Distribution/Features/Store/IStoreRepository.cs

@@ -13,4 +13,5 @@ public interface IStoreRepository
     void Update(Models.Store entity);
     void Remove(Models.Store entity);
     Task<List<Models.ShopPO>> GetOrdersForDashboardAsync(Guid storeId, DateTime periodStart, DateTime periodEndExclusive);
+    Task<List<Models.Invoice>> GetInvoicesForAnalyticsAsync(Guid storeId);
 }

Distribution/Features/Store/StoreController.cs

@@ -92,6 +92,13 @@ public class StoreController(StoreService service) : ControllerBase
         return result is null ? NotFound() : Ok(result);
     }
 
+    [HttpGet("{id:guid}/analytics")]
+    public async Task<IActionResult> GetAnalytics(Guid id, [FromQuery] int months = 12, [FromQuery] int overdueDays = 30)
+    {
+        var result = await service.GetAnalyticsAsync(id, months, overdueDays);
+        return result is null ? NotFound() : Ok(result);
+    }
+
     [HttpPatch("{id:guid}/status")]
     public async Task<IActionResult> PatchStatus(Guid id, PatchStoreStatusRequest request, CancellationToken ct)
     {

Distribution/Features/Store/StoreDTOs.cs

@@ -59,3 +59,40 @@ public record SchemeEligibilityResponse(bool Eligible, string? Reason);
 public record PatchStoreStatusRequest(bool IsActive);
 
 public record StoreDashboardResponse(Guid StoreId, string Period, int OrderCount, decimal TotalOrderValue, DateTime? LastOrderDate);
+
+public record StoreAnalyticsSummary(
+    decimal TotalSales,
+    decimal TotalCollected,
+    decimal Outstanding,
+    decimal OverdueAmount,
+    int OverdueInvoiceCount,
+    int InvoiceCount,
+    decimal AverageOrderValue,
+    DateTime? LastSaleDate,
+    decimal CreditLimit,
+    decimal CreditUtilizationPercent);
+
+public record StoreMonthlySales(string Month, decimal Invoiced, decimal Collected, decimal Outstanding);
+
+public record StoreTopProduct(Guid ItemId, string Name, int Quantity, decimal Revenue, DateTime LastSoldAt);
+
+public record StoreAgeingBucket(string Label, decimal Amount, int InvoiceCount);
+
+public record StoreAnalyticsInvoice(
+    Guid InvoiceId,
+    DateTime InvoiceDate,
+    DateTime DueDate,
+    decimal TotalAmount,
+    decimal PaidAmount,
+    decimal Balance,
+    string PaymentStatus,
+    int DaysOverdue);
+
+public record StoreAnalyticsResponse(
+    Guid StoreId,
+    int OverdueDays,
+    StoreAnalyticsSummary Summary,
+    List<StoreMonthlySales> MonthlySales,
+    List<StoreTopProduct> TopProducts,
+    List<StoreAgeingBucket> Ageing,
+    List<StoreAnalyticsInvoice> Invoices);

Distribution/Features/Store/StoreRepository.cs

@@ -51,4 +51,12 @@ public class StoreRepository(AppDBContext context) : IStoreRepository
         await context.ShopPOs
             .Where(o => o.FK_StoreId == storeId && o.IsActive && o.CreatedAt >= periodStart && o.CreatedAt < periodEndExclusive)
             .ToListAsync();
+
+    public async Task<List<Models.Invoice>> GetInvoicesForAnalyticsAsync(Guid storeId) =>
+        await context.Invoices
+            .AsNoTracking()
+            .Include(i => i.Payments)
+            .Include(i => i.ShopPO).ThenInclude(p => p.Items).ThenInclude(x => x.Item)
+            .Where(i => i.IsActive && i.Status != InvoiceStatus.Draft && i.ShopPO.FK_StoreId == storeId)
+            .ToListAsync();
 }

