using System;
using System.Buffers;
using System.Buffers.Binary;
using System.Collections.Generic;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Jobs;
using Server;
using Server.Network;

namespace Benchmarks
{
    [SimpleJob(RuntimeMoniker.NetCoreApp50)]
    public class BenchmarkPacketConstruction
    {
        public List<BuyItemState> m_States;

        [GlobalSetup]
        public void SetUp()
        {
            m_States = new List<BuyItemState>
            {
                new("Name 1", 0x1000, 0x2000, 1000, 1, 10, 1024),
                new("Name 2", 0x1001, 0x2001, 1001, 1, 10, 1024),
                new("Name 3", 0x1002, 0x2002, 1002, 1, 10, 1024),
                new("Name 4", 0x1003, 0x2003, 1003, 1, 10, 1024),
                new("Name 5", 0x1004, 0x2004, 1004, 1, 10, 1024),
                new("Name 6", 0x1005, 0x2005, 1005, 1, 10, 1024),
                new("Name 7", 0x1006, 0x2006, 1006, 1, 10, 1024),
                new("Name 8", 0x1007, 0x2007, 1007, 1, 10, 1024),
                new("Name 9", 0x1008, 0x2008, 1008, 1, 10, 1024),
                new("Name A", 0x1009, 0x2009, 1009, 1, 10, 1024),
                new("Name 10", 0x1000, 0x2000, 1000, 1, 10, 1024),
                new("Name 20", 0x1001, 0x2001, 1001, 1, 10, 1024),
                new("Name 30", 0x1002, 0x2002, 1002, 1, 10, 1024),
                new("Name 40", 0x1003, 0x2003, 1003, 1, 10, 1024),
                new("Name 50", 0x1004, 0x2004, 1004, 1, 10, 1024),
                new("Name 60", 0x1005, 0x2005, 1005, 1, 10, 1024),
                new("Name 70", 0x1006, 0x2006, 1006, 1, 10, 1024),
                new("Name 80", 0x1007, 0x2007, 1007, 1, 10, 1024),
                new("Name 90", 0x1008, 0x2008, 1008, 1, 10, 1024),
                new("Name A0", 0x1009, 0x2009, 1009, 1, 10, 1024),
                new("Name 11", 0x1000, 0x2000, 1000, 1, 10, 1024),
                new("Name 21", 0x1001, 0x2001, 1001, 1, 10, 1024),
                new("Name 31", 0x1002, 0x2002, 1002, 1, 10, 1024),
                new("Name 41", 0x1003, 0x2003, 1003, 1, 10, 1024),
                new("Name 51", 0x1004, 0x2004, 1004, 1, 10, 1024),
                new("Name 61", 0x1005, 0x2005, 1005, 1, 10, 1024),
                new("Name 71", 0x1006, 0x2006, 1006, 1, 10, 1024),
                new("Name 81", 0x1007, 0x2007, 1007, 1, 10, 1024),
                new("Name 91", 0x1008, 0x2008, 1008, 1, 10, 1024),
                new("Name A1", 0x1009, 0x2009, 1009, 1, 10, 1024)
            };
        }

        [Benchmark]
        public Packet TestPacketConstruction()
        {
            Packet p = new VendorBuyContent(m_States);
            p.Compile(false, out _);
            return p;
        }

        [Benchmark]
        public int TestInlineRefConstruction()
        {
            var buyStates = m_States;

            int length = 5 + buyStates.Count * 19;

            Span<byte> data = stackalloc byte[length];

            int pos = 0;
            data.Write(ref pos, (byte)0x3C);
            data.Write(ref pos, (ushort)length);
            data.Write(ref pos, (ushort)buyStates.Count);

            for (int i = buyStates.Count - 1; i >= 0; i--)
            {
                BuyItemState buyState = buyStates[i];

                data.Write(ref pos, buyState.MySerial);
                data.Write(ref pos, (ushort)buyState.ItemID);
                data.Write(ref pos, (byte)0);
                data.Write(ref pos, (ushort)buyState.Amount);
                data.Write(ref pos, (ushort)(i + 1));
                data.Write(ref pos, (ushort)0x1);
                data.Write(ref pos, buyState.ContainerSerial);
                data.Write(ref pos, (ushort)buyState.Hue);
            }

            return data.Length;
        }

        [Benchmark]
        public int TestInlineConstruction()
        {
            var buyStates = m_States;

            Span<byte> data = stackalloc byte[5 + buyStates.Count * 19];
            data[0] = 0x3C;
            BinaryPrimitives.WriteUInt16BigEndian(data.Slice(1, 2), (ushort)data.Length);
            BinaryPrimitives.WriteUInt16BigEndian(data.Slice(3, 2), (ushort)buyStates.Count);
            int pos = 4;


            for (int i = buyStates.Count - 1; i >= 0; i--)
            {
                BuyItemState buyState = buyStates[i];
                BinaryPrimitives.WriteUInt32BigEndian(data.Slice(pos, 4), buyState.MySerial);
                pos += 4;
                BinaryPrimitives.WriteUInt16BigEndian(data.Slice(pos, 2), (ushort)buyState.ItemID);
                pos += 2;
                data[pos++] = 0;
                BinaryPrimitives.WriteUInt16BigEndian(data.Slice(pos, 2), (ushort)buyState.Amount);
                pos += 2;
                BinaryPrimitives.WriteUInt16BigEndian(data.Slice(pos, 2), (ushort)(i + 1));
                pos += 2;
                BinaryPrimitives.WriteUInt16BigEndian(data.Slice(pos, 2), 0x1);
                pos += 2;
                BinaryPrimitives.WriteUInt32BigEndian(data.Slice(pos, 4), buyState.ContainerSerial);
                pos += 4;
                BinaryPrimitives.WriteUInt16BigEndian(data.Slice(pos, 2), (ushort)(buyState.Hue));
                pos += 2;
            }

            return data.Length;
        }

        [Benchmark]
        public int TestSpanWriterConstruction()
        {
            var buyStates = m_States;

            int length = 5 + buyStates.Count * 19;

            SpanWriter w = new SpanWriter(stackalloc byte[length]);

            w.Write((byte)0x3C);              // Packet ID
            w.Write((ushort)length);          // Length
            w.Write((ushort)buyStates.Count); // Length

            for (int i = buyStates.Count - 1; i >= 0; i--)
            {
                BuyItemState buyState = buyStates[i];
                w.Write(buyState.MySerial);
                w.Write((ushort)buyState.ItemID);
                w.Write((byte)0);
                w.Write((ushort)(i + 1)); // X
                w.Write((ushort)0x1);     // Y
                w.Write(buyState.ContainerSerial);
                w.Write((ushort)buyState.Hue);
            }

            return w.Position;
        }
    }
}