using Ryujinx.Audio.Integration;
using Ryujinx.Audio.Renderer.Server;
using Ryujinx.Common;
using Ryujinx.Common.Logging;
using Ryujinx.Memory;
using System;
using System.Buffers;
using System.Collections.Generic;
using System.Runtime.CompilerServices;

namespace Ryujinx.Audio.Renderer.Dsp.Command
{
    public class CommandList : IDisposable
    {
        public ulong StartTime { get; private set; }
        public ulong EndTime { get; private set; }
        public uint SampleCount { get; }
        public uint SampleRate { get; }

        public Memory<float> Buffers { get; }
        public uint BufferCount { get; }

        private readonly static ObjectPool<List<ICommand>> CommandsListPool = new(() => new List<ICommand>(256));
        public List<ICommand> Commands { get; }

        public IVirtualMemoryManager MemoryManager { get; }

        public IHardwareDevice OutputDevice { get; private set; }

        private readonly int _sampleCount;
        private readonly int _buffersEntryCount;
        private readonly MemoryHandle _buffersMemoryHandle;

        public CommandList(AudioRenderSystem renderSystem) : this(renderSystem.MemoryManager,
                                                                  renderSystem.GetMixBuffer(),
                                                                  renderSystem.GetSampleCount(),
                                                                  renderSystem.GetSampleRate(),
                                                                  renderSystem.GetMixBufferCount(),
                                                                  renderSystem.GetVoiceChannelCountMax())
        {
        }

        public CommandList(IVirtualMemoryManager memoryManager, Memory<float> mixBuffer, uint sampleCount, uint sampleRate, uint mixBufferCount, uint voiceChannelCountMax)
        {
            SampleCount = sampleCount;
            _sampleCount = (int)SampleCount;
            SampleRate = sampleRate;
            BufferCount = mixBufferCount + voiceChannelCountMax;
            Buffers = mixBuffer;
            Commands = CommandsListPool.Allocate();
            MemoryManager = memoryManager;

            _buffersEntryCount = Buffers.Length;
            _buffersMemoryHandle = Buffers.Pin();
        }

        public void AddCommand(ICommand command)
        {
            Commands.Add(command);
        }

        public void AddCommand<T>(T command) where T : unmanaged, ICommand
        {
            throw new NotImplementedException();
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public unsafe nint GetBufferPointer(int index)
        {
            if (index >= 0 && index < _buffersEntryCount)
            {
                return (nint)((float*)_buffersMemoryHandle.Pointer + index * _sampleCount);
            }

            throw new ArgumentOutOfRangeException(nameof(index), index, null);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public unsafe void ClearBuffer(int index)
        {
            Unsafe.InitBlock((void*)GetBufferPointer(index), 0, SampleCount * sizeof(float));
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public unsafe void ClearBuffers()
        {
            Unsafe.InitBlock(_buffersMemoryHandle.Pointer, 0, (uint)_buffersEntryCount * sizeof(float));
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public unsafe void CopyBuffer(int outputBufferIndex, int inputBufferIndex)
        {
            Unsafe.CopyBlock((void*)GetBufferPointer(outputBufferIndex), (void*)GetBufferPointer(inputBufferIndex), SampleCount * sizeof(float));
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public Span<float> GetBuffer(int index)
        {
            if (index < 0 || index >= _buffersEntryCount)
            {
                return Span<float>.Empty;
            }

            unsafe
            {
                return new Span<float>((float*)_buffersMemoryHandle.Pointer + index * _sampleCount, _sampleCount);
            }
        }

        public ulong GetTimeElapsedSinceDspStartedProcessing()
        {
            return (ulong)PerformanceCounter.ElapsedNanoseconds - StartTime;
        }

        public void Process(IHardwareDevice outputDevice)
        {
            OutputDevice = outputDevice;

            StartTime = (ulong)PerformanceCounter.ElapsedNanoseconds;

            foreach (ICommand command in Commands)
            {
                if (command.Enabled)
                {
                    bool shouldMeter = command.ShouldMeter();

                    long startTime = 0;

                    if (shouldMeter)
                    {
                        startTime = PerformanceCounter.ElapsedNanoseconds;
                    }
                    
                    command.Process(this);

                    if (shouldMeter)
                    {
                        ulong effectiveElapsedTime = (ulong)(PerformanceCounter.ElapsedNanoseconds - startTime);

                        if (effectiveElapsedTime > command.EstimatedProcessingTime)
                        {
                            Logger.Warning?.Print(LogClass.AudioRenderer, $"Command {command.GetType().Name} took {effectiveElapsedTime}ns (expected {command.EstimatedProcessingTime}ns)");
                        }
                    }
                }
                
                CommandBuffer.ReleaseCommand(command);
            }

            EndTime = (ulong)PerformanceCounter.ElapsedNanoseconds;
        }

        public void Dispose()
        {
            Commands.Clear();
            CommandsListPool.Release(Commands);
            GC.SuppressFinalize(this);
            _buffersMemoryHandle.Dispose();
        }
    }
}
