using Svelto.DataStructures;
using Svelto.ECS.Internal;
using Svelto.ECS.Reference;

namespace Svelto.ECS
{
    public readonly ref struct EntityInitializer
    {
        public EntityInitializer
            (EGID id, FasterDictionary<RefWrapperType, ITypeSafeDictionary> group, in EntityReference reference)
        {
            _group         = group;
            _ID            = id;
            this.reference = reference;
        }

        public   EGID            EGID => _ID;
        public readonly EntityReference reference;

        public void Init<T>(T initializer) where T : struct, IEntityComponent
        {
            if (_group.TryGetValue(new RefWrapperType(ComponentBuilder<T>.ENTITY_COMPONENT_TYPE)
                                 , out var typeSafeDictionary) == false)
                return;

            var dictionary = (ITypeSafeDictionary<T>) typeSafeDictionary;

            if (ComponentBuilder<T>.HAS_EGID)
                SetEGIDWithoutBoxing<T>.SetIDWithoutBoxing(ref initializer, _ID);

            if (dictionary.TryFindIndex(_ID.entityID, out var findElementIndex))
                dictionary.GetDirectValueByRef(findElementIndex) = initializer;
        }

        public ref T GetOrCreate<T>() where T : struct, IEntityComponent
        {
            ref var entityDictionary = ref _group.GetOrCreate(
                new RefWrapperType(ComponentBuilder<T>.ENTITY_COMPONENT_TYPE), TypeSafeDictionaryFactory<T>.Create);
            var dictionary = (ITypeSafeDictionary<T>) entityDictionary;

            return ref dictionary.GetOrCreate(_ID.entityID);
        }

        public ref T Get<T>() where T : struct, IEntityComponent
        {
            return ref (_group[new RefWrapperType(ComponentBuilder<T>.ENTITY_COMPONENT_TYPE)] as ITypeSafeDictionary<T>)
                [_ID.entityID];
        }

        public bool Has<T>() where T : struct, IEntityComponent
        {
            if (_group.TryGetValue(new RefWrapperType(ComponentBuilder<T>.ENTITY_COMPONENT_TYPE)
                                 , out var typeSafeDictionary))
            {
                var dictionary = (ITypeSafeDictionary<T>) typeSafeDictionary;

                if (dictionary.ContainsKey(_ID.entityID))
                    return true;
            }

            return false;
        }

        readonly EGID                                                  _ID;
        readonly FasterDictionary<RefWrapperType, ITypeSafeDictionary> _group;
    }
}