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

namespace ProposalSystem.Tests.Services;

/// <summary>
/// PR4: Proposal delivery tests. Verifies that:
/// 1. MarkSent succeeds (transition completes) even when the email service throws.
/// 2. Email is sent when customer and PDF exist.
/// 3. Email is skipped gracefully when customer or PDF is missing.
/// </summary>
public class ProposalDeliveryTests : IDisposable
{
    private readonly Infrastructure.Data.ProposalDbContext _db;
    private readonly ICurrentUserService _currentUser;
    private readonly IAuditService _audit;
    private readonly IJobPublisher _jobPublisher;
    private readonly IProposalNumberGenerator _numberGenerator;
    private readonly IEmailService _emailService;
    private readonly IS3Service _s3Service;
    private readonly ProposalService _sut;
    private readonly Guid _userId;

    public ProposalDeliveryTests()
    {
        _db = DbContextFactory.Create();
        _currentUser = Substitute.For<ICurrentUserService>();
        _audit = Substitute.For<IAuditService>();
        _jobPublisher = Substitute.For<IJobPublisher>();
        _numberGenerator = Substitute.For<IProposalNumberGenerator>();
        _emailService = Substitute.For<IEmailService>();
        _s3Service = Substitute.For<IS3Service>();

        _userId = Guid.NewGuid();
        _currentUser.UserId.Returns(_userId);
        _currentUser.Role.Returns(UserRole.Admin);

        _db.Users.Add(new User
        {
            Id = _userId,
            CognitoSub = $"sub-{_userId}",
            Email = "admin@test.com",
            DisplayName = "Test Admin",
            Role = UserRole.Admin,
            CreatedAt = DateTime.UtcNow,
            UpdatedAt = DateTime.UtcNow,
        });
        _db.SaveChanges();

        var config = new ConfigurationBuilder()
            .AddInMemoryCollection(new Dictionary<string, string?>
            {
                { "GENERATED_BUCKET", "test-bucket" },
            })
            .Build();

        _sut = new ProposalService(_db, _currentUser, _numberGenerator, _audit, _jobPublisher,
            _emailService, _s3Service, config,
            Substitute.For<ILogger<ProposalService>>());
    }

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

    [Fact(DisplayName = "PR4: MarkSent completes transition even when email service throws")]
    public async Task MarkSentAsync_EmailServiceThrows_TransitionStillCompletes()
    {
        // Arrange — customer with email and a generated PDF
        var proposal = CreateProposal(ProposalStatus.Approved, "Failing Customer");
        _db.Proposals.Add(proposal);

        _db.Customers.Add(new Customer
        {
            Id = Guid.NewGuid(),
            Name = "Failing Customer",
            ContactEmail = "test@example.com",
            CreatedAt = DateTime.UtcNow,
            UpdatedAt = DateTime.UtcNow,
        });

        _db.GeneratedPdfs.Add(new GeneratedPdf
        {
            Id = Guid.NewGuid(),
            ProposalId = proposal.Id,
            Revision = 1,
            S3Key = "pdfs/test.pdf",
            GeneratedAt = DateTime.UtcNow,
            GeneratedById = _userId,
        });
        await _db.SaveChangesAsync();

        _s3Service.GeneratePresignedDownloadUrlAsync(Arg.Any<string>(), Arg.Any<string>(), Arg.Any<int>())
            .Returns("https://s3.example.com/test.pdf");

        // Make the email service throw
        _emailService.SendProposalDeliveryAsync(
            Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<CancellationToken>())
            .Throws(new InvalidOperationException("SES is down"));

        // Act — should NOT throw
        var result = await _sut.MarkSentAsync(proposal.Id, Ver(proposal.Id));

        // Assert — transition completed despite email failure
        result.Status.Should().Be(ProposalStatus.Sent);
        result.SentAt.Should().NotBeNull();
    }

    [Fact(DisplayName = "PR4: MarkSent sends email when customer and PDF exist")]
    public async Task MarkSentAsync_CustomerAndPdfExist_SendsEmail()
    {
        // Arrange
        var proposal = CreateProposal(ProposalStatus.Approved, "Acme Corp");
        _db.Proposals.Add(proposal);

        _db.Customers.Add(new Customer
        {
            Id = Guid.NewGuid(),
            Name = "Acme Corp",
            ContactEmail = "billing@acme.com",
            CreatedAt = DateTime.UtcNow,
            UpdatedAt = DateTime.UtcNow,
        });

