using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using Microsoft.Extensions.DependencyInjection;

namespace BITKit.Entities
{
    public class Entity : IEntity, IDisposable
    {
        public int Id { get; set; } = Guid.NewGuid().GetHashCode();
        public CancellationToken CancellationToken { get; set; }

        public IServiceProvider ServiceProvider => _serviceProvider ??= ServiceCollection.BuildServiceProvider();
        private ServiceProvider _serviceProvider;
        public IServiceCollection ServiceCollection
        {
            get
            {
                if (_serviceCollection is not null) return _serviceCollection;
                _serviceCollection = new ServiceCollection();
                _serviceCollection.AddSingleton<IEntity>(this);
                return _serviceCollection;
            }
        }

        private IServiceCollection _serviceCollection;

        public void Inject(object obj)
        {
            foreach (var fieldInfo in obj.GetType().GetFields(ReflectionHelper.Flags))
            {
                if (Attribute.IsDefined(fieldInfo, typeof(InjectAttribute)))
                {
                    fieldInfo.SetValue(obj, ServiceProvider.GetService(fieldInfo.FieldType));
                }
            }
        }

        public void Dispose()
        {
            _serviceProvider.Dispose();
        }
    }
}