class PagesController < ApplicationController
  require 'base64'
  require 'openssl'
  require 'active_support'
  require 'net/http'

  def canvas
    @app_id = '176818735711209'
    @secret = 'dc1e1300b441bf7a664b37f6593dd608'
    @fb_uri = 'https://www.facebook.com/dialog/oauth'
    @client_id = '176818735711209'
    @redirect_uri = 'http://empty-spring-91.heroku.com/canvas'
    @scope = 'email,user_birthday,friends_birthday'
    @response_type = 'token'
    @title = 'ika app'

    #@query = parse_signed_request(request.query_string,@secret)
  end

  private

    def base64_url_decode(str)
     str += '=' * (4 - str.length.modulo(4))
     Base64.decode64(str.tr('-_','+/'))
    end

    def parse_signed_request(signed_request,secret)
      encoded_sig, payload = signed_request.split('.')
      sig = base64_url_decode(encoded_sig)
      data = ActiveSupport::JSON.decode(base64_url_decode(payload));

      if data["algorithm"].upcase != "HMAC-SHA256"
        logger.debug "Unknow algorithm. Expecting HMAC-SHA256"
        return nil
      end

      expected_sig = OpenSSL::HMAC.digest('sha256', payload, secret)

      if sig != expected_sig
        logger.debug "Bad signed JSON signature!"
        return nil
      end

      return data
    end

    def parse_request(query_string)
      query_string.split(/&/).inject({}) do |hash, setting|
        key, val = setting.split(/=/)
        hash[key.to_sym] = val
        hash
      end
    end

    def get_content(url)
      Net::HTTP.get_response(URI.parse(url)).body
    end

end