using Sandbox.MovieMaker;

namespace Editor.MovieMaker;

#nullable enable

public enum TickStyle
{
	TimeLabel,
	Major,
	Minor
}

public record struct TimelineTick( TickStyle Style, MovieTime Interval );

partial class Session
{
	private const float MinMajorTickWidth = 70f;
	private const float MinMinorTickWidth = 6f;

	public TimelineTick MajorTick
	{
		get
		{
			MovieTime majorTime = 1d;

			foreach ( var tickScale in TickScales )
			{
				if ( TimeToPixels( majorTime ) < MinMajorTickWidth )
				{
					majorTime = 1d * tickScale;
				}
				else
				{
					break;
				}
			}

			return new TimelineTick( TickStyle.Major, majorTime );
		}
	}

	public TimelineTick MinorTick
	{
		get
		{
			var minorTime = MovieTime.FromFrames( 1, FrameRate );

			while ( TimeToPixels( minorTime ) < MinMinorTickWidth )
			{
				minorTime *= 2;
			}

			return new TimelineTick( TickStyle.Minor, minorTime );
		}
	}

	public IEnumerable<TimelineTick> Ticks
	{
		get
		{
			var major = MajorTick;

			yield return major with { Style = TickStyle.TimeLabel };
			yield return major;
			yield return MinorTick;
		}
	}

	private static IEnumerable<int> TickScales
	{
		get
		{
			for ( var i = 1; i <= 1_000_000; i *= 10 )
			{
				yield return i;
				yield return i * 2;
				yield return i * 5;
			}
		}
	}
}