feat(reports): отчёт «Прибыль» (выручка − COGS) (P1-10)

GET /api/reports/profit с группировками period:day/week/month, product,
group (по группе товаров). Cost-snapshot — Product.Cost (скользящее
среднее, документировано как приближение; точный FIFO требует партий).
Маржа = profit/revenue·100. Защита от деления на ноль при нулевой
выручке (пустой период → margin = 0, не NaN).

Возвраты вычитаются и из выручки, и из COGS (returned line делает
−Quantity·UnitPrice выручки и −Quantity·Cost себестоимости).

Export CSV/XLSX через тот же ReportExport.

Web: /reports/profit с KPI-плашками (общая выручка/себестоимость/прибыль
+ маржа) — прибыль зелёным/красным в зависимости от знака.

Тесты: 3 интеграционных (simple profit calc 4×100−4×50=200=50%; empty
period → пустой набор без 500/NaN; tenant-изоляция).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/food-market.api/Controllers/Reports/ProfitReportController.cs

@@ -0,0 +1,173 @@
+using System.Globalization;
+using foodmarket.Domain.Inventory;
+using foodmarket.Domain.Sales;
+using foodmarket.Infrastructure.Persistence;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+
+namespace foodmarket.Api.Controllers.Reports;
+
+/// <summary>Отчёт «Прибыль».
+///
+/// Выручка − себестоимость, маржа, рентабельность по периодам / товарам /
+/// группам товаров. Cost-snapshot берётся из <see cref="StockMovement.UnitCost"/>
+/// сопоставленного по (documentId, productId): движение тип `RetailSale`
+/// или `CustomerReturn` несёт UnitCost = `RetailSaleLine.UnitPrice`… НО для
+/// расчёта прибыли нам нужна СЕБЕСТОИМОСТЬ, а не цена продажи. Поэтому
+/// фактически берём `Product.Cost` (текущее скользящее среднее) как
+/// COGS-snapshot — это приближение; точный COGS требует партий или
+/// fetch'а на момент продажи. Документируем как компромисс.
+///
+/// Multi-tenant: query-filter работает прозрачно.</summary>
+[ApiController]
+[Authorize]
+[Route("api/reports/profit")]
+public class ProfitReportController : ControllerBase
+{
+    private readonly AppDbContext _db;
+    public ProfitReportController(AppDbContext db) => _db = db;
+
+    public record ProfitRow(
+        string Key, string Label,
+        decimal Revenue, decimal Cost, decimal Profit,
+        decimal MarginPercent, decimal Quantity);
+
+    private record FlatRow(
+        Guid SaleId, DateTime Date,
+        Guid ProductId, string ProductName, string? ProductArticle,
+        Guid? ProductGroupId, string? ProductGroupName,
+        decimal Revenue, decimal Cost, decimal Quantity);
+
+    [HttpGet]
+    public async Task<ActionResult<IReadOnlyList<ProfitRow>>> Get(
+        [FromQuery] DateTime? from,
+        [FromQuery] DateTime? to,
+        [FromQuery] string groupBy = "period:day",
+        [FromQuery] Guid? storeId = null,
+        [FromQuery] Guid? productGroupId = null,
+        CancellationToken ct = default)
+    {
+        var range = ResolveRange(from, to);
+        var flat = await FetchAsync(range, storeId, productGroupId, ct);
+        return Ok(Group(flat, groupBy));
+    }
+
+    [HttpGet("export")]
+    public async Task<IActionResult> Export(
+        [FromQuery] DateTime? from,
+        [FromQuery] DateTime? to,
+        [FromQuery] string groupBy = "period:day",
+        [FromQuery] Guid? storeId = null,
+        [FromQuery] Guid? productGroupId = null,
+        [FromQuery] string format = "csv",
+        CancellationToken ct = default)
+    {
+        var range = ResolveRange(from, to);
+        var flat = await FetchAsync(range, storeId, productGroupId, ct);
+        var rows = Group(flat, groupBy);
+        var name = $"profit-{groupBy.Replace(':', '-')}-{range.From:yyyyMMdd}-{range.To:yyyyMMdd}";
+        var headers = new[] { "Ключ", "Группа", "Выручка", "Себестоимость", "Прибыль", "Маржа,%", "Количество" };
+        return format.ToLower() switch
+        {
+            "xlsx" => ReportExport.Xlsx(rows, name, "Profit", headers),
+            _      => ReportExport.Csv(rows, name, headers),
+        };
+    }
+
+    private static DateRange ResolveRange(DateTime? from, DateTime? to)
+    {
+        var t = to ?? DateTime.UtcNow;
+        var f = from ?? t.AddDays(-30);
+        return new DateRange(f, t);
+    }
+
+    private async Task<List<FlatRow>> FetchAsync(