Distribution/Features/Store/StoreService.cs

@@ -253,4 +253,92 @@ public class StoreService(IStoreRepository repo, IUnitOfWork uow, ICurrentUserSe
             orders.Sum(o => o.TotalAmount),
             orders.Count == 0 ? null : orders.Max(o => o.CreatedAt));
     }
+
+    public async Task<StoreAnalyticsResponse?> GetAnalyticsAsync(Guid id, int months, int overdueDays)
+    {
+        var store = await repo.GetByIdAsync(id);
+        if (store is null) return null;
+        if (!await HasStoreScopeAsync(id)) return null;
+
+        months = Math.Clamp(months, 1, 36);
+        overdueDays = Math.Clamp(overdueDays, 0, 365);
+        var now = DateTime.Now;
+        var from = new DateTime(now.Year, now.Month, 1).AddMonths(-(months - 1));
+
+        var invoices = (await repo.GetInvoicesForAnalyticsAsync(id))
+            .Select(i =>
+            {
+                var date = i.FinalizedAt ?? i.CreatedAt;
+                var paid = i.Payments.Where(p => p.IsActive).Sum(p => p.Amount);
+                var balance = Math.Max(0, i.TotalAmount - paid);
+                var due = date.AddDays(overdueDays);
+                var daysOverdue = balance > 0 && now > due ? (int)(now - due).TotalDays : 0;
+                return (Invoice: i, Date: date, Due: due, Paid: paid, Balance: balance, DaysOverdue: daysOverdue);
+            })
+            .ToList();
+
+        var inRange = invoices.Where(x => x.Date >= from).ToList();
+        var totalSales = inRange.Sum(x => x.Invoice.TotalAmount);
+        var overdue = invoices.Where(x => x.DaysOverdue > 0).ToList();
+
+        var summary = new StoreAnalyticsSummary(
+            totalSales,
+            inRange.Sum(x => x.Paid),
+            invoices.Sum(x => x.Balance),
+            overdue.Sum(x => x.Balance),
+            overdue.Count,
+            inRange.Count,
+            inRange.Count == 0 ? 0 : Math.Round(totalSales / inRange.Count, 2),
+            invoices.Count == 0 ? null : invoices.Max(x => x.Date),
+            store.CreditLimit,
+            store.CreditLimit > 0 ? Math.Round(store.OutstandingBalance / store.CreditLimit * 100, 1) : 0);
+
+        var monthly = Enumerable.Range(0, months)
+            .Select(n => from.AddMonths(n))
+            .Select(m => new StoreMonthlySales(
+                m.ToString("yyyy-MM"),
+                inRange.Where(x => x.Date.Year == m.Year && x.Date.Month == m.Month).Sum(x => x.Invoice.TotalAmount),
+                inRange.Where(x => x.Date.Year == m.Year && x.Date.Month == m.Month).Sum(x => x.Paid),
+                invoices
+                    .Where(x => x.Date < m.AddMonths(1))
+                    .Sum(x => Math.Max(0, x.Invoice.TotalAmount - x.Invoice.Payments.Where(p => p.IsActive && p.CollectedAt < m.AddMonths(1)).Sum(p => p.Amount)))))
+            .ToList();
+
+        var topProducts = inRange
+            .SelectMany(x => x.Invoice.ShopPO.Items.Select(it => (it, x.Date)))
+            .GroupBy(t => t.it.FK_ItemId)
+            .Select(g => new StoreTopProduct(
+                g.Key,
+                g.First().it.Item?.Name ?? "Unknown",
+                g.Sum(t => t.it.QuantityFulfilled > 0 ? t.it.QuantityFulfilled : t.it.Quantity),
+                g.Sum(t => (t.it.QuantityFulfilled > 0 ? t.it.QuantityFulfilled : t.it.Quantity) * t.it.UnitPrice),
+                g.Max(t => t.Date)))
+            .OrderByDescending(p => p.Revenue)
+            .Take(10)
+            .ToList();
+
+        var unpaid = invoices.Where(x => x.Balance > 0).ToList();
+        StoreAgeingBucket Bucket(string label, Func<int, bool> match)
+        {
+            var items = unpaid.Where(x => match(x.DaysOverdue)).ToList();
+            return new StoreAgeingBucket(label, items.Sum(x => x.Balance), items.Count);
+        }
+        var ageing = new List<StoreAgeingBucket>
+        {
+            Bucket("Current", d => d <= 0),
+            Bucket("1-30", d => d is >= 1 and <= 30),
+            Bucket("31-60", d => d is >= 31 and <= 60),
+            Bucket("61-90", d => d is >= 61 and <= 90),
+            Bucket("90+", d => d > 90)
+        };
+
+        var list = invoices
+            .OrderByDescending(x => x.Date)
+            .Select(x => new StoreAnalyticsInvoice(
+                x.Invoice.Id, x.Date, x.Due, x.Invoice.TotalAmount, x.Paid, x.Balance,
+                x.Invoice.PaymentStatus.ToString(), x.DaysOverdue))
+            .ToList();
+
+        return new StoreAnalyticsResponse(id, overdueDays, summary, monthly, topProducts, ageing, list);
+    }
 }