using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using UnityEngine;

namespace NewHorizons.Utility
{
    public static class AudioUtility
    {
        // Thank you https://answers.unity.com/questions/737002/wav-byte-to-audioclip.html?_ga=2.94866780.194866897.1641426110-1837936344.1635819725

        // convert two bytes to one float in the range -1 to 1
        static float bytesToFloat(byte firstByte, byte secondByte)
        {
            // convert two bytes to one short (little endian)
            short s = (short)((secondByte << 8) | firstByte);
            // convert to range from -1 to (just below) 1
            return s / 32768.0F;
        }

        static int bytesToInt(byte[] bytes, int offset = 0)
        {
            int value = 0;
            for (int i = 0; i < 4; i++)
            {
                value |= ((int)bytes[offset + i]) << (i * 8);
            }
            return value;
        }

        private static byte[] GetBytes(string filename)
        {
            return File.ReadAllBytes(filename);
        }

        // Returns left and right double arrays. 'right' will be null if sound is mono.
        public static AudioClip LoadWAV(string filename) 
        {
            var wav = GetBytes(filename);

            // Determine if mono or stereo
            var ChannelCount = wav[22];     // Forget byte 23 as 99.999% of WAVs are 1 or 2 channels

            // Get the frequency
            var Frequency = bytesToInt(wav, 24);

            // Get past all the other sub chunks to get to the data subchunk:
            int pos = 12;   // First Subchunk ID from 12 to 16

            // Keep iterating until we find the data chunk (i.e. 64 61 74 61 ...... (i.e. 100 97 116 97 in decimal))
            while (!(wav[pos] == 100 && wav[pos + 1] == 97 && wav[pos + 2] == 116 && wav[pos + 3] == 97))
            {
                pos += 4;
                int chunkSize = wav[pos] + wav[pos + 1] * 256 + wav[pos + 2] * 65536 + wav[pos + 3] * 16777216;
                pos += 4 + chunkSize;
            }
            pos += 8;

            // Pos is now positioned to start of actual sound data.
            var SampleCount = (wav.Length - pos) / 2;     // 2 bytes per sample (16 bit sound mono)
            if (ChannelCount == 2) SampleCount /= 2;        // 4 bytes per sample (16 bit stereo)

            // Allocate memory (right will be null if only mono sound)
            var LeftChannel = new float[SampleCount];
            float[] RightChannel;
            if (ChannelCount == 2) RightChannel = new float[SampleCount];
            else RightChannel = null;

            // Write to double array/s:
            int i = 0;
            while (pos < wav.Length)
            {
                LeftChannel[i] = bytesToFloat(wav[pos], wav[pos + 1]);
                pos += 2;
                if (ChannelCount == 2)
                {
                    RightChannel[i] = bytesToFloat(wav[pos], wav[pos + 1]);
                    pos += 2;
                }
                i++;
            }

            AudioClip audioClip = AudioClip.Create("testSound", SampleCount, 1, Frequency, false);
            audioClip.SetData(LeftChannel, 0);
            return audioClip;
        }
    }
}