+        DateRange range, Guid? storeId, Guid? productGroupId, CancellationToken ct)
+    {
+        // Берём строки проведённых чеков с присоединённым Product (для Cost-snapshot
+        // и группы) и ProductGroup (для имени). Возврат вычитается из выручки и
+        // из COGS (продали по цене X с себестоимостью C → returned восстанавливает).
+        var q = from l in _db.RetailSaleLines.AsNoTracking()
+                join s in _db.RetailSales.AsNoTracking() on l.RetailSaleId equals s.Id
+                join p in _db.Products.AsNoTracking() on l.ProductId equals p.Id
+                where s.Status == RetailSaleStatus.Posted
+                      && s.Date >= range.From && s.Date <= range.To
+                select new { l, s, p };
+
+        if (storeId is not null) q = q.Where(x => x.s.StoreId == storeId);
+        if (productGroupId is not null) q = q.Where(x => x.p.ProductGroupId == productGroupId);
+
+        var flat = await q
+            .Select(x => new FlatRow(
+                x.s.Id, x.s.Date,
+                x.l.ProductId, x.p.Name, x.p.Article,
+                x.p.ProductGroupId,
+                x.p.ProductGroupId == null ? null
+                    : _db.ProductGroups.Where(g => g.Id == x.p.ProductGroupId).Select(g => g.Name).FirstOrDefault(),
+                x.s.IsReturn ? -x.l.LineTotal : x.l.LineTotal,
+                // COGS-snapshot: Quantity × Product.Cost (текущее скользящее среднее).
+                // Документировано как приближение; точный COGS требует партий.
+                (x.s.IsReturn ? -x.l.Quantity : x.l.Quantity) * x.p.Cost,
+                x.s.IsReturn ? -x.l.Quantity : x.l.Quantity))
+            .ToListAsync(ct);
+
+        return flat;
+    }
+
+    private static List<ProfitRow> Group(List<FlatRow> flat, string groupBy)
+    {
+        IEnumerable<IGrouping<(string Key, string Label), FlatRow>> grouped;
+        switch (groupBy)
+        {
+            case "period:day":
+                grouped = flat.GroupBy(x => (
+                    Key: x.Date.ToString("yyyy-MM-dd", CultureInfo.InvariantCulture),
+                    Label: x.Date.ToString("yyyy-MM-dd", CultureInfo.InvariantCulture)));
+                break;
+            case "period:week":
+                var cal = CultureInfo.InvariantCulture.Calendar;
+                grouped = flat.GroupBy(x =>
+                {
+                    var w = cal.GetWeekOfYear(x.Date, CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday);
+                    return (Key: $"{x.Date.Year:0000}-W{w:00}", Label: $"{x.Date.Year:0000} нед. {w:00}");
+                });
+                break;
+            case "period:month":
+                grouped = flat.GroupBy(x => (
+                    Key: $"{x.Date.Year:0000}-{x.Date.Month:00}",
+                    Label: $"{x.Date.Year:0000}-{x.Date.Month:00}"));
+                break;
+            case "product":
+                grouped = flat.GroupBy(x => (
+                    Key: x.ProductId.ToString(),
+                    Label: x.ProductName + (x.ProductArticle is not null ? " · " + x.ProductArticle : "")));
+                break;
+            case "group":
+                grouped = flat.GroupBy(x => (
+                    Key: (x.ProductGroupId ?? Guid.Empty).ToString(),
+                    Label: string.IsNullOrEmpty(x.ProductGroupName) ? "Без группы" : x.ProductGroupName));
+                break;
+            default:
+                return new();
+        }
+
+        return grouped
+            .Select(g =>
+            {
+                var revenue = g.Sum(x => x.Revenue);
+                var cost = g.Sum(x => x.Cost);
+                var profit = revenue - cost;
+                // Защита от деления на ноль: при нулевой выручке маржа = 0
+                // (а не NaN/Infinity). Бывает при чисто возвратных периодах,
+                // когда продажи отсутствуют.
+                var margin = revenue == 0m ? 0m : Math.Round(profit / revenue * 100m, 2);
+                return new ProfitRow(
+                    g.Key.Key, g.Key.Label,
+                    revenue, cost, profit, margin,
+                    g.Sum(x => x.Quantity));
+            })
+            .OrderByDescending(r => r.Profit)
+            .ToList();
+    }
+}

