AnalyticsServiceTests.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using FluentAssertions;
using Microsoft.EntityFrameworkCore;
using ParcelTracking.Application.Services;
using ParcelTracking.Application.DTOs.Stats;
using ParcelTracking.Domain.Enums;
using ParcelTracking.Domain.Entities;
using ParcelTracking.Infrastructure.Data;
using Xunit;

namespace ParcelTracking.Application.Tests
{
    public class AnalyticsServiceTests
    {
        private DbContextOptions<ParcelTrackingDbContext> CreateInMemoryOptions()
        {
            return new DbContextOptionsBuilder<ParcelTrackingDbContext>()
                .UseInMemoryDatabase(Guid.NewGuid().ToString())
                .Options;
        }

        [Fact]
        public async Task GetParcelCountByStatusAsync_ReturnsAllStatusesWithCounts()
        {
            // Arrange
            var options = CreateInMemoryOptions();
            await using var db = new ParcelTrackingDbContext(options);

            // Seed data with different statuses
            var parcels = new List<Parcel>
            {
                new Parcel { Id = Guid.NewGuid(), Status = ParcelStatus.Delivered, CreatedAt = DateTimeOffset.UtcNow },
                new Parcel { Id = Guid.NewGuid(), Status = ParcelStatus.Delivered, CreatedAt = DateTimeOffset.UtcNow },
                new Parcel { Id = Guid.NewGuid(), Status = ParcelStatus.InTransit, CreatedAt = DateTimeOffset.UtcNow },
                new Parcel { Id = Guid.NewGuid(), Status = ParcelStatus.Exception, CreatedAt = DateTimeOffset.UtcNow },
                new Parcel { Id = Guid.NewGuid(), Status = ParcelStatus.Exception, CreatedAt = DateTimeOffset.UtcNow },
                new Parcel { Id = Guid.NewGuid(), Status = ParcelStatus.Exception, CreatedAt = DateTimeOffset.UtcNow }
            };

            db.Parcels.AddRange(parcels);
            await db.SaveChangesAsync();

            var service = new AnalyticsService(db);

            // Act
            var result = await service.GetParcelCountByStatusAsync();

            // Assert
            result.Should().HaveCount(Enum.GetValues<ParcelStatus>().Length);

            var deliveredCount = result.First(r => r.Status == ParcelStatus.Delivered.ToString());
            deliveredCount.Count.Should().Be(2);

            var inTransitCount = result.First(r => r.Status == ParcelStatus.InTransit.ToString());
            inTransitCount.Count.Should().Be(1);

            var exceptionCount = result.First(r => r.Status == ParcelStatus.Exception.ToString());
            exceptionCount.Count.Should().Be(3);

            // Check that statuses with 0 count are included
            var labelCreatedCount = result.First(r => r.Status == ParcelStatus.LabelCreated.ToString());
            labelCreatedCount.Count.Should().Be(0);
        }

        [Fact]
        public async Task GetParcelCountByStatusAsync_EmptyDatabase_ReturnsAllStatusesWithZeroCounts()
        {
            // Arrange
            var options = CreateInMemoryOptions();
            await using var db = new ParcelTrackingDbContext(options);

            var service = new AnalyticsService(db);

            // Act
            var result = await service.GetParcelCountByStatusAsync();

            // Assert
            result.Should().HaveCount(Enum.GetValues<ParcelStatus>().Length);
            result.All(r => r.Count == 0).Should().BeTrue();
        }

        [Fact]
        public async Task GetDeliveryPerformanceAsync_CalculatesMetricsCorrectly()
        {
            // Arrange
            var options = CreateInMemoryOptions();
            await using var db = new ParcelTrackingDbContext(options);

            var from = DateTimeOffset.UtcNow.AddDays(-10);
            var to = DateTimeOffset.UtcNow.AddDays(1);

