using Amphora;
using Azimuth;
using UnitTestSharp;

namespace Konis.UnitTests
{
    public class ParticleChannelTests : TestFixture
    {
        private static Particle Fresh()
        {
            return new Particle { Lifetime = 1 };
        }

        public class OfTests : TestFixture
        {
            public void AVariationOfZero_IsAZeroChannelThatTakesNoColumn()
            {
                int columnCount = 3;

                ParticleChannel channel = ParticleChannel.Of(Variation.None, ref columnCount);

                CheckEqual(ChannelMode.Zero, channel.Mode);
                CheckEqual(0f, channel.Value);
                CheckEqual(-1, channel.Column);
                CheckEqual(3, columnCount);
            }

            public void ARangeWithNoWidthAboveZero_IsAConstantChannelThatTakesNoColumn()
            {
                int columnCount = 3;

                ParticleChannel channel = ParticleChannel.Of(2.5, ref columnCount);

                CheckEqual(ChannelMode.Constant, channel.Mode);
                CheckEqual(2.5f, channel.Value);
                CheckEqual(-1, channel.Column);
                CheckEqual(3, columnCount);
            }

            public void ARangeWithNoWidthBelowZero_IsAConstantChannel()
            {
                int columnCount = 0;

                ParticleChannel channel = ParticleChannel.Of(-9.5, ref columnCount);

                CheckEqual(ChannelMode.Constant, channel.Mode);
                CheckEqual(-9.5f, channel.Value);
            }

            public void ARangeWithWidth_IsAPerParticleChannelThatTakesTheNextColumn()
            {
                int columnCount = 3;

                ParticleChannel channel = ParticleChannel.Of(new Variation(1, 2), ref columnCount);

                CheckEqual(ChannelMode.PerParticle, channel.Mode);
                CheckEqual(0f, channel.Value);
                CheckEqual(3, channel.Column);
                CheckEqual(4, columnCount);
            }

            public void ARangeWithWidthStartingAtZero_IsAPerParticleChannel()
            {
                int columnCount = 0;

                CheckEqual(ChannelMode.PerParticle,
                    ParticleChannel.Of(new Variation(0, 1), ref columnCount).Mode);
            }

            public void RangesWithWidth_TakeConsecutiveColumns()
            {
                int columnCount = 0;

                ParticleChannel first = ParticleChannel.Of(new Variation(0, 1), ref columnCount);
                ParticleChannel second = ParticleChannel.Of(new Variation(0, 1), ref columnCount);

                CheckEqual(0, first.Column);
                CheckEqual(1, second.Column);
                CheckEqual(2, columnCount);
            }

            public void KeepsTheVariation()
            {
                int columnCount = 0;
                var variation = new Variation(1, 2);

                CheckEqual(2.0, ParticleChannel.Of(variation, ref columnCount).Variation.Maximum.Value);
            }
        }

        public class BirthTests : TestFixture
        {
            public void PerParticle_DrawsTheParticlesValueIntoItsColumn()
            {
                int columnCount = 0;
                ParticleChannel channel = ParticleChannel.Of(new Variation(0, 16), ref columnCount);
                var store = new ParticleStore(capacity: 2, columnCount: columnCount);
                store.Add(Fresh());
                int index = store.Add(Fresh());
                ScriptedGenerator random = ScriptedGenerator.OfUnits(0.5);

                channel.Birth(store, index, random);

                CheckEqual(8f, store.Columns[0][1]);
                CheckEqual(0f, store.Columns[0][0]);
                CheckEqual(0, random.Remaining);
            }

            public void Constant_TakesNoRandomNumber()
            {
                int columnCount = 0;
                ParticleChannel channel = ParticleChannel.Of(3, ref columnCount);
                var store = new ParticleStore(capacity: 1, columnCount: columnCount);
                int index = store.Add(Fresh());
                ScriptedGenerator random = ScriptedGenerator.OfUnits(0.25);

                channel.Birth(store, index, random);

                CheckEqual(1, random.Remaining);
            }

            public void Zero_TakesNoRandomNumber()
            {
                int columnCount = 0;
                ParticleChannel channel = ParticleChannel.Of(Variation.None, ref columnCount);
                var store = new ParticleStore(capacity: 1, columnCount: columnCount);
                int index = store.Add(Fresh());
                ScriptedGenerator random = ScriptedGenerator.OfUnits(0.25);

                channel.Birth(store, index, random);

                CheckEqual(1, random.Remaining);
            }
        }

        public class GetTests : TestFixture
        {
            public void PerParticle_ReadsTheParticlesColumnEntry()
            {
                int columnCount = 0;
                ParticleChannel channel = ParticleChannel.Of(new Variation(0, 1), ref columnCount);
                var store = new ParticleStore(capacity: 2, columnCount: columnCount);
                store.Add(Fresh());
                store.Add(Fresh());
                store.Columns[0][1] = 6;

                CheckEqual(6f, channel.Get(store, 1));
                CheckEqual(0f, channel.Get(store, 0));
            }

            public void Constant_IsTheValueForEveryParticle()
            {
                int columnCount = 0;
                ParticleChannel channel = ParticleChannel.Of(2.5, ref columnCount);
                var store = new ParticleStore(capacity: 1, columnCount: columnCount);
                store.Add(Fresh());

                CheckEqual(2.5f, channel.Get(store, 0));
            }

            public void Zero_IsZero()
            {
                int columnCount = 0;
                ParticleChannel channel = ParticleChannel.Of(Variation.None, ref columnCount);
                var store = new ParticleStore(capacity: 1, columnCount: columnCount);
                store.Add(Fresh());

                CheckEqual(0f, channel.Get(store, 0));
            }
        }
    }
}