src/food-market.web/src/App.tsx

@@ -40,6 +40,7 @@ import { SupplierReturnsPage } from '@/pages/SupplierReturnsPage'
 import { SupplierReturnEditPage } from '@/pages/SupplierReturnEditPage'
 import { SalesReportPage } from '@/pages/SalesReportPage'
 import { StockReportPage } from '@/pages/StockReportPage'
+import { ProfitReportPage } from '@/pages/ProfitReportPage'
 import { RetailSalesPage } from '@/pages/RetailSalesPage'
 import { RetailSaleEditPage } from '@/pages/RetailSaleEditPage'
 import { AppLayout } from '@/components/AppLayout'
@@ -129,6 +130,7 @@ export default function App() {
               <Route path="/purchases/supplier-returns/:id" element={<SupplierReturnEditPage />} />
               <Route path="/reports/sales" element={<SalesReportPage />} />
               <Route path="/reports/stock" element={<StockReportPage />} />
+              <Route path="/reports/profit" element={<ProfitReportPage />} />
               <Route path="/sales/retail" element={<RetailSalesPage />} />
               <Route path="/sales/retail/new" element={<RetailSaleEditPage />} />
               <Route path="/sales/retail/:id" element={<RetailSaleEditPage />} />

src/food-market.web/src/components/AppLayout.tsx

@@ -7,7 +7,7 @@ import { cn } from '@/lib/utils'
 import {
   LayoutDashboard, Package, FolderTree, Ruler, Tag,
   Users, Warehouse, Store as StoreIcon, LogOut, Download, UserCog, Shield, ShieldCheck,
-  Boxes, History, TruckIcon, ShoppingCart, Settings, Menu, X, PackagePlus, PackageMinus, ArrowRightLeft, ClipboardCheck, Undo2, BarChart3,
+  Boxes, History, TruckIcon, ShoppingCart, Settings, Menu, X, PackagePlus, PackageMinus, ArrowRightLeft, ClipboardCheck, Undo2, BarChart3, TrendingUp,
 } from 'lucide-react'
 import { Logo } from './Logo'
 import { SuperAdminAsOrgBanner } from './SuperAdminAsOrgBanner'
@@ -113,6 +113,7 @@ function buildNav(roles: string[]): NavSection[] {
     sections.push({ group: 'Отчёты', items: [
       { to: '/reports/sales', icon: BarChart3, label: 'Продажи' },
       { to: '/reports/stock', icon: Boxes, label: 'Остатки на дату' },
+      { to: '/reports/profit', icon: TrendingUp, label: 'Прибыль' },
     ]})
   }
 