        _db.GeneratedPdfs.Add(new GeneratedPdf
        {
            Id = Guid.NewGuid(),
            ProposalId = proposal.Id,
            Revision = 1,
            S3Key = "pdfs/acme.pdf",
            GeneratedAt = DateTime.UtcNow,
            GeneratedById = _userId,
        });
        await _db.SaveChangesAsync();

        _s3Service.GeneratePresignedDownloadUrlAsync("test-bucket", "pdfs/acme.pdf", 7 * 24 * 60)
            .Returns("https://s3.example.com/acme.pdf");

        // Act
        var result = await _sut.MarkSentAsync(proposal.Id, Ver(proposal.Id));

        // Assert
        result.Status.Should().Be(ProposalStatus.Sent);
        await _emailService.Received(1).SendProposalDeliveryAsync(
            "billing@acme.com",
            proposal.ProposalNumber,
            "Acme Corp",
            "https://s3.example.com/acme.pdf",
            Arg.Any<CancellationToken>());
    }

    [Fact(DisplayName = "PR4: MarkSent skips email when customer has no ContactEmail")]
    public async Task MarkSentAsync_NoContactEmail_SkipsEmail()
    {
        // Arrange
        var proposal = CreateProposal(ProposalStatus.Approved, "No Email Corp");
        _db.Proposals.Add(proposal);

        _db.Customers.Add(new Customer
        {
            Id = Guid.NewGuid(),
            Name = "No Email Corp",
            ContactEmail = null,
            CreatedAt = DateTime.UtcNow,
            UpdatedAt = DateTime.UtcNow,
        });
        await _db.SaveChangesAsync();

        // Act
        var result = await _sut.MarkSentAsync(proposal.Id, Ver(proposal.Id));

        // Assert
        result.Status.Should().Be(ProposalStatus.Sent);
        await _emailService.DidNotReceive().SendProposalDeliveryAsync(
            Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<CancellationToken>());
    }

    [Fact(DisplayName = "PR4: MarkSent skips email when no customer record matches")]
    public async Task MarkSentAsync_NoCustomerRecord_SkipsEmail()
    {
        // Arrange — no customer in DB
        var proposal = CreateProposal(ProposalStatus.Approved, "Unknown Customer");
        _db.Proposals.Add(proposal);
        await _db.SaveChangesAsync();

        // Act
        var result = await _sut.MarkSentAsync(proposal.Id, Ver(proposal.Id));

        // Assert
        result.Status.Should().Be(ProposalStatus.Sent);
        await _emailService.DidNotReceive().SendProposalDeliveryAsync(
            Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<CancellationToken>());
    }

    [Fact(DisplayName = "PR4: MarkSent skips email when no PDF has been generated")]
    public async Task MarkSentAsync_NoPdfGenerated_SkipsEmail()
    {
        // Arrange — customer exists but no PDF
        var proposal = CreateProposal(ProposalStatus.Approved, "PDF-less Corp");
        _db.Proposals.Add(proposal);

        _db.Customers.Add(new Customer
        {
            Id = Guid.NewGuid(),
            Name = "PDF-less Corp",
            ContactEmail = "contact@pdfless.com",
            CreatedAt = DateTime.UtcNow,
            UpdatedAt = DateTime.UtcNow,
        });
        await _db.SaveChangesAsync();

        // Act
        var result = await _sut.MarkSentAsync(proposal.Id, Ver(proposal.Id));

        // Assert
        result.Status.Should().Be(ProposalStatus.Sent);
        await _emailService.DidNotReceive().SendProposalDeliveryAsync(
            Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<CancellationToken>());
    }

    private Proposal CreateProposal(ProposalStatus status, string customerName)
    {
        return new Proposal
        {
            Id = Guid.NewGuid(),
            ProposalNumber = $"SHI-2026-{Guid.NewGuid():N}"[..16],
            WorkOrderNumber = "WO-001",
            CustomerName = customerName,
            CustomerAddress = "123 Test St",
            ScopeOfWork = "Test scope of work",
            ServiceCategory = ServiceCategory.HVAC,
            Priority = Priority.Standard,
            Status = status,
            Notes = "",
            SubmittedById = _userId,
            SubmittedAt = DateTime.UtcNow.AddDays(-1),
            CurrentRevision = 1,
            CreatedAt = DateTime.UtcNow.AddDays(-1),
            UpdatedAt = DateTime.UtcNow.AddDays(-1),
        };
    }
    private string Ver(Guid id) =>
        ProposalSystem.Application.Common.RowVersionCodec.Encode(_db.Proposals.Find(id)?.Version ?? 1);

}