using System;
using System.IO;

namespace MoonWorks.Audio
{
    /// <summary>
    /// For streaming long playback. Reads an OGG file.
    /// </summary>
    public class DynamicSound : Sound, IDisposable
    {
        internal override FAudio.FAudioWaveFormatEx Format { get; }

        // FIXME: what should this value be?
        public const int BUFFER_SIZE = 1024 * 128;

        internal IntPtr FileHandle { get; }
        internal FAudio.stb_vorbis_info Info { get; }

        private bool IsDisposed;

        public DynamicSound(AudioDevice device, FileInfo fileInfo) : base(device)
        {
            FileHandle = FAudio.stb_vorbis_open_filename(fileInfo.FullName, out var error, IntPtr.Zero);

            if (error != 0)
            {
                Logger.LogError("Error opening OGG file!");
                throw new AudioLoadException("Error opening OGG file!");
            }

            Info = FAudio.stb_vorbis_get_info(FileHandle);

            var blockAlign = (ushort)(4 * Info.channels);

            Format = new FAudio.FAudioWaveFormatEx
            {
                wFormatTag = 3,
                wBitsPerSample = 32,
                nChannels = (ushort) Info.channels,
                nBlockAlign = blockAlign,
                nSamplesPerSec = Info.sample_rate,
                nAvgBytesPerSec = blockAlign * Info.sample_rate,
                cbSize = 0
            };
        }

        public DynamicSoundInstance CreateInstance()
        {
            var instance = new DynamicSoundInstance(Device, this, false);
            Device.AddDynamicSoundInstance(instance);
            return instance;
        }

        protected virtual void Dispose(bool disposing)
        {
            if (!IsDisposed)
            {
                if (disposing)
                {
                    // dispose managed state (managed objects)
                }

                FAudio.stb_vorbis_close(FileHandle);
                IsDisposed = true;
            }
        }

        // override finalizer only if 'Dispose(bool disposing)' has code to free unmanaged resources
        ~DynamicSound()
        {
            // Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
            Dispose(disposing: false);
        }

        public void Dispose()
        {
            // Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
            Dispose(disposing: true);
            GC.SuppressFinalize(this);
        }
    }
}