using System;
using System.Text;

namespace SocketHttpListener
{
    /// <summary>
    /// Contains the event data associated with a <see cref="WebSocket.OnMessage"/> event.
    /// </summary>
    /// <remarks>
    /// A <see cref="WebSocket.OnMessage"/> event occurs when the <see cref="WebSocket"/> receives
    /// a text or binary data frame.
    /// If you want to get the received data, you access the <see cref="Data"/> or
    /// <see cref="RawData"/> property.
    /// </remarks>
    public class MessageEventArgs : EventArgs
    {
        #region Private Fields

        private string _data;
        private Opcode _opcode;
        private byte[] _rawData;

        #endregion

        #region Internal Constructors

        internal MessageEventArgs(Opcode opcode, byte[] data)
        {
            _opcode = opcode;
            _rawData = data;
            _data = convertToString(opcode, data);
        }

        internal MessageEventArgs(Opcode opcode, PayloadData payload)
        {
            _opcode = opcode;
            _rawData = payload.ApplicationData;
            _data = convertToString(opcode, _rawData);
        }

        #endregion

        #region Public Properties

        /// <summary>
        /// Gets the received data as a <see cref="string"/>.
        /// </summary>
        /// <value>
        /// A <see cref="string"/> that contains the received data.
        /// </value>
        public string Data => _data;

        /// <summary>
        /// Gets the received data as an array of <see cref="byte"/>.
        /// </summary>
        /// <value>
        /// An array of <see cref="byte"/> that contains the received data.
        /// </value>
        public byte[] RawData => _rawData;

        /// <summary>
        /// Gets the type of the received data.
        /// </summary>
        /// <value>
        /// One of the <see cref="Opcode"/> values, indicates the type of the received data.
        /// </value>
        public Opcode Type => _opcode;

        #endregion

        #region Private Methods

        private static string convertToString(Opcode opcode, byte[] data)
        {
            return data.Length == 0
                   ? string.Empty
                   : opcode == Opcode.Text
                     ? Encoding.UTF8.GetString(data, 0, data.Length)
                     : opcode.ToString();
        }

        #endregion
    }
}