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

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

        public static Stack<ItemType> PushedInOrder<ItemType>(params ItemType[] items)
        {
            var returnMe = new Stack<ItemType>();
            foreach (ItemType item in items)
            {
                returnMe.Push(item);
            }

            return returnMe;
        }

        public class WriteTests : TestFixture
        {
            public void Stack_IsAListOfItsItemsInTheOrderTheyWerePushed()
            {
                SaveNode node = Session().ToNode(PushedInOrder(3, 1, 2), typeof(Stack<int>));

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

            public void Writing_LeavesTheStackAsItWas()
            {
                Stack<int> value = PushedInOrder(3, 1, 2);
                Session().ToNode(value, typeof(Stack<int>));

                CheckEqual(new[] { 2, 1, 3 }, value.ToArray());
            }

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

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

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

            public void Stack_RoundTripsWithTheSameTopAndOrder()
            {
                SaveSession session = Session();
                SaveNode node = session.ToNode(PushedInOrder("b", "a", "c"), typeof(Stack<string>));
                var loaded = (Stack<string>)session.FromNode(node, typeof(Stack<string>));

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

            public void StackThroughLuaText_RoundTrips()
            {
                SaveSession session = Session();
                SaveNode saved = session.ToNode(PushedInOrder(new Point(1.5, 0), new Point(0, -2)),
                    typeof(Stack<Point>));
                var loaded = (Stack<Point>)session.FromNode(SaveConvertersTests.ThroughLuaText(saved),
                    typeof(Stack<Point>));

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

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

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

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

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

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

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

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

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

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

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

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

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

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