using JdeScoping.Core.Interfaces;
using JdeScoping.Core.Models.Enums;
using JdeScoping.Core.Models.Search;
using JdeScoping.Core.Models.SearchResults;
using JdeScoping.DataSync.Contracts;
using JdeScoping.DataSync.Options;
using JdeScoping.DataSync.Services;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using NSubstitute;
using NSubstitute.ExceptionExtensions;
using Shouldly;

using MsOptions = Microsoft.Extensions.Options.Options;

namespace JdeScoping.DataSync.Tests.Services;

/// <summary>
/// Unit tests for SearchExecutionService.
/// Tests cancellation handling, error paths, and success scenarios.
/// </summary>
public class SearchExecutionServiceTests
{
    private readonly ISearchRepository _searchRepository;
    private readonly ISearchProcessor _searchProcessor;
    private readonly IExcelExportService _excelExportService;
    private readonly ISearchNotificationService _notificationService;
    private readonly IOptions<WorkProcessorOptions> _options;
    private readonly ILogger<SearchExecutionService> _logger;

    public SearchExecutionServiceTests()
    {
        _searchRepository = Substitute.For<ISearchRepository>();
        _searchProcessor = Substitute.For<ISearchProcessor>();
        _excelExportService = Substitute.For<IExcelExportService>();
        _notificationService = Substitute.For<ISearchNotificationService>();
        _options = MsOptions.Create(new WorkProcessorOptions { SearchTimeout = TimeSpan.FromSeconds(30) });
        _logger = Substitute.For<ILogger<SearchExecutionService>>();
    }

    #region Constructor Tests

    [Fact]
    public void Constructor_WithNullSearchRepository_ThrowsArgumentNullException()
    {
        // Act & Assert
        Should.Throw<ArgumentNullException>(() =>
            new SearchExecutionService(
                null!,
                _searchProcessor,
                _excelExportService,
                _notificationService,
                _options,
                _logger));
    }

    [Fact]
    public void Constructor_WithNullSearchProcessor_ThrowsArgumentNullException()
    {
        // Act & Assert
        Should.Throw<ArgumentNullException>(() =>
            new SearchExecutionService(
                _searchRepository,
                null!,
                _excelExportService,
                _notificationService,
                _options,
                _logger));
    }

    [Fact]
    public void Constructor_WithNullExcelExportService_ThrowsArgumentNullException()
    {
        // Act & Assert
        Should.Throw<ArgumentNullException>(() =>
            new SearchExecutionService(
                _searchRepository,
                _searchProcessor,
                null!,
                _notificationService,
                _options,
                _logger));
    }

    [Fact]
    public void Constructor_WithNullNotificationService_ThrowsArgumentNullException()
    {
        // Act & Assert
        Should.Throw<ArgumentNullException>(() =>
            new SearchExecutionService(
                _searchRepository,
                _searchProcessor,
                _excelExportService,
                null!,
                _options,
                _logger));
    }

    [Fact]
    public void Constructor_WithNullOptions_ThrowsArgumentNullException()
    {
        // Act & Assert
        Should.Throw<ArgumentNullException>(() =>
            new SearchExecutionService(
                _searchRepository,
                _searchProcessor,
                _excelExportService,
                _notificationService,
                null!,
                _logger));
    }

    [Fact]
    public void Constructor_WithNullLogger_ThrowsArgumentNullException()
    {
        // Act & Assert
        Should.Throw<ArgumentNullException>(() =>
            new SearchExecutionService(
                _searchRepository,
                _searchProcessor,
                _excelExportService,
                _notificationService,
                _options,
                null!));
    }

    [Fact]
    public void Constructor_WithValidDependencies_CreatesInstance()
    {
        // Act
        var sut = CreateService();

        // Assert
        sut.ShouldNotBeNull();
    }

    #endregion

    #region ExecuteSearchAsync Success Path

    [Fact]
    public async Task ExecuteSearchAsync_Success_StartsSearch()
    {
        // Arrange
        var search = new Search { Id = 1, Status = SearchStatus.Queued };
        var model = new SearchModel { Id = 1, Results = [] };
        var excelBytes = new byte[] { 1, 2, 3 };

