using System;
using System.Collections.Generic;
using System.Text;
using Encompass;
using Encompass.Engines;
using NUnit.Framework;

namespace Tests
{
    public class SpawnerTest
    {
        struct TestComponent : IComponent { }
        struct SpawnMessageA : IMessage { }

        static Entity resultEntity;

        [Emits(typeof(SpawnMessageA))]
        class MessageEmitter : Engine
        {
            public override void Update(double dt)
            {
                EmitMessage(new SpawnMessageA());
            }
        }

        class TestSpawner : Spawner<SpawnMessageA>
        {
            protected override void Spawn(SpawnMessageA message)
            {
                resultEntity = CreateEntity();
                resultEntity.AddComponent(new TestComponent());
            }
        }

        [Test]
        public void RunsSpawnMethodOnMessageRead()
        {
            var worldBuilder = new WorldBuilder();
            worldBuilder.AddEngine(new MessageEmitter());
            worldBuilder.AddEngine(new TestSpawner());

            var world = worldBuilder.Build();

            world.Update(0.01);

            Assert.That(resultEntity.HasComponent<TestComponent>(), Is.True);

            var id = resultEntity.id;

            world.Update(0.01);

            Assert.That(resultEntity.id, Is.Not.EqualTo(id));
        }
    }
}