using BuildFlow.Application.Document.Handlers;
using BuildFlow.Application.Document.Queries;
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 Microsoft.AspNetCore.Http;
using Microsoft.EntityFrameworkCore;
using Xunit;

namespace BuildFlow.Rag.Tests;

/// <summary>
/// 文档切片预览测试。预览只提取并分块，不生成 embedding，也不写入正式分块表。
/// </summary>
public class PreviewDocumentChunksQueryHandlerTests
{
    [Fact]
    public async Task HandleShouldReturnDryRunChunksWithoutPersistingDocumentChunks()
    {
        var options = new DbContextOptionsBuilder<RagDbContext>()
            .UseInMemoryDatabase($"rag-preview-{Guid.NewGuid():N}")
            .Options;
        await using var db = new RagDbContext(options);
        var kbId = Guid.NewGuid();
        var docId = Guid.NewGuid();
        var filePath = Path.Combine(Path.GetTempPath(), $"preview-{Guid.NewGuid():N}.md");
        await File.WriteAllTextAsync(filePath, "# 第一章\n\nBuildFlow 文档切片预览。\n\n# 第二章\n\n上传后先看切片，再手动处理向量。");

        try
        {
            await db.KnowledgeBases.AddAsync(new KnowledgeBaseEntity
            {
                Id = kbId,
                Name = "预览知识库",
                ChunkSize = 40,
                ChunkOverlap = 5,
                ChunkingMode = ChunkingModeEnum.Heading,
                EmbeddingModel = "text-embedding-embeddinggemma-300m",
                Status = KnowledgeBaseStatusEnum.Active,
                CreatedBy = "test",
                UpdatedBy = "test",
                OperatorIP = "127.0.0.1",
            });
            await db.Documents.AddAsync(new DocumentEntity
            {
                Id = docId,
                KnowledgeBaseId = kbId,
                Title = "preview.md",
                FileName = "preview.md",
                FilePath = filePath,
                FileSize = 64,
                ContentType = "text/markdown",
                Status = DocumentStatusEnum.Pending,
                CreatedBy = "test",
                UpdatedBy = "test",
                OperatorIP = "127.0.0.1",
            });
            await db.SaveChangesAsync();

            var handler = new PreviewDocumentChunksQueryHandler(
                db,
                new StubDocumentExtractorFactory(),
                new TextChunker(),
                new StubFileStorageClient(),
                new HttpContextAccessor());

            var result = await handler.Handle(new PreviewDocumentChunksQuery(docId), CancellationToken.None);

            Assert.Equal(2, result.Count);
            Assert.All(result, chunk => Assert.False(chunk.HasEmbedding));
            Assert.Contains("第一章", result[0].Content);
            Assert.Contains("第二章", result[1].Content);
            Assert.Equal(0, await db.DocumentChunks.CountAsync());
        }
        finally
        {
            File.Delete(filePath);
        }
    }

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

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

        public async Task<ExtractedDocument> ExtractAsync(string filePath, CancellationToken ct = default)
        {
            return new ExtractedDocument
            {
                Content = await File.ReadAllTextAsync(filePath, ct),
                Title = Path.GetFileName(filePath),
            };
        }
    }

    private sealed class StubFileStorageClient : IFileStorageClient
    {
        public Task UploadAsync(
            string bucket,
            string objectKey,
            Stream content,
            string contentType,
            string? authToken,
            CancellationToken ct = default) => Task.CompletedTask;

        public Task<Stream> DownloadAsync(string bucket, string objectKey, string? authToken, CancellationToken ct = default)
            => throw new InvalidOperationException("本用例不应下载文件服务对象");
    }
}