using System;
using System.Collections.Generic;
using System.Numerics;
using System.Text;
using BasicServer.Management;

namespace BasicServer.Arch {
    public sealed class Packet : IDisposable {
        private List<byte> _buffer;

        private bool _disposed;
        private byte[] _readableBuffer;
        private int _readPos;

        /// <summary>Creates a new empty packet (without an ID).</summary>
        public Packet() {
            _buffer = new List<byte>(); // Initialize buffer
            _readPos = 0; // Set readPos to 0
        }

        /// <summary>Creates a new packet with a given ID. Used for sending.</summary>
        /// <param name="packetTypeId">The packetType ID.</param>
        /// <param name="packetActionId">The packetAction ID.</param>
        public Packet(int packetTypeId, int packetActionId) {
            _buffer = new List<byte>(); // Initialize buffer
            _readPos = 0; // Set readPos to 0

            Write(packetTypeId); // Write packet ids to the buffer
            Write(packetActionId);
        }

        /// <summary>Creates a packet from which data can be read. Used for receiving.</summary>
        /// <param name="data">The bytes to add to the packet.</param>
        public Packet(byte[] data) {
            _buffer = new List<byte>(); // Initialize buffer
            _readPos = 0; // Set readPos to 0

            SetBytes(data);
        }

        public void Dispose() {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        private void Dispose(bool disposing) {
            if (_disposed)
                return;
            
            if (disposing) {
                _buffer = null;
                _readableBuffer = null;
                _readPos = 0;
            }

            _disposed = true;
        }

        #region Functions
        /// <summary>Sets the packet's content and prepares it to be read.</summary>
        /// <param name="data">The bytes to add to the packet.</param>
        public void SetBytes(byte[] data) {
            Write(data);
            _readableBuffer = _buffer.ToArray();
        }

        /// <summary>Inserts the length of the packet's content at the start of the buffer.</summary>
        public void WriteLength() {
            _buffer.InsertRange(0, BitConverter.GetBytes(_buffer.Count)); // Insert the byte length of the packet at the very beginning
        }

        /// <summary>Inserts the given int at the start of the buffer.</summary>
        /// <param name="value">The int to insert.</param>
        public void InsertInt(int value) {
            _buffer.InsertRange(0, BitConverter.GetBytes(value)); // Insert the int at the start of the buffer
        }

        /// <summary>Gets the packet's content in array form.</summary>
        public byte[] ToArray() {
            _readableBuffer = _buffer.ToArray();
            return _readableBuffer;
        }

        /// <summary>Gets the length of the packet's content.</summary>
        public int Length() {
            return _buffer.Count; // Return the length of buffer
        }

        /// <summary>Gets the length of the unread data contained in the packet.</summary>
        public int UnreadLength() {
            return Length() - _readPos; // Return the remaining length (unread)
        }

        /// <summary>Resets the packet instance to allow it to be reused.</summary>
        /// <param name="shouldReset">Whether or not to reset the packet.</param>
        public void Reset(bool shouldReset = true) {
            if (shouldReset) {
                _buffer.Clear(); // Clear buffer
                _readableBuffer = null;
                _readPos = 0; // Reset readPos
            } else {
                _readPos -= 4; // "Unread" the last read int
            }
        }
        #endregion

        #region Write Data
        /// <summary>Adds a byte to the packet.</summary>
        /// <param name="value">The byte to add.</param>
        public void Write(byte value) {
            _buffer.Add(value);
        }

        /// <summary>Adds an array of bytes to the packet.</summary>
        /// <param name="value">The byte array to add.</param>
        public void Write(IEnumerable<byte> value) {
            _buffer.AddRange(value);
        }

        /// <summary>Adds a short to the packet.</summary>
        /// <param name="value">The short to add.</param>
        public void Write(short value) {
            _buffer.AddRange(BitConverter.GetBytes(value));
        }

        /// <summary>Adds an int to the packet.</summary>
        /// <param name="value">The int to add.</param>
        public void Write(int value) {
            _buffer.AddRange(BitConverter.GetBytes(value));
        }

