using FluentAssertions;
using Microsoft.Extensions.Logging.Abstractions;
using Moq;
using SatelliteProvider.Common.DTO;
using SatelliteProvider.Common.Interfaces;
using SatelliteProvider.Common.Utils;
using SatelliteProvider.DataAccess.Models;
using SatelliteProvider.DataAccess.Repositories;
using SatelliteProvider.Services.RouteManagement;
using SatelliteProvider.Tests.Fixtures;

namespace SatelliteProvider.Tests;

public class RouteServiceTests
{
    private static RouteService BuildService(
        Mock<IRouteRepository> routeRepo,
        Mock<IRegionService> regionService)
    {
        return new RouteService(routeRepo.Object, regionService.Object, NullLogger<RouteService>.Instance);
    }

    private static CreateRouteRequest BuildRequest(IEnumerable<(double Lat, double Lon)> points, double regionSize = 500, int zoom = 18, bool requestMaps = false, Geofences? geofences = null)
    {
        return new CreateRouteRequest
        {
            Id = Guid.NewGuid(),
            Name = "test route",
            Description = "unit test route",
            RegionSizeMeters = regionSize,
            ZoomLevel = zoom,
            Points = points.Select(p => new RoutePoint { Latitude = p.Lat, Longitude = p.Lon }).ToList(),
            RequestMaps = requestMaps,
            Geofences = geofences,
        };
    }

    [Fact]
    public async Task CreateRouteAsync_DuplicateId_ReturnsExistingRoute_NoReinsertion_AZ362_AC2()
    {
        // Arrange
        var existingId = Guid.NewGuid();
        var existingEntity = new RouteEntity
        {
            Id = existingId,
            Name = "previously-created route",
            Description = "first POST won this id",
            RegionSizeMeters = 500,
            ZoomLevel = 18,
            TotalDistanceMeters = 1234.5,
            TotalPoints = 7,
            RequestMaps = false,
            CreateTilesZip = false,
            MapsReady = false,
            CreatedAt = DateTime.UtcNow.AddMinutes(-10),
            UpdatedAt = DateTime.UtcNow.AddMinutes(-10),
        };
        var existingPoints = new List<RoutePointEntity>
        {
            new() { Id = Guid.NewGuid(), RouteId = existingId, SequenceNumber = 0, Latitude = 47.46, Longitude = 37.64, PointType = "start", SegmentIndex = 0 },
            new() { Id = Guid.NewGuid(), RouteId = existingId, SequenceNumber = 1, Latitude = 47.47, Longitude = 37.65, PointType = "end", SegmentIndex = 0 },
        };
        var routeRepo = new Mock<IRouteRepository>(MockBehavior.Strict);
        routeRepo.Setup(r => r.GetByIdAsync(existingId)).ReturnsAsync(existingEntity);
        routeRepo.Setup(r => r.GetRoutePointsAsync(existingId)).ReturnsAsync(existingPoints);
        var regionService = new Mock<IRegionService>(MockBehavior.Strict);
        var service = BuildService(routeRepo, regionService);

        var retryRequest = BuildRequest(TestCoordinates.Route.Route01Points);
        retryRequest.Id = existingId;

        // Act
        var result = await service.CreateRouteAsync(retryRequest);

        // Assert
        result.Id.Should().Be(existingId);
        result.Name.Should().Be("previously-created route", "AZ-362: returns the existing route's persisted name, not the retry payload's name");
        result.TotalPoints.Should().Be(7, "AZ-362: returns the existing route's persisted point count");
        routeRepo.Verify(r => r.InsertRouteAsync(It.IsAny<RouteEntity>()), Times.Never,
            "AZ-362: duplicate Id must not re-insert the route");
        routeRepo.Verify(r => r.InsertRoutePointsAsync(It.IsAny<List<RoutePointEntity>>()), Times.Never,
            "AZ-362: duplicate Id must not re-insert points");
        regionService.VerifyNoOtherCalls();
    }

    [Fact]
    public async Task CreateRouteAsync_TwoPointRoute_GeneratesIntermediatePointsAtMax200mSpacing_BT06_AC1()
    {
        // Arrange
        var routeRepo = new Mock<IRouteRepository>();
        var regionService = new Mock<IRegionService>();
        var service = BuildService(routeRepo, regionService);

        var request = BuildRequest(TestCoordinates.Route.Route01Points, regionSize: 500, zoom: 18);

        // Act
        var result = await service.CreateRouteAsync(request);

        // Assert
        result.TotalPoints.Should().BeGreaterThan(2, "intermediate points must be inserted between user-supplied points");
        result.Points.Should().HaveCount(result.TotalPoints);

        // Spacing AC: every consecutive pair within a segment must be ≤200m apart.
        for (int i = 1; i < result.Points.Count; i++)
        {
            var prev = result.Points[i - 1];
            var cur = result.Points[i];
            var distance = GeoUtils.CalculateDistance(
                new GeoPoint(prev.Latitude, prev.Longitude),
                new GeoPoint(cur.Latitude, cur.Longitude));
            distance.Should().BeLessThanOrEqualTo(200.5, $"point {i - 1}→{i} must be ≤200m");
        }
    }

