#!/usr/bin/env ruby
# -*- coding: utf-8 -*-
# $Id: google-pr.rb,v b205c14e4ef5 2007-01-15 13:53 +0300 $
# (C) 2006-2007 under terms of LGPL v2.1 
# by Vsevolod S. Balashov <vsevolod@balashov.name>
# based on 3rd party code snippets (see comments)

require '
                uri
                '
require '
                open-uri
                '

module 
                SEO

  # http://blog.outer-court.com/archive/2004_06_27_index.html#108834386239051706
  class 
                GooglePR

    def 
                initialize
                (
                uri
                )
      @uri = uri
    end

    M
                =
                0x100000000 # modulo for unsigned int 32bit(4byte)

    def 
                m1
                (
                a
                ,
                b
                ,
                c
                ,
                d
                )
      (((
                a
                +(
                M
                -
                b
                )+(
                M
                -
                c
                ))%
                M
                )^(
                d
                %
                M
                ))%
                M # mix/power mod
    end

    def 
                i2c
                (
                i
                )
      [
                i
                &
                0xff
                , i
                >>
                8
                &
                0xff
                , i
                >>
                16
                &
                0xff
                , i
                >>
                24
                &
                0xff
                ]
    end

    def 
                c2i
                (
                s
                ,
                k
                =
                0
                )
      ((
                s
                [
                k
                +
                3
                ].
                to_i
                *
                0x100
                +
                s
                [
                k
                +
                2
                ].
                to_i
                )*
                0x100
                +
                s
                [
                k
                +
                1
                ].
                to_i
                )*
                0x100
                +
                s
                [
                k
                ].
                to_i
    end

    def 
                mix
                (
                a
                ,
                b
                ,
                c
                )
      a = a
                %
                M
                ; b = b
                %
                M
                ; c = c
                %
                M
      a = m1
                (
                a
                ,
                b
                ,
                c
                , c >> 13
                ); b = m1
                (
                b
                ,
                c
                ,
                a
                , a <<  8
                ); c = m1
                (
                c
                ,
                a
                ,
                b
                , b >> 13
                )
      a = m1
                (
                a
                ,
                b
                ,
                c
                , c >> 12
                ); b = m1
                (
                b
                ,
                c
                ,
                a
                , a << 16
                ); c = m1
                (
                c
                ,
                a
                ,
                b
                , b >>  5
                )
      a = m1
                (
                a
                ,
                b
                ,
                c
                , c >>  3
                ); b = m1
                (
                b
                ,
                c
                ,
                a
                , a << 10
                ); c = m1
                (
                c
                ,
                a
                ,
                b
                , b >> 15
                )
      [
                a
                , b
                , c
                ]
    end

    def 
                old_cn
                (
                iurl = '
                info:
                ' + @uri
                )
      a = 0x9E3779B9
                ; b = 0x9E3779B9
                ; c = 0xE6359A60
      len = iurl
                .
                size 
      k = 0
      while (
                len >= k + 12
                ) do
        a += c2i
                (
                iurl
                ,
                k
                ); b += c2i
                (
                iurl
                ,
                k
                +
                4
                ); c += c2i
                (
                iurl
                ,
                k
                +
                8
                )
        a
                , b
                , c = mix
                (
                a
                , b
                , c
                )
        k = k + 12
      end
      a += c2i
                (
                iurl
                ,
                k
                ); b += c2i
                (
                iurl
                ,
                k
                +
                4
                ); c += (
                c2i
                (
                iurl
                ,
                k
                +
                8
                ) << 8
                ) + len
      a
                ,
                b
                ,
                c = mix
                (
                a
                ,
                b
                ,
                c
                )
      return c
    end

    def 
                cn
      ch = old_cn
      ch = ((
                ch
                /
                7
                ) << 2
                ) | ((
                ch
                -(
                ch
                /
                13
                ).
                floor
                *
                13
                )&
                7
                )
      new_url = []
      20
                .
                times { i2c
                (
                ch
                ).
                each { |
                i
                | new_url << i }; ch -= 9 }
      ('
                6
                ' + old_cn
                (
                new_url
                ).
                to_s
                ).
                to_i
    end

    def 
                request_uri
      # http://www.bigbold.com/snippets/posts/show/1260 + _ -> %5F
      "
                http://toolbarqueries.google.com/search?client=navclient-auto&hl=en&ch=#{cn}&ie=UTF-8&oe=UTF-8&features=Rank&q=info:#{URI.escape(@uri, /[^-.!~*'()a-zA-Z\d]/)}
                
                "
    end
 
    def 
                page_rank
                (
                uri = @uri
                )
      @uri = uri if uri != @uri
      open
                (
                request_uri
                ) { |
                f
                | return $1
                .
                to_i if f
                .
                string =~ /
                Rank_1:\d:(\d+)
                / }
      nil
    end

    private :m1
                , :i2c
                , :c2i
                , :mix
                , :old_cn
    attr_accessor :uri
  end

end

if __FILE__ == $0 and 1 == ARGV
                .
                size
  puts SEO
                ::
                GooglePR
                .
                new
                (
                ARGV
                [
                0
                ]).
                page_rank
end