src/food-market.web/src/pages/ProfitReportPage.tsx

@@ -0,0 +1,177 @@
+import { useState } from 'react'
+import { useQuery } from '@tanstack/react-query'
+import { Download } from 'lucide-react'
+import { api } from '@/lib/api'
+import { Button } from '@/components/Button'
+import { Field, Select } from '@/components/Field'
+import { DateField } from '@/components/DateField'
+import { useStores, useProductGroups } from '@/lib/useLookups'
+import { useOrgSettings } from '@/lib/useOrgSettings'
+import { type ProfitReportRow } from '@/lib/types'
+
+const GROUPS = [
+  { value: 'period:day',   label: 'По дням' },
+  { value: 'period:week',  label: 'По неделям' },
+  { value: 'period:month', label: 'По месяцам' },
+  { value: 'product',      label: 'По товарам' },
+  { value: 'group',        label: 'По группам товаров' },
+] as const
+
+export function ProfitReportPage() {
+  const todayIso = () => new Date().toISOString().slice(0, 10)
+  const monthAgoIso = () => {
+    const d = new Date(); d.setDate(d.getDate() - 30)
+    return d.toISOString().slice(0, 10)
+  }
+
+  const [from, setFrom] = useState<string>(monthAgoIso())
+  const [to, setTo] = useState<string>(todayIso())
+  const [groupBy, setGroupBy] = useState<string>('period:day')
+  const [storeId, setStoreId] = useState<string>('')
+  const [productGroupId, setProductGroupId] = useState<string>('')
+
+  const stores = useStores()
+  const groups = useProductGroups()
+  const org = useOrgSettings()
+  const fractional = org.data?.allowFractionalPrices ?? false
+  const moneyFmt = fractional
+    ? { minimumFractionDigits: 2, maximumFractionDigits: 2 }
+    : { maximumFractionDigits: 0 }
+
+  const params = (extra: Record<string, string> = {}) => {
+    const p = new URLSearchParams({
+      from: new Date(from).toISOString(),
+      to: new Date(`${to}T23:59:59`).toISOString(),
+      groupBy,
+      ...extra,
+    })
+    if (storeId) p.set('storeId', storeId)
+    if (productGroupId) p.set('productGroupId', productGroupId)
+    return p
+  }
+
+  const rep = useQuery({
+    queryKey: ['profit-report', from, to, groupBy, storeId, productGroupId],
+    queryFn: async () => (await api.get<ProfitReportRow[]>(`/api/reports/profit?${params()}`)).data,
+  })
+
+  const exportFile = async (format: 'csv' | 'xlsx') => {
+    const resp = await api.get(`/api/reports/profit/export?${params({ format })}`, { responseType: 'blob' })
+    const blob = new Blob([resp.data])
+    const url = URL.createObjectURL(blob)
+    const a = document.createElement('a')
+    a.href = url
+    const cd = resp.headers['content-disposition'] as string | undefined
+    const match = cd?.match(/filename="?([^";]+)"?/i)
+    a.download = match?.[1] ?? `profit-report.${format}`
+    document.body.appendChild(a)
+    a.click()
+    a.remove()
+    URL.revokeObjectURL(url)
+  }
+
+  const totalRev = rep.data?.reduce((s, r) => s + r.revenue, 0) ?? 0
+  const totalCost = rep.data?.reduce((s, r) => s + r.cost, 0) ?? 0
+  const totalProf = totalRev - totalCost
+  const totalMargin = totalRev === 0 ? 0 : Math.round((totalProf / totalRev) * 10000) / 100
+
+  return (
+    <div className="flex flex-col h-full">
+      <div className="px-6 py-4 border-b border-slate-200 dark:border-slate-800 bg-white dark:bg-slate-900">
+        <h1 className="text-lg font-semibold text-slate-900 dark:text-slate-100">Отчёт «Прибыль»</h1>
+        <p className="text-xs text-slate-500 mt-1">
+          Выручка − себестоимость = прибыль. COGS-snapshot — Product.Cost
+          (скользящее среднее на момент запроса; приближённая оценка).
+        </p>
+      </div>
+      <div className="flex-1 overflow-auto">
+        <div className="max-w-6xl mx-auto p-3 sm:p-6 space-y-4">
+          <section className="bg-white dark:bg-slate-900 rounded-lg border border-slate-200 dark:border-slate-800 p-4">
+            <div className="grid grid-cols-1 md:grid-cols-5 gap-x-4 gap-y-3 items-end">
+              <Field label="От">
+                <DateField value={from} onChange={(v) => setFrom(v ?? todayIso())} />
+              </Field>
+              <Field label="До">
+                <DateField value={to} onChange={(v) => setTo(v ?? todayIso())} />
+              </Field>
+              <Field label="Группировка">
+                <Select value={groupBy} onChange={(e) => setGroupBy(e.target.value)}>
+                  {GROUPS.map((g) => <option key={g.value} value={g.value}>{g.label}</option>)}
+                </Select>
+              </Field>
+              <Field label="Склад">
+                <Select value={storeId} onChange={(e) => setStoreId(e.target.value)}>
+                  <option value="">Все</option>
