using System.Collections.Generic;
using System.IO;
using System.Linq;
using UnitTestSharp;

namespace Vellum.UnitTests
{
    public class LinkedListConverterTests : TestFixture
    {
        public static SaveSession Session()
        {
            return SaveConvertersTests.TestConverters().CreateSession();
        }

        public class WriteTests : TestFixture
        {
            public void List_IsAListOfItsItemsFirstToLast()
            {
                SaveNode node = Session().ToNode(new LinkedList<int>(new[] { 3, 1, 2 }), typeof(LinkedList<int>));

                CheckEqual(SaveNode.Kinds.List, node.Kind);
                CheckEqual(new[] { "3", "1", "2" }, node.Items.Select(item => item.Text).ToArray());
            }

            public void NullList_IsNull()
            {
                CheckEqual(SaveNode.Kinds.Null, Session().ToNode(null, typeof(LinkedList<int>)).Kind);
            }
        }

        public class ReadTests : TestFixture
        {
            public void LinkedListHoldingItself_ReadsAsALinkedListHoldingItself()
            {
                SaveNode node = SaveNode.NewList();
                node.Items.Add(node);
                var loaded = (LinkedList<object>)new SaveConverters(new SaveConverter[0]).CreateSession()
                    .FromNode(node, typeof(LinkedList<object>));

                CheckTrue(ReferenceEquals(loaded, loaded.First.Value));
            }

            public void List_RoundTripsInTheSameOrder()
            {
                SaveSession session = Session();
                SaveNode node = session.ToNode(new LinkedList<string>(new[] { "b", null, "c" }),
                    typeof(LinkedList<string>));
                var loaded = (LinkedList<string>)session.FromNode(node, typeof(LinkedList<string>));

                CheckEqual(new[] { "b", null, "c" }, loaded.ToArray());
            }

            public void ListThroughLuaText_RoundTrips()
            {
                SaveSession session = Session();
                var value = new LinkedList<Point>(new[] { new Point(1.5, 0), new Point(0, -2) });
                SaveNode node = SaveConvertersTests.ThroughLuaText(session.ToNode(value, typeof(LinkedList<Point>)));
                var loaded = (LinkedList<Point>)session.FromNode(node, typeof(LinkedList<Point>));

                CheckEqual(1.5, loaded.First.Value.X);
                CheckEqual(-2.0, loaded.Last.Value.Y);
            }

            public void EmptyListThroughLuaText_RoundTrips()
            {
                SaveSession session = Session();
                SaveNode node = SaveConvertersTests.ThroughLuaText(
                    session.ToNode(new LinkedList<int>(), typeof(LinkedList<int>)));

                CheckEqual(0, ((LinkedList<int>)session.FromNode(node, typeof(LinkedList<int>))).Count);
            }

            public void NullForAList_IsNull()
            {
                CheckNull(Session().FromNode(SaveNode.Null, typeof(LinkedList<int>)));
            }

            public void NodeThatIsNotAList_Throws()
            {
                CheckThrow(typeof(InvalidDataException));
                Session().FromNode(SaveNode.OfText("3"), typeof(LinkedList<int>));
            }
        }

        public class TryListChildrenTests : TestFixture
        {
            public void EachItem_IsListedAsTheItemType()
            {
                var value = new LinkedList<Waypoint>(new[] { new Waypoint { Name = "a" }, null });
                SaveNode node = Session().ToNode(value, typeof(LinkedList<Waypoint>));
                var children = new ChildList();

                CheckTrue(new LinkedListConverter<Waypoint>().TryListChildren(node, children));
                CheckEqual(2, children.Count);
                CheckTrue(ReferenceEquals(node.Items[0], children.NodeAt(0)));
                CheckEqual(typeof(Waypoint), children.TypeAt(1));
            }

            public void EmptyLinkedList_ListsNothingAndSucceeds()
            {
                var children = new ChildList();

                CheckTrue(new LinkedListConverter<int>().TryListChildren(SaveNode.NewList(), children));
                CheckEqual(0, children.Count);
            }

            public void NodeThatIsNotAList_ReturnsFalse()
            {
                CheckFalse(new LinkedListConverter<int>().TryListChildren(SaveNode.OfText("3"), new ChildList()));
            }
        }

        public class AllocateTests : TestFixture
        {
            public void SavedValue_GivesAnEmptyCollection()
            {
                SaveSession session = SaveConvertersTests.Session();
                SaveNode node = session.ToNode(new LinkedList<int>(new[] { 3, 1, 2 }));

                CheckEqual(0, new LinkedListConverter<int>().Allocate(node, session).Count);
            }

            public void NodeOfTheWrongShape_Throws()
            {
                CheckThrow(typeof(InvalidDataException));
                new LinkedListConverter<int>().Allocate(SaveNode.OfText("3"), SaveConvertersTests.Session());
            }
        }

        public class FillTests : TestFixture
        {
            public void SavedValue_AddsWhatReadLoads()
            {
                SaveSession session = SaveConvertersTests.Session();
                SaveNode node = session.ToNode(new LinkedList<int>(new[] { 3, 1, 2 }));
                var converter = new LinkedListConverter<int>();
                LinkedList<int> filled = converter.Allocate(node, session);
                converter.Fill(filled, node, session);

                CheckTrue(converter.Read(node, SaveConvertersTests.Session()).SequenceEqual(filled));
            }
        }

        public class FillNeedsFilledPartTests : TestFixture
        {
            public void AnyType_IsFalse()
            {
                CheckFalse(new LinkedListConverter<int>().FillNeedsFilledPart(typeof(int)));
            }
        }
    }
}