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

namespace DanieleMarotta.RiversongCodeShowcase
{
    public class EntityIdMapUpdateSystem : GameSystem, IInitializable, IDisposable, IOnWorldGenerationCompletedCallback
    {
        [InjectService]
        private IEntityCollection _entityCollection;

        [InjectService]
        private ISignalBus _signalBus;

        [InjectService]
        private World _world;

        [InjectService]
        private GameConfig _config;

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

        public UniTask InitializeAsync()
        {
            _entityCollection.On<ConstructionSite>().Added += OnConstructionSiteAdded;
            _entityCollection.On<ConstructionSite>().Removed += OnConstructionSiteRemoved;
            _entityCollection.On<Building>().Added += OnBuildingAdded;
            _entityCollection.On<Building>().Removed += OnBuildingRemoved;
            _signalBus.Subscribe<WorldGenerationCompletedSignal>(OnWorldGenerationCompleted);
            _signalBus.Subscribe<RawResourcesRemovedSignal>(OnRawResourcesRemoved);

            return UniTask.CompletedTask;
        }

        public void Dispose()
        {
            _entityCollection.On<ConstructionSite>().Added -= OnConstructionSiteAdded;
            _entityCollection.On<ConstructionSite>().Removed -= OnConstructionSiteRemoved;
            _entityCollection.On<Building>().Added -= OnBuildingAdded;
            _entityCollection.On<Building>().Removed -= OnBuildingRemoved;
            _signalBus.Unsubscribe<WorldGenerationCompletedSignal>(OnWorldGenerationCompleted);
            _signalBus.Unsubscribe<RawResourcesRemovedSignal>(OnRawResourcesRemoved);
        }

        private void OnConstructionSiteAdded(ConstructionSite constructionSite)
        {
            _world.EntityIdMap.SetBuildingId(constructionSite.Rect, constructionSite.Id);
        }

        private void OnConstructionSiteRemoved(ConstructionSite constructionSite)
        {
            _world.EntityIdMap.SetBuildingId(constructionSite.Rect, Entity.InvalidId);
        }

        private void OnBuildingAdded(Building building)
        {
            _world.EntityIdMap.SetBuildingId(building.Rect, building.Id);
        }

        private void OnBuildingRemoved(Building building)
        {
            _world.EntityIdMap.SetBuildingId(building.Rect, Entity.InvalidId);
        }

        private void OnWorldGenerationCompleted(WorldGenerationCompletedSignal signal)
        {
            signal.Callbacks.Add(this);
        }

        public UniTask OnWorldGenerationCompletedAsync(World world)
        {
            foreach (var resourceNode in _world.RawResources) _world.EntityIdMap.SetResourceNodeId(resourceNode.Tile, resourceNode.DefinitionId);

            return UniTask.CompletedTask;
        }

        private void OnRawResourcesRemoved(RawResourcesRemovedSignal signal)
        {
            using var resourceNodesScope = ListPool<(int, bool)>.Get(out var resourceNodes);

            foreach (var removedResourceNode in signal.ResourceNodes)
            {
                resourceNodes.Clear();
                _world.RawResources.GetResourceNodes(TileRect.OneTile(removedResourceNode.Tile), _config.GeneralSettings.BaseElevation, resourceNodes);

                var definitionId = Entity.InvalidId;
                if (resourceNodes.Count > 0)
                {
                    var (resourceId, _) = resourceNodes[0];
                    _world.RawResources.TryGetResourceNode(resourceId, out var resourceNode);
                    definitionId = resourceNode.DefinitionId;
                }
                _world.EntityIdMap.SetResourceNodeId(removedResourceNode.Tile, definitionId);
            }
        }
    }
}