using FastEndpoints;
using MediatR;
using RAG.Application.RagQA.Commands;
using RAG.Application.RagQA.DTOs;

namespace RAG.Api.Endpoints.RAG;

/// <summary>
/// RAG 一次性问答端点（非流式）。返回完整答案 + 命中的来源片段，
/// 适合轻量查询或非交互场景；交互式前端优先用 /rag/stream 获得流式体验。
/// </summary>
public class RAGQueryEndpoint(IMediator mediator) : Endpoint<RAGQueryRequest, RAGQueryResponse>
{
    public override void Configure()
    {
        Post("/rag/query");
        AllowAnonymous();
    }

    public override async Task HandleAsync(RAGQueryRequest req, CancellationToken ct)
    {
        var result = await mediator.Send(new RAGQueryCommand(req.KnowledgeBaseId, req.Question), ct);
        await Send.OkAsync(result, ct);
    }
}

/// <summary>
/// RAG 问答请求校验。/rag/query 与 /rag/stream 共用同一请求 DTO，故此校验对两个端点同时生效。
/// </summary>
public class RAGQueryRequestValidator : Validator<RAGQueryRequest>
{
    public RAGQueryRequestValidator()
    {
        RuleFor(x => x.KnowledgeBaseId).NotEmpty().WithMessage("知识库 ID 不能为空");

        RuleFor(x => x.Question)
            .NotEmpty().WithMessage("问题不能为空")
            .MaximumLength(1000).WithMessage("问题不能超过 1000 个字符");
    }
}