using Amphora;
using System;
using System.Runtime.InteropServices;
using UnitTestSharp;

namespace Susurrus.XAudio2.UnitTests
{
    public class XAudio2SoundTests : TestFixture
    {
        public static byte[] ReadBack(XAudio2Buffer buffer)
        {
            byte[] returnMe = new byte[buffer.AudioBytes];
            Marshal.Copy(buffer.AudioData, returnMe, 0, returnMe.Length);
            return returnMe;
        }

        public class CtorTests : TestFixture
        {
            public void TakesItsShapeFromTheDecodedSound()
            {
                DecodedSound decoded = SilentSounds.Of(
                    frameCount: 22050, channelCount: 2, sampleRate: 44100, format: SampleFormat.Float32);

                XAudio2Sound sound = new XAudio2Sound(decoded);

                CheckEqual(TimeSpan.FromSeconds(0.5), sound.Duration);
                CheckEqual(2, sound.ChannelCount);
                CheckEqual(44100, sound.SampleRate);
                CheckEqual(SampleFormat.Float32, sound.Format);
                CheckEqual(22050 * 2 * 4, sound.ByteCount);
                CheckEqual(22050, sound.FrameCount);
            }

            public void StartsUnheldAndUnpinned()
            {
                XAudio2Sound sound = new XAudio2Sound(SilentSounds.Short());

                CheckEqual(0, sound.HoldCount);
                CheckFalse(sound.IsPinned);
            }

            public void Null_Throws()
            {
                CheckThrow(typeof(ArgumentNullException));
                new XAudio2Sound(null);
            }
        }

        public class AcquireBufferTests : TestFixture
        {
            public void HoldsACopyOfTheSamples()
            {
                byte[] source = { 1, 2, 3, 4 };
                XAudio2Sound sound = new XAudio2Sound(new DecodedSound(
                    new ByteView(source), sampleRate: 8000, channelCount: 1, SampleFormat.Pcm16));
                source[0] = 99;

                XAudio2Buffer buffer = sound.AcquireBuffer();
                byte[] copy = ReadBack(buffer);
                sound.ReleaseBuffer();

                CheckEqual(4, copy.Length);
                CheckEqual((byte)1, copy[0]);
                CheckEqual((byte)2, copy[1]);
                CheckEqual((byte)3, copy[2]);
                CheckEqual((byte)4, copy[3]);
            }

            public void CopiesOnlyTheViewedBytes()
            {
                byte[] source = { 9, 9, 5, 6, 9, 9 };
                XAudio2Sound sound = new XAudio2Sound(new DecodedSound(
                    new ByteView(source, startIndex: 2, endIndex: 4), sampleRate: 8000, channelCount: 1,
                    SampleFormat.Pcm16));

                XAudio2Buffer buffer = sound.AcquireBuffer();
                byte[] copy = ReadBack(buffer);
                sound.ReleaseBuffer();

                CheckEqual(2, copy.Length);
                CheckEqual((byte)5, copy[0]);
                CheckEqual((byte)6, copy[1]);
            }

            public void WithNoLoop_RepeatsNothing()
            {
                XAudio2Sound sound = new XAudio2Sound(SilentSounds.Short());

                XAudio2Buffer buffer = sound.AcquireBuffer();
                sound.ReleaseBuffer();

                CheckEqual(0u, buffer.LoopCount);
                CheckEqual(0u, buffer.LoopLength);
            }

            public void AWholeLoop_RepeatsEveryFrameForever()
            {
                XAudio2Sound sound = new XAudio2Sound(SilentSounds.Short());

                XAudio2Buffer buffer = sound.AcquireBuffer(Loop.Whole);
                sound.ReleaseBuffer();

                CheckEqual(0u, buffer.LoopBegin);
                CheckEqual(480u, buffer.LoopLength);
                CheckEqual(XAudio2Buffer.LoopInfinite, buffer.LoopCount);
            }

            public void ARegion_RepeatsFromItsStartFrameToItsEndFrame()
            {
                XAudio2Sound sound = new XAudio2Sound(SilentSounds.Short());
                Loop loop = new Loop(TimeSpan.FromMilliseconds(2), TimeSpan.FromMilliseconds(6));

