analytics and statistics

Webshop.Application/DTOs/Admin/AnalyticsDto.cs

@@ -0,0 +1,114 @@
+// src/Webshop.Application/DTOs/Admin/AnalyticsDto.cs
+using System.Collections.Generic;
+
+namespace Webshop.Application.DTOs.Admin
+{
+    /// <summary>
+    /// Fasst alle relevanten Analysedaten und KPIs für den Admin-Bereich zusammen.
+    /// </summary>
+    public class AnalyticsDto
+    {
+        /// <summary>
+        /// Die wichtigsten Kennzahlen (Key Performance Indicators).
+        /// </summary>
+        public KpiSummaryDto KpiSummary { get; set; } = new KpiSummaryDto();
+
+        /// <summary>
+        /// Eine Liste von Datenpunkten für Umsatz-Charts (z.B. Umsatz pro Tag).
+        /// </summary>
+        public List<SalesDataPointDto> SalesOverTime { get; set; } = new List<SalesDataPointDto>();
+
+        /// <summary>
+        /// Die Top 10 der meistverkauften Produkte im ausgewählten Zeitraum.
+        /// </summary>
+        public List<TopProductDto> TopPerformingProducts { get; set; } = new List<TopProductDto>();
+
+        /// <summary>
+        /// Informationen zum aktuellen Lagerbestand.
+        /// </summary>
+        public InventoryStatusDto InventoryStatus { get; set; } = new InventoryStatusDto();
+    }
+
+    /// <summary>
+    /// Die wichtigsten Kennzahlen (Key Performance Indicators).
+    /// </summary>
+    public class KpiSummaryDto
+    {
+        /// <summary>
+        /// Der Gesamtumsatz (netto) im ausgewählten Zeitraum.
+        /// </summary>
+        public decimal TotalRevenue { get; set; }
+
+        /// <summary>
+        /// Die Gesamtzahl der Bestellungen im ausgewählten Zeitraum.
+        /// </summary>
+        public int TotalOrders { get; set; }
+
+        /// <summary>
+        /// Die Gesamtzahl aller registrierten Kunden.
+        /// </summary>
+        public int TotalCustomers { get; set; }
+
+        /// <summary>
+        /// Die Anzahl der Neukunden, die sich im ausgewählten Zeitraum registriert haben.
+        /// </summary>
+        public int NewCustomersThisPeriod { get; set; }
+
+        /// <summary>
+        /// Der durchschnittliche Wert einer Bestellung im ausgewählten Zeitraum.
+        /// </summary>
+        public decimal AverageOrderValue { get; set; }
+    }
+
+    /// <summary>
+    /// Ein Datenpunkt für Umsatz-Charts (z.B. Umsatz pro Tag).
+    /// </summary>
+    public class SalesDataPointDto
+    {
+        /// <summary>
+        /// Das Datum des Datenpunkts im Format 'yyyy-MM-dd'.
+        /// </summary>
+        public string Date { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Der an diesem Tag generierte Umsatz.
+        /// </summary>
+        public decimal Revenue { get; set; }
+    }
+
+    /// <summary>
+    /// Repräsentiert ein gut verkauftes Produkt.
+    /// </summary>
+    public class TopProductDto
+    {
+        public Guid ProductId { get; set; }
+        public string Name { get; set; } = string.Empty;
+        public string Sku { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Die Gesamtzahl der verkauften Einheiten im ausgewählten Zeitraum.
+        /// </summary>
+        public int UnitsSold { get; set; }
+
+        /// <summary>
+        /// Der Gesamtumsatz, der mit diesem Produkt im ausgewählten Zeitraum erzielt wurde.
+        /// </summary>
+        public decimal TotalRevenue { get; set; }
+    }
+
+    /// <summary>
+    /// Informationen zum Lagerbestand.
+    /// </summary>
+    public class InventoryStatusDto
+    {
+        /// <summary>
+        /// Die Anzahl der Produkte, deren Lagerbestand unter dem in den Einstellungen definierten Schwellenwert liegt.
+        /// </summary>
+        public int ProductsWithLowStock { get; set; }
+
+        /// <summary>
+        /// Der prozentuale Anteil der Produkte, die auf Lager sind (Menge > 0).
+        /// </summary>
+        public double OverallStockAvailabilityPercentage { get; set; }
+    }
+}

