using System.Collections.Generic;
using MonoGame.Extended.Graphics;
using Xunit;

namespace MonoGame.Extended.ECS.Tests
{
    public class ComponentManagerTests
    {
        [Fact]
        public void GetMapperForType()
        {
            var componentManager = new ComponentManager();
            var transformMapper = componentManager.GetMapper<Transform2>();
            var spriteMapper = componentManager.GetMapper<Sprite>();

            Assert.IsType<ComponentMapper<Transform2>>(transformMapper);
            Assert.IsType<ComponentMapper<Sprite>>(spriteMapper);
            Assert.Equal(0, transformMapper.Id);
            Assert.Equal(1, spriteMapper.Id);
            Assert.Same(spriteMapper, componentManager.GetMapper<Sprite>());
        }

        [Fact]
        public void GetComponentTypeId()
        {
            var componentManager = new ComponentManager();

            Assert.Equal(0, componentManager.GetComponentTypeId(typeof(Transform2)));
            Assert.Equal(1, componentManager.GetComponentTypeId(typeof(Sprite)));
            Assert.Equal(0, componentManager.GetComponentTypeId(typeof(Transform2)));
        }

        //[Fact]
        //public void GetCompositionIdentity()
        //{
        //    var compositionBits = new BitArray(3)
        //    {
        //        [0] = true,
        //        [1] = false,
        //        [2] = true
        //    };
        //    var componentManager = new ComponentManager();
        //    var identity = componentManager.GetCompositionIdentity(compositionBits);

        //    Assert.Equal(0b101, identity);
        //}

        
        [Fact]
        public void GetMapperForTypeByIndexer()
        {
            var componentManager = new ComponentManager();
            var transformMapper = componentManager[typeof(Transform2)];
            var spriteMapper = componentManager[typeof(Sprite)];

            Assert.IsType<ComponentMapper<Transform2>>(transformMapper);
            Assert.IsType<ComponentMapper<Sprite>>(spriteMapper);
            Assert.Equal(0, transformMapper.Id);
            Assert.Equal(1, spriteMapper.Id);
            Assert.Same(spriteMapper, componentManager[typeof(Sprite)]);
        }

        [Fact]
        public void EnumerateMappers()
        {
            var componentManager = new ComponentManager();

            var transformMapper = componentManager.GetMapper<Transform2>();
            var spriteMapper = componentManager.GetMapper<Sprite>();
            var cameraMapper = componentManager.GetMapper<OrthographicCamera>();

            List<ComponentMapper> enumeratedMappers = new List<ComponentMapper>();

            foreach (ComponentMapper mapper in componentManager)
            {
                enumeratedMappers.Add(mapper);
            }

            Assert.Equal(3, enumeratedMappers.Count);
            Assert.Contains(transformMapper, enumeratedMappers);
            Assert.Contains(spriteMapper, enumeratedMappers);
            Assert.Contains(cameraMapper, enumeratedMappers);
        }
    }
}