'use strict';

/**
 * 拣选库位动销分析 —— 业务库取数
 *
 *   库存：rpt.jst_packInventoryInfo 按 wms_co_id + 仓位 汇总 qty（仓位为空的行不参与）
 *   类型：bin_group 为空 → 拣选位；否则取 bin_group（业务库目前只有「存货」）
 *   销量：rpt.jst_Orders × rpt.jst_OrderItem，按 send_date，排除 Delete/Cancelled
 *   分摊：SKU 销量 ÷ 该 SKU 占用的同类型仓位数，再按库位累加
 *         保证「全部库位销量之和 = 全仓销量」
 *   日销：库位销量 / 窗口天数 → 分档得到动销等级
 */

const { PICKING_BIN_GRADE_RULES } = require('../config/pickingBinSalesAnalysis');

/** mssql 不支持数组参数，按位展开成 @p0,@p1... */
function buildInClause(values, prefix) {
  const params = {};
  const clause = values
    .map((v, i) => {
      const key = `${prefix}${i}`;
      params[key] = v;
      return `@${key}`;
    })
    .join(',');
  return { clause, params };
}

/**
 * 日销分档表达式：从高档往低档依次命中，最后一档「销售=0」由 salesQty <= 0 兜底。
 */
function buildGradeCase(salesExpr = 'ISNULL(x.salesQty, 0)', daysParam = '@days') {
  const branches = PICKING_BIN_GRADE_RULES
    .filter((rule) => rule.lower > 0)
    .map((rule) => {
      const daily = `(${salesExpr} / ${daysParam})`;
      const lower = `${daily} >= ${rule.lower}`;
      const upper = rule.upper == null ? null : `${daily} < ${rule.upper}`;
      const cond = upper ? `${lower} AND ${upper}` : lower;
      return `WHEN ${cond} THEN '${rule.key}'`;
    });

  return `
      CASE
        ${branches.join('\n        ')}
        WHEN ${salesExpr} > 0 THEN 'slow2'
        ELSE 'zero'
      END`;
}

/**
 * 拉取各仓库每个仓位的库存、销量、日销与动销等级。
 *
 * @param {object} cloudDb 业务库实例
 * @param {string[]} wmsCoIds 仓库编码
 * @param {{shipFrom:string, shipTo:string, days:number, binTypes?:string[]}} options
 * @returns {Promise<Array<{wmsCoId:string, binName:string, binType:string,
 *   stockQty:number, skuCount:number, salesQty:number, dailySales:number, gradeKey:string}>>}
 */
async function fetchPickingBinRows(cloudDb, wmsCoIds, options = {}) {
  if (!cloudDb || typeof cloudDb.query !== 'function') {
    throw new TypeError('fetchPickingBinRows 的第一个参数必须是业务库实例');
  }
  const { shipFrom, shipTo, days, binTypes } = options;
  if (!Array.isArray(wmsCoIds) || wmsCoIds.length === 0) return [];
  if (!shipFrom || !shipTo || !days) return [];

  const binIn = buildInClause(wmsCoIds, 'w');
  const shipIn = buildInClause(wmsCoIds, 'v');
  const gradeCase = buildGradeCase();

  // 仓位类型过滤（不传 = 全部类型）
  let typeFilter = '';
  const typeParams = {};
  if (Array.isArray(binTypes) && binTypes.length > 0) {
    const t = buildInClause(binTypes, 't');
    Object.assign(typeParams, t.params);
    typeFilter = `AND a.binType IN (${t.clause})`;
  }

