using System;
using System.Collections.Generic;
using System.Linq;
using Cysharp.Threading.Tasks;
using Unity.Mathematics;
using UnityEngine;
using Object = UnityEngine.Object;

namespace DanieleMarotta.RiversongCodeShowcase
{
    public class RoadVisualizationManager : GameSystem, IInitializable, IDisposable
    {
        [InjectService]
        private GameConfig _config;

        [InjectService]
        private IScene _scene;

        [InjectService]
        private ISignalBus _signalBus;

        [InjectService]
        private ITileSpace _tileSpace;

        [InjectService]
        private World _world;

        private readonly List<GameObject> _prefabs = new();

        private readonly Dictionary<int2, GameObject> _visualizations = new();

        private GameObject _placementVfxPrefab;

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

        public async UniTask InitializeAsync()
        {
            var tilePrefabTasks = _config.Roads.Tiles.Select(tilePrefabRef => tilePrefabRef.LoadAssetAsync().ToUniTask()).ToArray();
            var placementVfxTask = _config.Roads.PlacementVfxPrefab.LoadAssetAsync().ToUniTask();

            var tilePrefabs = await UniTask.WhenAll(tilePrefabTasks);
            _prefabs.AddRange(tilePrefabs);
            _placementVfxPrefab = await placementVfxTask;

            _signalBus.Subscribe<RoadTileUpdatedSignal>(OnRoadTileChanged);
        }

        public void Dispose()
        {
            foreach (var tilePrefabRef in _config.Roads.Tiles) tilePrefabRef.ReleaseAsset();

            _config.Roads.PlacementVfxPrefab.ReleaseAsset();

            _signalBus.Unsubscribe<RoadTileUpdatedSignal>(OnRoadTileChanged);
        }

        private void OnRoadTileChanged(RoadTileUpdatedSignal signal)
        {
            var tile = signal.Tile;

            UpdateTile(tile);
            if (tile.x > 0) UpdateTile(tile + new int2(-1, 0));
            if (tile.x < _world.Size.x - 1) UpdateTile(tile + new int2(1, 0));
            if (tile.y > 0) UpdateTile(tile + new int2(0, -1));
            if (tile.y < _world.Size.y - 1) UpdateTile(tile + new int2(0, 1));

            if (signal.RoadTileAdded) SpawnPlacementVfx(tile);
        }

        private void UpdateTile(int2 tile)
        {
            if (_visualizations.TryGetValue(tile, out var visualization))
            {
                Object.Destroy(visualization);
                _visualizations.Remove(tile);
            }

            if (!_world.RoadNetwork.IsRoadTile(tile)) return;

            visualization = Object.Instantiate(GetRoadTilePrefab(tile), _scene.SceneFolders.RoadTiles);
            visualization.transform.position = _tileSpace.TileToWorld(tile) + new Vector3(0, 0.001f, 0);

            _visualizations.Add(tile, visualization);
        }

        private GameObject GetRoadTilePrefab(int2 tile)
        {
            var connectivity = _world.RoadNetwork.GetConnectivity(tile);
            return _prefabs[(int)connectivity];
        }

        private void SpawnPlacementVfx(int2 tile)
        {
            var position = _tileSpace.TileToWorld(tile);
            Object.Instantiate(_placementVfxPrefab, position, Quaternion.identity);
        }
    }
}