using ProjectM.Simulation;
using Unity.Entities;
using Unity.Mathematics;
using Unity.NetCode;
using Unity.Transforms;

namespace ProjectM.Client
{
    /// <summary>
    /// Client-only sender for build + upgrade RPCs. Keyboard: B builds a Turret at the local player's current
    /// grid cell; U upgrades ability damage. Editor-only statics (PlaceStructure / PlaceTurret / UpgradeAbility)
    /// drive the same path from execute_code for headless validation (a one-shot key can't be injected on an
    /// unfocused editor — the StorageOpSendSystem idiom). Managed SystemBase (reads the Input System);
    /// UnityEngine.InputSystem is fully qualified to avoid the ProjectM.Simulation.PlayerInput name collision.
    /// The server re-validates legality + cost authoritatively; this only sends a hint.
    /// </summary>
    [WorldSystemFilter(WorldSystemFilterFlags.ClientSimulation)]
    public partial class BuildSendSystem : SystemBase
    {
#if UNITY_EDITOR
        struct PendingBuild { public byte Type; public int CellX; public int CellZ; }
        static readonly System.Collections.Generic.Queue<PendingBuild> s_PendingBuild =
            new System.Collections.Generic.Queue<PendingBuild>();
        static int s_PendingUpgrades = 0;

        /// <summary>EDITOR / execute_code hook: queue a structure placement at a specific cell.</summary>
        public static void PlaceStructure(byte type, int cellX, int cellZ) =>
            s_PendingBuild.Enqueue(new PendingBuild { Type = type, CellX = cellX, CellZ = cellZ });

        /// <summary>EDITOR / execute_code hook: queue a turret placement at a specific cell.</summary>
        public static void PlaceTurret(int cellX, int cellZ) => PlaceStructure(StructureType.Turret, cellX, cellZ);

        /// <summary>EDITOR / execute_code hook: queue an ability-damage upgrade.</summary>
        public static void UpgradeAbility() => s_PendingUpgrades++;
#endif

        protected override void OnCreate()
        {
            RequireForUpdate<NetworkId>();
        }

        protected override void OnUpdate()
        {
            if (!SystemAPI.TryGetSingletonEntity<NetworkId>(out var connection))
                return;

            var keyboard = UnityEngine.InputSystem.Keyboard.current;
            if (keyboard != null)
            {
                if (keyboard.bKey.wasPressedThisFrame && TryGetLocalPlayerCell(out int2 cell))
                    SendBuild(connection, StructureType.Turret, cell.x, cell.y);
                if (keyboard.uKey.wasPressedThisFrame)
                    SendUpgrade(connection);
            }

#if UNITY_EDITOR
            while (s_PendingBuild.Count > 0)
            {
                var b = s_PendingBuild.Dequeue();
                SendBuild(connection, b.Type, b.CellX, b.CellZ);
            }
            while (s_PendingUpgrades > 0)
            {
                s_PendingUpgrades--;
                SendUpgrade(connection);
            }
#endif
        }

        bool TryGetLocalPlayerCell(out int2 cell)
        {
            cell = default;
            if (!SystemAPI.TryGetSingleton<BaseAnchor>(out var anchor))
                return false;
            foreach (var xform in SystemAPI.Query<RefRO<LocalTransform>>().WithAll<GhostOwnerIsLocal, PlayerTag>())
            {
                cell = BaseGridMath.WorldToCell(anchor, xform.ValueRO.Position);
                return true;
            }
            return false;
        }

        void SendBuild(Entity connection, byte type, int cellX, int cellZ)
        {
            var e = EntityManager.CreateEntity();
            EntityManager.AddComponentData(e, new BuildPlaceRequest { StructureType = type, CellX = cellX, CellZ = cellZ });
            EntityManager.AddComponentData(e, new SendRpcCommandRequest { TargetConnection = connection });
        }

        void SendUpgrade(Entity connection)
        {
            var e = EntityManager.CreateEntity();
            EntityManager.AddComponentData(e, new AbilityUpgradeRequest());
            EntityManager.AddComponentData(e, new SendRpcCommandRequest { TargetConnection = connection });
        }
    }
}