            var parcels = new List<Parcel>
            {
                // Delivered on time
                new Parcel
                {
                    Id = Guid.NewGuid(),
                    Status = ParcelStatus.Delivered,
                    CreatedAt = from.AddDays(1),
                    EstimatedDeliveryDate = from.AddDays(3),
                    ActualDeliveryDate = from.AddDays(2)
                },
                // Delivered late
                new Parcel
                {
                    Id = Guid.NewGuid(),
                    Status = ParcelStatus.Delivered,
                    CreatedAt = from.AddDays(1),
                    EstimatedDeliveryDate = from.AddDays(2),
                    ActualDeliveryDate = from.AddDays(3)
                },
                // In transit
                new Parcel
                {
                    Id = Guid.NewGuid(),
                    Status = ParcelStatus.InTransit,
                    CreatedAt = from.AddDays(1),
                    EstimatedDeliveryDate = from.AddDays(5)
                },
                // Out for delivery
                new Parcel
                {
                    Id = Guid.NewGuid(),
                    Status = ParcelStatus.OutForDelivery,
                    CreatedAt = from.AddDays(1),
                    EstimatedDeliveryDate = from.AddDays(5)
                },
                // Exception
                new Parcel
                {
                    Id = Guid.NewGuid(),
                    Status = ParcelStatus.Exception,
                    CreatedAt = from.AddDays(1),
                    EstimatedDeliveryDate = from.AddDays(5)
                },
                // Outside date range (should not be counted)
                new Parcel
                {
                    Id = Guid.NewGuid(),
                    Status = ParcelStatus.Delivered,
                    CreatedAt = from.AddDays(-5),
                    EstimatedDeliveryDate = from.AddDays(-3),
                    ActualDeliveryDate = from.AddDays(-4)
                }
            };

            db.Parcels.AddRange(parcels);
            await db.SaveChangesAsync();

            var service = new AnalyticsService(db);

            // Act
            var result = await service.GetDeliveryPerformanceAsync(from, to);

            // Assert
            result.TotalParcels.Should().Be(5);
            result.Delivered.Should().Be(2);
            result.InTransit.Should().Be(2); // InTransit + OutForDelivery
            result.Exceptions.Should().Be(1);
            result.OnTimePercentage.Should().Be(50.0); // 1 out of 2 delivered on time
            result.AverageDeliveryTimeHours.Should().BeApproximately(36.0, 0.1); // Average of 24h and 48h
        }

        [Fact]
        public async Task GetDeliveryPerformanceAsync_NoDeliveredParcels_ReturnsZeroMetrics()
        {
            // Arrange
            var options = CreateInMemoryOptions();
            await using var db = new ParcelTrackingDbContext(options);

            var from = DateTimeOffset.UtcNow.AddDays(-10);
            var to = DateTimeOffset.UtcNow.AddDays(1);

            var parcels = new List<Parcel>
            {
                new Parcel
                {
                    Id = Guid.NewGuid(),
                    Status = ParcelStatus.InTransit,
                    CreatedAt = from.AddDays(1),
                    EstimatedDeliveryDate = from.AddDays(5)
                }
            };

            db.Parcels.AddRange(parcels);
            await db.SaveChangesAsync();

            var service = new AnalyticsService(db);

            // Act
            var result = await service.GetDeliveryPerformanceAsync(from, to);

            // Assert
            result.TotalParcels.Should().Be(1);
            result.Delivered.Should().Be(0);
            result.InTransit.Should().Be(1);
            result.Exceptions.Should().Be(0);
            result.OnTimePercentage.Should().Be(0);
            result.AverageDeliveryTimeHours.Should().Be(0);
        }

        [Fact]
        public async Task GetDeliveryPerformanceAsync_NoParcelsInDateRange_ReturnsZeroMetrics()
        {
            // Arrange
            var options = CreateInMemoryOptions();
            await using var db = new ParcelTrackingDbContext(options);

            var from = DateTimeOffset.UtcNow.AddDays(-10);
            var to = DateTimeOffset.UtcNow.AddDays(-5);

            var service = new AnalyticsService(db);

            // Act
            var result = await service.GetDeliveryPerformanceAsync(from, to);

            // Assert
            result.TotalParcels.Should().Be(0);
            result.Delivered.Should().Be(0);
            result.InTransit.Should().Be(0);
            result.Exceptions.Should().Be(0);
            result.OnTimePercentage.Should().Be(0);
            result.AverageDeliveryTimeHours.Should().Be(0);
        }
    }
}