using BuildFlow.Application.Document.Commands;
using BuildFlow.Application.Document.Handlers;
using BuildFlow.Domain.Entities.Document;
using BuildFlow.Domain.Entities.KnowledgeBase;
using BuildFlow.Domain.Enums;
using BuildFlow.Domain.Interfaces;
using BuildFlow.Infrastructure.AI;
using BuildFlow.Infrastructure.Persistence;
using BuildFlow.Rag.Tests.Stub;
using BuildFlow.Shared.Domain.Exceptions;
using File.Application.Features.Files.DTOs;
using File.Application.Features.Files.Queries;
using MediatR;
using Microsoft.EntityFrameworkCore;
using Moq;
using Xunit;

namespace BuildFlow.Rag.Tests;

/// <summary>
/// 文档处理测试。远端对象必须通过 File Application 下载，并在提取后释放响应流。
/// </summary>
public class ProcessDocumentCommandHandlerTests
{
    [Fact]
    public async Task Handle_ShouldDownloadThroughFileQueryAndDisposeStream()
    {
        await using var db = CreateDb();
        var knowledgeBaseId = Guid.NewGuid();
        var documentId = Guid.NewGuid();
        SeedRemoteDocument(db, knowledgeBaseId, documentId);
        await db.SaveChangesAsync();
        var stream = new TrackingMemoryStream("empty"u8.ToArray());
        var mediator = new Mock<IMediator>();
        mediator.Setup(m => m.Send(
                It.Is<DownloadFileQuery>(query => query.ObjectKey == "docs/kb/document.md"),
                It.IsAny<CancellationToken>()))
            .ReturnsAsync(new DownloadFileResult(stream, "text/markdown", "document.md"));
        var handler = new ProcessDocumentCommandHandler(
            db,
            new EmptyDocumentExtractorFactory(),
            new TextChunker(),
            new StubEmbeddingService(),
            mediator.Object);

        await Assert.ThrowsAsync<BusinessException>(() => handler.Handle(
            new ProcessDocumentCommand(documentId), CancellationToken.None));

        Assert.True(stream.IsDisposed);
        mediator.Verify(m => m.Send(
            It.Is<DownloadFileQuery>(query => query.ObjectKey == "docs/kb/document.md"),
            It.IsAny<CancellationToken>()), Times.Once);
    }

    private static RagDbContext CreateDb() => new(
        new DbContextOptionsBuilder<RagDbContext>()
            .UseInMemoryDatabase($"rag-process-{Guid.NewGuid():N}")
            .Options);

    private static void SeedRemoteDocument(RagDbContext db, Guid knowledgeBaseId, Guid documentId)
    {
        db.KnowledgeBases.Add(new KnowledgeBaseEntity
        {
            Id = knowledgeBaseId,
            Name = "Process",
            Status = KnowledgeBaseStatusEnum.Active,
            CreatedBy = "test",
            UpdatedBy = "test",
            OperatorIP = "127.0.0.1",
        });
        db.Documents.Add(new DocumentEntity
        {
            Id = documentId,
            KnowledgeBaseId = knowledgeBaseId,
            Title = "document.md",
            FileName = "document.md",
            FilePath = "rag-documents/docs/kb/document.md",
            FileSize = 5,
            ContentType = "text/markdown",
            Status = DocumentStatusEnum.Pending,
            CreatedBy = "test",
            UpdatedBy = "test",
            OperatorIP = "127.0.0.1",
        });
    }

    private sealed class EmptyDocumentExtractorFactory : IDocumentExtractorFactory
    {
        public IDocumentExtractor GetExtractor(string fileNameOrExtension) => new EmptyDocumentExtractor();
    }

    private sealed class EmptyDocumentExtractor : IDocumentExtractor
    {
        public IReadOnlyCollection<string> SupportedExtensions { get; init; } = ["md"];

        public Task<ExtractedDocument> ExtractAsync(string filePath, CancellationToken ct = default) =>
            Task.FromResult(new ExtractedDocument { Content = " " });
    }
}