using System;
using System.Collections.Generic;
using NUnit.Framework;

namespace Chernobyl.Values
{
    // ReSharper disable ObjectCreationAsStatement

    [TestFixture, Description("Tests for the Select<TSource, TResult> type.")]
    public class SelectTests : ValueTests<IValue<string>, string>
    {
        //----------------------------------------------------------------------
        // Select(IValue<TSource>, Func<TSource, TResult>) Tests
        //----------------------------------------------------------------------

        [Test, Description("Ensures Select(IValue<TSource>, Func<TSource, TResult>) " +
                           "throws an ArgumentNullException when its first argument " +
                           "is null.")]
        public void ConstructorValueFuncFirstArgumentNullException()
        {
            Assert.Throws<ArgumentNullException>(() => new Select<int, string>(null, i => i.ToString()));
        }

        [Test, Description("Ensures Select(IValue<TSource>, Func<TSource, TResult>) " +
                           "throws an ArgumentNullException when its second argument " +
                           "is null.")]
        public void ConstructorValueFuncSecondArgumentNullException()
        {
            Assert.Throws<ArgumentNullException>(() => new Select<int, string>(new DynamicContainer<int>(0), null));
        }

        //----------------------------------------------------------------------
        // Select(IValue<TSource>, Func<TSource, TResult>, IEqualityComparer<TResult>) Tests
        //----------------------------------------------------------------------

        [Test, Description("Ensures Select(IValue<TSource>, Func<TSource, TResult>, IEqualityComparer<TResult>) " +
                           "throws an ArgumentNullException when its first argument " +
                           "is null.")]
        public void ConstructorValueFuncIEqualityComparerFirstArgumentNullException()
        {
            Assert.Throws<ArgumentNullException>(() => new Select<int, string>(null, i => i.ToString(), EqualityComparer<string>.Default));
        }

        [Test, Description("Ensures Select(IValue<TSource>, Func<TSource, TResult>, IEqualityComparer<TResult>) " +
                           "throws an ArgumentNullException when its second argument " +
                           "is null.")]
        public void ConstructorValueFuncIEqualityComparerSecondArgumentNullException()
        {
            Assert.Throws<ArgumentNullException>(() => new Select<int, string>(new DynamicContainer<int>(0), null, EqualityComparer<string>.Default));
        }

        [Test, Description("Ensures Select(IValue<TSource>, Func<TSource, TResult>, IEqualityComparer<TResult>) " +
                           "throws an ArgumentNullException when its third argument " +
                           "is null.")]
        public void ConstructorValueFuncIEqualityComparerThirdArgumentNullException()
        {
            Assert.Throws<ArgumentNullException>(() => new Select<int, string>(new DynamicContainer<int>(0), i => i.ToString(), null));
        }

        //----------------------------------------------------------------------
        // Utility
        //----------------------------------------------------------------------

        protected override ValueTests<IValue<string>, string>.Wrapper CreateValue()
        {
            return new Wrapper();
        }

        protected new class Wrapper : ValueTests<IValue<string>, string>.Wrapper
        {
            public Wrapper()
                : base(null, "0", "5")
            {
                _container.IsReady = false;
                TestInstance = new Select<int, string>(_container, i => i.ToString());
            }

            public override void MakeReady()
            {
                // Not needed. Select doesn't become ready.
                _container.IsReady = true;
            }

            public override void ChangeValue()
            {
                _container.Value = 5;
            }

            public override void FakeChangeValue()
            {
                _container.Value = _container.Value;
            }

            readonly DynamicContainer _container = new DynamicContainer(0);

            /// <summary>
            /// Type to help with testing.
            /// </summary>
            public class DynamicContainer : DynamicContainer<int>
            {
                public DynamicContainer(int value)
                    : base(value)
                {
                    IsReady = false;
                }

                public new bool IsReady
                {
                    get { return base.IsReady; }
                    set { base.IsReady = value; }
                }
            }
        }
    }

    // ReSharper restore ObjectCreationAsStatement
}