        /// <summary>Adds a long to the packet.</summary>
        /// <param name="value">The long to add.</param>
        public void Write(long value) {
            _buffer.AddRange(BitConverter.GetBytes(value));
        }

        /// <summary>Adds a float to the packet.</summary>
        /// <param name="value">The float to add.</param>
        public void Write(float value) {
            _buffer.AddRange(BitConverter.GetBytes(value));
        }

        /// <summary>Adds a bool to the packet.</summary>
        /// <param name="value">The bool to add.</param>
        public void Write(bool value) {
            _buffer.AddRange(BitConverter.GetBytes(value));
        }

        /// <summary>Adds a string to the packet.</summary>
        /// <param name="value">The string to add.</param>
        public void Write(string value) {
            Write(value.Length); // Add the length of the string to the packet
            _buffer.AddRange(Encoding.ASCII.GetBytes(value)); // Add the string itself
        }

        /// <summary>Adds a Vector3 to the packet.</summary>
        /// <param name="value">The Vector3 to add.</param>
        public void Write(Vector3 value) {
            Write(value.X);
            Write(value.Y);
            Write(value.Z);
        }

        /// <summary>Adds a Quaternion to the packet.</summary>
        /// <param name="value">The Quaternion to add.</param>
        public void Write(Quaternion value) {
            Write(value.X);
            Write(value.Y);
            Write(value.Z);
            Write(value.W);
        }

        /// <summary>Adds a Room to the packet.</summary>
        /// <param name="value">The Room to add.</param>
        public void Write(Room value) {
            Write(value.Id);
            Write(value.Name);
            Write(value.IsLocked);
            Write(value.Leader.Id);
            Write(value.MaxPlayers);
            Write(value.CurrentPlayers);
            foreach (var client in value.Clients) {
                Write(client.Id);
                Write(client.Name);
            }
        }

        /// <summary>Adds ClientProperties to the packet.</summary>
        /// <param name="value">ClientProperties to add.</param>
        public void Write(Dictionary<int, Room.ClientProperties> value) {
            Write(value.Count);
            foreach (var (key, clientProperties) in value) {
                Write(key);
                Write(clientProperties.IsLeader);
                Write(clientProperties.IsReady);
                Write(clientProperties.ColorId);
            }
        }
        
        #endregion

        #region Read Data
        /// <summary>Reads a byte from the packet.</summary>
        /// <param name="moveReadPos">Whether or not to move the buffer's read position.</param>
        public byte ReadByte(bool moveReadPos = true) {
            if (_buffer.Count > _readPos) {
                // If there are unread bytes
                var value = _readableBuffer[_readPos]; // Get the byte at readPos' position
                if (moveReadPos)
                    // If _moveReadPos is true
                    _readPos += 1; // Increase readPos by 1
                return value; // Return the byte
            }

            throw new Exception("Could not read value of type 'byte'!");
        }

        /// <summary>Reads an array of bytes from the packet.</summary>
        /// <param name="length">The length of the byte array.</param>
        /// <param name="moveReadPos">Whether or not to move the buffer's read position.</param>
        public byte[] ReadBytes(int length, bool moveReadPos = true) {
            if (_buffer.Count > _readPos) {
                // If there are unread bytes
                var value = _buffer.GetRange(_readPos, length).ToArray(); // Get the bytes at readPos' position with a range of _length
                if (moveReadPos)
                    // If _moveReadPos is true
                    _readPos += length; // Increase readPos by _length
                return value; // Return the bytes
            }

            throw new Exception("Could not read value of type 'byte[]'!");
        }

        /// <summary>Reads a short from the packet.</summary>
        /// <param name="moveReadPos">Whether or not to move the buffer's read position.</param>
        public short ReadShort(bool moveReadPos = true) {
            if (_buffer.Count > _readPos) {
                // If there are unread bytes
                var value = BitConverter.ToInt16(_readableBuffer, _readPos); // Convert the bytes to a short
                if (moveReadPos)
                    // If _moveReadPos is true and there are unread bytes
                    _readPos += 2; // Increase readPos by 2
                return value; // Return the short
            }