        _searchProcessor.ExecuteSearchToModelAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns(model);
        _excelExportService.GenerateAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns(excelBytes);

        var sut = CreateService();

        // Act
        await sut.ExecuteSearchAsync(search);

        // Assert
        await _searchRepository.Received(1).StartSearchAsync(1, Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task ExecuteSearchAsync_Success_ExecutesSearchProcessor()
    {
        // Arrange
        var search = new Search { Id = 42, Status = SearchStatus.Queued };
        var model = new SearchModel { Id = 42, Results = [] };
        var excelBytes = new byte[] { 1, 2, 3 };

        _searchProcessor.ExecuteSearchToModelAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns(model);
        _excelExportService.GenerateAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns(excelBytes);

        var sut = CreateService();

        // Act
        await sut.ExecuteSearchAsync(search);

        // Assert
        await _searchProcessor.Received(1).ExecuteSearchToModelAsync(
            Arg.Is<SearchModel>(m => m.Id == 42),
            Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task ExecuteSearchAsync_Success_GeneratesExcel()
    {
        // Arrange
        var search = new Search { Id = 1, Status = SearchStatus.Queued };
        var model = new SearchModel { Id = 1, Results = [] };
        var excelBytes = new byte[] { 1, 2, 3 };

        _searchProcessor.ExecuteSearchToModelAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns(model);
        _excelExportService.GenerateAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns(excelBytes);

        var sut = CreateService();

        // Act
        await sut.ExecuteSearchAsync(search);

        // Assert
        await _excelExportService.Received(1).GenerateAsync(
            Arg.Any<SearchModel>(),
            Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task ExecuteSearchAsync_Success_CompletesWithEndedStatus()
    {
        // Arrange
        var search = new Search { Id = 1, Status = SearchStatus.Queued };
        var model = new SearchModel { Id = 1, Results = [] };
        var excelBytes = new byte[] { 1, 2, 3 };

        _searchProcessor.ExecuteSearchToModelAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns(model);
        _excelExportService.GenerateAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns(excelBytes);

        var sut = CreateService();

        // Act
        await sut.ExecuteSearchAsync(search);

        // Assert
        await _searchRepository.Received(1).CompleteSearchAsync(1, true, excelBytes, Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task ExecuteSearchAsync_Success_SendsNotifications()
    {
        // Arrange
        var search = new Search { Id = 1, Status = SearchStatus.Queued };
        var model = new SearchModel { Id = 1, Results = [] };
        var excelBytes = new byte[] { 1, 2, 3 };

        _searchProcessor.ExecuteSearchToModelAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns(model);
        _excelExportService.GenerateAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns(excelBytes);

        var sut = CreateService();

        // Act
        await sut.ExecuteSearchAsync(search);

        // Assert - Should receive 2 notifications: one for Running, one for Ended
        await _notificationService.Received(2).NotifySearchUpdateAsync(search, Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task ExecuteSearchAsync_Success_UpdatesSearchStatus()
    {
        // Arrange
        var search = new Search { Id = 1, Status = SearchStatus.Queued };
        var model = new SearchModel { Id = 1, Results = [] };
        var excelBytes = new byte[] { 1, 2, 3 };

        _searchProcessor.ExecuteSearchToModelAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns(model);
        _excelExportService.GenerateAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns(excelBytes);

        var sut = CreateService();

        // Act
        await sut.ExecuteSearchAsync(search);

        // Assert
        search.Status.ShouldBe(SearchStatus.Ended);
        search.EndDt.ShouldNotBeNull();
    }

    #endregion

    #region ExecuteSearchAsync Error Path

    [Fact]
    public async Task ExecuteSearchAsync_ProcessorThrows_MarksAsError()
    {
        // Arrange
        var search = new Search { Id = 1, Status = SearchStatus.Queued };
        _searchProcessor.ExecuteSearchToModelAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .ThrowsAsync(new InvalidOperationException("Test error"));

        var sut = CreateService();

