using System.Threading.RateLimiting;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

namespace StartupHelpers;

public static class RateLimitingExtensions
{
    public static void AddPublicApiRateLimiting(this IServiceCollection services)
    {
        services.AddRateLimiter(options =>
        {
            options.GlobalLimiter = PartitionedRateLimiter.Create<HttpContext, string>(httpContext =>
            {
                var ip = httpContext.Connection.RemoteIpAddress?.ToString() ?? "unknown";
                return RateLimitPartition.GetFixedWindowLimiter(
                    partitionKey: ip,
                    factory: _ => new FixedWindowRateLimiterOptions
                    {
                        PermitLimit = 120,
                        Window = TimeSpan.FromMinutes(1),
                        QueueLimit = 0,
                        AutoReplenishment = true
                    });
            });

            options.AddPolicy("contact", httpContext =>
            {
                var ip = httpContext.Connection.RemoteIpAddress?.ToString() ?? "unknown";
                return RateLimitPartition.GetFixedWindowLimiter(
                    partitionKey: ip,
                    factory: _ => new FixedWindowRateLimiterOptions
                    {
                        PermitLimit = 5,
                        Window = TimeSpan.FromMinutes(1),
                        QueueLimit = 0,
                        AutoReplenishment = true
                    });
            });

            options.AddPolicy("cv-matcher", httpContext =>
            {
                var ip = httpContext.Connection.RemoteIpAddress?.ToString() ?? "unknown";
                return RateLimitPartition.GetFixedWindowLimiter(
                    partitionKey: ip,
                    factory: _ => new FixedWindowRateLimiterOptions
                    {
                        PermitLimit = 10,
                        Window = TimeSpan.FromMinutes(10),
                        QueueLimit = 0,
                        AutoReplenishment = true
                    });
            });

            options.RejectionStatusCode = StatusCodes.Status429TooManyRequests;
            options.OnRejected = async (context, ct) =>
            {
                var logger = context.HttpContext.RequestServices
                    .GetRequiredService<ILoggerFactory>()
                    .CreateLogger("RateLimiting");

                var ip = context.HttpContext.Connection.RemoteIpAddress?.ToString() ?? "unknown";
                var endpoint = context.HttpContext.Request.Path;

                logger.LogWarning("Rate limit exceeded for {Endpoint} from IP {IP}", endpoint, ip);

                context.HttpContext.Response.ContentType = "application/json";
                await context.HttpContext.Response.WriteAsync("""{"error":"Too many requests. Try again later."}""", ct);
            };
        });
    }
}