes = await runner.query(q.GET_SHIPPED_AMOUNTS_BY_ORDER_PATTERN, {
        companyId,
        pattern,
        excludeShipmentId: null,
      });
      const shippedAmountBySku = new Map();
      for (const row of shippedRes.rows ?? []) {
        const key = lineKey(row.sku, row.name);
        shippedAmountBySku.set(key, (shippedAmountBySku.get(key) || 0) + Number(row.shippedAmount || 0));
      }

      // 5. Determine warehouse and load stock for tracked articles
      let targetWarehouseId = input.warehouseId ?? input.warehouse_id;
      if (targetWarehouseId != null) {
        targetWarehouseId = Number(targetWarehouseId);
      } else {
        const defWh = await runner.query(q.GET_DEFAULT_WAREHOUSE, { companyId });
        targetWarehouseId = defWh.rows[0]?.id ?? null;
      }

      const articleInfoBySku = new Map();
      const remainingStockBySku = new Map();

      for (const sku of orderAmountBySku.keys()) {
        if (sku.startsWith('\u0000name:')) continue; // SKU-less lines carry no stock
        const artRes = await runner.query(q.GET_ARTICLE_TRACK_STOCK, { companyId, sku });
        const art = artRes.rows[0];
        const isTracked = Number(art?.track_stock ?? 0) === 1;
        let availableStock = Infinity;

        if (isTracked && targetWarehouseId != null) {
          const stockRes = await runner.query(q.GET_ARTICLE_WAREHOUSE_STOCK, {
            warehouseId: targetWarehouseId,
            companyId,
            sku,
            articleId: art?.id ?? null,
          });
          availableStock = Number(stockRes.rows[0]?.stock ?? 0);
        }

        articleInfoBySku.set(sku, {
          articleId: art?.id,
          isTracked,
          availableStock,
        });
        remainingStockBySku.set(sku, availableStock);
      }

      // 6. Determine lines to ship
      const linesToInsert = [];
      const proposedBySku = new Map();

      for (const line of input.lines) {
        const rawSku = String(line?.sku ?? '').trim();
        let sku = rawSku;
        let shipSku = rawSku;
        let label = rawSku;
        if (!rawSku) {
          // SKU-less line: referenced by order line id
          const target = orderLineById.get(Number(line?.orderLineId));
          if (!target || String(target.sku ?? '').trim()) {
            throw new Error(`Article (${line?.orderLineId ?? ''}) is not part of order (${order.number})`);
          }
          sku = lineKey(null, target.name);
          shipSku = null;
          label = String(target.name ?? '').trim();
        }
        if (!orderAmountBySku.has(sku)) {
          throw new Error(`Article (${label}) is not part of order (${order.number})`);
        }
        if (Number(orderLineBySku.get(sku)?.shippable) === 0) {
          throw new Error(`Article (${label}) is not shippable`);
        }

        const ordered = orderAmountBySku.get(sku) || 0;
        const alreadyShipped = shippedAmountBySku.get(sku) || 0;
        const remaining = Math.round((ordered - alreadyShipped) * 1000) / 1000;

        let amount;
        if (line.amount !== undefined && line.amount !== null) {
          amount = Number(line.amount);
          if (!Number.isFinite(amount) || amount === 0) {
            throw new Error('Invalid lines');
          }
        } else {
          // Default to remaining quantity
          if (remaining <= 0) {
            throw new Error(`Shipment amount exceeds ordered amount for article (${label})`);
          }
          amount = remaining;
        }

        const currentProposed = proposedBySku.get(sku) || 0;
        if (amount > 0 && alreadyShipped + currentProposed + amount > ordered) {
          throw new Error(`Shipment amount exceeds ordered amount for article (${label})`);
        }

        const info = articleInfoBySku.get(sku);
        if (amount > 0 && info?.isTracked) {
          const available = remainingStockBySku.get(sku) ?? 0;
          if (amount > available) {
            throw new Error(`Insufficient stock for article (${sku}): available ${available}, requested ${amount}`);
          }
          remainingStockBySku.set(sku, available - amount);
        }

        proposedBySku.set(sku, currentProposed + amount);

        const ol = orderLineBySku.get(sku);
        linesToInsert.push({
          sku: shipSku || null,
          name: shipSku ? (line.name ?? ol?.name ?? shipSku) : ol.name,
          pu: line.pu !== undefined ? line.pu : (ol?.pu ?? 1),
          amount,
          net: line.net !== undefined ? Number(line.net) : Number(ol?.net ?? 0),
          rebate: line.rebate !== undefined ? Number(line.rebate) : Number(ol?.rebate ?? 0),
          taxrate: line.taxrate !== undefined ? Number(line.taxrate) : Number(ol?.taxrate ?? 0),
          comment: line.comment !== undefined ? (line.comment ? String(line.comment) : null) : (ol?.comment ?? null),
          shippable: true,
        });
      }

      // 6. Resolve next index <y>
      const existingShipmentsRes = await runner.query(q.LIST_SHIPMENTS_BY_ORDER_NUMBER_PATTERN, {
        companyId,
        pattern,
      });
      const existingShipments = existingShipmentsRes.rows ?? [];

      let maxY = 0;
      const prefixExact = `${order.number}${shipmentPrefix}`;
      for (const s of existingShipments) {
        const num = String(s.number || '');
        if (num.startsWith(prefixExact)) {
          const suffix = parseInt(num.slice(prefixExact.length), 10);
          if (Number.isInteger(suffix) && suffix > maxY) {
            maxY = suffix;
          }
        }
      }
      const nextY = Math.max(existingShipments.length + 1, maxY + 1);
      const shipmentNumber = `${order.number}${shipmentPrefix}${nextY}`;

      await assertUniqueManifestNumber(runner, {
        companyId,
        type: 'shipment',
        number: shipmentNumber,
        errorMessage: 'Shipment number already exists',
      });

      // 7. Create shipment manifest header
      const createdRes = await runner.query(q.CREATE_MANIFEST, {
        companyId,
        number: shipmentNumber,
        type: 'shipment',
        entityId: order.entityId ?? null,
        externalNumber,
        date: shipmentDate,
        createdAt: new Date(),
      });
      const manifestId = createdRes.rows[0]?.id ?? createdRes.insertId;

      // 8. Insert lines
      await insertLines(runner, {
        manifestId,
        lines: linesToInsert,
        ensureTax,
      });

      // 8b. Create the shipping (carrier) atomically with the shipment. Must run before the
      // summary state ('delivered') is written, as that would block shipping creation.
      await createShipping(googleAuthId, { ...input.shipping, manifestId }, innerTx);

      // 9. Synchronize order/retoure summary row and shipment summary row
      if (order.type === 'retoure') {
        await syncRetoureSummary(runner, { companyId, manifestId: orderId });
      } else {
        await syncOrderSummary(runner, { companyId, manifestId: orderId });
      }
      const validState = input.state && ['new', 'delivered'].includes(String(input.state).trim().toLowerCase())
        ? String(input.state).trim().toLowerCase()
        : 'new';

      await syncShipmentSummary(runner, {
        companyId,
        manifestId,
        orderId,
        orderNumber: order.number,
        state: validState,
      });

      return loadShipment(runner, q, companyId, manifestId);
    };

    if (tx) {
      return run(makeRunner(provider, tx), tx);
    }
    if (typeof provider?.transaction === 'function') {
      return provider.transaction((runner, innerTx) => run(runner, innerTx));
    }
    return run(makeRunner(provider));
  };
}