        // Act
        await sut.ExecuteSearchAsync(search);

        // Assert
        await _searchRepository.Received(1).CompleteSearchAsync(1, false, null, Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task ExecuteSearchAsync_ExcelGeneratorThrows_MarksAsError()
    {
        // Arrange
        var search = new Search { Id = 1, Status = SearchStatus.Queued };
        var model = new SearchModel { Id = 1, Results = [] };

        _searchProcessor.ExecuteSearchToModelAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns(model);
        _excelExportService.GenerateAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .ThrowsAsync(new InvalidOperationException("Excel generation failed"));

        var sut = CreateService();

        // Act
        await sut.ExecuteSearchAsync(search);

        // Assert
        await _searchRepository.Received(1).CompleteSearchAsync(1, false, null, Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task ExecuteSearchAsync_ProcessorThrows_UpdatesSearchStatusToError()
    {
        // Arrange
        var search = new Search { Id = 1, Status = SearchStatus.Queued };
        _searchProcessor.ExecuteSearchToModelAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .ThrowsAsync(new InvalidOperationException("Test error"));

        var sut = CreateService();

        // Act
        await sut.ExecuteSearchAsync(search);

        // Assert
        search.Status.ShouldBe(SearchStatus.Error);
        search.EndDt.ShouldNotBeNull();
    }

    [Fact]
    public async Task ExecuteSearchAsync_ProcessorThrows_SendsErrorNotification()
    {
        // Arrange
        var search = new Search { Id = 1, Status = SearchStatus.Queued };
        _searchProcessor.ExecuteSearchToModelAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .ThrowsAsync(new InvalidOperationException("Test error"));

        var sut = CreateService();

        // Act
        await sut.ExecuteSearchAsync(search);

        // Assert - Should receive 2 notifications: one for Running, one for Error
        await _notificationService.Received(2).NotifySearchUpdateAsync(search, Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task ExecuteSearchAsync_ErrorDuringComplete_DoesNotThrow()
    {
        // Arrange
        var search = new Search { Id = 1, Status = SearchStatus.Queued };
        _searchProcessor.ExecuteSearchToModelAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .ThrowsAsync(new InvalidOperationException("Test error"));
        _searchRepository.CompleteSearchAsync(Arg.Any<int>(), Arg.Any<bool>(), Arg.Any<byte[]?>(), Arg.Any<CancellationToken>())
            .ThrowsAsync(new InvalidOperationException("DB error"));

        var sut = CreateService();

        // Act & Assert - Should not throw
        await Should.NotThrowAsync(() => sut.ExecuteSearchAsync(search));
    }

    #endregion

    #region ExecuteSearchAsync Host Shutdown

    [Fact]
    public async Task ExecuteSearchAsync_HostShutdown_DoesNotMarkAsError()
    {
        // Arrange
        var search = new Search { Id = 1, Status = SearchStatus.Queued };
        using var cts = new CancellationTokenSource();

        _searchProcessor.ExecuteSearchToModelAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns<SearchModel>(callInfo =>
            {
                cts.Cancel();
                throw new OperationCanceledException(cts.Token);
            });

        var sut = CreateService();

        // Act
        await sut.ExecuteSearchAsync(search, cts.Token);

        // Assert - Should NOT call CompleteSearchAsync with success=false
        await _searchRepository.DidNotReceive().CompleteSearchAsync(
            Arg.Any<int>(), false, Arg.Any<byte[]?>(), Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task ExecuteSearchAsync_HostShutdown_DoesNotUpdateStatusToError()
    {
        // Arrange
        var search = new Search { Id = 1, Status = SearchStatus.Queued };
        using var cts = new CancellationTokenSource();

        _searchProcessor.ExecuteSearchToModelAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns<SearchModel>(callInfo =>
            {
                cts.Cancel();
                throw new OperationCanceledException(cts.Token);
            });

        var sut = CreateService();

        // Act
        await sut.ExecuteSearchAsync(search, cts.Token);