    [Fact]
    public async Task CreateRouteAsync_TwoPointRoute_FirstAndLastUserPointsKeepTheirRoles_BT06_AC2()
    {
        // Arrange
        var service = BuildService(new Mock<IRouteRepository>(), new Mock<IRegionService>());
        var request = BuildRequest(TestCoordinates.Route.Route01Points);

        // Act
        var result = await service.CreateRouteAsync(request);

        // Assert
        result.Points.First().PointType.Should().Be("start", "first user-supplied point");
        result.Points.Last().PointType.Should().Be("end", "last user-supplied point");
        result.Points.Skip(1).Take(result.Points.Count - 2).Should().OnlyContain(p => p.PointType == "intermediate",
            "every middle point in a 2-point route is interpolated");
    }

    [Fact]
    public async Task CreateRouteAsync_TenPointRoute_HasOneStartOneEndAndOnlyIntermediatesBetween_BT10()
    {
        // Arrange
        var service = BuildService(new Mock<IRouteRepository>(), new Mock<IRegionService>());
        var request = BuildRequest(TestCoordinates.Route.Route04Points, regionSize: 300);

        // Act
        var result = await service.CreateRouteAsync(request);

        // Assert
        result.Points.Count(p => p.PointType == "start").Should().Be(1);
        result.Points.Count(p => p.PointType == "end").Should().Be(1);
        result.Points.Count(p => p.PointType == "action").Should().Be(8, "8 middle user-supplied waypoints in a 10-point route");
        result.Points.Should().Contain(p => p.PointType == "intermediate", "long route always interpolates");
    }

    [Fact]
    public async Task CreateRouteAsync_TwentyPointRoute_HasOneStartOneEndAndEighteenAction_BT12()
    {
        // Arrange
        var service = BuildService(new Mock<IRouteRepository>(), new Mock<IRegionService>());
        var request = BuildRequest(TestCoordinates.Route.Route06Points, regionSize: 300);

        // Act
        var result = await service.CreateRouteAsync(request);

        // Assert
        result.Points.Count(p => p.PointType == "start").Should().Be(1);
        result.Points.Count(p => p.PointType == "end").Should().Be(1);
        result.Points.Count(p => p.PointType == "action").Should().Be(18, "18 middle user-supplied waypoints in a 20-point route");
    }

    [Fact]
    public async Task CreateRouteAsync_ComputesTotalDistanceViaHaversine_AC3()
    {
        // Arrange
        var service = BuildService(new Mock<IRouteRepository>(), new Mock<IRegionService>());
        var request = BuildRequest(TestCoordinates.Route.Route01Points);

        // Act
        var result = await service.CreateRouteAsync(request);

        // Assert: distance is positive and equals the sum of consecutive spacings ± rounding.
        result.TotalDistanceMeters.Should().BeGreaterThan(0);

        var summed = 0.0;
        for (int i = 1; i < result.Points.Count; i++)
        {
            var prev = result.Points[i - 1];
            var cur = result.Points[i];
            summed += GeoUtils.CalculateDistance(
                new GeoPoint(prev.Latitude, prev.Longitude),
                new GeoPoint(cur.Latitude, cur.Longitude));
        }
        result.TotalDistanceMeters.Should().BeApproximately(summed, 1.0,
            "TotalDistanceMeters must equal Σ Haversine(point[i-1], point[i])");
    }

    [Fact]
    public async Task CreateRouteAsync_LessThanTwoPoints_Throws_BTN03_AC4()
    {
        // Arrange
        var service = BuildService(new Mock<IRouteRepository>(), new Mock<IRegionService>());
        var request = BuildRequest(new[] { (47.461747, 37.647063) });

        // Act
        Func<Task> act = () => service.CreateRouteAsync(request);

        // Assert
        await act.Should().ThrowAsync<ArgumentException>()
            .WithMessage("*at least 2 points*");
    }

    [Fact]
    public async Task CreateRouteAsync_InvalidRegionSize_Throws()
    {
        // Arrange
        var service = BuildService(new Mock<IRouteRepository>(), new Mock<IRegionService>());
        var request = BuildRequest(TestCoordinates.Route.Route01Points, regionSize: 50);

        // Act
        Func<Task> act = () => service.CreateRouteAsync(request);

        // Assert
        await act.Should().ThrowAsync<ArgumentException>()
            .WithMessage("*Region size must be between 100 and 10000*");
    }

    [Fact]
    public async Task CreateRouteAsync_GeofenceWithZeroZeroCorner_Throws_BTN04()
    {
        // Arrange
        var service = BuildService(new Mock<IRouteRepository>(), new Mock<IRegionService>());
        var geofences = new Geofences
        {
            Polygons = new List<GeofencePolygon>
            {
                new() { NorthWest = new GeoPoint(0, 0), SouthEast = new GeoPoint(0, 0) },
            },
        };
        var request = BuildRequest(TestCoordinates.Route.Route01Points, geofences: geofences);

