using NUnit.Framework;
using ProjectM.Server;
using ProjectM.Simulation;
using Unity.Core;
using Unity.Entities;
using Unity.Mathematics;
using Unity.Transforms;

namespace ProjectM.Tests
{
    /// <summary>
    /// Plain-Entities EditMode tests for the server-only <see cref="ExpeditionGateSystem"/> (walk-in region
    /// transit). A bare world is seeded with an <c>ExpeditionGate</c> (+ LocalTransform) and a player
    /// (RegionTag + LocalTransform + PlayerTag). A player whose region matches the gate's FromRegion and who is
    /// within the gate radius is transited (RegionTag flipped + LocalTransform teleported to ArrivalPos).
    /// Returning to base signals the ThreatDirector (the post-expedition retaliation source) exactly once. Pins
    /// the proximity gate, the region/radius guards, and the return signal.
    /// </summary>
    public class ExpeditionGateSystemTests
    {
        static (World world, SimulationSystemGroup group) MakeWorld(string name)
        {
            var world = new World(name);
            var group = world.GetOrCreateSystemManaged<SimulationSystemGroup>();
            group.AddSystemToUpdateList(world.GetOrCreateSystem<ExpeditionGateSystem>());
            group.SortSystems();
            world.SetTime(new TimeData(elapsedTime: 0f, deltaTime: 1f / 60f));
            return (world, group);
        }

        static void MakeGate(EntityManager em, float3 pos, byte from, byte to, float radius, float3 arrival)
        {
            var e = em.CreateEntity();
            em.AddComponentData(e, LocalTransform.FromPosition(pos));
            em.AddComponentData(e, new ExpeditionGate { FromRegion = from, ToRegion = to, Radius = radius, ArrivalPos = arrival });
        }

        static Entity MakePlayer(EntityManager em, float3 pos, byte region)
        {
            var e = em.CreateEntity();
            em.AddComponentData(e, LocalTransform.FromPosition(pos));
            em.AddComponentData(e, new RegionTag { Region = region });
            em.AddComponent<PlayerTag>(e);
            return e;
        }

        [Test]
        public void Player_In_Gate_Radius_Is_Transited_And_Teleported()
        {
            var (world, group) = MakeWorld("GateTransitWorld");
            using (world)
            {
                var em = world.EntityManager;
                var arrival = new float3(1000, 1, 0);
                MakeGate(em, new float3(0, 1, 0), RegionId.Base, RegionId.Expedition, radius: 15f, arrival: arrival);
                var player = MakePlayer(em, new float3(5, 1, 0), RegionId.Base);

                group.Update();

                Assert.AreEqual(RegionId.Expedition, em.GetComponentData<RegionTag>(player).Region,
                    "Region flips to the gate's ToRegion.");
                var p = em.GetComponentData<LocalTransform>(player).Position;
                Assert.AreEqual(1000f, p.x, 1e-3f, "Player is teleported to the gate's ArrivalPos (x).");
                Assert.AreEqual(0f, p.z, 1e-3f, "Player is teleported to the gate's ArrivalPos (z).");
            }
        }

        [Test]
        public void Player_Outside_Radius_Is_Not_Transited()
        {
            var (world, group) = MakeWorld("GateNoTransitWorld");
            using (world)
            {
                var em = world.EntityManager;
                MakeGate(em, new float3(0, 1, 0), RegionId.Base, RegionId.Expedition, radius: 15f, arrival: new float3(1000, 1, 0));
                var player = MakePlayer(em, new float3(50, 1, 0), RegionId.Base);

                group.Update();

                Assert.AreEqual(RegionId.Base, em.GetComponentData<RegionTag>(player).Region,
                    "A player beyond the gate radius stays in its region.");
            }
        }

        [Test]
        public void Player_Wrong_Region_Is_Not_Transited()
        {
            var (world, group) = MakeWorld("GateWrongRegionWorld");
            using (world)
            {
                var em = world.EntityManager;
                // Gate only acts on players currently in the Base region.
                MakeGate(em, new float3(0, 1, 0), RegionId.Base, RegionId.Expedition, radius: 15f, arrival: new float3(1000, 1, 0));
                var player = MakePlayer(em, new float3(1, 1, 0), RegionId.Expedition);

                group.Update();

                Assert.AreEqual(RegionId.Expedition, em.GetComponentData<RegionTag>(player).Region,
                    "A player whose region does not match FromRegion is ignored even inside the radius.");
            }
        }

        [Test]
        public void Return_To_Base_Signals_ThreatDirector_Once()
        {
            var (world, group) = MakeWorld("GateReturnSignalWorld");
            using (world)
            {
                var em = world.EntityManager;
                MakeGate(em, new float3(0, 1, 0), RegionId.Expedition, RegionId.Base, radius: 15f, arrival: new float3(0, 1, 0));
                MakePlayer(em, new float3(3, 1, 0), RegionId.Expedition);

                var threat = em.CreateEntity(typeof(ThreatState));
                em.SetComponentData(threat, new ThreatState());

                group.Update();

                var ts = em.GetComponentData<ThreatState>(threat);
                Assert.AreEqual(1, ts.PendingReturns,
                    "Returning to base signals the ThreatDirector exactly once (the gate teleports the returner out of its radius).");
                Assert.AreEqual(1, ts.ExpeditionsCompleted, "A completed expedition is counted.");
            }
        }
    }
}