using System;
using System.IO;
using System.Collections;
using System.Diagnostics;
using System.Web;
using System.Net;



namespace WebKeySoft.Net
{
	/// <summary>
	/// Summary description for GoogleRanker.
	/// </summary>
	public class GoogleRanker
	{

		#region Private members

		private const uint GOOGLE_MAGIC = 0xE6359A60;

		private UriEx url;

		#endregion

		#region Public properties

		public UriEx Url
		{
			get { return url; } 
			set { url = value; }
		}

		public int Rank
		{
			get { return this.getRank(url); }
		}

		public uint CheckSum
		{
			get { return this.GoogleCH(this.strord("info:"+url.AbsoluteUri)); }
		}		

		#endregion

		#region Constructor

		public GoogleRanker(UriEx url)
		{
			this.url = url;
		}


		#endregion

		#region Private methods

		private uint GoogleCH(uint [] url)
		{
			return GoogleCH(url, null);
		}

		private uint GoogleCH(uint [] url, object length)
		{
			return GoogleCH(url, length, GOOGLE_MAGIC);
		}

		private uint GoogleCH(uint [] url, object l, uint init)
		{
			uint a, b, c, k, len, length;			
			uint [] mix;
			if (l == null)
				length = Convert.ToUInt32(url.Length); 
			else
				length = (uint)l;

			a = b = Convert.ToUInt32(0x9E3779B9);
			c = init;
			k = 0;
			len = length;
			while(len >= 12) 
			{
				a += (url[k+0] +(url[k+1]<<8) +(url[k+2]<<16) +(url[k+3]<<24));
				b += (url[k+4] +(url[k+5]<<8) +(url[k+6]<<16) +(url[k+7]<<24));
				c += (url[k+8] +(url[k+9]<<8) +(url[k+10]<<16)+(url[k+11]<<24));
				mix = _mix(a,b,c);
				a = mix[0]; b = mix[1]; c = mix[2];
				k += 12;
				len -= 12;
			}

			c += length;
			switch(len)              /* all the case statements fall through */
			{
				case 11: c+=(url[k+10]<<24);
					c+=(url[k+9]<<16);
					c+=(url[k+8]<<8);
					b+=(url[k+7]<<24);
					b+=(url[k+6]<<16);
					b+=(url[k+5]<<8);
					b+=(url[k+4]);
					a+=(url[k+3]<<24);
					a+=(url[k+2]<<16);
					a+=(url[k+1]<<8);
					a+=(url[k+0]);
					break;
				case 10: c+=(url[k+9]<<16);
					c+=(url[k+8]<<8);
					b+=(url[k+7]<<24);
					b+=(url[k+6]<<16);
					b+=(url[k+5]<<8);
					b+=(url[k+4]);
					a+=(url[k+3]<<24);
					a+=(url[k+2]<<16);
					a+=(url[k+1]<<8);
					a+=(url[k+0]);
					break;
				case 9 : c+=(url[k+8]<<8);	
					b+=(url[k+7]<<24);
					b+=(url[k+6]<<16);
					b+=(url[k+5]<<8);
					b+=(url[k+4]);
					a+=(url[k+3]<<24);
					a+=(url[k+2]<<16);
					a+=(url[k+1]<<8);
					a+=(url[k+0]);
					break;
				case 8 : b+=(url[k+7]<<24);
					b+=(url[k+6]<<16);
					b+=(url[k+5]<<8);
					b+=(url[k+4]);
					a+=(url[k+3]<<24);
					a+=(url[k+2]<<16);
					a+=(url[k+1]<<8);
					a+=(url[k+0]);
					break;
				case 7 : b+=(url[k+6]<<16);
					b+=(url[k+5]<<8);
					b+=(url[k+4]);
					a+=(url[k+3]<<24);
					a+=(url[k+2]<<16);
					a+=(url[k+1]<<8);
					a+=(url[k+0]);
					break;
				case 6 : b+=(url[k+5]<<8);
					b+=(url[k+4]);
					a+=(url[k+3]<<24);
					a+=(url[k+2]<<16);
					a+=(url[k+1]<<8);
					a+=(url[k+0]);
					break;
				case 5 : b+=(url[k+4]);
					a+=(url[k+3]<<24);
					a+=(url[k+2]<<16);
					a+=(url[k+1]<<8);
					a+=(url[k+0]);
					break;
				case 4 : a+=(url[k+3]<<24);
					a+=(url[k+2]<<16);
					a+=(url[k+1]<<8);
					a+=(url[k+0]);
					break;
				case 3 : a+=(url[k+2]<<16);
					a+=(url[k+1]<<8);
					a+=(url[k+0]);
					break;
				case 2 : a+=(url[k+1]<<8);
					a+=(url[k+0]);
					break;
				case 1 : a+=(url[k+0]);
					break;
					/* case 0: nothing left to add */
			}
			mix = _mix(a,b,c);
			/*-------------------------------------------- report the result */
			return mix[2];
		}

		private uint zeroFill(uint a, uint b)
		{			
			uint ubase1 = 2147483648;
			uint ubase2 = 0x40000000;
			int un = 1;
			uint z = ubase1;
			if ((z & a) != 0)
			{
				a = (a>>1);
				a &= (~z);
				a |= ubase2;
				a = (a>>((int)b-un));
				//Debug.WriteLine("b="+b);
			}
			else
			{
				a = (a>>(int)b);
			}
			return a;
		}

		private uint[] _mix(uint a, uint b, uint c)
		{
			a -= b; a -= c; a ^= zeroFill(c,13);
			b -= c; b -= a; b ^= (a<<8);
			c -= a; c -= b; c ^= (zeroFill(b,13));
			a -= b; a -= c; a ^= (zeroFill(c,12));
			b -= c; b -= a; b ^= (a<<16);
			c -= a; c -= b; c ^= (zeroFill(b,5));
			a -= b; a -= c; a ^= (zeroFill(c,3));   
			b -= c; b -= a; b ^= (a<<10);
			c -= a; c -= b; c ^= (zeroFill(b,15));
			return new uint[]{a,b,c};
		}

		

		private uint [] strord(string str)
		{
			
			uint [] result = new uint[str.Length];
			for(int i=0;i<str.Length;i++) 
				result[i] = Convert.ToUInt32(str[i]);			
			return result;
		}

		private int GetPageRank(string result)
		{
			try 
			{
				string [] parts = result.Split(':');			
				return Convert.ToInt32(parts[2].TrimEnd('\n'));
			}
			catch {	}
			return 0;
		}

		private int getRank(UriEx url)
		{		
			uint ch;	
			int idx = url.AbsoluteUri.IndexOf("?");
			string strurl = idx == -1 ? url.AbsoluteUri : url.AbsoluteUri.Substring(0,idx+1);
			ch = GoogleCH(strord("info:"+strurl));

			string file2 = "http://www.google.com/search?client=navclient-auto&ch=6"+(int)ch+"&features=Rank&q=info:"+strurl;
			string data = "";
			try 
			{
				if (WebPage.UseProxy)
					GlobalProxySelection.Select = new WebProxy(WebPage.Proxy);
				HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(file2);
				HttpWebResponse res = (HttpWebResponse)req.GetResponse();
				data = new StreamReader(res.GetResponseStream()).ReadToEnd();
				if (WebPage.UseProxy)
					GlobalProxySelection.Select = GlobalProxySelection.GetEmptyWebProxy();
			}
			catch(Exception)
			{
				//Debug.WriteLine(ex.Message);
				return -1;
			}		
			return GetPageRank(data);			
		}

		#endregion
		
	}
}