'use strict';

/**
 * 智能问数 · 指标查询工具
 * ----------------------------------------------------------------------------
 * metric_query：按指标 key 查逐日序列（支持派生指标如 7 日移动平均）。
 * 模型引用指标 key，聚合口径全部由指标层决定——比率加权/比值/移动平均都不许自算。
 * 移动平均窗口取「当日及前 N-1 天内已有数据的天」（缺数日按实算，不插值）。
 */

const metrics = require('../metrics.js');
const { eachDay, ymdDash } = require('./lake.js');

const z2 = (n) => String(n).padStart(2, '0');
function dayShift(ymd, delta) {
  const d = new Date(Number(ymd.slice(0, 4)), Number(ymd.slice(4, 6)) - 1, Number(ymd.slice(6, 8)));
  d.setDate(d.getDate() + delta);
  return `${d.getFullYear()}${z2(d.getMonth() + 1)}${z2(d.getDate())}`;
}

function metricSanitize(args, ctx) {
  const a = args || {};
  const m = metrics.get(String(a.metric || ''));
  if (!m) {
    throw new Error(`未知指标：${a.metric}。可用指标：\n${metrics.manifestText()}`);
  }
  const { shops, dateRange } = ctx;
  const from = /^\d{8}$/.test(String(a.from || '')) ? String(a.from) : dateRange.from;
  const to = /^\d{8}$/.test(String(a.to || '')) ? String(a.to) : dateRange.to;
  let shopIds = null;
  if (Array.isArray(a.shops) && a.shops.length) {
    const nlQuery = require('../../../nl-query.js');
    shopIds = nlQuery.matchShopsByName(shops, a.shops);
    if (!shopIds) throw new Error(`门店名未匹配：${a.shops.join('、')}`);
  }
  return {
    metric: String(a.metric),
    from: from < dateRange.from ? dateRange.from : from,
    to: to > dateRange.to ? dateRange.to : to,
    shopIds,
    window: m.window || 1,
  };
}

function metricHandler(ctx, args) {
  const { svc, entityKey } = ctx;
  const { metric, from, to, shopIds, window } = args;
  const def = metrics.get(metric);
  const reg = new Map((svc.REPORT_COLUMNS || []).map((c) => [c.key, c]));
  const unitFmt = { money: (v) => `${Math.round(v).toLocaleString('zh-CN')}元`, pct: (v) => `${(v * 100).toFixed(2)}%`, int: (v) => String(Math.round(v)) };

  // 派生移动平均需要窗口前置数据：多取 window-1 天
  const leadFrom = window > 1 ? dayShift(from, -(window - 1)) : from;
  let rows = svc.store.queryRows(entityKey, { from: leadFrom, to, scope: 'shop' });
  if (shopIds) {
    const wanted = new Set(shopIds.map(String));
    rows = rows.filter((r) => wanted.has(String(r.shopId)));
  }
  const byDate = new Map();
  for (const r of rows) {
    if (!byDate.has(r.date)) byDate.set(r.date, []);
    byDate.get(r.date).push(r);
  }
  const dayVal = (d) => metrics.dayValue(def.base || metric, byDate.get(d) || []);

  const days = eachDay(from, to);
  const series = [];
  for (const d of days) {
    let value = null;
    if (window > 1) {
      const win = [];
      for (let i = 0; i < window; i++) {
        const v = dayVal(dayShift(d, -i));
        if (v != null) win.push(v);
      }
      value = win.length ? +(win.reduce((s, x) => s + x, 0) / win.length).toFixed(2) : null;
    } else {
      value = dayVal(d);
    }
    series.push({ date: d, value });
  }

  const values = series.map((s) => s.value).filter((v) => v != null);
  const fmt = unitFmt[def.unit] || ((v) => String(v));
  const lines = [`${def.name}（${ymdDash(from)} ~ ${ymdDash(to)}${window > 1 ? `，${window} 日移动平均，缺数日按实算` : ''}）：`];
  for (const s of series) lines.push(`  ${ymdDash(s.date)}：${s.value == null ? '无数据' : fmt(s.value)}`);
  if (values.length) {
    const avg = values.reduce((s, x) => s + x, 0) / values.length;
    lines.push(`区间：均值 ${fmt(+avg.toFixed(2))}，最高 ${fmt(Math.max(...values))}，最低 ${fmt(Math.min(...values))}。`);
  } else {
    lines.push('区间内无数据。');
  }
  return {
    summary: lines.join('\n'),
    data: {
      metric, name: def.name, unit: def.unit, from, to, window,
      series, totalRows: series.length,
      stats: values.length ? { avg: +(values.reduce((s, x) => s + x, 0) / values.length).toFixed(2), max: Math.max(...values), min: Math.min(...values) } : null,
    },
  };
}

module.exports = { metricSanitize, metricHandler };