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

public class EndGameConditionChecker : IDisposable
{
    public event Action<EndgameReason> OnEndGameCondition;

    private bool _isDisposed = false;
    private float startTime;
    private float endTime;
    public float TimeRest => limitedByTime ? endTime - Time.time : - 1;

        private bool limitedByTime;
    private CancellationTokenSource _cts;

    private WeaponModel weaponModel;
    private Health playerHealth;
    public EndGameConditionChecker(WeaponModel weaponModel, Health playerHealth, int sessionTimeMinutes = 0)
    {
        if(weaponModel == null)
            throw new ArgumentNullException("WeaponModel is null");
        if (playerHealth == null)
            throw new ArgumentNullException("PlayerHealth is null");

        this.weaponModel = weaponModel;
        this.playerHealth = playerHealth;

        weaponModel.OnNoAmmo += NoAmmoHandler;
        playerHealth.Died += PlayerDiedHandler;

        limitedByTime = sessionTimeMinutes > 0;
        if(limitedByTime )
        {
            startTime = Time.time;
            endTime = startTime + sessionTimeMinutes * 60;
            _cts = new CancellationTokenSource();
            CheckTimeout(_cts).Forget();
        }
    }

    public void Dispose()
    {
        if(_isDisposed) return;
        _isDisposed = true;

        _cts?.Cancel();
        _cts?.Dispose();
        _cts = null;

        weaponModel.OnNoAmmo -= NoAmmoHandler;
        playerHealth.Died -= PlayerDiedHandler;

        weaponModel = null;
        playerHealth = null;
    }

    private void PlayerDiedHandler(Vector3 obj) => TerminateSession(EndgameReason.Death);
    private void NoAmmoHandler() => TerminateSession(EndgameReason.NoAmmo);

    private void TerminateSession(EndgameReason reason)
    {
        if (_isDisposed) return;
        OnEndGameCondition?.Invoke(reason);
        Dispose();
    }

    private async UniTaskVoid CheckTimeout(CancellationTokenSource cts)
    {
        try
        {
            while (!cts.IsCancellationRequested)
            {
                if (TimeRest <= 0)
                {
                    TerminateSession(EndgameReason.Timeout);
                    break;
                }
                await UniTask.Delay(1000, cancellationToken: cts.Token);
            }
        }
        catch (OperationCanceledException) 
        {
            // ожидаемая отмена
        }
    }

    public enum EndgameReason
    {
        Timeout,
        Death,
        NoAmmo
    }
}