using System.Diagnostics;

namespace lib;

public readonly ref struct Defer
{
	private readonly Action _onDispose;

	public Defer( Action onDispose )
	{
		_onDispose = onDispose;
	}

	public void Dispose()
	{
		_onDispose?.Invoke();
	}

	public static Defer Do( Action action ) => new Defer( action );
}


	public readonly ref struct Timed
	{
		private readonly long _startTimestamp;
		private readonly Action<TimeSpan> _onDispose;

		public Timed( Action<TimeSpan> onDispose )
		{
			_onDispose = onDispose;
			_startTimestamp = Stopwatch.GetTimestamp();
		}

		public void Dispose()
		{
			// Calculate elapsed ticks
			long endTimestamp = Stopwatch.GetTimestamp();
			long elapsedTicks = endTimestamp - _startTimestamp;

			// Convert to TimeSpan based on system timer frequency
			// (Standard formula for high-resolution timing)
			double seconds = (double)elapsedTicks / Stopwatch.Frequency;
			var elapsed = TimeSpan.FromSeconds( seconds );

			_onDispose?.Invoke( elapsed );
		}

		// Optional: Allow peeking at the time without stopping
		public TimeSpan Elapsed
		{
			get
			{
				long current = Stopwatch.GetTimestamp();
				return TimeSpan.FromSeconds( (double)( current - _startTimestamp ) / Stopwatch.Frequency );
			}
		}

	public static Timed Do( Action<TimeSpan> action ) => new Timed( action );


}


static public class Exec
{
	static public void RunIf( bool condition, Action func )
	{
		if( condition )
			func();
	}

	static public T RunIf<T>( bool condition, Func<T> func, T ret = default! )
	{
		if( condition )
			return func();
		return ret;
	}
}