using ProjectM.Simulation;
using Unity.Burst;
using Unity.Collections;
using Unity.Entities;
using Unity.NetCode;

namespace ProjectM.Server
{
    /// <summary>
    /// Server receiver for <see cref="PortalInteractRequest"/> — a participant interacting the room-exit portal during
    /// RoomExplore. Honored ONLY when <c>RunInfo.Lifecycle==RoomExplore</c> and the sender is an EXPEDITION player
    /// (region gate, the RouteSelect idiom). Sets the server-only <see cref="PortalCommand"/> latch IN-PLACE; it does
    /// NOT write RunInfo or tear the room down — RunDirectorSystem (the sole FSM/teardown owner) consumes the latch and
    /// advances. Plain server group, before RunDirectorSystem; requests ALWAYS destroyed; NO CyclePhase edge.
    /// </summary>
    [BurstCompile]
    [WorldSystemFilter(WorldSystemFilterFlags.ServerSimulation)]
    [UpdateInGroup(typeof(SimulationSystemGroup))]
    [UpdateBefore(typeof(RunDirectorSystem))]
    public partial struct PortalInteractReceiveSystem : ISystem
    {
        [BurstCompile]
        public void OnCreate(ref SystemState state)
        {
            var b = new EntityQueryBuilder(Allocator.Temp).WithAll<PortalInteractRequest, ReceiveRpcCommandRequest>();
            state.RequireForUpdate(state.GetEntityQuery(b));
            state.RequireForUpdate<RunInfo>();
            state.RequireForUpdate<PortalCommand>();
        }

        [BurstCompile]
        public void OnUpdate(ref SystemState state)
        {
            var dirEntity = SystemAPI.GetSingletonEntity<RunInfo>();
            bool gateOpen = SystemAPI.GetComponent<RunInfo>(dirEntity).Lifecycle == RunLifecycle.RoomExplore;

            // Sender region lookup (N3 idiom): a base-bound joiner cannot pull the party out of the room.
            var regionByConn = new NativeHashMap<int, byte>(8, Allocator.Temp);
            foreach (var (owner, region) in
                     SystemAPI.Query<RefRO<GhostOwner>, RefRO<RegionTag>>().WithAll<PlayerTag>())
                regionByConn[owner.ValueRO.NetworkId] = region.ValueRO.Region;

            bool interacted = SystemAPI.GetComponent<PortalCommand>(dirEntity).HasInteract != 0;

            var ecb = new EntityCommandBuffer(Allocator.Temp);
            foreach (var (receive, requestEntity) in
                     SystemAPI.Query<RefRO<ReceiveRpcCommandRequest>>().WithAll<PortalInteractRequest>().WithEntityAccess())
            {
                var conn = receive.ValueRO.SourceConnection;
                bool valid = gateOpen && !interacted
                    && SystemAPI.HasComponent<NetworkId>(conn)
                    && regionByConn.TryGetValue(SystemAPI.GetComponent<NetworkId>(conn).Value, out byte senderRegion)
                    && senderRegion == RegionId.Expedition;
                if (valid)
                {
                    SystemAPI.SetComponent(dirEntity, new PortalCommand { HasInteract = 1 });
                    interacted = true;
                }
                ecb.DestroyEntity(requestEntity);
            }
            ecb.Playback(state.EntityManager);
            ecb.Dispose();
            regionByConn.Dispose();
        }
    }
}