using System;
using UnityEngine;
namespace OnDeviceAgent.Inference
{

    public sealed class FloatRingBuffer
    {
        readonly float[] m_Buffer;
        int m_Start;
        int m_Count;

        public FloatRingBuffer(int capacity)
        {
            m_Buffer = new float[capacity];
        }

        public int Count => m_Count;
        public int Capacity => m_Buffer.Length;

        public float this[int index] => m_Buffer[PhysicalIndex(index)];

        public void Clear()
        {
            m_Start = 0;
            m_Count = 0;
        }

        public void Add(float value)
        {
            if (m_Count == m_Buffer.Length)
            {
                m_Buffer[m_Start] = value;
                m_Start = (m_Start + 1) % m_Buffer.Length;
                return;
            }

            m_Buffer[PhysicalIndex(m_Count)] = value;
            m_Count++;
        }

        public void AddRange(float[] source, int length)
        {
            AddRange(source, 0, length);
        }

        public void AddRange(float[] source, int sourceIndex, int length)
        {
            if (length >= m_Buffer.Length)
            {
                Array.Copy(source, sourceIndex + length - m_Buffer.Length, m_Buffer, 0, m_Buffer.Length);
                m_Start = 0;
                m_Count = m_Buffer.Length;
                return;
            }

            var overflow = m_Count + length - m_Buffer.Length;
            if (overflow > 0)
                RemoveFromStart(overflow);

            CopyInto(source, sourceIndex, PhysicalIndex(m_Count), length);
            m_Count += length;
        }

        public void CopyTo(int sourceIndex, float[] destination, int destinationIndex, int length)
        {
            var physicalIndex = PhysicalIndex(sourceIndex);
            var firstLength = Mathf.Min(length, m_Buffer.Length - physicalIndex);
            Array.Copy(m_Buffer, physicalIndex, destination, destinationIndex, firstLength);

            var remaining = length - firstLength;
            if (remaining > 0)
                Array.Copy(m_Buffer, 0, destination, destinationIndex + firstLength, remaining);
        }

        public void CopyLatest(int length, float[] destination, int destinationIndex)
        {
            CopyTo(m_Count - length, destination, destinationIndex, length);
        }

        public void RemoveFromStart(int length)
        {
            m_Start = PhysicalIndex(length);
            m_Count -= length;
        }

        int PhysicalIndex(int logicalIndex)
        {
            var index = m_Start + logicalIndex;
            return index >= m_Buffer.Length ? index - m_Buffer.Length : index;
        }

        void CopyInto(float[] source, int sourceIndex, int destinationIndex, int length)
        {
            var firstLength = Mathf.Min(length, m_Buffer.Length - destinationIndex);
            Array.Copy(source, sourceIndex, m_Buffer, destinationIndex, firstLength);

            var remaining = length - firstLength;
            if (remaining > 0)
                Array.Copy(source, sourceIndex + firstLength, m_Buffer, 0, remaining);
        }
    }
}