using UnityEngine;
using System;

namespace Photon.Voice.Unity
{
    // Wraps UnityEngine.Microphone with Voice.IAudioStream interface.
    public class MicWrapper : IAudioReader<float>
    {
        private AudioClip mic;
        private string device;
        ILogger logger;

        public MicWrapper(string device, int suggestedFrequency, ILogger logger)
        {
            try
            {
                this.device = device;
                this.logger = logger;

                int frequency;
                this.Error = UnityMicrophone.CheckDevice(logger, "[PV] MicWrapper: ", device, suggestedFrequency, out frequency);
                if (this.Error != null)
                {
                    return;
                }

                this.mic = UnityMicrophone.Start(device, true, 1, frequency);
                logger.Log(LogLevel.Info, "[PV] MicWrapper: microphone '{0}' initialized, frequency = {1}, channels = {2}.", device, this.mic.frequency, this.mic.channels);
            }
            catch (Exception e)
            {
                Error = e.ToString();
                if (Error == null) // should never happen but since Error used as validity flag, make sure that it's not null
                {
                    Error = "Exception in MicWrapper constructor";
                }
                logger.Log(LogLevel.Error, "[PV] MicWrapper: " + Error);
            }
        }

        public int SamplingRate { get { return Error == null ? this.mic.frequency : 0; } }
        public int Channels { get { return Error == null ? this.mic.channels : 0; } }
        public string Error { get; private set; }

        public void Dispose()
        {
            UnityMicrophone.End(this.device);
        }

        private int micPrevPos;
        private int micLoopCnt;
        private int readAbsPos;

        public bool Read(float[] buffer)
        {
            if (Error != null)
            {
                return false;
            }
            int micPos = UnityMicrophone.GetPosition(this.device);
            // loop detection
            if (micPos < micPrevPos)
            {
                micLoopCnt++;
            }
            micPrevPos = micPos;

            var micAbsPos = micLoopCnt * this.mic.samples + micPos;

            if (mic.channels == 0)
            {
                Error = "Number of channels is 0 in Read()";
                logger.Log(LogLevel.Error, "[PV] MicWrapper: " + Error);
                return false;
            }
            var bufferSamplesCount = buffer.Length / mic.channels;

            var nextReadPos = this.readAbsPos + bufferSamplesCount;
            if (nextReadPos < micAbsPos)
            {
                this.mic.GetData(buffer, this.readAbsPos % this.mic.samples);
                this.readAbsPos = nextReadPos;
                return true;
            }
            else
            {
                return false;
            }
        }
    }
}