using System;
using System.Collections.Generic;
using Cysharp.Threading.Tasks;

namespace DanieleMarotta.RiversongCodeShowcase
{
    [Service(typeof(IFailedPathCache))]
    public class FailedPathCacheSystem : GameSystem, IInitializable, IDisposable, IFailedPathCache
    {
        [InjectService]
        private ISignalBus _signalBus;

        private HashSet<ulong> _failedPaths = new();

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

        public UniTask InitializeAsync()
        {
            _signalBus.Subscribe<BuildingDeletedSignal>(InvalidateCacheOnSignal);
            _signalBus.Subscribe<RoadTileUpdatedSignal>(InvalidateCacheOnSignal);

            return UniTask.CompletedTask;
        }

        public void Dispose()
        {
            _signalBus.Unsubscribe<BuildingDeletedSignal>(InvalidateCacheOnSignal);
            _signalBus.Unsubscribe<RoadTileUpdatedSignal>(InvalidateCacheOnSignal);
        }

        private void InvalidateCacheOnSignal<T>(T signal)
        {
            Invalidate();
        }

        public void FailPath(int sourceId, int targetId)
        {
            _failedPaths.Add(MakeKey(sourceId, targetId));
        }

        public bool IsKnownFailedPath(int sourceId, int targetId)
        {
            return _failedPaths.Contains(MakeKey(sourceId, targetId));
        }

        public void Invalidate()
        {
            _failedPaths.Clear();
        }

        private ulong MakeKey(int sourceId, int targetId)
        {
            return sourceId < targetId ? ((ulong)sourceId << 32) | (uint)targetId : ((ulong)targetId << 32) | (uint)sourceId;
        }
    }
}