using UnitTestSharp;

namespace Prism.UnitTests
{
    public class TintColorTests : TestFixture
    {
        public class ToArgbTests : TestFixture
        {
            public void MatchesTheColorItTintsBy()
            {
                var tint = new TintColor(0.1, 0.4, 0.7, 0.9);

                CheckEqual(((Color)tint).ToArgb(), tint.ToArgb());
            }

            public void Default_IsOpaqueWhite()
            {
                CheckEqual(unchecked((int)0xFFFFFFFF), default(TintColor).ToArgb());
            }

            public void FullyTransparentBlack_IsZero()
            {
                CheckEqual(0, new TintColor(0, 0, 0, 0).ToArgb());
            }
        }

        public class IsWhiteTests : TestFixture
        {
            public void Default_IsWhite()
            {
                CheckTrue(default(TintColor).IsWhite);
            }

            public void OpaqueWhite_IsWhite()
            {
                CheckTrue(new TintColor(1, 1, 1, 1).IsWhite);
            }

            public void AnyOtherColor_IsNot()
            {
                CheckFalse(new TintColor(1, 1, 0.9, 1).IsWhite);
                CheckFalse(new TintColor(1, 1, 1, 0.9).IsWhite);
                CheckFalse(new TintColor(0.9, 1, 1, 1).IsWhite);
                CheckFalse(new TintColor(1, 0.9, 1, 1).IsWhite);
            }
        }

        public class ApplyTests : TestFixture
        {
            public void White_LeavesTheColorAlone()
            {
                CheckEqual(unchecked((int)0x80123456), default(TintColor).Apply(unchecked((int)0x80123456)));
            }

            public void MultipliesEachChannel()
            {
                var tint = new TintColor(1, 0, 0.5, 1);

                CheckEqual(unchecked((int)0xFFFF0040), tint.Apply(unchecked((int)0xFFFFFF80)));
            }

            public void MultipliesTheAlphaToo()
            {
                var tint = new TintColor(1, 1, 1, 0.5);

                CheckEqual(unchecked((int)0x7FFFFFFF), tint.Apply(unchecked((int)0xFFFFFFFF)));
            }

            public void TransparentBlack_ClearsEverything()
            {
                CheckEqual(0, new TintColor(0, 0, 0, 0).Apply(unchecked((int)0xFFFFFFFF)));
            }

            public void RoundsToTheNearestValue()
            {
                var tint = new TintColor(0.5, 0.5, 0.5, 1);

                CheckEqual(unchecked((int)0xFF010101), tint.Apply(unchecked((int)0xFF020202)));
            }
        }

        public class MultiplyOperatorTests : TestFixture
        {
            public void WhiteTimesATint_IsThatTint()
            {
                var tint = new TintColor(1, 0.5, 0, 1);

                CheckEqual(tint.ToArgb(), (default(TintColor) * tint).ToArgb());
            }

            public void ATintTimesWhite_IsThatTint()
            {
                var tint = new TintColor(1, 0.5, 0, 1);

                CheckEqual(tint.ToArgb(), (tint * default(TintColor)).ToArgb());
            }

            public void MultipliesEachChannel()
            {
                var product = new TintColor(1, 1, 0, 1) * new TintColor(1, 0, 1, 0.5);

                CheckEqual(unchecked((int)0x7FFF0000), product.ToArgb());
            }

            public void MatchesApplyingBothOneAfterTheOther()
            {
                var first = new TintColor(0.3, 0.9, 0.5, 0.8);
                var second = new TintColor(0.7, 0.2, 1, 0.6);
                int argb = unchecked((int)0xFFC8A064);

                CheckEqual(second.Apply(first.Apply(argb)), (first * second).Apply(argb));
            }
        }

        public class CtorTests : TestFixture
        {
            public void WithoutAlpha_IsOpaque()
            {
                CheckEqual(new TintColor(1, 0.5, 0, 1).ToArgb(), new TintColor(1, 0.5, 0).ToArgb());
            }

            public void WithAlpha_TintsEachChannelByItsFraction()
            {
                var tint = new TintColor(1, 0, 0.25, 0.5);

                CheckEqual(unchecked((int)0x7FFF0040), tint.Apply(unchecked((int)0xFFFFFFFF)));
            }

            public void AFractionOutsideZeroToOne_Throws()
            {
                CheckThrow(typeof(System.ArgumentOutOfRangeException));
                new TintColor(1.5, 0, 0);
            }

            public void NaNFraction_Throws()
            {
                CheckThrow(typeof(System.ArgumentOutOfRangeException));
                new TintColor(0, 0, 0, double.NaN);
            }
        }

        public class ColorConversionTests : TestFixture
        {
            public void FromColor_TintsByThatColor()
            {
                TintColor tint = Color.FromArgb(128, 255, 0, 64);

                CheckEqual(unchecked((int)0x80FF0040), tint.ToArgb());
            }

            public void FromColor_OfOpaqueWhite_IsWhite()
            {
                TintColor tint = Colors.White;

                CheckTrue(tint.IsWhite);
            }

            public void ToColor_UndoesFromColor()
            {
                Color original = Color.FromArgb(77, 12, 34, 56);
                TintColor tint = original;

                CheckEqual(original, (Color)tint);
            }
        }
    }
}