+                  {stores.data?.map((s) => <option key={s.id} value={s.id}>{s.name}</option>)}
+                </Select>
+              </Field>
+              <Field label="Группа товаров">
+                <Select value={productGroupId} onChange={(e) => setProductGroupId(e.target.value)}>
+                  <option value="">Все</option>
+                  {groups.data?.map((g) => <option key={g.id} value={g.id}>{g.name}</option>)}
+                </Select>
+              </Field>
+            </div>
+            <div className="mt-4 flex flex-wrap gap-3 items-center justify-between">
+              <div className="flex gap-2 text-sm">
+                <span className="px-3 py-1.5 rounded bg-slate-50 dark:bg-slate-800/60">
+                  Выручка: <span className="font-mono font-semibold">{totalRev.toLocaleString('ru', moneyFmt)}</span>
+                </span>
+                <span className="px-3 py-1.5 rounded bg-slate-50 dark:bg-slate-800/60">
+                  Себестоимость: <span className="font-mono font-semibold">{totalCost.toLocaleString('ru', moneyFmt)}</span>
+                </span>
+                <span className={`px-3 py-1.5 rounded font-semibold ${totalProf >= 0 ? 'bg-green-50 text-green-700' : 'bg-red-50 text-red-700'}`}>
+                  Прибыль: <span className="font-mono">{totalProf.toLocaleString('ru', moneyFmt)}</span>
+                  <span className="ml-2 text-xs">({totalMargin.toFixed(2)}%)</span>
+                </span>
+              </div>
+              <div className="flex gap-2">
+                <Button type="button" variant="secondary" size="sm" onClick={() => exportFile('csv')}>
+                  <Download className="w-4 h-4" /> CSV
+                </Button>
+                <Button type="button" variant="secondary" size="sm" onClick={() => exportFile('xlsx')}>
+                  <Download className="w-4 h-4" /> XLSX
+                </Button>
+              </div>
+            </div>
+          </section>
+
+          <section className="bg-white dark:bg-slate-900 rounded-lg border border-slate-200 dark:border-slate-800 p-4">
+            {rep.isLoading && <div className="text-sm text-slate-500 py-6 text-center">Загружаю…</div>}
+            {!rep.isLoading && (rep.data?.length ?? 0) === 0 && (
+              <div className="text-sm text-slate-500 py-6 text-center">За период нет данных.</div>
+            )}
+            {!rep.isLoading && rep.data && rep.data.length > 0 && (
+              <div className="overflow-x-auto">
+                <table className="w-full text-sm">
+                  <thead className="text-left">
+                    <tr className="border-b border-slate-200 dark:border-slate-700">
+                      <th className="py-2 pr-3 font-medium text-xs uppercase text-slate-500">Группа</th>
+                      <th className="py-2 px-3 font-medium text-xs uppercase text-slate-500 w-[130px] text-right">Выручка</th>
+                      <th className="py-2 px-3 font-medium text-xs uppercase text-slate-500 w-[130px] text-right">Себест.</th>
+                      <th className="py-2 px-3 font-medium text-xs uppercase text-slate-500 w-[130px] text-right">Прибыль</th>
+                      <th className="py-2 px-3 font-medium text-xs uppercase text-slate-500 w-[110px] text-right">Маржа,%</th>
+                      <th className="py-2 px-3 font-medium text-xs uppercase text-slate-500 w-[120px] text-right">Кол-во</th>
+                    </tr>
+                  </thead>
+                  <tbody>
+                    {rep.data.map((r) => (
+                      <tr key={r.key} className="border-b border-slate-100 dark:border-slate-800 hover:bg-slate-50 dark:hover:bg-slate-800/30">
+                        <td className="py-2 pr-3">{r.label}</td>
+                        <td className="py-2 px-3 text-right font-mono">{r.revenue.toLocaleString('ru', moneyFmt)}</td>
+                        <td className="py-2 px-3 text-right font-mono text-slate-500">{r.cost.toLocaleString('ru', moneyFmt)}</td>
+                        <td className={`py-2 px-3 text-right font-mono ${r.profit >= 0 ? 'text-green-700' : 'text-red-700'}`}>{r.profit.toLocaleString('ru', moneyFmt)}</td>
+                        <td className="py-2 px-3 text-right font-mono">{r.marginPercent.toFixed(2)}</td>
+                        <td className="py-2 px-3 text-right font-mono text-slate-500">{r.quantity.toLocaleString('ru')}</td>
+                      </tr>
+                    ))}
+                  </tbody>
+                </table>
+              </div>
+            )}
+          </section>
+        </div>
+      </div>
+    </div>
+  )
+}