Webshop.Application/Services/Admin/AdminAnalyticsService.cs

@@ -0,0 +1,116 @@
+// src/Webshop.Application/Services/Admin/AdminAnalyticsService.cs
+using Microsoft.EntityFrameworkCore;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Webshop.Application.DTOs.Admin;
+using Webshop.Application.Services.Admin.Interfaces;
+using Webshop.Domain.Enums;
+using Webshop.Domain.Interfaces;
+using Webshop.Infrastructure.Data;
+
+namespace Webshop.Application.Services.Admin
+{
+    public class AdminAnalyticsService : IAdminAnalyticsService
+    {
+        private readonly ApplicationDbContext _context;
+        private readonly ISettingService _settingService;
+
+        public AdminAnalyticsService(ApplicationDbContext context, ISettingService settingService)
+        {
+            _context = context;
+            _settingService = settingService;
+        }
+
+        public async Task<AnalyticsDto> GetAnalyticsAsync(AnalyticsPeriod period)
+        {
+            var startDate = GetStartDateFromPeriod(period);
+
+            var filteredOrders = await _context.Orders
+                .Where(o => o.OrderDate >= startDate && o.OrderStatus != OrderStatus.Cancelled.ToString())
+                .ToListAsync();
+
+            var analyticsDto = new AnalyticsDto
+            {
+                KpiSummary = await GetKpiSummaryAsync(startDate, filteredOrders),
+                SalesOverTime = GetSalesOverTime(filteredOrders),
+                TopPerformingProducts = await GetTopPerformingProductsAsync(startDate),
+                InventoryStatus = await GetInventoryStatusAsync()
+            };
+
+            return analyticsDto;
+        }
+
+        private async Task<KpiSummaryDto> GetKpiSummaryAsync(DateTimeOffset startDate, List<Domain.Entities.Order> filteredOrders)
+        {
+            var totalRevenue = filteredOrders.Sum(o => o.OrderTotal);
+            var totalOrders = filteredOrders.Count;
+
+            return new KpiSummaryDto
+            {
+                TotalRevenue = totalRevenue,
+                TotalOrders = totalOrders,
+                TotalCustomers = await _context.Customers.CountAsync(),
+                NewCustomersThisPeriod = await _context.Users.CountAsync(u => u.CreatedDate >= startDate),
+                AverageOrderValue = totalOrders > 0 ? totalRevenue / totalOrders : 0
+            };
+        }
+
+        private List<SalesDataPointDto> GetSalesOverTime(List<Domain.Entities.Order> orders)
+        {
+            return orders
+                .GroupBy(o => o.OrderDate.Date)
+                .Select(g => new SalesDataPointDto
+                {
+                    Date = g.Key.ToString("yyyy-MM-dd"),
+                    Revenue = g.Sum(o => o.OrderTotal)
+                })
+                .OrderBy(dp => dp.Date)
+                .ToList();
+        }
+
+        private async Task<List<TopProductDto>> GetTopPerformingProductsAsync(DateTimeOffset startDate)
+        {
+            return await _context.OrderItems
+                .Where(oi => oi.Order.OrderDate >= startDate && oi.ProductId.HasValue)
+                .GroupBy(oi => new { oi.ProductId, oi.ProductName, oi.ProductSKU })
+                .Select(g => new TopProductDto
+                {
+                    ProductId = g.Key.ProductId!.Value,
+                    Name = g.Key.ProductName,
+                    Sku = g.Key.ProductSKU,
+                    UnitsSold = g.Sum(oi => oi.Quantity),
+                    TotalRevenue = g.Sum(oi => oi.TotalPrice)
+                })
+                .OrderByDescending(p => p.UnitsSold)
+                .Take(10)
+                .ToListAsync();
+        }
+
+        private async Task<InventoryStatusDto> GetInventoryStatusAsync()
+        {
+            var lowStockThreshold = await _settingService.GetSettingValueAsync<int>("LowStockThreshold", 10);
+
+            var totalProducts = await _context.Products.CountAsync(p => p.IsActive);
+            var productsInStock = await _context.Products.CountAsync(p => p.IsActive && p.StockQuantity > 0);
+            var productsWithLowStock = await _context.Products.CountAsync(p => p.IsActive && p.StockQuantity > 0 && p.StockQuantity <= lowStockThreshold);
+
+            return new InventoryStatusDto
+            {
+                ProductsWithLowStock = productsWithLowStock,
+                OverallStockAvailabilityPercentage = totalProducts > 0 ? Math.Round((double)productsInStock / totalProducts * 100, 2) : 0
+            };
+        }
+
+        private DateTimeOffset GetStartDateFromPeriod(AnalyticsPeriod period)
+        {
+            return period switch
+            {
+                AnalyticsPeriod.Last7Days => DateTimeOffset.UtcNow.AddDays(-7),
+                AnalyticsPeriod.Last30Days => DateTimeOffset.UtcNow.AddDays(-30),
+                _ => DateTimeOffset.MinValue
+            };
+        }
+    }
+}

Webshop.Application/Services/Admin/Interfaces/IAdminAnalyticsService.cs

@@ -0,0 +1,13 @@
+// src/Webshop.Application/Services/Admin/Interfaces/IAdminAnalyticsService.cs
+using System.Threading.Tasks;
+using Webshop.Application.DTOs.Admin;
+
+namespace Webshop.Application.Services.Admin.Interfaces
+{
+    public enum AnalyticsPeriod { Last7Days, Last30Days, AllTime }
+
+    public interface IAdminAnalyticsService
+    {
+        Task<AnalyticsDto> GetAnalyticsAsync(AnalyticsPeriod period);
+    }
+}