using NUnit.Framework;
using Stylet.Xaml;
using System;

namespace StyletUnitTests
{
    [TestFixture]
    public class EqualityConverterTests
    {
        private EqualityConverter converter;

        [SetUp]
        public void SetUp()
        {
            this.converter = new EqualityConverter();
        }

        [Test]
        public void InstanceReturnsASingletonInstance()
        {
            Assert.NotNull(EqualityConverter.Instance);
            Assert.AreEqual(EqualityConverter.Instance, EqualityConverter.Instance);
        }

        [Test]
        public void ReturnsNullIfNullPassed()
        {
            Assert.Null(this.converter.Convert(null, null, null, null));
        }

        [Test]
        public void ReturnsNullIfEmptyArrayPassed()
        {
            Assert.Null(this.converter.Convert(new object[0], null, null, null));
        }

        [Test]
        public void ReturnsTrueIfASingleItemGiven()
        {
            var value = this.converter.Convert(new object[] { 5 }, null, null, null);
            Assert.IsInstanceOf<bool>(value);
            Assert.True((bool)value);
        }

        [Test]
        public void ReturnsTrueIfAllItemsAreEqual()
        {
            var obj = new object();
            var value = this.converter.Convert(new[] { obj, obj, obj }, null, null, null);
            Assert.IsInstanceOf<bool>(value);
            Assert.True((bool)value);
        }

        [Test]
        public void ReturnsFalseIfAllItemsAreEqualAndInvertIsTrue()
        {
            var obj = new object();
            this.converter.Invert = true;
            var value = this.converter.Convert(new[] { obj, obj, obj }, null, null, null);
            Assert.IsInstanceOf<bool>(value);
            Assert.False((bool)value);
        }

        [Test]
        public void ReturnsFalseIfOneItemsDiffers()
        {
            var obj = new object();
            var value = this.converter.Convert(new[] { obj, new object(), obj }, null, null, null);
            Assert.IsInstanceOf<bool>(value);
            Assert.False((bool)value);
        }

        [Test]
        public void ReturnsTrueIfOneItemsDiffersAndInvertIsTrue()
        {
            var obj = new object();
            var value = this.converter.Convert(new[] { obj, new object(), obj }, null, null, null);
            Assert.IsInstanceOf<bool>(value);
            Assert.False((bool)value);
        }

        [Test]
        public void ConvertBackThrows()
        {
            Assert.Throws<NotImplementedException>(() => this.converter.ConvertBack(null, null, null, null));
        }
    }
}