require 'net/http'
require 'hpricot' 
require 'rss/maker'
require 'uri'

class EMB 
    attr_writer :realm, :user, :password

    def initialize ( realm = 'chs_programming', user='zichun', password='paksux' )
        @realm, @user, @password = realm, user, password
        @cookies = []
        @cookie_string = ''
    end
    
    def get_cookie
        http = Net::HTTP.new('smb.chs.edu.sg', 80)
        resp,data = http.post('/cgi-bin/emb/login.pl',
                    "userid=#{@user}&password=#{@password}&login=+++Login+++", 
                    {'referer'=>'http://smb.chs.edu.sg/emb/'+@realm+'/',
                     'user_agent'=>'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9) Gecko/2008051206 Firefox/3.0'
                     })
        resp.get_fields('set-cookie').each { |x|
            @cookies << x
            @cookie_string += x.split("\; ")[0] + "\;"
        }
        @cookie_string
    end
    def get_main
        http = Net::HTTP.new('smb.chs.edu.sg', 80)
        http.get('/cgi-bin/emb/view.pl?date', {'Cookie'=>@cookie_string})
    end
    def get_msg (link)
        url = URI.parse(link)
        http = Net::HTTP.new('smb.chs.edu.sg',80)
        http.get( url.path+'?'+url.query, {'Cookie'=>@cookie_string} )
    end
end

emb_client = EMB.new
emb_client.get_cookie
res = emb_client.get_main

version = "2.0"

content = RSS::Maker.make(version) { |m|
    m.channel.title = "EMB CHS_PROGRAMMING"
    m.channel.link = "http://smb.chs.edu.sg/emb/chs_programming"
    m.channel.description = "Extracted messages from chs_programming EMB"
    m.items.do_sort = true

    doc = Hpricot(res.body)
     
    for i in 2...(doc/"form").length
        item = m.items.new_item
        x = (doc/"form")[i]
        item.title = (x/"a").text
        item.link = "http://smb.chs.edu.sg/emb/chs_programming/"
        item.date = Time.parse(((x/"font")[0]).innerHTML.strip) 
        emb_body = Hpricot(emb_client.get_msg( x.at("a")['href'] ).body)
        item.description = emb_body.at("pre")
        item.author = (x/"td")[2].innerHTML.strip    
    end
}

$stdout.write(content)