using System;
using Cysharp.Threading.Tasks;
using UnityEngine;

namespace DanieleMarotta.RiversongCodeShowcase
{
    [GameSystemGroup(typeof(LateGameSystemGroup))]
    public class GlobalShaderParametersSystem : GameSystem, IInitializable, IDisposable, IUpdatable
    {
        [InjectService]
        private World _world;

        [InjectService]
        private ISignalBus _signalBus;

        public GlobalShaderParametersSystem(IServiceLocator serviceLocator) : base(serviceLocator)
        {
        }

        public UniTask InitializeAsync()
        {
            _signalBus.Subscribe<WorldReadySignal>(OnWorldReady);
            return UniTask.CompletedTask;
        }

        public void Dispose()
        {
            _signalBus.Unsubscribe<WorldReadySignal>(OnWorldReady);
        }

        public void Update()
        {
            var t = Time.unscaledTime;
            Shader.SetGlobalVector(ShaderProperties.UnscaledTime, new Vector4(t / 20, t, t * 2, t * 3));
        }

        private void OnWorldReady(WorldReadySignal signal)
        {
            Shader.SetGlobalVector(ShaderProperties.WorldSize, new Vector4(_world.Size.x, _world.Size.y, 0, 0));
            Shader.SetGlobalVector(ShaderProperties.InverseWorldSize, new Vector2(1 / (float)_world.Size.x, 1 / (float)_world.Size.y));
        }
    }
}