            throw new Exception("Could not read value of type 'short'!");
        }

        /// <summary>Reads an int from the packet.</summary>
        /// <param name="moveReadPos">Whether or not to move the buffer's read position.</param>
        public int ReadInt(bool moveReadPos = true) {
            if (_buffer.Count > _readPos) {
                // If there are unread bytes
                var value = BitConverter.ToInt32(_readableBuffer, _readPos); // Convert the bytes to an int
                if (moveReadPos)
                    // If _moveReadPos is true
                    _readPos += 4; // Increase readPos by 4
                return value; // Return the int
            }

            throw new Exception("Could not read value of type 'int'!");
        }

        /// <summary>Reads a long from the packet.</summary>
        /// <param name="moveReadPos">Whether or not to move the buffer's read position.</param>
        public long ReadLong(bool moveReadPos = true) {
            if (_buffer.Count > _readPos) {
                // If there are unread bytes
                var value = BitConverter.ToInt64(_readableBuffer, _readPos); // Convert the bytes to a long
                if (moveReadPos)
                    // If _moveReadPos is true
                    _readPos += 8; // Increase readPos by 8
                return value; // Return the long
            }

            throw new Exception("Could not read value of type 'long'!");
        }

        /// <summary>Reads a float from the packet.</summary>
        /// <param name="moveReadPos">Whether or not to move the buffer's read position.</param>
        public float ReadFloat(bool moveReadPos = true) {
            if (_buffer.Count > _readPos) {
                // If there are unread bytes
                var value = BitConverter.ToSingle(_readableBuffer, _readPos); // Convert the bytes to a float
                if (moveReadPos)
                    // If _moveReadPos is true
                    _readPos += 4; // Increase readPos by 4
                return value; // Return the float
            }

            throw new Exception("Could not read value of type 'float'!");
        }

        /// <summary>Reads a bool from the packet.</summary>
        /// <param name="moveReadPos">Whether or not to move the buffer's read position.</param>
        public bool ReadBool(bool moveReadPos = true) {
            if (_buffer.Count > _readPos) {
                // If there are unread bytes
                var value = BitConverter.ToBoolean(_readableBuffer, _readPos); // Convert the bytes to a bool
                if (moveReadPos)
                    // If _moveReadPos is true
                    _readPos += 1; // Increase readPos by 1
                return value; // Return the bool
            }

            throw new Exception("Could not read value of type 'bool'!");
        }

        /// <summary>Reads a string from the packet.</summary>
        /// <param name="moveReadPos">Whether or not to move the buffer's read position.</param>
        public string ReadString(bool moveReadPos = true) {
            try {
                var length = ReadInt(); // Get the length of the string
                var value = Encoding.ASCII.GetString(_readableBuffer, _readPos, length); // Convert the bytes to a string
                if (moveReadPos && value.Length > 0)
                    // If _moveReadPos is true string is not empty
                    _readPos += length; // Increase readPos by the length of the string
                return value; // Return the string
            } catch {
                throw new Exception("Could not read value of type 'string'!");
            }
        }

        /// <summary>Reads a Vector3 from the packet.</summary>
        /// <param name="moveReadPos">Whether or not to move the buffer's read position.</param>
        public Vector3 ReadVector3(bool moveReadPos = true) {
            return new(ReadFloat(moveReadPos), ReadFloat(moveReadPos), ReadFloat(moveReadPos));
        }

        /// <summary>Reads a Quaternion from the packet.</summary>
        /// <param name="moveReadPos">Whether or not to move the buffer's read position.</param>
        public Quaternion ReadQuaternion(bool moveReadPos = true) {
            return new(ReadFloat(moveReadPos), ReadFloat(moveReadPos), ReadFloat(moveReadPos), ReadFloat(moveReadPos));
        }
        #endregion
    }
}