using System;

namespace AX.AudioSystem
{
    public class OpusDecoder : IDisposable
    {
        public const int FrameMaxSize = 5760;

        private IntPtr handle = IntPtr.Zero;
        private int channels;

        public OpusDecoder(SamplingRate samplingRate, Channel channels)
        {
            if (samplingRate != SamplingRate.Sampling08000 &&
                samplingRate != SamplingRate.Sampling12000 &&
                samplingRate != SamplingRate.Sampling16000 &&
                samplingRate != SamplingRate.Sampling24000 &&
                samplingRate != SamplingRate.Sampling48000)
                throw new ArgumentOutOfRangeException("samplingRate");

            if (channels != Channel.Mono && channels != Channel.Stereo)
                throw new ArgumentOutOfRangeException("channels");

            this.channels = (int)channels;
            handle = OpusNative.OpusDecoderCreate(samplingRate, channels);
        }

        public int Decode(byte[] packetData, float[] pcm)
        {
            int bandwidth = OpusNative.opus_packet_get_bandwidth(packetData);

            int samplesDecoded = 0;

            if (bandwidth == (int)OpusErrorCode.InvalidPacket)
                samplesDecoded = OpusNative.OpusDecode(handle, null, pcm, channels, 0);
            else
                samplesDecoded = OpusNative.OpusDecode(handle, packetData, pcm, channels, 0);

            return samplesDecoded;
        }

        public int Decode(byte[] packetData, short[] pcm)
        {
            int bandwidth = OpusNative.opus_packet_get_bandwidth(packetData);

            int samplesDecoded = 0;

            if (bandwidth == (int)OpusErrorCode.InvalidPacket)
                samplesDecoded = OpusNative.OpusDecode(handle, null, pcm, channels, 0);
            else
                samplesDecoded = OpusNative.OpusDecode(handle, packetData, pcm, channels, 0);

            return samplesDecoded;
        }

        public void Dispose()
        {
            if (handle != IntPtr.Zero)
            {
                OpusNative.OpusDecoderDestroy(handle);
                handle = IntPtr.Zero;
            }
        }
    }
}