#region License
/*
 * PayloadData.cs
 *
 * The MIT License
 *
 * Copyright (c) 2012-2013 sta.blockhead
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
#endregion

using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;

namespace WebSocketSharp
{
  internal class PayloadData : IEnumerable<byte>
  {
    #region Public Const Fields

    public const ulong MaxLength = long.MaxValue;

    #endregion

    #region Public Constructors

    public PayloadData ()
      : this (new byte []{})
    {
    }

    public PayloadData (byte [] appData)
      : this (new byte []{}, appData)
    {
    }

    public PayloadData (string appData)
      : this (Encoding.UTF8.GetBytes (appData))
    {
    }

    public PayloadData (byte [] appData, bool masked)
      : this (new byte []{}, appData, masked)
    {
    }

    public PayloadData (byte [] extData, byte [] appData)
      : this (extData, appData, false)
    {
    }

    public PayloadData (byte [] extData, byte [] appData, bool masked)
    {
      if ((ulong) extData.LongLength + (ulong) appData.LongLength > MaxLength)
        throw new ArgumentOutOfRangeException (
          "The length of 'extData' plus 'appData' must be less than MaxLength.");

      ExtensionData = extData;
      ApplicationData = appData;
      IsMasked = masked;
    }

    #endregion

    #region Internal Properties

    internal bool ContainsReservedCloseStatusCode {
      get {
        return ApplicationData.Length > 1
               ? ApplicationData.SubArray (0, 2).ToUInt16 (ByteOrder.Big).IsReserved ()
               : false;
      }
    }

    internal bool IsMasked {
      get; private set;
    }

    #endregion

    #region Public Properties

    public byte [] ExtensionData {
      get; private set;
    }

    public byte [] ApplicationData {
      get; private set;
    }

    public ulong Length {
      get {
        return (ulong) (ExtensionData.LongLength + ApplicationData.LongLength);
      }
    }

    #endregion

    #region Private Methods

    private static void mask (byte [] src, byte [] key)
    {
      for (long i = 0; i < src.LongLength; i++)
        src [i] = (byte) (src [i] ^ key [i % 4]);
    }

    #endregion

    #region Internal Methods

    #endregion

    #region Public Methods

    public IEnumerator<byte> GetEnumerator ()
    {
      foreach (byte b in ExtensionData)
        yield return b;

      foreach (byte b in ApplicationData)
        yield return b;
    }

    public void Mask (byte [] maskingKey)
    {
      if (ExtensionData.LongLength > 0)
        mask (ExtensionData, maskingKey);

      if (ApplicationData.LongLength > 0)
        mask (ApplicationData, maskingKey);

      IsMasked = !IsMasked;
    }

    public byte [] ToByteArray ()
    {
      return ExtensionData.LongLength > 0
             ? this.ToArray ()
             : ApplicationData;
    }

    public override string ToString ()
    {
      return BitConverter.ToString (ToByteArray ());
    }

    #endregion

    #region Explicitly Implemented Interface Members

    IEnumerator IEnumerable.GetEnumerator ()
    {
      return GetEnumerator ();
    }

    #endregion
  }
}