NALU/src/Nalu.Web/Endpoints/PlaygroundEndpoints.cs

using System.Collections.Concurrent;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Caching.Memory;
using Nalu.Web.Models;
using Nalu.Web.Services;
using Nalu.Web.Services.LlmRouter;

namespace Nalu.Web.Endpoints;

public static class PlaygroundEndpoints
{
    private const int DailyLimit = 10;

    public static void MapPlaygroundEndpoints(this WebApplication app)
    {
        app.MapPost("/v1/playground/extract/{validator}", async (
            string validator,
            HttpContext ctx,
            [FromBody] ExtractionRequest req,
            ExtractionPipeline pipeline,
            IMemoryCache cache,
            CancellationToken ct) =>
        {
            // IP-based rate limit: 10 calls/IP/day
            var ip = ctx.Connection.RemoteIpAddress?.ToString() ?? "unknown";
            var cacheKey = $"pg:{ip}:{DateTime.UtcNow:yyyyMMdd}";

            var count = cache.GetOrCreate(cacheKey, e =>
            {
                e.AbsoluteExpiration = DateTime.UtcNow.Date.AddDays(1);
                return 0;
            });

            if (count >= DailyLimit)
                return Results.Json(new { error = "Limite diário de 10 chamadas atingido. Crie uma conta para 3.000 créditos grátis." }, statusCode: 429);

            cache.Set(cacheKey, count + 1, new MemoryCacheEntryOptions
            {
                AbsoluteExpiration = DateTime.UtcNow.Date.AddDays(1)
            });

            ctx.Response.Headers["X-Playground-Calls-Remaining"] = (DailyLimit - count - 1).ToString();

            try
            {
                var result = await pipeline.ExecuteAsync($"validate_{validator.Replace("-", "_")}", req, ct);
                return Results.Ok(result);
            }
            catch (Exception ex)
            {
                return Results.Json(new { error = ex.Message }, statusCode: 503);
            }
        })
        .AllowAnonymous()
        .WithTags("Playground")
        .WithSummary("Playground — sem auth, 10 chamadas/IP/dia");
    }
}