using System;

namespace FractalVisualizer.Audio;

public sealed class AudioSampleRingBuffer
{
    private readonly float[] _buffer;
    private readonly object _sync = new();

    private int _writeIndex;
    private int _readIndex;
    private int _count;

    public AudioSampleRingBuffer(int capacity)
    {
        if (capacity <= 0)
        {
            throw new ArgumentOutOfRangeException(nameof(capacity));
        }

        _buffer = new float[capacity];
    }

    public int Capacity => _buffer.Length;

    public int Count
    {
        get
        {
            lock (_sync)
            {
                return _count;
            }
        }
    }

    public void Clear()
    {
        lock (_sync)
        {
            _writeIndex = 0;
            _readIndex = 0;
            _count = 0;
        }
    }

    public void Write(ReadOnlySpan<float> samples)
    {
        lock (_sync)
        {
            for (int i = 0; i < samples.Length; i++)
            {
                _buffer[_writeIndex] = samples[i];
                _writeIndex = (_writeIndex + 1) % _buffer.Length;

                if (_count == _buffer.Length)
                {
                    _readIndex = (_readIndex + 1) % _buffer.Length;
                }
                else
                {
                    _count++;
                }
            }
        }
    }

    public bool TryRead(Span<float> destination)
    {
        lock (_sync)
        {
            if (_count < destination.Length)
            {
                return false;
            }

            for (int i = 0; i < destination.Length; i++)
            {
                destination[i] = _buffer[_readIndex];
                _readIndex = (_readIndex + 1) % _buffer.Length;
            }

            _count -= destination.Length;
            return true;
        }
    }
}