using Unity.Mathematics;
using UnityEngine;

namespace DanieleMarotta.RiversongCodeShowcase
{
    [GameSystemGroup(typeof(DefaultAgentsSystemGroup))]
    [UpdateAfter(typeof(IntentExecutionSystem))]
    public class AgentAnimationSystem : GameSystem, IUpdatable
    {
        [InjectService]
        private IEntityCollection _entityCollection;

        [InjectService]
        private IAgentVisualizationCollection _agentVisualizationCollection;

        [InjectService]
        private IProductCatalog _productCatalog;

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

        public void Update()
        {
            foreach (Agent agent in _entityCollection.GetInternalEntityList(typeof(Agent)))
            {
                if (!_agentVisualizationCollection.TryGetVisualization(agent.Id, out var visualization)) continue;

                const float minVelocitySq = 0.01f;
                visualization.UpdateAnimationState(math.lengthsq(agent.Velocity) > minVelocitySq);

                UpdateCarriedProduct(agent, visualization);
            }
        }

        private void UpdateCarriedProduct(Agent agent, AgentVisualization visualization)
        {
            var carriedProduct = visualization.CarriedProductVisualization;
            if (!carriedProduct) return;

            var isCarryingProduct = agent.CarriedProductHandle != IProductCatalog.InvalidHandle;

            var targetWeight = isCarryingProduct ? 1 : 0;
            var weight = Mathf.MoveTowards(carriedProduct.GetAnimatorLayerWeight(), targetWeight, 10 * Time.deltaTime);
            carriedProduct.SetAnimatorLayerWeight(weight);

            if (isCarryingProduct)
                SetProductVisualization(carriedProduct, agent.CarriedProductHandle);
            else
                ClearProductVisualization(carriedProduct);
        }

        private void SetProductVisualization(AgentCarriedProductVisualization carriedProduct, int productHandle)
        {
            if (carriedProduct.IsShowingCarriedProduct()) return;

            var product = _productCatalog.GetProduct(productHandle);
            var productVisualization = (GameObject)Object.Instantiate(product.CarriedVisualization.Asset);
            carriedProduct.SetProductVisualization(productVisualization);
        }

        private void ClearProductVisualization(AgentCarriedProductVisualization carriedProduct)
        {
            if (!carriedProduct.ClearProductVisualization(out var productVisualization)) return;
            Object.Destroy(productVisualization);
        }
    }
}