using System;
using System.Diagnostics;
using System.Threading;
using System.Threading.Tasks;

namespace Conjure.Arcade.Overlay
{
    public class TickEngine
    {
        private readonly Action _tickAction;
        private readonly int _targetFps;
        private readonly CancellationTokenSource _cancellationSource;
        private bool _isRunning;

        public TickEngine(Action tickAction, int targetFps = 60)
        {
            _tickAction = tickAction;
            _targetFps = targetFps;
            _cancellationSource = new CancellationTokenSource();
        }

        public void Start()
        {
            if (_isRunning) return;
            
            _isRunning = true;
            Task.Run(RunTickLoop, _cancellationSource.Token);
        }

        public void Stop()
        {
            _isRunning = false;
            _cancellationSource.Cancel();
        }

        private async Task RunTickLoop()
        {
            var stopwatch = new Stopwatch();
            var targetFrameTime = TimeSpan.FromSeconds(1.0 / _targetFps);

            while (_isRunning && !_cancellationSource.Token.IsCancellationRequested)
            {
                stopwatch.Restart();
                
                try
                {
                    _tickAction();
                }
                catch (Exception ex)
                {
                    Debug.WriteLine($"Error in tick loop: {ex}");
                }

                var elapsed = stopwatch.Elapsed;
                if (elapsed < targetFrameTime)
                {
                    await Task.Delay(targetFrameTime - elapsed);
                }
            }
        }
    }
}