using System.Diagnostics;

namespace Shogi.Domain.YetToBeAssimilatedIntoDDD.Pathing
{
    [DebuggerDisplay("{Direction} - {Distance}")]
    public class Path
    {
        public Vector2 Direction { get; }
        public Distance Distance { get; }
        public Path(Vector2 direction, Distance distance = Distance.OneStep)
        {
            Direction = direction;
            Distance = distance;
        }

        public Path Invert() => new(Vector2.Negate(Direction), Distance);
    }

    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.Direction, end);
                var shortestDistance = Vector2.Distance(start + shortestPath.Direction, end);
                if (distance < shortestDistance)
                {
                    shortestPath = path;
                }
            }
            return shortestPath;
        }
    }
}