        // Act
        Func<Task> act = () => service.CreateRouteAsync(request);

        // Assert
        await act.Should().ThrowAsync<ArgumentException>()
            .WithMessage("*coordinates cannot be (0,0)*");
    }

    [Fact]
    public async Task CreateRouteAsync_GeofenceWithInvertedCorners_Throws_BTN05()
    {
        // Arrange
        var service = BuildService(new Mock<IRouteRepository>(), new Mock<IRegionService>());
        var geofences = new Geofences
        {
            Polygons = new List<GeofencePolygon>
            {
                // northWest.Lat (48.250) <= southEast.Lat (48.280) → invalid
                new() { NorthWest = new GeoPoint(48.250, 37.370), SouthEast = new GeoPoint(48.280, 37.395) },
            },
        };
        var request = BuildRequest(TestCoordinates.Route.Route01Points, geofences: geofences);

        // Act
        Func<Task> act = () => service.CreateRouteAsync(request);

        // Assert
        await act.Should().ThrowAsync<ArgumentException>()
            .WithMessage("*northWest latitude*");
    }

    [Fact]
    public async Task CreateRouteAsync_ValidGeofence_QueuesGeofenceRegions_BT11()
    {
        // Arrange
        var routeRepo = new Mock<IRouteRepository>();
        var regionService = new Mock<IRegionService>();

        regionService
            .Setup(r => r.RequestRegionAsync(It.IsAny<Guid>(), It.IsAny<double>(), It.IsAny<double>(), It.IsAny<double>(), It.IsAny<int>(), false))
            .ReturnsAsync(new RegionStatus { Status = "queued" });

        var service = BuildService(routeRepo, regionService);

        var geofences = new Geofences
        {
            Polygons = new List<GeofencePolygon>
            {
                new() { NorthWest = new GeoPoint(48.280, 37.370), SouthEast = new GeoPoint(48.265, 37.395) },
            },
        };
        var request = BuildRequest(TestCoordinates.Route.Route04Points, regionSize: 300, geofences: geofences);

        // Act
        var result = await service.CreateRouteAsync(request);

        // Assert
        result.TotalPoints.Should().BeGreaterThan(0);
        regionService.Verify(r => r.RequestRegionAsync(
            It.IsAny<Guid>(), It.IsAny<double>(), It.IsAny<double>(),
            300, It.IsAny<int>(), false), Times.AtLeastOnce,
            "geofence creates at least one region request");
        routeRepo.Verify(r => r.LinkRouteToRegionAsync(
            request.Id, It.IsAny<Guid>(), true, 0), Times.AtLeastOnce,
            "geofence regions are linked to the route with isGeofence=true");
    }

    [Fact]
    public async Task GetRouteAsync_KnownId_ReturnsRouteWithPoints_BT07()
    {
        // Arrange
        var routeRepo = new Mock<IRouteRepository>();
        var id = Guid.NewGuid();
        var routeEntity = new RouteEntity
        {
            Id = id,
            Name = "test",
            RegionSizeMeters = 500,
            ZoomLevel = 18,
            TotalDistanceMeters = 1234,
            TotalPoints = 4,
        };
        routeRepo.Setup(r => r.GetByIdAsync(id)).ReturnsAsync(routeEntity);
        routeRepo.Setup(r => r.GetRoutePointsAsync(id)).ReturnsAsync(new List<RoutePointEntity>
        {
            new() { Id = Guid.NewGuid(), RouteId = id, SequenceNumber = 0, Latitude = 1, Longitude = 2, PointType = "start", SegmentIndex = 0 },
            new() { Id = Guid.NewGuid(), RouteId = id, SequenceNumber = 1, Latitude = 3, Longitude = 4, PointType = "end", SegmentIndex = 1 },
        });

        var service = BuildService(routeRepo, new Mock<IRegionService>());

        // Act
        var result = await service.GetRouteAsync(id);

        // Assert
        result.Should().NotBeNull();
        result!.Id.Should().Be(id);
        result.Points.Should().HaveCount(2);
        result.Points[0].PointType.Should().Be("start");
        result.Points[1].PointType.Should().Be("end");
    }

    [Fact]
    public async Task GetRouteAsync_UnknownId_ReturnsNull()
    {
        // Arrange
        var routeRepo = new Mock<IRouteRepository>();
        routeRepo.Setup(r => r.GetByIdAsync(It.IsAny<Guid>())).ReturnsAsync((RouteEntity?)null);
        var service = BuildService(routeRepo, new Mock<IRegionService>());

        // Act
        var result = await service.GetRouteAsync(Guid.NewGuid());

        // Assert
        result.Should().BeNull();
    }
}