// Copyright (c) 2012-2023 Wojciech Figat. All rights reserved.

using System;
using System.Text;
using FlaxEngine.Assertions;

namespace FlaxEngine.Networking
{
    public unsafe partial struct NetworkMessage
    {
        /// <summary>
        /// Writes raw bytes into the message.
        /// </summary>
        /// <param name="bytes">The bytes that will be written.</param>
        /// <param name="length">The amount of bytes to write from the bytes pointer.</param>
        public void WriteBytes(byte* bytes, int length)
        {
            Assert.IsTrue(Position + length <= BufferSize, $"Could not write data of length {length} into message with id={MessageId}! Current write position={Position}");
            Utils.MemoryCopy(new IntPtr(Buffer + Position), new IntPtr(bytes), (ulong)length);
            Position += (uint)length;
            Length = Position;
        }

        /// <summary>
        /// Reads raw bytes from the message into the given byte array.
        /// </summary>
        /// <param name="buffer">
        /// The buffer pointer that will be used to store the bytes.
        /// Should be of the same length as length or longer.
        /// </param>
        /// <param name="length">The minimal amount of bytes that the buffer contains.</param>
        public void ReadBytes(byte* buffer, int length)
        {
            Assert.IsTrue(Position + length <= Length, $"Could not read data of length {length} from message with id={MessageId} and size of {Length}B! Current read position={Position}");
            Utils.MemoryCopy(new IntPtr(buffer), new IntPtr(Buffer + Position), (ulong)length);
            Position += (uint)length;
        }

        /// <summary>
        /// Writes raw bytes into the message.
        /// </summary>
        /// <param name="bytes">The bytes that will be written.</param>
        /// <param name="length">The amount of bytes to write from the bytes array.</param>
        public void WriteBytes(byte[] bytes, int length)
        {
            fixed (byte* bytesPtr = bytes)
            {
                WriteBytes(bytesPtr, length);
            }
        }

        /// <summary>
        /// Reads raw bytes from the message into the given byte array.
        /// </summary>
        /// <param name="buffer">
        /// The buffer that will be used to store the bytes.
        /// Should be of the same length as length or longer.
        /// </param>
        /// <param name="length">The minimal amount of bytes that the buffer contains.</param>
        public void ReadBytes(byte[] buffer, int length)
        {
            fixed (byte* bufferPtr = buffer)
            {
                ReadBytes(bufferPtr, length);
            }
        }

        /// <summary>
        /// Writes data of type <see cref="Int64"/> into the message.
        /// </summary>
        public void WriteInt64(long value)
        {
            WriteBytes((byte*)&value, sizeof(long));
        }

        /// <summary>
        /// Reads and returns data of type <see cref="Int64"/> from the message.
        /// </summary>
        public long ReadInt64()
        {
            long value = 0;
            ReadBytes((byte*)&value, sizeof(long));
            return value;
        }

        /// <summary>
        /// Writes data of type <see cref="Int32"/> into the message.
        /// </summary>
        public void WriteInt32(int value)
        {
            WriteBytes((byte*)&value, sizeof(int));
        }

        /// <summary>
        /// Reads and returns data of type <see cref="Int32"/> from the message.
        /// </summary>
        public int ReadInt32()
        {
            int value = 0;
            ReadBytes((byte*)&value, sizeof(int));
            return value;
        }

        /// <summary>
        /// Writes data of type <see cref="Int16"/> into the message.
        /// </summary>
        public void WriteInt16(short value)
        {
            WriteBytes((byte*)&value, sizeof(short));
        }

        /// <summary>
        /// Reads and returns data of type <see cref="Int16"/> from the message.
        /// </summary>
        public short ReadInt16()
        {
            short value = 0;
            ReadBytes((byte*)&value, sizeof(short));
            return value;
        }

        /// <summary>
        /// Writes data of type <see cref="SByte"/> into the message.
        /// </summary>
        public void WriteSByte(sbyte value)
        {
            WriteBytes((byte*)&value, sizeof(sbyte));
        }

        /// <summary>
        /// Reads and returns data of type <see cref="SByte"/> from the message.
        /// </summary>
        public sbyte ReadSByte()
        {
            sbyte value = 0;
            ReadBytes((byte*)&value, sizeof(sbyte));
            return value;
        }

        /// <summary>
        /// Writes data of type <see cref="UInt64"/> into the message.
        /// </summary>
        public void WriteUInt64(ulong value)
        {
            WriteBytes((byte*)&value, sizeof(ulong));
        }

        /// <summary>
        /// Reads and returns data of type <see cref="UInt64"/> from the message.
        /// </summary>
        public ulong ReadUInt64()
        {
            ulong value = 0;
            ReadBytes((byte*)&value, sizeof(ulong));
            return value;
        }

        /// <summary>
        /// Writes data of type <see cref="UInt32"/> into the message.
        /// </summary>
        public void WriteUInt32(uint value)
        {
            WriteBytes((byte*)&value, sizeof(uint));
        }

        /// <summary>
        /// Reads and returns data of type <see cref="UInt32"/> from the message.
        /// </summary>
        public uint ReadUInt32()
        {
            uint value = 0;
            ReadBytes((byte*)&value, sizeof(uint));
            return value;
        }

        /// <summary>
        /// Writes data of type <see cref="UInt16"/> into the message.
        /// </summary>
        public void WriteUInt16(ushort value)
        {
            WriteBytes((byte*)&value, sizeof(ushort));
        }

        /// <summary>
        /// Reads and returns data of type <see cref="UInt16"/> from the message.
        /// </summary>
        public ushort ReadUInt16()
        {
            ushort value = 0;
            ReadBytes((byte*)&value, sizeof(ushort));
            return value;
        }

