using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;

namespace GameOfLife.Entities
{
    public class Projections : ReadOnlyCollection<Pattern>
    {
        public Dictionary<Pattern, Pattern> BoundaryCells { get; }

        public Projections(IEnumerable<Pattern> pattern) 
            : base(pattern.SelectMany(GeneratePatterns).Distinct().ToList())
        {
            BoundaryCells = this.ToDictionary(p => p, p => p.GetBoundary);
        }

        public Projections(Pattern pattern) : this(new[] { pattern }) { }

        private static List<Pattern> GeneratePatterns(Pattern pattern) =>
            new[]
            {
                pattern.Normalize(),
                pattern.Rotate(1).Normalize(),
                pattern.Rotate(2).Normalize(),
                pattern.Rotate(3).Normalize(),
                pattern.ReflectX().Normalize(),
                pattern.ReflectY().Normalize(),
                pattern.ReflectX().Rotate().Normalize(),
                pattern.ReflectY().Rotate().Normalize()
            }.Distinct().ToList();
    }
}