using BuildFlow.Application.Chat.Commands;
using BuildFlow.Application.Chat.Handlers;
using BuildFlow.Domain.Entities;
using BuildFlow.Domain.Enums;
using BuildFlow.Infrastructure.Persistence;
using BuildFlow.Rag.Tests.Stub;
using BuildFlow.Shared.Domain.Common;
using BuildFlow.Shared.Domain.Exceptions;
using BuildFlow.Shared.Infrastructure;
using FluentAssertions;
using Microsoft.EntityFrameworkCore;
using Xunit;

namespace BuildFlow.Rag.Tests;

/// <summary>
/// [SOP-RAG-02] 多轮对话端到端测试。
/// 不依赖 pgvector。验证:CreateConversation → SendMessage(两轮)→ 历史拼装 → cache 一致性。
/// 飞书文档: https://ecn1rid3e27z.feishu.cn/wiki/CBrcwbDH6ialzFkF1cgcnvKenHM
/// </summary>
public class ChatEndToEndTests
{
    private static RagDbContext CreateDb(string name)
    {
        // 挂生产 AuditInterceptor,自动填充 CreatedBy/UpdatedBy/OperatorIP 等审计字段
        // (InMemory 默认无拦截器,导致必填审计字段为空抛 DbUpdateException)
        var userContext = new TestCurrentUserContext();
        var options = new DbContextOptionsBuilder<RagDbContext>()
            .UseInMemoryDatabase($"rag-chat-{name}-{Guid.NewGuid():N}")
            .AddInterceptors(new AuditInterceptor(userContext))
            .Options;
        return new RagDbContext(options);
    }

    private static void SeedConversation(RagDbContext db, Guid conversationId, Guid userId)
    {
        db.Conversations.Add(new Conversation
        {
            Id = conversationId,
            Title = "测试会话",
            UserId = userId
        });
        db.SaveChanges();
    }

    [Fact]
    public async Task CreateConversation_ReturnsConversationDto()
    {
        // Given
        await using var db = CreateDb("create");
        var userContext = new TestCurrentUserContext();
        var handler = new CreateConversationCommandHandler(db, userContext);

        // When
        var result = await handler.Handle(
            new CreateConversationCommand("我的对话", null),
            CancellationToken.None);

        // Then
        result.Title.Should().Be("我的对话");
        result.UserId.Should().Be(Guid.Parse(userContext.UserId));
        result.Id.Should().NotBeEmpty();
        db.Conversations.Should().ContainSingle();
    }

    [Fact]
    public async Task SendMessage_TwoRounds_HistoryAssembledAndCacheConsistent()
    {
        // Given: 已创建会话 + 两轮对话
        await using var db = CreateDb("multi-turn");
        var userId = Guid.Parse(new TestCurrentUserContext().UserId);
        var conversationId = Guid.NewGuid();
        SeedConversation(db, conversationId, userId);

        var cache = new StubChatMessageCache();
        var chatAgent = new StubAIChatAgent { ReplyText = "你好！我是 AI 助手。" };
        var handler = new SendMessageCommandHandler(db, chatAgent, cache);

        // When: 第一轮
        var round1 = await handler.Handle(
            new SendMessageCommand(conversationId, "你好"),
            CancellationToken.None);

        // Then: 第一轮返回 messageId + 内容
        round1.MessageId.Should().NotBeEmpty();
        round1.Content.Should().Be("你好！我是 AI 助手。");

        // DB: 1 user + 1 assistant = 2 条消息
        db.ChatMessages.Should().HaveCount(2);
        db.ChatMessages.Count(m => m.Role == ChatRole.User).Should().Be(1);
        db.ChatMessages.Count(m => m.Role == ChatRole.Assistant).Should().Be(1);

        // Cache: 同步 2 条
        cache.Count(conversationId).Should().Be(2, "cache 与 DB 一致");

        // When: 第二轮(验证历史拼装 - Stub chatAgent 不依赖历史但 Handler 应查历史)
        var round2 = await handler.Handle(
            new SendMessageCommand(conversationId, "我刚才说了什么?"),
            CancellationToken.None);

        // Then: 第二轮同样返回
        round2.MessageId.Should().NotBeEmpty();
        round2.Content.Should().NotBeNullOrEmpty();

        // DB: 累计 4 条(2 user + 2 assistant)
        db.ChatMessages.Should().HaveCount(4);
        cache.Count(conversationId).Should().Be(4, "两轮后 cache 4 条");
    }

    [Fact]
    public async Task SendMessage_ConversationNotFound_ThrowsNotFoundException()
    {
        // Given: 会话不存在
        await using var db = CreateDb("not-found");
        var cache = new StubChatMessageCache();
        var chatAgent = new StubAIChatAgent();
        var handler = new SendMessageCommandHandler(db, chatAgent, cache);

        // When/Then: 发消息到不存在的会话
        var act = async () => await handler.Handle(
            new SendMessageCommand(Guid.NewGuid(), "内容"),
            CancellationToken.None);

        await act.Should().ThrowAsync<NotFoundException>();
    }

    [Fact]
    public async Task CreateConversation_UnauthorizedUser_Throws()
    {
        // Given: UserId = "system"(未授权)
        await using var db = CreateDb("unauth");
        var userContext = new TestCurrentUserContext { UserId = "system" };
        var handler = new CreateConversationCommandHandler(db, userContext);

        // When/Then
        var act = async () => await handler.Handle(
            new CreateConversationCommand("x", null),
            CancellationToken.None);

        await act.Should().ThrowAsync<UnauthorizedException>("未授权用户不能创建会话");
    }
}