        /// <summary>
        /// Writes data of type <see cref="Byte"/> into the message.
        /// </summary>
        public void WriteByte(byte value)
        {
            WriteBytes(&value, sizeof(byte));
        }

        /// <summary>
        /// Reads and returns data of type <see cref="Byte"/> from the message.
        /// </summary>
        public byte ReadByte()
        {
            byte value = 0;
            ReadBytes(&value, sizeof(byte));
            return value;
        }

        /// <summary>
        /// Writes data of type <see cref="Single"/> into the message.
        /// </summary>
        public void WriteSingle(float value)
        {
            WriteBytes((byte*)&value, sizeof(float));
        }

        /// <summary>
        /// Reads and returns data of type <see cref="Single"/> from the message.
        /// </summary>
        public float ReadSingle()
        {
            float value = 0.0f;
            ReadBytes((byte*)&value, sizeof(float));
            return value;
        }

        /// <summary>
        /// Writes data of type <see cref="Double"/> into the message.
        /// </summary>
        public void WriteDouble(double value)
        {
            WriteBytes((byte*)&value, sizeof(double));
        }

        /// <summary>
        /// Reads and returns data of type <see cref="Double"/> from the message.
        /// </summary>
        public double ReadDouble()
        {
            double value = 0.0;
            ReadBytes((byte*)&value, sizeof(double));
            return value;
        }

        /// <summary>
        /// Writes data of type <see cref="string"/> into the message. UTF-16 encoded.
        /// </summary>
        public void WriteString(string value)
        {
            // Note: Make sure that this is consistent with the C++ message API!
            
            var data = Encoding.Unicode.GetBytes(value);
            var dataLength = data.Length;
            var stringLength = value.Length;
            
            WriteUInt16((ushort)stringLength); // TODO: Use 1-byte length when possible
            WriteBytes(data, dataLength);
        }

        /// <summary>
        /// Reads and returns data of type <see cref="string"/> from the message. UTF-16 encoded.
        /// </summary>
        public string ReadString()
        {
            // Note: Make sure that this is consistent with the C++ message API!
            
            var stringLength = ReadUInt16(); // In chars
            var dataLength = stringLength * sizeof(char); // In bytes
            var bytes = stackalloc char[stringLength];
            
            ReadBytes((byte*)bytes, dataLength);
            return new string(bytes, 0, stringLength);
        }

        /// <summary>
        /// Writes data of type <see cref="Guid"/> into the message.
        /// </summary>
        public void WriteGuid(Guid value)
        {
            WriteBytes((byte*)&value, sizeof(Guid));
        }

        /// <summary>
        /// Reads and returns data of type <see cref="Guid"/> from the message.
        /// </summary>
        public Guid ReadGuid()
        {
            var guidData = stackalloc Guid[1];
            ReadBytes((byte*)guidData, sizeof(Guid));
            return guidData[0];
        }

        /// <summary>
        /// Writes data of type <see cref="Vector2"/> into the message.
        /// </summary>
        public void WriteVector2(Vector2 value)
        {
            WriteSingle((float)value.X);
            WriteSingle((float)value.Y);
        }

        /// <summary>
        /// Reads and returns data of type <see cref="Vector2"/> from the message.
        /// </summary>
        public Vector2 ReadVector2()
        {
            return new Vector2(ReadSingle(), ReadSingle());
        }

        /// <summary>
        /// Writes data of type <see cref="Vector3"/> into the message.
        /// </summary>
        public void WriteVector3(Vector3 value)
        {
            WriteSingle((float)value.X);
            WriteSingle((float)value.Y);
            WriteSingle((float)value.Z);
        }

        /// <summary>
        /// Reads and returns data of type <see cref="Vector3"/> from the message.
        /// </summary>
        public Vector3 ReadVector3()
        {
            return new Vector3(ReadSingle(), ReadSingle(), ReadSingle());
        }

        /// <summary>
        /// Writes data of type <see cref="Vector4"/> into the message.
        /// </summary>
        public void WriteVector4(Vector4 value)
        {
            WriteSingle((float)value.X);
            WriteSingle((float)value.Y);
            WriteSingle((float)value.Z);
            WriteSingle((float)value.W);
        }

        /// <summary>
        /// Reads and returns data of type <see cref="Vector4"/> from the message.
        /// </summary>
        public Vector4 ReadVector4()
        {
            return new Vector4(ReadSingle(), ReadSingle(), ReadSingle(), ReadSingle());
        }

        /// <summary>
        /// Writes data of type <see cref="Quaternion"/> into the message.
        /// </summary>
        public void WriteQuaternion(Quaternion value)
        {
            WriteSingle(value.X);
            WriteSingle(value.Y);
            WriteSingle(value.Z);
            WriteSingle(value.W);
        }

        /// <summary>
        /// Reads and returns data of type <see cref="Quaternion"/> from the message.
        /// </summary>
        public Quaternion ReadQuaternion()
        {
            return new Quaternion(ReadSingle(), ReadSingle(), ReadSingle(), ReadSingle());
        }

        /// <summary>
        /// Writes data of type <see cref="Boolean"/> into the message.
        /// </summary>
        public void WriteBoolean(bool value)
        {
            WriteBytes((byte*)&value, sizeof(bool));
        }

        /// <summary>
        /// Reads and returns data of type <see cref="Boolean"/> from the message.
        /// </summary>
        public bool ReadBoolean()
        {
            bool value = default;
            ReadBytes((byte*)&value, sizeof(bool));
            return value;
        }
    }
}