using FluentAssertions;
using Microsoft.Extensions.Logging;
using NSubstitute;
using NSubstitute.ExceptionExtensions;
using ProposalSystem.Application.DTOs;
using ProposalSystem.Application.Interfaces;
using ProposalSystem.Domain.Entities;
using ProposalSystem.Infrastructure.Services;
using ProposalSystem.Tests.Helpers;
using Xunit;

namespace ProposalSystem.Tests.Services;

/// <summary>
/// PR5: Tests for PricingLibraryService. Verifies CRUD behavior and that
/// create/update publish "library-ingest" SQS jobs for KB sync.
/// </summary>
public class PricingLibraryServiceTests : IDisposable
{
    private readonly Infrastructure.Data.ProposalDbContext _db;
    private readonly IJobPublisher _jobPublisher;
    private readonly PricingLibraryService _sut;

    public PricingLibraryServiceTests()
    {
        _db = DbContextFactory.Create();
        _jobPublisher = Substitute.For<IJobPublisher>();

        _sut = new PricingLibraryService(
            _db,
            _jobPublisher,
            Substitute.For<ILogger<PricingLibraryService>>());
    }

    public void Dispose()
    {
        _db.Dispose();
    }

    #region Create

    [Fact(DisplayName = "PR5: Create returns item with generated Id and timestamps")]
    public async Task CreateAsync_ReturnsItemWithIdAndTimestamps()
    {
        var request = new CreatePricingLibraryItemRequest(
            Title: "HVAC Filter Replacement",
            Description: "Standard filter replacement service",
            ServiceCategory: ServiceCategory.HVAC,
            Unit: "ea",
            UnitPrice: 45.00m,
            Keywords: "filter HVAC maintenance",
            Source: "Manual"
        );

        var result = await _sut.CreateAsync(request);

        result.Id.Should().NotBe(Guid.Empty);
        result.Title.Should().Be("HVAC Filter Replacement");
        result.Description.Should().Be("Standard filter replacement service");
        result.ServiceCategory.Should().Be(ServiceCategory.HVAC);
        result.Unit.Should().Be("ea");
        result.UnitPrice.Should().Be(45.00m);
        result.Keywords.Should().Be("filter HVAC maintenance");
        result.Source.Should().Be("Manual");
        result.CreatedAt.Should().BeCloseTo(DateTime.UtcNow, TimeSpan.FromSeconds(5));
        result.UpdatedAt.Should().BeCloseTo(DateTime.UtcNow, TimeSpan.FromSeconds(5));
    }

    [Fact(DisplayName = "PR5: Create defaults Source to 'Manual' when null")]
    public async Task CreateAsync_DefaultsSourceToManual()
    {
        var request = new CreatePricingLibraryItemRequest(
            Title: "Basic Item",
            Description: null,
            ServiceCategory: ServiceCategory.General,
            Unit: null,
            UnitPrice: null,
            Keywords: null,
            Source: null
        );

        var result = await _sut.CreateAsync(request);

        result.Source.Should().Be("Manual");
    }

    [Fact(DisplayName = "PR5: Create publishes library-ingest job with pricingLibraryItemId")]
    public async Task CreateAsync_PublishesLibraryIngestJob()
    {
        var request = new CreatePricingLibraryItemRequest(
            Title: "Test Item",
            Description: null,
            ServiceCategory: ServiceCategory.General,
            Unit: null,
            UnitPrice: null,
            Keywords: null,
            Source: null
        );

        var result = await _sut.CreateAsync(request);

        await _jobPublisher.Received(1).PublishAsync(
            "library-ingest",
            Arg.Is<object>(o => o.ToString()!.Contains(result.Id.ToString())),
            Arg.Any<CancellationToken>());
    }

    [Fact(DisplayName = "PR5: Create succeeds even when job publish fails (no rollback)")]
    public async Task CreateAsync_JobPublishFails_DoesNotRollBack()
    {
        _jobPublisher.PublishAsync(Arg.Any<string>(), Arg.Any<object>(), Arg.Any<CancellationToken>())
            .Throws(new InvalidOperationException("SQS is down"));

        var request = new CreatePricingLibraryItemRequest(
            Title: "Resilient Item",
            Description: null,
            ServiceCategory: ServiceCategory.General,
            Unit: null,
            UnitPrice: null,
            Keywords: null,
            Source: null
        );

        var result = await _sut.CreateAsync(request);

        result.Title.Should().Be("Resilient Item");
        // Verify item was persisted despite job publish failure
        var dbItem = await _db.PricingLibraryItems.FindAsync(result.Id);
        dbItem.Should().NotBeNull();
    }

    #endregion

    #region Update

    [Fact(DisplayName = "PR5: Update modifies provided fields and publishes ingest job")]
    public async Task UpdateAsync_ModifiesFieldsAndPublishesJob()
    {
        // Seed an item
        var originalUpdatedAt = DateTime.UtcNow.AddDays(-1);
        var item = new PricingLibraryItem
        {
            Id = Guid.NewGuid(),
            Title = "Original Title",
            Description = "Original",
            ServiceCategory = ServiceCategory.General,
            Unit = "ea",
            UnitPrice = 10.00m,
            Keywords = "original",
            Source = "Manual",
            CreatedAt = DateTime.UtcNow.AddDays(-1),
            UpdatedAt = originalUpdatedAt,
        };
        _db.PricingLibraryItems.Add(item);
        await _db.SaveChangesAsync();

        var request = new UpdatePricingLibraryItemRequest(
            Title: "Updated Title",
            Description: null,
            ServiceCategory: ServiceCategory.Electrical,
            Unit: null,
            UnitPrice: 99.99m,
            Keywords: null
        );

        var result = await _sut.UpdateAsync(item.Id, request);

        result.Should().NotBeNull();
        result!.Title.Should().Be("Updated Title");
        result.ServiceCategory.Should().Be(ServiceCategory.Electrical);
        result.UnitPrice.Should().Be(99.99m);
        result.UpdatedAt.Should().BeAfter(originalUpdatedAt);

        await _jobPublisher.Received(1).PublishAsync(
            "library-ingest",
            Arg.Is<object>(o => o.ToString()!.Contains(item.Id.ToString())),
            Arg.Any<CancellationToken>());
    }

