using System;

namespace Susurrus.XAudio2.UnitTests
{
    /// <summary>
    /// An engine with a mastering voice, which needs a machine that has XAudio2 and an audio device.
    /// </summary>
    public class TestDevice : IDisposable
    {
        public const int SampleRate = 44100;

        public XAudio2Engine Engine { get; }
        public MasteringVoice Master { get; }

        private TestDevice(XAudio2Engine engine, MasteringVoice master)
        {
            this.Engine = engine;
            this.Master = master;
        }

        /// <summary>
        /// Returns the device, or null on a machine that can't play sound.
        /// </summary>
        public static TestDevice Open()
        {
            var engine = XAudio2Engine.Create();

            if (!engine.IsOk)
            {
                return null;
            }

            var master = engine.Value.CreateMasteringVoice();

            if (!master.IsOk)
            {
                engine.Value.Dispose();
                return null;
            }

            return new TestDevice(engine.Value, master.Value);
        }

        public static WaveFormatEx MonoFormat()
        {
            return WaveFormatEx.Of(SampleFormat.Pcm16, channelCount: 1, sampleRate: SampleRate);
        }

        public SourceVoice MonoVoice(float maxFrequencyRatio = 2f)
        {
            WaveFormatEx format = MonoFormat();
            return Engine.CreateSourceVoice(format, maxFrequencyRatio).Value;
        }

        public void Dispose()
        {
            Master.Destroy();
            Engine.Dispose();
        }
    }
}