using System.Collections.Generic;
using ProjectM.Simulation;
using Unity.Entities;
using Unity.NetCode;
using UnityEngine;

namespace ProjectM.Client
{
    /// <summary>
    /// Client-side class-pick sender: a static enqueue (the Staging class-select HUD buttons) drained into
    /// <see cref="ClassSelectRequest"/> RPCs (the MetaSpendSendSystem idiom). Carries only the class id; the server
    /// re-validates the phase + applies the full swap. Statics reset on play-enter (the stale-bridge hazard).
    /// </summary>
    [WorldSystemFilter(WorldSystemFilterFlags.ClientSimulation)]
    public partial class ClassSelectSendSystem : SystemBase
    {
        static readonly Queue<byte> s_Queue = new();

        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
        static void ResetStatics() => s_Queue.Clear();

        /// <summary>Queue a class pick (0=Warrior, 1=Ranger). The Staging class buttons drive this.</summary>
        public static void RequestClass(byte classId) => s_Queue.Enqueue(classId);

        protected override void OnCreate() => RequireForUpdate<NetworkId>();

        protected override void OnUpdate()
        {
            while (s_Queue.Count > 0)
            {
                var req = EntityManager.CreateEntity(typeof(ClassSelectRequest), typeof(SendRpcCommandRequest));
                EntityManager.SetComponentData(req, new ClassSelectRequest { ClassId = s_Queue.Dequeue() });
            }
        }
    }
}