using System.Diagnostics;
using static Shogi.Domain.YetToBeAssimilatedIntoDDD.Pathing.Path;

namespace Shogi.Domain.YetToBeAssimilatedIntoDDD.Pathing;

[DebuggerDisplay("{Step} - {Distance}")]
public record Path
{
	public Vector2 Step { get; }
	public Vector2 NormalizedStep => Vector2.Normalize(Step);
	public Distance Distance { get; }

	/// <summary>
	/// 
	/// </summary>
	/// <param name="step">The smallest distance that can occur during a move.</param>
	/// <param name="distance"></param>
	public Path(Vector2 step, Distance distance = Distance.OneStep)
	{
		Step = step;
		this.Distance = distance;
	}
	public Path Invert() => new(Vector2.Negate(Step), Distance);

	//public enum PathingResult
	//{
	//	Obstructed,
	//	CompletedWithoutObstruction
	//}
}

public static class PathExtensions
{
	public static Path GetNearestPath(this IEnumerable<Path> paths, Vector2 start, Vector2 end)
	{
		if (!paths.DefaultIfEmpty().Any())
		{
			throw new ArgumentException("No paths to get nearest path from.");
		}

		var shortestPath = paths.First();
		foreach (var path in paths.Skip(1))
		{
			var distance = Vector2.Distance(start + path.Step, end);
			var shortestDistance = Vector2.Distance(start + shortestPath.Step, end);
			if (distance < shortestDistance)
			{
				shortestPath = path;
			}
		}
		return shortestPath;
	}
}