tests/food-market.IntegrationTests/ProfitReportTests.cs

@@ -0,0 +1,98 @@
+using System.Net.Http.Json;
+using System.Text.Json;
+using FluentAssertions;
+using foodmarket.IntegrationTests.Support;
+using Xunit;
+
+namespace foodmarket.IntegrationTests;
+
+[Collection(ApiCollection.Name)]
+public class ProfitReportTests
+{
+    private readonly ApiFactory _factory;
+    public ProfitReportTests(ApiFactory factory) => _factory = factory;
+    private static string RandomBarcode()
+        => string.Concat(Enumerable.Range(0, 13).Select(_ => Random.Shared.Next(0, 10)));
+
+    /// <summary>Купили 10 шт по 50 (cost после Supply post = 50), продали 4 шт по
+    /// 100. Прибыль = 400 − 200 = 200, маржа = 50%.</summary>
+    [Fact]
+    public async Task Profit_simple_supply_sale()
+    {
+        var api = new ApiActor(_factory.CreateClient());
+        await api.SignupAndLoginAsync($"prft-{Guid.NewGuid():N}");
+        var refs = await api.LoadRefsAsync();
+        var supplierId = await api.CreateCounterpartyAsync($"S-{Guid.NewGuid():N}");
+        var p1 = await api.CreateProductAsync(refs, $"P-{Guid.NewGuid():N}", 100m, RandomBarcode());
+
+        // Приёмка: 10 шт по 50.
+        var sup = await api.Http.PostAsJsonAsync("/api/purchases/supplies", new {
+            date = DateTime.UtcNow, supplierId, storeId = refs.StoreId, currencyId = refs.CurrencyId,
+            notes = "init", lines = new[] { new { productId = p1, quantity = 10m, unitPrice = 50m } } });
+        sup.EnsureSuccessStatusCode();
+        var supId = (await sup.Content.ReadFromJsonAsync<JsonElement>()).GetProperty("id").GetString();
+        (await api.Http.PostAsJsonAsync($"/api/purchases/supplies/{supId}/post", new { })).EnsureSuccessStatusCode();
+
+        // Продажа: 4 шт по 100.
+        var sale = await api.Http.PostAsJsonAsync("/api/sales/retail", new {
+            date = DateTime.UtcNow, storeId = refs.StoreId, retailPointId = (string?)null,
+            customerId = (string?)null, currencyId = refs.CurrencyId, payment = 0, paidCash = 400m, paidCard = 0m,
+            lines = new[] { new { productId = p1, quantity = 4m, unitPrice = 100m, discount = 0m, vatPercent = 12m } },
+            notes = "sale" });
+        sale.EnsureSuccessStatusCode();
+        var sid = (await sale.Content.ReadFromJsonAsync<JsonElement>()).GetProperty("id").GetString();
+        (await api.Http.PostAsJsonAsync($"/api/sales/retail/{sid}/post", new { })).EnsureSuccessStatusCode();
+
+        var rep = await api.GetJsonAsync("/api/reports/profit?groupBy=product");
+        var r = rep.EnumerateArray().First(x => x.GetProperty("key").GetString() == p1);
+        r.GetProperty("revenue").GetDecimal().Should().Be(400m);
+        r.GetProperty("cost").GetDecimal().Should().Be(200m);
+        r.GetProperty("profit").GetDecimal().Should().Be(200m);
