using NUnit.Framework;
using ProjectM.Server;
using Unity.Entities;
using Unity.NetCode;

namespace ProjectM.Tests
{
    /// <summary>
    /// Regression pin for the RPC-leak class the 2026-08-06 audit reproduced live: every RPC receiver in this
    /// project gates itself behind RequireForUpdate on a scene-baked singleton, so in a scene missing that
    /// singleton the receiver never runs and the request entity is never destroyed. Netcode's own stale-RPC
    /// warning Consume()s but never destroys, and is compiled out of player builds — so the entities accumulated
    /// forever, worst in a shipped build.
    ///
    /// <see cref="StaleRpcReaperSystem"/> is the terminal drain. These tests pin the two halves of its contract:
    /// an aged UNCONSUMED request is destroyed, and a CONSUMED one is left alone for its owning receiver.
    /// </summary>
    public class StaleRpcReaperSystemTests
    {
        [Test]
        public void Unconsumed_Request_Is_Destroyed_Once_It_Has_Aged()
        {
            var (world, group) = TestWorld.Make<StaleRpcReaperSystem>("ReaperAged", tick: 100, server: true);
            using (world)
            {
                var em = world.EntityManager;
                var e = em.CreateEntity();
                // Age 2 == "survived a full frame unhandled" (the reaper's k_MaxAgeFrames).
                em.AddComponentData(e, new ReceiveRpcCommandRequest { SourceConnection = Entity.Null, Age = 2 });

                group.Update();

                Assert.IsFalse(em.Exists(e),
                    "an unconsumed RPC request that outlived its receiving frame must be reaped, not leaked forever.");
            }
        }

        [Test]
        public void Fresh_Request_Survives_So_A_Late_Receiver_Still_Sees_It()
        {
            var (world, group) = TestWorld.Make<StaleRpcReaperSystem>("ReaperFresh", tick: 100, server: true);
            using (world)
            {
                var em = world.EntityManager;
                var e = em.CreateEntity();
                em.AddComponentData(e, new ReceiveRpcCommandRequest { SourceConnection = Entity.Null, Age = 0 });

                group.Update();

                Assert.IsTrue(em.Exists(e),
                    "a request that arrived this frame must NOT be reaped — a receiver ordered later still owns it.");
            }
        }

        [Test]
        public void Consumed_Request_Is_Left_To_Its_Receiver()
        {
            var (world, group) = TestWorld.Make<StaleRpcReaperSystem>("ReaperConsumed", tick: 100, server: true);
            using (world)
            {
                var em = world.EntityManager;
                var e = em.CreateEntity();
                var recv = new ReceiveRpcCommandRequest { SourceConnection = Entity.Null, Age = 250 };
                recv.Consume();
                em.AddComponentData(e, recv);

                group.Update();

                Assert.IsTrue(em.Exists(e),
                    "a CONSUMED request belongs to the receiver that consumed it; the reaper must not race it.");
            }
        }
    }
}