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

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

        public class WriteTests : TestFixture
        {
            public void Queue_IsAListOfItsItemsNextToLeaveFirst()
            {
                var value = new Queue<int>(new[] { 3, 1, 2 });
                value.Dequeue();
                value.Enqueue(9);
                SaveNode node = Session().ToNode(value, typeof(Queue<int>));

                CheckEqual(SaveNode.Kinds.List, node.Kind);
                CheckEqual(new[] { "1", "2", "9" }, node.Items.Select(item => item.Text).ToArray());
            }

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

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

                CheckTrue(ReferenceEquals(loaded, loaded.Peek()));
            }

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

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

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

                CheckEqual(1.5, loaded.Dequeue().X);
                CheckEqual(-2.0, loaded.Dequeue().Y);
            }

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

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

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

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

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

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

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

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

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

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

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

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

        public class FillTests : TestFixture
        {
            public void SavedValue_AddsWhatReadLoads()
            {
                SaveSession session = SaveConvertersTests.Session();
                SaveNode node = session.ToNode(new Queue<int>(new[] { 3, 1, 2 }));
                var converter = new QueueConverter<int>();
                Queue<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 QueueConverter<int>().FillNeedsFilledPart(typeof(int)));
            }
        }
    }
}