+        r.GetProperty("marginPercent").GetDecimal().Should().Be(50m);
+    }
+
+    /// <summary>Защита от деления на ноль: при нулевой выручке (продажи=0) margin=0,
+    /// а не NaN/Infinity. Проверяем что хотя бы пустой набор возвращается без 500.</summary>
+    [Fact]
+    public async Task Empty_period_returns_no_rows_no_division_by_zero()
+    {
+        var api = new ApiActor(_factory.CreateClient());
+        await api.SignupAndLoginAsync($"prft-emp-{Guid.NewGuid():N}");
+
+        var pastFrom = DateTime.UtcNow.AddYears(-5).ToString("o");
+        var pastTo = DateTime.UtcNow.AddYears(-4).ToString("o");
+        var rep = await api.GetJsonAsync($"/api/reports/profit?groupBy=product&from={Uri.EscapeDataString(pastFrom)}&to={Uri.EscapeDataString(pastTo)}");
+        rep.EnumerateArray().Should().BeEmpty();
+    }
+
+    [Fact]
+    public async Task Tenant_isolation_profit()
+    {
+        var a = new ApiActor(_factory.CreateClient());
+        var b = new ApiActor(_factory.CreateClient());
+        await a.SignupAndLoginAsync($"prft-iso-a-{Guid.NewGuid():N}");
+        await b.SignupAndLoginAsync($"prft-iso-b-{Guid.NewGuid():N}");
+        var refsA = await a.LoadRefsAsync();
+        var supplierA = await a.CreateCounterpartyAsync($"S-{Guid.NewGuid():N}");
+        var pA = await a.CreateProductAsync(refsA, $"PA-{Guid.NewGuid():N}", 100m, RandomBarcode());
+
+        var sup = await a.Http.PostAsJsonAsync("/api/purchases/supplies", new {
+            date = DateTime.UtcNow, supplierId = supplierA, storeId = refsA.StoreId, currencyId = refsA.CurrencyId,
+            notes = "init", lines = new[] { new { productId = pA, quantity = 5m, unitPrice = 20m } } });
+        sup.EnsureSuccessStatusCode();
+        var supId = (await sup.Content.ReadFromJsonAsync<JsonElement>()).GetProperty("id").GetString();
+        (await a.Http.PostAsJsonAsync($"/api/purchases/supplies/{supId}/post", new { })).EnsureSuccessStatusCode();
+
+        var sale = await a.Http.PostAsJsonAsync("/api/sales/retail", new {
+            date = DateTime.UtcNow, storeId = refsA.StoreId, retailPointId = (string?)null,
+            customerId = (string?)null, currencyId = refsA.CurrencyId, payment = 0, paidCash = 100m, paidCard = 0m,
+            lines = new[] { new { productId = pA, quantity = 1m, unitPrice = 100m, discount = 0m, vatPercent = 12m } },
+            notes = "sale" });
+        sale.EnsureSuccessStatusCode();
+        var sid = (await sale.Content.ReadFromJsonAsync<JsonElement>()).GetProperty("id").GetString();
+        (await a.Http.PostAsJsonAsync($"/api/sales/retail/{sid}/post", new { })).EnsureSuccessStatusCode();
+
+        var repB = await b.GetJsonAsync("/api/reports/profit?groupBy=product");
+        repB.EnumerateArray().Should().NotContain(x => x.GetProperty("key").GetString() == pA);
+    }
+}