TechbloxModdingAPI/TechbloxModdingAPI/Blocks/Engines/RemovalEngine.cs

using System.Reflection;

using HarmonyLib;
using RobocraftX.Blocks;
using RobocraftX.Common;
using Svelto.Common;
using Svelto.ECS;
using Svelto.ECS.Native;

using TechbloxModdingAPI.Engines;
using TechbloxModdingAPI.Utility;

namespace TechbloxModdingAPI.Blocks.Engines
{
    public class RemovalEngine : IApiEngine
    {
        private static IEntityFunctions _entityFunctions;
        private static MachineGraphConnectionEntityFactory _connectionFactory;

        public bool RemoveBlock(EGID target)
        {
            if (!entitiesDB.Exists<MachineGraphConnectionsEntityStruct>(target))
                return false;
            var connections = entitiesDB.QueryEntity<MachineGraphConnectionsEntityStruct>(target);
            var groups = entitiesDB.FindGroups<MachineGraphConnectionsEntityStruct>();
            using var connStructMapper = //The allocator needs to be persistent because that's what is used in the Dispose() method
                entitiesDB.QueryNativeMappedEntities<MachineGraphConnectionsEntityStruct>(groups, Allocator.Persistent);
            for (int i = connections.connections.Count<MachineConnectionStruct>() - 1; i >= 0; i--)
                _connectionFactory.RemoveConnection(connections, i, connStructMapper);
            _entityFunctions.RemoveEntity<BlockEntityDescriptor>(target);
            return true;
        }

        public void Ready()
        {
        }

        public EntitiesDB entitiesDB { get; set; }

        public void Dispose()
        {
        }

        public string Name { get; } = "TechbloxModdingAPIRemovalGameEngine";

		public bool isRemovable => false;

		[HarmonyPatch]
        class FactoryObtainerPatch
        {
            static void Postfix(IEntityFunctions entityFunctions,
                MachineGraphConnectionEntityFactory machineGraphConnectionEntityFactory)
            {
                _entityFunctions = entityFunctions;
                _connectionFactory = machineGraphConnectionEntityFactory;
                Logging.MetaDebugLog("Requirements injected.");
            }

            static MethodBase TargetMethod(Harmony instance)
            {
                return AccessTools.TypeByName("RobocraftX.CR.MachineEditing.RemoveBlockEngine").GetConstructors()[0];
            }
        }
    }
}