    [Fact(DisplayName = "PR5: Update returns null for non-existent item")]
    public async Task UpdateAsync_NonExistentItem_ReturnsNull()
    {
        var request = new UpdatePricingLibraryItemRequest(
            Title: "Does Not Exist",
            Description: null,
            ServiceCategory: null,
            Unit: null,
            UnitPrice: null,
            Keywords: null
        );

        var result = await _sut.UpdateAsync(Guid.NewGuid(), request);

        result.Should().BeNull();
    }

    [Fact(DisplayName = "PR5: Update succeeds even when job publish fails (no rollback)")]
    public async Task UpdateAsync_JobPublishFails_DoesNotRollBack()
    {
        var item = new PricingLibraryItem
        {
            Id = Guid.NewGuid(),
            Title = "Will Be Updated",
            ServiceCategory = ServiceCategory.General,
            Source = "Manual",
            CreatedAt = DateTime.UtcNow,
            UpdatedAt = DateTime.UtcNow,
        };
        _db.PricingLibraryItems.Add(item);
        await _db.SaveChangesAsync();

        _jobPublisher.PublishAsync(Arg.Any<string>(), Arg.Any<object>(), Arg.Any<CancellationToken>())
            .Throws(new InvalidOperationException("SQS is down"));

        var request = new UpdatePricingLibraryItemRequest(
            Title: "Updated Despite SQS Failure",
            Description: null,
            ServiceCategory: null,
            Unit: null,
            UnitPrice: null,
            Keywords: null
        );

        var result = await _sut.UpdateAsync(item.Id, request);

        result.Should().NotBeNull();
        result!.Title.Should().Be("Updated Despite SQS Failure");
    }

    #endregion

    #region GetById

    [Fact(DisplayName = "PR5: GetById returns item when it exists")]
    public async Task GetByIdAsync_ExistingItem_ReturnsItem()
    {
        var item = new PricingLibraryItem
        {
            Id = Guid.NewGuid(),
            Title = "Findable Item",
            ServiceCategory = ServiceCategory.Plumbing,
            Source = "Manual",
            CreatedAt = DateTime.UtcNow,
            UpdatedAt = DateTime.UtcNow,
        };
        _db.PricingLibraryItems.Add(item);
        await _db.SaveChangesAsync();

        var result = await _sut.GetByIdAsync(item.Id);

        result.Should().NotBeNull();
        result!.Id.Should().Be(item.Id);
        result.Title.Should().Be("Findable Item");
    }

    [Fact(DisplayName = "PR5: GetById returns null for non-existent item")]
    public async Task GetByIdAsync_NonExistentItem_ReturnsNull()
    {
        var result = await _sut.GetByIdAsync(Guid.NewGuid());

        result.Should().BeNull();
    }

    #endregion

    #region Delete

    [Fact(DisplayName = "PR5: Delete removes item and returns true")]
    public async Task DeleteAsync_ExistingItem_RemovesAndReturnsTrue()
    {
        var item = new PricingLibraryItem
        {
            Id = Guid.NewGuid(),
            Title = "To Be Deleted",
            ServiceCategory = ServiceCategory.General,
            Source = "Manual",
            CreatedAt = DateTime.UtcNow,
            UpdatedAt = DateTime.UtcNow,
        };
        _db.PricingLibraryItems.Add(item);
        await _db.SaveChangesAsync();

        var result = await _sut.DeleteAsync(item.Id);

        result.Should().BeTrue();
        var dbItem = await _db.PricingLibraryItems.FindAsync(item.Id);
        dbItem.Should().BeNull();
    }

    [Fact(DisplayName = "PR5: Delete returns false for non-existent item")]
    public async Task DeleteAsync_NonExistentItem_ReturnsFalse()
    {
        var result = await _sut.DeleteAsync(Guid.NewGuid());

        result.Should().BeFalse();
    }

    #endregion

    #region List

    [Fact(DisplayName = "PR5: List returns paginated results ordered by title")]
    public async Task ListAsync_ReturnsPaginatedResults()
    {
        // Seed 3 items
        var items = new[]
        {
            new PricingLibraryItem { Id = Guid.NewGuid(), Title = "Charlie", ServiceCategory = ServiceCategory.General, Source = "Manual", CreatedAt = DateTime.UtcNow, UpdatedAt = DateTime.UtcNow },
            new PricingLibraryItem { Id = Guid.NewGuid(), Title = "Alpha", ServiceCategory = ServiceCategory.HVAC, Source = "Manual", CreatedAt = DateTime.UtcNow, UpdatedAt = DateTime.UtcNow },
            new PricingLibraryItem { Id = Guid.NewGuid(), Title = "Bravo", ServiceCategory = ServiceCategory.Plumbing, Source = "Manual", CreatedAt = DateTime.UtcNow, UpdatedAt = DateTime.UtcNow },
        };
        _db.PricingLibraryItems.AddRange(items);
        await _db.SaveChangesAsync();

        var result = await _sut.ListAsync(1, 2);

        result.TotalCount.Should().Be(3);
        result.Page.Should().Be(1);
        result.PageSize.Should().Be(2);
        result.Items.Should().HaveCount(2);
        result.Items[0].Title.Should().Be("Alpha");
        result.Items[1].Title.Should().Be("Bravo");
    }

    #endregion
}