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

namespace Vellum.UnitTests
{
    public partial class DictionaryObjectKeyTests : UnitTestSharp.TestFixture
    {
        [Saveable]
        public partial class Link
        {
            public Link Previous;
            public Holder Owner;
        }

        [Saveable]
        public partial class Holder
        {
            public Dictionary<Link, int> Numbers = new Dictionary<Link, int>();
        }

        public static Holder HolderOfAChain(int length)
        {
            var holder = new Holder();
            Link previous = null;

            for (int i = 0; i < length; ++i)
            {
                previous = new Link { Previous = previous, Owner = holder };
                holder.Numbers.Add(previous, i);
            }

            return holder;
        }

        public static SaveSession NewSession()
        {
            return SaveConverters.For(typeof(DictionaryObjectKeyTests).Assembly).CreateSession();
        }

        public static Holder ThroughText(Holder holder)
        {
            SaveNode save = SaveNode.NewTable();
            save.Entries["holder"] = NewSession().ToNode(holder);
            SaveNode parsed = LuaSaveFormat.Parse(LuaSaveFormat.Format(save));

            return NewSession().FromNode<Holder>(parsed.RequireEntry("holder"));
        }

        public class TextRoundTripTests : UnitTestSharp.TestFixture
        {
            public void KeysLinkedInAChainFarPastTheNestingLimit_SurviveTheText()
            {
                Holder loaded = ThroughText(HolderOfAChain(100));

                CheckEqual(100, loaded.Numbers.Count);
                CheckEqual(Enumerable.Range(0, 100).ToArray(), loaded.Numbers.Values.ToArray());
            }

            public void KeysKeepTheirLinks()
            {
                Holder loaded = ThroughText(HolderOfAChain(3));
                List<Link> keys = loaded.Numbers.Keys.ToList();

                CheckNull(keys[0].Previous);
                CheckTrue(ReferenceEquals(keys[0], keys[1].Previous));
                CheckTrue(ReferenceEquals(keys[1], keys[2].Previous));
                CheckTrue(ReferenceEquals(loaded, keys[2].Owner));
            }

            public void NoEntries_StaysEmpty()
            {
                CheckEqual(0, ThroughText(new Holder()).Numbers.Count);
            }
        }
    }
}