  const sqlText = `
    WITH bin AS (
      SELECT p.wms_co_id AS wmsCoId,
             LTRIM(RTRIM(p.bin)) AS binName,
             CASE WHEN ISNULL(p.bin_group, '') = '' THEN N'${'拣选'}'
                  ELSE LTRIM(RTRIM(p.bin_group)) END AS binType,
             p.sku_id AS skuId,
             SUM(CAST(ISNULL(p.qty, 0) AS DECIMAL(18, 2))) AS binSkuQty
        FROM rpt.jst_packInventoryInfo p
       WHERE p.wms_co_id IN (${binIn.clause})
         AND ISNULL(p.bin, '') <> ''
         AND ISNULL(p.qty, 0) <> 0
       GROUP BY p.wms_co_id,
                LTRIM(RTRIM(p.bin)),
                CASE WHEN ISNULL(p.bin_group, '') = '' THEN N'${'拣选'}'
                     ELSE LTRIM(RTRIM(p.bin_group)) END,
                p.sku_id
    ),
    binSpan AS (
      SELECT wmsCoId, skuId, binType, COUNT(DISTINCT binName) AS binCount
        FROM bin
       GROUP BY wmsCoId, skuId, binType
    ),
    ship AS (
      SELECT o.wms_co_id AS wmsCoId,
             oi.sku_id   AS skuId,
             SUM(CAST(ISNULL(oi.qty, 0) AS DECIMAL(18, 2))) AS salesQty
        FROM rpt.jst_OrderItem oi
        JOIN rpt.jst_Orders o ON o.o_id = oi.o_id
       WHERE o.wms_co_id IN (${shipIn.clause})
         AND o.send_date >= @shipFrom
         AND o.send_date < @shipTo
         AND ISNULL(o.status, '') NOT IN ('Delete', 'Cancelled')
       GROUP BY o.wms_co_id, oi.sku_id
    ),
    binSales AS (
      SELECT b.wmsCoId,
             b.binName,
             b.binType,
             SUM(CAST(ISNULL(s.salesQty, 0) AS DECIMAL(18, 4)) / NULLIF(sp.binCount, 0)) AS salesQty
        FROM bin b
        JOIN binSpan sp
          ON sp.wmsCoId = b.wmsCoId AND sp.skuId = b.skuId AND sp.binType = b.binType
        LEFT JOIN ship s
          ON s.wmsCoId = b.wmsCoId AND s.skuId = b.skuId
       GROUP BY b.wmsCoId, b.binName, b.binType
    ),
    binAgg AS (
      SELECT wmsCoId,
             binName,
             binType,
             SUM(binSkuQty) AS stockQty,
             COUNT(DISTINCT skuId) AS skuCount
        FROM bin
       GROUP BY wmsCoId, binName, binType
    )
    SELECT a.wmsCoId,
           a.binName,
           a.binType,
           CAST(a.stockQty AS DECIMAL(18, 2))                     AS stockQty,
           CAST(a.skuCount AS INT)                                AS skuCount,
           CAST(ISNULL(x.salesQty, 0) AS DECIMAL(18, 2))          AS salesQty,
           CAST(ISNULL(x.salesQty, 0) / @days AS DECIMAL(18, 4))  AS dailySales,
           ${gradeCase}                                           AS gradeKey
      FROM binAgg a
      LEFT JOIN binSales x
        ON x.wmsCoId = a.wmsCoId AND x.binName = a.binName AND x.binType = a.binType
     WHERE ABS(ISNULL(a.stockQty, 0)) > 0.0001
       ${typeFilter}
     ORDER BY a.wmsCoId, a.binType, a.binName`;

  const rows = await cloudDb.query(
    sqlText,
    {
      ...binIn.params,
      ...shipIn.params,
      ...typeParams,
      shipFrom,
      shipTo,
      days,
    },
    { requestTimeout: 120000 }
  );

  return rows.map((r) => ({
    wmsCoId: String(r.wmsCoId),
    binName: r.binName || '',
    binType: r.binType || '',
    stockQty: Number(r.stockQty) || 0,
    skuCount: Number(r.skuCount) || 0,
    salesQty: Number(r.salesQty) || 0,
    dailySales: Number(r.dailySales) || 0,
    gradeKey: r.gradeKey || 'zero',
  }));
}

module.exports = {
  buildGradeCase,
  buildInClause,
  fetchPickingBinRows,
};