using System.Reflection;
using Unity.Entities;
using UnityEngine;
using UnityEngine.LowLevel;
using UnityEngine.PlayerLoop;

public class WorldBootStrap : ICustomBootstrap
{

    static MethodInfo insertManagerIntoSubsystemListMethod = typeof(ScriptBehaviourUpdateOrder).GetMethod("InsertManagerIntoSubsystemList", BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Static);

    public bool Initialize(string defaultWorldName)
    {
        Debug.Log("Executing World Bootstrap");
        var world = new World("Custom World");
        World.DefaultGameObjectInjectionWorld = world;
        var systems = DefaultWorldInitialization.GetAllSystems(WorldSystemFilterFlags.Default);
        DefaultWorldInitialization.AddSystemsToRootLevelSystemGroups(world, systems);
        UpdatePlayerLoop(world);
        return true;
    }

    //public struct Settings
    //{
    //    public float DefaultFixedTimeStep;
    //}

    public static void UpdatePlayerLoop(World world)
    {
        var playerLoop = PlayerLoop.GetDefaultPlayerLoop();
        if (ScriptBehaviourUpdateOrder.CurrentPlayerLoop.subSystemList != null)
            playerLoop = ScriptBehaviourUpdateOrder.CurrentPlayerLoop;
        if (world != null)
        {
            for (var i = 0; i < playerLoop.subSystemList.Length; ++i)
            {
                int subsystemListLength = playerLoop.subSystemList[i].subSystemList.Length;
                if (playerLoop.subSystemList[i].type == typeof(Update))
                {
                    var newSubsystemList = new PlayerLoopSystem[subsystemListLength + 1];
                    for (var j = 0; j < subsystemListLength; ++j)
                        newSubsystemList[j] = playerLoop.subSystemList[i].subSystemList[j];

                    var mgr = world.GetOrCreateSystem<SimulationSystemGroup>();
                    //string json = File.ReadAllText(Application.dataPath + "/settings.json");
                    //Settings settings = JsonUtility.FromJson<Settings>(json);
                    var temp = world.GetOrCreateSystem<FixedRateManagerSystem>();
                    temp.EnableFixedRateWithCatchUp(mgr, (1f / 48f));
                    Time.fixedDeltaTime = (1f / 48f);
                    var genericMethod = insertManagerIntoSubsystemListMethod.MakeGenericMethod(mgr.GetType());
                    genericMethod.Invoke(null, new object[] { newSubsystemList, subsystemListLength + 0, mgr });
                    playerLoop.subSystemList[i].subSystemList = newSubsystemList;
                }
                else if (playerLoop.subSystemList[i].type == typeof(PreLateUpdate))
                {
                    var newSubsystemList = new PlayerLoopSystem[subsystemListLength + 1];
                    for (var j = 0; j < subsystemListLength; ++j)
                        newSubsystemList[j] = playerLoop.subSystemList[i].subSystemList[j];
                    var mgr = world.GetOrCreateSystem<PresentationSystemGroup>();
                    var genericMethod = insertManagerIntoSubsystemListMethod.MakeGenericMethod(mgr.GetType());
                    genericMethod.Invoke(null, new object[] { newSubsystemList, subsystemListLength + 0, mgr });
                    playerLoop.subSystemList[i].subSystemList = newSubsystemList;
                }
                else if (playerLoop.subSystemList[i].type == typeof(Initialization))
                {
                    var newSubsystemList = new PlayerLoopSystem[subsystemListLength + 1];
                    for (var j = 0; j < subsystemListLength; ++j)
                        newSubsystemList[j] = playerLoop.subSystemList[i].subSystemList[j];
                    var mgr = world.GetOrCreateSystem<InitializationSystemGroup>();
                    var genericMethod = insertManagerIntoSubsystemListMethod.MakeGenericMethod(mgr.GetType());
                    genericMethod.Invoke(null, new object[] { newSubsystemList, subsystemListLength + 0, mgr });
                    playerLoop.subSystemList[i].subSystemList = newSubsystemList;
                }
            }
        }

        ScriptBehaviourUpdateOrder.SetPlayerLoop(playerLoop);
    }
}