        // Assert - Status should still be Running (not Error)
        search.Status.ShouldBe(SearchStatus.Running);
    }

    [Fact]
    public async Task ExecuteSearchAsync_HostShutdown_DoesNotThrow()
    {
        // Arrange
        var search = new Search { Id = 1, Status = SearchStatus.Queued };
        using var cts = new CancellationTokenSource();

        _searchProcessor.ExecuteSearchToModelAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns<SearchModel>(callInfo =>
            {
                cts.Cancel();
                throw new OperationCanceledException(cts.Token);
            });

        var sut = CreateService();

        // Act & Assert - Should not throw
        await Should.NotThrowAsync(() => sut.ExecuteSearchAsync(search, cts.Token));
    }

    #endregion

    #region ExecuteSearchAsync Timeout

    [Fact]
    public async Task ExecuteSearchAsync_Timeout_MarksAsError()
    {
        // Arrange
        var search = new Search { Id = 1, Status = SearchStatus.Queued };
        var shortTimeoutOptions = MsOptions.Create(new WorkProcessorOptions { SearchTimeout = TimeSpan.FromMilliseconds(50) });

        _searchProcessor.ExecuteSearchToModelAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns(async callInfo =>
            {
                var ct = callInfo.Arg<CancellationToken>();
                await Task.Delay(TimeSpan.FromSeconds(5), ct); // Will be canceled by timeout
                return new SearchModel();
            });

        var sut = new SearchExecutionService(
            _searchRepository,
            _searchProcessor,
            _excelExportService,
            _notificationService,
            shortTimeoutOptions,
            _logger);

        // Act
        await sut.ExecuteSearchAsync(search);

        // Assert
        await _searchRepository.Received(1).CompleteSearchAsync(1, false, null, Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task ExecuteSearchAsync_Timeout_UpdatesStatusToError()
    {
        // Arrange
        var search = new Search { Id = 1, Status = SearchStatus.Queued };
        var shortTimeoutOptions = MsOptions.Create(new WorkProcessorOptions { SearchTimeout = TimeSpan.FromMilliseconds(50) });

        _searchProcessor.ExecuteSearchToModelAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns(async callInfo =>
            {
                var ct = callInfo.Arg<CancellationToken>();
                await Task.Delay(TimeSpan.FromSeconds(5), ct); // Will be canceled by timeout
                return new SearchModel();
            });

        var sut = new SearchExecutionService(
            _searchRepository,
            _searchProcessor,
            _excelExportService,
            _notificationService,
            shortTimeoutOptions,
            _logger);

        // Act
        await sut.ExecuteSearchAsync(search);

        // Assert
        search.Status.ShouldBe(SearchStatus.Error);
    }

    #endregion

    #region Notification Resilience

    [Fact]
    public async Task ExecuteSearchAsync_NotificationFails_ContinuesExecution()
    {
        // Arrange
        var search = new Search { Id = 1, Status = SearchStatus.Queued };
        var model = new SearchModel { Id = 1, Results = [] };
        var excelBytes = new byte[] { 1, 2, 3 };

        _searchProcessor.ExecuteSearchToModelAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns(model);
        _excelExportService.GenerateAsync(Arg.Any<SearchModel>(), Arg.Any<CancellationToken>())
            .Returns(excelBytes);
        _notificationService.NotifySearchUpdateAsync(Arg.Any<Search>(), Arg.Any<CancellationToken>())
            .ThrowsAsync(new InvalidOperationException("SignalR error"));

        var sut = CreateService();

        // Act
        await sut.ExecuteSearchAsync(search);

        // Assert - Should still complete successfully despite notification failures
        await _searchRepository.Received(1).CompleteSearchAsync(1, true, excelBytes, Arg.Any<CancellationToken>());
    }

    #endregion

    private SearchExecutionService CreateService()
    {
        return new SearchExecutionService(
            _searchRepository,
            _searchProcessor,
            _excelExportService,
            _notificationService,
            _options,
            _logger);
    }
}