#region MIT License
/**
 * PayloadData.cs
 *
 * The MIT License
 *
 * Copyright (c) 2012 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.Linq;
using System.Text;

namespace WebSocketSharp.Frame
{
  public class PayloadData : IEnumerable<byte>
  {

    #region Public Static Fields

    public static readonly ulong MaxLength;

    #endregion

    #region Properties

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

    public bool IsMasked { get; private set; }

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

    #endregion

    #region Static Constructor

    static PayloadData()
    {
      MaxLength = long.MaxValue;
    }

    #endregion

    #region Public Constructors

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

    public PayloadData(byte[] appData)
    : this(new byte[]{}, 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)
    {
      Func<string, Action> func = s => () =>
      {
        string message = String.Format("{0} must not be null.", s);
        throw new ArgumentNullException(message);
      };
      extData.IsNullDo(func("extData"));
      appData.IsNullDo(func("appData"));

      if ((ulong)extData.LongLength + (ulong)appData.LongLength > MaxLength)
      {
        throw new ArgumentOutOfRangeException("Plus extData length and appData lenght must be less than MaxLength.");
      }

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

    #endregion

    #region Private Methods

    private void mask(byte[] src, byte[] key)
    {
      if (key.Length != 4)
      {
        throw new ArgumentOutOfRangeException("key length must be 4.");
      }

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

    #endregion

    #region Public Methods

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

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

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

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

      IsMasked = !IsMasked;
    }

    public byte[] ToBytes()
    {
      if (ExtensionData.LongLength > 0)
      {
        return ExtensionData.Concat(ApplicationData).ToArray();
      }
      else
      {
        return ApplicationData;
      }
    }

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

    #endregion
  }
}