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

namespace DanieleMarotta.RiversongCodeShowcase
{
    public class HouseTierCountTrackingSystem : GameSystem, IInitializable, IDisposable
    {
        [InjectService]
        private ISignalBus _signalBus;

        [InjectService]
        private World _world;

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

        public UniTask InitializeAsync()
        {
            _signalBus.Subscribe<BuildingCreatedSignal>(OnBuildingCreated);
            _signalBus.Subscribe<BuildingDeletedSignal>(OnBuildingDeleted);
            _signalBus.Subscribe<BuildingUpgradedSignal>(OnBuildingUpgraded);

            return UniTask.CompletedTask;
        }

        public void Dispose()
        {
            _signalBus.Unsubscribe<BuildingCreatedSignal>(OnBuildingCreated);
            _signalBus.Unsubscribe<BuildingDeletedSignal>(OnBuildingDeleted);
            _signalBus.Unsubscribe<BuildingUpgradedSignal>(OnBuildingUpgraded);
        }

        private void OnBuildingCreated(BuildingCreatedSignal signal)
        {
            var building = signal.Building;
            if (!building.Definition.IsHouse) return;

            UpdateTierCount(building.TierIndex, 1);
        }

        private void OnBuildingDeleted(BuildingDeletedSignal signal)
        {
            var building = signal.Building;
            if (!building.Definition.IsHouse) return;

            UpdateTierCount(building.TierIndex, -1);
        }

        private void OnBuildingUpgraded(BuildingUpgradedSignal signal)
        {
            var building = signal.Building;
            if (!building.Definition.IsHouse) return;

            if (building.TierIndex > 0) UpdateTierCount(building.TierIndex - 1, -1);
            UpdateTierCount(building.TierIndex, 1);
        }

        private void UpdateTierCount(int tierIndex, int delta)
        {
            if (!ValidateTierIndex(tierIndex)) return;

            var countsByTier = _world.PopulationState.HouseCountsByTier;

            var updatedCount = countsByTier[tierIndex] + delta;
            if (updatedCount < 0)
            {
                Debug.LogError($"Attempted to decrease house count for tier {tierIndex} that was already at 0");
                return;
            }

            countsByTier[tierIndex] = updatedCount;
        }

        private bool ValidateTierIndex(int tierIndex)
        {
            if (tierIndex is >= 0 and < WorldPopulationState.MaxBuildingTier) return true;

            Debug.LogError($"Invalid tier index {tierIndex}");

            return false;
        }
    }
}