                XAudio2Buffer buffer = sound.AcquireBuffer(loop);
                sound.ReleaseBuffer();

                CheckEqual(96u, buffer.LoopBegin);
                CheckEqual(192u, buffer.LoopLength);
            }

            public void ARegionWithNoEnd_RepeatsToTheLastFrame()
            {
                XAudio2Sound sound = new XAudio2Sound(SilentSounds.Short());

                XAudio2Buffer buffer = sound.AcquireBuffer(new Loop(TimeSpan.FromMilliseconds(2)));
                sound.ReleaseBuffer();

                CheckEqual(96u, buffer.LoopBegin);
                CheckEqual(384u, buffer.LoopLength);
            }

            public void AWholeLoop_CoversEveryFrameOfASoundWhoseDurationWasRoundedDown()
            {
                XAudio2Sound sound = new XAudio2Sound(SilentSounds.Of(frameCount: 1000, sampleRate: 44100));

                XAudio2Buffer buffer = sound.AcquireBuffer(Loop.Whole);
                sound.ReleaseBuffer();

                CheckEqual(1000u, buffer.LoopLength);
            }

            public void ALoopPastTheEndOfTheSound_Throws()
            {
                XAudio2Sound sound = new XAudio2Sound(SilentSounds.Short());

                CheckThrow(typeof(ArgumentOutOfRangeException));
                sound.AcquireBuffer(new Loop(TimeSpan.Zero, TimeSpan.FromSeconds(1)));
            }

            public void MarksTheEndOfTheStream()
            {
                XAudio2Sound sound = new XAudio2Sound(SilentSounds.Short());

                CheckEqual(XAudio2Buffer.EndOfStream, sound.AcquireBuffer().Flags);
                sound.ReleaseBuffer();
            }

            public void ASoundWithNoSamples_HasNoBytes()
            {
                XAudio2Sound sound = new XAudio2Sound(SilentSounds.Of(frameCount: 0));

                XAudio2Buffer buffer = sound.AcquireBuffer();
                sound.ReleaseBuffer();

                CheckEqual((uint)0, buffer.AudioBytes);
            }

            public void PinsTheSamplesAndCountsTheHold()
            {
                XAudio2Sound sound = new XAudio2Sound(SilentSounds.Short());

                sound.AcquireBuffer();

                CheckEqual(1, sound.HoldCount);
                CheckTrue(sound.IsPinned);
                sound.ReleaseBuffer();
            }

            public void ASecondHold_SharesTheAddress()
            {
                XAudio2Sound sound = new XAudio2Sound(SilentSounds.Short());

                XAudio2Buffer first = sound.AcquireBuffer();
                XAudio2Buffer second = sound.AcquireBuffer();

                CheckEqual(2, sound.HoldCount);
                CheckTrue(first.AudioData == second.AudioData);
                sound.ReleaseBuffer();
                sound.ReleaseBuffer();
            }
        }

        public class ReleaseBufferTests : TestFixture
        {
            public void TheLastRelease_Unpins()
            {
                XAudio2Sound sound = new XAudio2Sound(SilentSounds.Short());
                sound.AcquireBuffer();

                sound.ReleaseBuffer();

                CheckEqual(0, sound.HoldCount);
                CheckFalse(sound.IsPinned);
            }

            public void AnEarlierRelease_KeepsThePin()
            {
                XAudio2Sound sound = new XAudio2Sound(SilentSounds.Short());
                sound.AcquireBuffer();
                sound.AcquireBuffer();

                sound.ReleaseBuffer();

                CheckEqual(1, sound.HoldCount);
                CheckTrue(sound.IsPinned);
                sound.ReleaseBuffer();
            }

            public void WithNoHold_Throws()
            {
                XAudio2Sound sound = new XAudio2Sound(SilentSounds.Short());

                CheckThrow(typeof(InvalidOperationException));
                sound.ReleaseBuffer();
            }

            public void AfterTheLastRelease_AcquiringPinsAgain()
            {
                XAudio2Sound sound = new XAudio2Sound(SilentSounds.Short());
                sound.AcquireBuffer();
                sound.ReleaseBuffer();

                sound.AcquireBuffer();

                CheckTrue(sound.IsPinned);
                sound.ReleaseBuffer();
            }
        }
    }
}