feat: Implement Day End Report feature logic

Distribution/Features/DayEndReport/DayEndReportService.cs

@@ -0,0 +1,96 @@
+using Distribution.Models;
+
+namespace Distribution.Features.DayEndReport;
+
+public class DayEndReportService(IDayEndReportRepository repo)
+{
+    public const int MaxRangeDays = 92;
+
+    public static DayEndFilter BuildFilter(DateTime? from, DateTime? to)
+    {
+        var end = (to ?? DateTime.Now).Date;
+        var start = (from ?? end.AddDays(-29)).Date;
+        return new DayEndFilter(start, end);
+    }
+
+    public static string? Validate(DayEndFilter f)
+    {
+        if (f.To < f.From) return "'to' must not be before 'from'.";
+        if ((f.To - f.From).TotalDays >= MaxRangeDays) return $"Date range cannot exceed {MaxRangeDays} days.";
+        return null;
+    }
+
+    public async Task<DayEndResponse> GetDayAsync(DateTime date)
+    {
+        var day = date.Date;
+        var data = await repo.GetDataAsync(new DayEndFilter(day, day));
+        var row = BuildRow(day, data);
+
+        var payments = data.Payments.Where(p => p.CollectedAt.Date == day).ToList();
+        var byMethod = Enum.GetValues<PaymentMethod>().Select(m =>
+        {
+            var rows = payments.Where(p => p.Method == m).ToList();
+            return new DayEndMethod(m.ToString(), rows.Count, rows.Sum(p => p.Amount));
+        }).ToList();
+
+        var expenses = data.Expenses
+            .Where(e => e.BillDate.Date == day)
+            .Select(e => new DayEndExpense(e.Id, e.Category, e.Payee, e.Description, e.Method?.ToString(), e.Amount))
+            .ToList();
+
+        return new DayEndResponse(row.Date, row, byMethod, expenses);
+    }
+
+    public async Task<DayEndDailyResponse> GetDailyAsync(DayEndFilter f)
+    {
+        var data = await repo.GetDataAsync(f);
+        var days = new List<DayEndRow>();
+        for (var d = f.From.Date; d <= f.To.Date; d = d.AddDays(1))
+            days.Add(BuildRow(d, data));
+
+        var totals = new DayEndRow(
+            "Total",
+            days.Sum(r => r.TotalSales), days.Sum(r => r.Collected), days.Sum(r => r.Due),
+            days.Sum(r => r.Cash), days.Sum(r => r.Cheque), days.Sum(r => r.Credit),
+            days.Sum(r => r.Returns), days.Sum(r => r.Expenses), days.Sum(r => r.Income),
+            days.Sum(r => r.InvoiceCount), days.Sum(r => r.PaymentCount),
+            days.Sum(r => r.CashCollected), days.Sum(r => r.CashExpensesPaid), days.Sum(r => r.NetCash));
+
+        return new DayEndDailyResponse(f.From, f.To, days, totals);
+    }
+
+    // Accrual basis: Income = sales (finalized invoices) - returns - expenses billed that day.
+    // Due is the unpaid part of that day's invoices as at the end of the day; Credit payments never count as paid.
+    private static DayEndRow BuildRow(DateTime day, DayEndData data)
+    {
+        var next = day.AddDays(1);
+
+        var invoices = data.Invoices.Where(i => i.FinalizedAt.Date == day).ToList();
+        var invoiceIds = invoices.Select(i => i.Id).ToHashSet();
+        var paidByInvoice = data.Payments
+            .Where(p => invoiceIds.Contains(p.InvoiceId) && p.Method != PaymentMethod.Credit && p.CollectedAt < next)
+            .GroupBy(p => p.InvoiceId)
+            .ToDictionary(g => g.Key, g => g.Sum(p => p.Amount));
+
+        var totalSales = invoices.Sum(i => i.Total);
+        var due = invoices.Sum(i => Math.Max(0m, i.Total - paidByInvoice.GetValueOrDefault(i.Id)));
+
+        var payments = data.Payments.Where(p => p.CollectedAt.Date == day).ToList();
+        var cash = payments.Where(p => p.Method == PaymentMethod.Cash).Sum(p => p.Amount);
+        var cheque = payments.Where(p => p.Method == PaymentMethod.Cheque).Sum(p => p.Amount);
+        var credit = payments.Where(p => p.Method == PaymentMethod.Credit).Sum(p => p.Amount);
+
+        var returns = data.Returns.Where(r => r.At.Date == day).Sum(r => r.Amount);
+        var expenses = data.Expenses.Where(e => e.BillDate.Date == day).Sum(e => e.Amount);
+        var cashExpensesPaid = data.Expenses
+            .Where(e => e.Method == PaymentMethod.Cash && e.PaidAt.HasValue && e.PaidAt.Value.Date == day)
+            .Sum(e => e.Amount);
+
+        return new DayEndRow(
+            day.ToString("yyyy-MM-dd"),
+            totalSales, cash + cheque, due, cash, cheque, credit,
+            returns, expenses, totalSales - returns - expenses,
+            invoices.Count, payments.Count,
+            cash, cashExpensesPaid, cash - cashExpensesPaid);
+    }
+}